Environmental Stresses in Crop Sciences

Study on expression of transcription factors AP2-Domain, HD-ZIP, WRKY and MYB in oily sunflower (Helianthus annuus L.) under drought stress

Elahe Akbari; Reza Darvishzadeh; Babak Abdollahi; Sina Besharat

Volume 14, Issue 3 , September 2021, Pages 569-583

https://doi.org/10.22077/escs.2020.2979.1769

Abstract

IntroductionSunflower (Helianthuse annuus L.) is an annual plant from Composite with a chromosome number of 2n = 2x = 34 which is widely cultivated for supplying edible oil. Drought is one of the most important environmental stresses that limits the growth and distribution of plant more than other factors. ... Read More IntroductionSunflower (Helianthuse annuus L.) is an annual plant from Composite with a chromosome number of 2n = 2x = 34 which is widely cultivated for supplying edible oil. Drought is one of the most important environmental stresses that limits the growth and distribution of plant more than other factors. This plant is classified as semi-tolerant to drought stress; however, its performance is negatively affected by drought. Transcription factors are molecules that play an important role in the understanding and transmission of stress messages as well as many physiological processes. One of the most effective ways to deal with stress is to produce resistant hybrids. Investigation and study of expression of genes post stress application and identification of genes involved in resistance and especially regulatory genes such as transcription factors is vital and necessary for molecular breeding programs. Materials and methodsIn order to investigate the effect of drought stress on the expression of transcription factors: AP2-Domain, HD-ZIP, WRKY and MYB in oilseed sunflower, two lines with different susceptibility to drought stress were selected and cultivated in a completely randomized design with three replications in greenhouse. The seeds were planted in 3 cm depth of 30 × 25 cm pots containing farm soil and sand mixture in the ratio of 2:1. The plants were grown in controlled conditions at 25 ± 3 °C, 65% relative humidity and 12 h dark-light photoperiod and were irrigated regularly at 100% of field capacity up to 8-leaf stage. After this stage, a number of pots were kept at the same field capacity however, some other were exposed to 80, 60 and 40% of field capacity. Samplings were done in two times, one and three weeks after drought stress application. The study of the expression of genes was performed using real time PCR by SYBR Green method. RNA extraction kit RNX-plusTM (Sinoclon Co., Iran) and complementary DNA (cDNA) synthesis Kit (Fermentas LIFE SCIENCE # K1621) were used according to the manufacturer's protocols. Quantitative reverse transcription-PCR (qRT-PCR) was performed in triplet using 6.25 μl of Maxima SYBR Green/ Fluorescein qPCR Master Mix (2X) (Thermo Fisher Scientific, Germany), 5 pM of forward and reverse primers and 50 ng of cDNA for each reaction in a final volume of 12.5μl. Relative gene expression was analyzed by comparative Ct method, 2−ΔΔC. Target gene was normalized by the reference gene, ACTIN and calibrated for each sample against the control. Results and discussionThe results of statistical analyzes showed that the expression of the genes in the susceptible and resistant lines of sunflower is different. Mean comparisons of expression of AP2-Domain, WRKY and MYB transcription factors in the two genotypes ENSAT254 (tolerant) and LC1064C (susceptible) showed that the expression level was not tangible in the first week after drought stress application, but the expression of genes was increased in 40% of field capacity in the third week post drought stress application especially in ENSAT254 genotype. In relation to HD-ZIP transcription factor, the expression was much higher in ENSAT254 genotype than LC1064C genotype in the first week of sampling at 40% stress intensity. In the third week of sampling, the expression level of both genotypes increased in 40% of field capacity, although the expression was slightly higher in LC1064C genotype. ConclusionsEarly expression of HD-ZIP transcription factor appears to be involved in increasing genotype resistance to drought stress. The results of the present study can be useful in sunflower improvements programs for producing and developing drought tolerant cultivars.

Drought stress

Identification of new miRNAs in rapeseed (Brassica napus L.) and their role in suppressing target genes

Morad Cheshmehnoor; Mohamad reza Behamta; Ali Akbar Shahnejat Busheri; Reza Abbasi; Bahram Alizadeh

Volume 14, Issue 3 , September 2021, Pages 585-594

https://doi.org/10.22077/escs.2020.3099.1795

Abstract

Introduction MicroRNAs(miRNAs) are a group of small non-coding RNAs of approximately 18 - 24 nucleotides that play a negative role in post-transcriptional changes in eukaryotes. The miRNAs are then loaded onto the argonate family proteins (AGO) to form a protein complex (RISC). The primary activity of ... Read More Introduction MicroRNAs(miRNAs) are a group of small non-coding RNAs of approximately 18 - 24 nucleotides that play a negative role in post-transcriptional changes in eukaryotes. The miRNAs are then loaded onto the argonate family proteins (AGO) to form a protein complex (RISC). The primary activity of the RISC complex is to direct the mature miRNA to the target RNA and to stop protein production (Megah et al., 2018). miRNAs are involved in response to abiotic stresses in plants such as drought; several miRNA families have been reported in response to drought stress in rice, tomato, Arabidopsis, Medicago truncatula, peach, barley and wheat (Akdogan et al., 2015). The purpose of this study was to identify new microRNAs and their role in suppressing and preventing expression of some of their target genes in rapeseed. Materials and Methods A total of 38589 known mature miRAN sequences were downloaded from the miRBase database. The miRNA sequences were used as known sequences to find conserved miRNAs based on homology search for miRNAs with rapeseed GSS sequences.103369 GSS for rapeseed was downloaded from NCBI database. Mature miRNA sequences were uploaded to the BLASTn algorithm to search for homology with rapeseed GSSs in Linux. The miRNA sequences as known sequences and the GSS sequences as sequences were compared with each other for homology search. GSSs with mature miRNA sequences up to four mismatches were selected as candidates (Zhang, 2005). GSS sequences were used instead of EST sequences because miRNAs can generate GSS sequences in addition to EST sequences. Consequently, GSSs were sequenced between the BLASTx miRNA sequences and the GSS coding sequences were deleted and only non-coding GSS sequences remained (Karimi et al., 2017). Mfold software was used to predict the secondary structure of candidate miRNAs (Vivek, 2018). ath-miR5021 and ath-miR8175 from Arabidopsis, bol-miR9410 and bol-miR9411 from wild cabbage and cas-miR11592 from Camelina sativa were selected from the psRNATarget website (Dai and Zhao, 2011. Results For miR5021: The NST1 target gene encodes a protein called Stress response protein NST1, which plays a role in regulating secondary wall thickness in plants and preventing its destruction against a variety of stresses (Mitsuda et al., 2005). For miR9410: The HST gene is one of the target genes that encodes an enzyme called Shikimate O-hydroxycinnamoyltransferase in plants, which participates in the phenylpropanoid biosynthesis and heat stress control in plants, propanoids as secondary metabolites during developmental stages. The plant is synthesized in response to stress conditions (Lukasik et al., 2013). Discussion Types of microRNAs and their role in suppressing target genes during live and abiotic stresses in barley, wheat, soybean, cucumber, alfalfa, olive, rice have been reported (Ozhuner et al., 2013). In this study, we tried to identify new microRNAs and their role in suppressing target genes for the first time in rapeseed. The results of this study showed that among the newly identified microRNAs, miR5021 and miR9410 families play an important role in suppressing NST1 and HST target genes, respectively, especially during stress in canola.. Therefore, identifying the molecular mechanism of these microRNAs and their target genes can help us in selecting drought and heat resistant varieties for rapeseed. A study of microRNAs for boron stress tolerance in leaves and roots of barley showed that of the four new microRNAs identified, miR408 was more involved in regulating cell signaling in leaves than the other three microRNAs (Ozhuner et al., 2013). Also, no response has been reported in hybrid and maize inbred lines for miR172 under drought and salt stress conditions (Kong et al., 2010). Therefore, understanding the cellular regulation mechanism for new microRNAs, including how to regulate the activity pathway of antioxidant enzymes such as superoxide dismutase in organs such as leaves, roots and shoots of canola, requires further investigation. Conclusions MicroRNAs can be used as a new molecular tool alongside existing classical breeding methods to improve the genetic status of plants to promote tolerance to a variety of biotic and abiotic stresses in plant breeding.

Non-destructive determination of protein and amino acids concentration and their relationship with grain yield affected by different irrigation, sowing date, cultivar and nitrogen treatments

Maryam Rahimi Jahangirlou; Gholam Abbas Akbari; Iraj َAlahdadi; Saeid Soufizadeh

Volume 14, Issue 3 , September 2021, Pages 595-603

https://doi.org/10.22077/escs.2020.2991.1773

Abstract

Introduction Maize (Zea mays L.) is an important component of human, livestock and poultry diet and its quality is increasingly being considered by the world market. In maize grain, protein and amino acids are important nutritional parameters that in addition to genetics, can be greatly affected by environmental ... Read More Introduction Maize (Zea mays L.) is an important component of human, livestock and poultry diet and its quality is increasingly being considered by the world market. In maize grain, protein and amino acids are important nutritional parameters that in addition to genetics, can be greatly affected by environmental factors and crop management practices. On the other hand, the increasing need for quality parameters such as protein requires the development of rapid and accurate measurement tools. Near-infrared (NIR) is a proven method for measuring the concentration of protein and amino acids, as it is described as a fast, low-cost, non-destructive and green method. Materials and methods In order to determine the effect of some agronomic factors on protein, total essential (EAA) and non-essential amino acids (NAA) and their relationships with maize grain yield, a field experiment was conducted in 2018 in a split-split plot factorial arrangement and as Randomized Complete Block Design (RCBD) with three replications where was considered irrigation intervals as main factor (12 days and 6 days intervals), planting date as sub factor (21 June and 22 July), maize cultivars (KSC704 and KSC260) and nitrogen fertilizer rate (zero and 400 kg ha-1 Urea) as factorial treatments. Irrigation with 6 days intervals, 400 kg ha-1 Urea and planting date 21 June were considered as typical non-stress conditions and common cultivation system of the region. At the physiological maturity stage, plants harvested from the second and third row of each plot were used to determine grain yield. The ears were shelled and the kernels were dried in a laboratory oven at the temperature of 60 °C until completely dry. Then grains were ground and the percentage of grain protein, EAA and NAA, were measured using a near infrared (NIR) spectrometer (model FOSS NIRS XDS – Denmark) in the wavelength range of 1100 to 2500 nm with five intervals. Data obtained were examined by analysis of variance using the F test by SAS (version 9). The F values were considered significant at the error probability level of 5% (p < 0.05). Minitab software (version 17) was used to calculate the correlation and regression coefficients. Results The results revealed that higher irrigation, nitrogen, early planting date, and KSC260 cultivar increased grain yield by 18.26, 8.03, 29.06 and 7.70%, respectively. The interaction effect of irrigation and nitrogen on protein concentration was significant (P ≤ 0.05). Lower irrigation and higher nitrogen fertilizer increased the protein by 0.78% compared with non-fertilizer treatment. The protein concentration in the KSC260 was higher than KSC 704 by 1.06%. The effect of irrigation on all amino acids excluding valine, lysine and tryptophan was significant and they were increased as irrigation intervals increased. Applying urea increased all amino acids except lysine. The effect of planting date on some amino acids was significant and they often were higher by late planting date. The effect of cultivar on all amino acids excluding asparagine, lysine and tryptophan was significant and was higher in KSC260 than KSC 704. Higher irrigation and nitrogen application decreased EAA to NAA ratio by 0.20 and 0.09%, respectively (P ≤ 0.05). Grain yield was positively correlated with protein, TAA and NAA concentration (Pearson’s r = 0.37, 0.35, 0.40, respectively). There was a positive and significant relationship between protein with EAA and NAA and the highest relationship was observed between protein and NAA (a=0.1545, R² = 0.32%, P ≤ 0.001). Conclusions Findings suggested that using higher irrigation and nitrogen fertilizer increased maize grain yield and also essential amino acids concentration, and decreased the ratio of essential amino acids to non-essential ones. Due to the high complexity and sensitivity of measuring qualitative characteristics such as protein concentration and composition, replicating this experiment in different years and locations is recommended, taking into account the higher levels of influential factors.

Drought stress

Investigation of delayed planting and cutting off irrigation effect on biochemical traits, relative water content and yield of two safflower (Carthamus tinctorius L.) cultivars

Fatemeh Bahadori; Ehsan Bijanzadeh; Ali Behpouri

Volume 14, Issue 3 , September 2021, Pages 605-618

https://doi.org/10.22077/escs.2020.3173.1810

Abstract

Introduction Water stress is a non-living stress that causes different biochemical and physiological reactions in the plant but the amount of damage caused by stress depends on the severity, time and duration of stress. Introducing the best planting date in combination with suitable irrigation regime ... Read More Introduction Water stress is a non-living stress that causes different biochemical and physiological reactions in the plant but the amount of damage caused by stress depends on the severity, time and duration of stress. Introducing the best planting date in combination with suitable irrigation regime is one of the effective strategies in stress management. Among the oilseeds that are compatible with the conditions of the country, safflower is known as a water-resistant plant due to its long roots, with high absorption capacity from deeper parts of the soil. Also, since planting time controls the phenological stages of the plant and the whole production, therefore, choosing the appropriate planting date and exposure to water stress is one of the most important determinants of crop production. The aim of this study was to investigate the effect of delayed planting date and irrigation regime on biochemical traits, relative water content, biomass yield and safflower seed yield. Materials and Methods In order to study delayed planting date and irrigation regime on biochemical traits, relative water content and seed yield of safflower, a field experiment was conducted as split factorial in a completely randomized block design with three replicates, during 2018-2019 growing season at research station of College of Agriculture and Natural Resources of Darab, Shiraz University. Experimental factors included irrigation regime as main factor at three levels of normal irrigation, cutting irrigation at flowering stage and cutting irrigation at seed filling stage, and sub-factors including three planting dates (6 December, 26 December and 15 January) and two safflower cultivars (Goldasht and local Isfahan). In this study, chlorophyll a content, chlorophyll b content, carotenoid content, catalase and peroxidase activity, relative water content, canopy temperature, biomass yield and grain yield of safflower cultivars were calculated. Finally, analysis of variance (ANOVA) was performed using SAS v. 9.4 and the means compared by LSD test at 1% probability level. Results Overall, the results showed that the measured traits were significantly affected by irrigation regime, planting date and cultivar. Cutting off irrigation at flowering reduced chlorophyll a and b content, relative water content and grain yield of safflower cultivars by 25, 15.38, 16.36 and 33.74%, respectively, while carotenoid, catalase enzyme content, peroxidase and canopy temperature were increased by 14.70, 22, 29.31 and 21.75, respectively. Also, delayed third planting date (15 January) decreased chlorophyll a and b content, catalase activity, peroxidase activity, biomass yield and grain yield while carotenoid content, relative water content and canopy temperature increased. Conclusion The highest yield was obtained in Isfahan local cultivar at the second planting date (26 December) in normal irrigation treatment which had no significant difference with cutting off irrigation at seed filling on the first sowing date (6 December) in Isfahan and Goldasht local cultivars. Water stress at flowering and grain filling stages decreased the grain yield by 52.32% and 34.54%, respectively. Under cutting off irrigation at grain filling stage, the plant has been able to compensate yield loss more than flowering stage by performing biochemical and enzymatic activities at the time of stress occurrence. Also, as the second planting date (26 December) increased chlorophyll a, b, carotenoid content, relative water content and canopy temperature and subsequently more yield was observed than the other two planting dates, so choosing the optimal planting date (26 December) and early mature Goldasht cultivar can play an important role in improving yield of safflower under late-season water stress conditions in Sothern Iran.

Drought stress

Evaluation of drought stress on unsaturated fatty acids and some physiological traits of four safflower (Carthamus tinctorius L.) cultivars in Jiroft

Bahareh Parsa Motlagh; Seyedeh Mahbubeh Mirmiran; Fatemeh Fateminick; Majid Mahmoudi

Volume 14, Issue 3 , September 2021, Pages 619-627

https://doi.org/10.22077/escs.2020.3179.1812

Abstract

Introduction Safflower (Carthamus tintorius L.) belongs to Compositae or Asteracea family. Safflower is a branching, thistle-like herbaceous annual. In semi-arid regions safflower is widely used for oil, natural color, biodiesel fuel and rottion (Nogales-Delgado et al., 2019). Safflower seed oil contains ... Read More Introduction Safflower (Carthamus tintorius L.) belongs to Compositae or Asteracea family. Safflower is a branching, thistle-like herbaceous annual. In semi-arid regions safflower is widely used for oil, natural color, biodiesel fuel and rottion (Nogales-Delgado et al., 2019). Safflower seed oil contains high amounts of saturated (palmitic and stearic) and unsaturated (oleic, linoleic, and linolenic) fatty acids that may be affected by abiotic drought stresses (García-Moreno et al., 2014). Water is one of the limiting factors affecting the physiological and biochemical processes of plants (Stránský et al., 2005). The severity and timing of drought stress affect seed and oil yield (Lovelli et al., 2007). One of the important issues in evaluating cultivars and genotypes for drought tolerance is quantitative measurement of drought tolerance indices. This study was carried out to determine the best drought tolerant cultivars of safflower with drought tolerance indices in Jiroft region. Materials and Methods A field experiment was conducted at the experiment station of Faculty of Agriculture, University of Jiroft at 2018-2019 growing season. A split plot with randomized complete block design with four replications was used. Main plots were two levels of irrigation regimes (irrigation after 80 mm cumulative evaporation from evaporation pan class A and no irrigation from flowering to maturity stage) and sub-plots included safflower cultivars including Sina, Padideh, Zarghan and Zhila. Irrigation was conducted as drip system. The first irrigation was done after sowing seeds. In order to dorought stress, plants were not irrigation at 50% flowering stage to the physiological maturity stage. Chlorophyll a, b (Arnon, 1967) and carotenoids (Lichtenthaler, 1987) were used. Fatty acids were measured by the method (Primomo et al., 2002). Analysis of variance was done by SAS vs 9.4 software.Comparison of mean treatments under stress and non-stress conditions with t-test and comparison mean cultivars based on LSD test were calculated at 5% level (p < 0.05.). Response to stress was evaluated in both stress and non-stress conditions using quantitative stress tolerance indices. Results Drought stress significantly reduced the traits studied in this study. The results showed that drought stress significantly reduced 1000-seed weight, seed yield, oil percentage and leaf chlorophyll content but leaf carotenoid content was not significant. Chlorophyll content was less than full irrigation and Zarghan had the highest chlorophyll content and Zhila had the lowest chlorophyll content. In safflower, drought stress decreased the amount of unsaturated fatty acid and the ratio of linolenic and linoleic acids (Hamrouni et al., 2001) and chlorophyll a, b and carotenoids contents (Chavoushi et al., 2020). Seed yield decreased by 20% in irrigation treatments during flowering to maturity. Zarghan cultivar had the highest seed yield (2473 kg ha-1) and highest oil content in complete irrigation, respectively. Zarghan cultivar (47.3% oil) and highest oil stability (30%) had the highest seed yield, respectively. Zarghan cultivar had the highest oleic acid (23.4%) and linoleic acid (76.3%) among cultivars. In the study of the effect of different irrigation regimes on grain yield and oil quality, seed yield of plants under complete irrigation was 28% higher than that of plants grown in limited irrigation (Pasandi et al., 2018). The results of this study were similar to and Smith, 2005. STI index was highest in Zaraghan and Phenida cultivars and lowest in Sina and Jila cultivars. Average productivity index (GMP) is more than unit indicating relative tolerance to stress. Phenid and Zarqan cultivars had high yield in both stress and non-stress conditions. Therefore, Zarghan, Sina, Padideh and Zhila had the lowest Relative Yield Index (RDY) and Yield Yield (YSI), respectively. Conclusion In general, the results of this study showed that Zarghan cultivar had the highest oleic acid (23.4%) and linoleic acid (76.3%) among cultivars. Based on drought tolerance indices, Zarghan and Padideh Cultivars had the highest indices of GMP, STI, MP, HM, and these indices were the same for determination of desirable cultivars. This study shows Sina cultivar was identified in low yield and stress sensitive conditions and Zarghan cultivar can be a promising crop for irrigated and Padideh is desirable non-irrigated areas under water stress conditions.

Light extinction coefficient and radiation use efficiency in different growth stages of tomato exposed to different irrigation regimes

Esmaeil Farrokhi; Mehdi Nassiri Mahallati; Alireza Koocheki; Seyed Alireza Beheshti

Volume 14, Issue 3 , September 2021, Pages 629-648

https://doi.org/10.22077/escs.2020.2960.1762

Abstract

Introduction A prerequisite to model crop growth is an appropriate quantification of crop canopy structure in response to management and environmental conditions. Under water stress, the light distributions over canopy depth are more complicated because water stress affects not only appearance and elongation ... Read More Introduction A prerequisite to model crop growth is an appropriate quantification of crop canopy structure in response to management and environmental conditions. Under water stress, the light distributions over canopy depth are more complicated because water stress affects not only appearance and elongation of leaves, but also morphological aspects of leaf positioning, leaf angle and azimuth angle (Archontoulis et al., 2011). Water stress reduces RUE by preventing effective photosynthesis for growth due to lower intercepted PAR as a result of reduced leaf area and leaf rolling or wilting (Wilson and Jamieson, 1985; Xianshi et al., 1998; Ngugi et al., 2013). We devised a two-year field experiment under different irrigation regimes at the two stage growths tomato with the aims of quantifying and describing the response of canopy light extinction coefficient, radiation use efficiencies, leaf area index and yield to reduced water at vegetative and reproductive stages of tomato in order to obtaining the best yield. Materials and methods A field experiment was conducted over two consecutive seasons (2016-2017) in the experimental field of Ferdowsi University of Mashhad located in Khorasan Razavi province, North East of Iran. The experiment was laid out in a split plot design with different irrigation regimes at the reproductive and at the vegetative stage as the main and subplot factors, replicated thrice. The following experimental factors were studied: three irrigation regimes (100= 100% of water requirement, 75= 75% of water requirement, 50= 50% of water requirement) and two crop growth stages (V= vegetative stage and R= Reproductive stage). The drip irrigation method was used for irrigation. The tomato water requirement was calculated using CROPWAT 8.0 software. The irrigation water was supplied based on total gross irrigation and obtained irrigation schedule of CROPWAT. In the both growing seasons, plant growth and physiological parameters were assessed in two weekly intervals on two plants per plot starting 45 days after transplanting (DAT) up to 145 DAT. Results Leaf area index (LAI) of tomato varied between irrigation regimes. According to ANOVA, the treatments had a significant effect on maximum LAI in both years (Table 5). The fraction of PAR intercepted by tomato canopy, measured in two years of study, increased from a few days after transplanting (May) onwards, reaching its maximum value in mid-August (around 100 DAT) in all treatments and later on decreased with progress of season till final measurement except 75V-100R and 50V-100R where the fraction of intercepted PAR raised up to the end of growing season (Fig. 5). As shown in Fig. 4, with increasing LAI, the transmitted fraction of radiation through the canopy decreased exponentially in all treatments. The highest and lowest k value was recorded by full irrigation treatment with 0.69 and 50V-50R treatment with 0.41, respectively. k values were strongly variable among different irrigation regimes. RUE altered according to amount of water applied at different growth stages. In this research, RUE values ranged from 0.38 to 0.9 g MJ-1. However, applying irrigation during vegetative stages could accelerate increase in leaf area, light interception and photosynthesis (Comas et al., 2019) and, thus, improve RUE. Timing of water stress had a significant effect (p < 0.01) on total fresh and dry fruit yield in both years of the experiment (Table 6). In general, tomato yield increased as the amount of irrigation water increased, however it was severely affected by timing applied irrigation. In 2016 and 2017 total fresh fruit approached 99.81 and 101.01 t ha-1 under full irrigation (100V-100R), significantly greater than that produced under full deficit irrigation (50V-50R) with 22.2 and 15.66 t ha-1, respectively (Fig. 7). Conclusion The experiment results clearly indicate adverse effect of water shortage on tomato yield, so that the highest fresh yield was obtained with full irrigation. However, the results suggest that this adverse effect can be reduced by a proper irrigation management at different growth stages. We showed that the effect of water provided at sensitive growth stage on the productivity of tomato was largely due to the positive effect of water apply on RUE.

Evaluation crop indices of canola spring genotypes in terminal drought stress conditions and foliar application of Potassium silicate

Mojdeh Sadat Khayat Moghadam; Ahmad Gholami; Amir Hossien Shirani Rad; Mahdi Baradaran Firoozabadi; Hamid Abbasdokht

Volume 14, Issue 3 , September 2021, Pages 649-663

https://doi.org/10.22077/escs.2020.2723.1787

Abstract

Introduction Drought is a restriction in crop production in arid and semiarid regions. It is forecast that climate change may cause droughts shortly. After oxygen, silicon (Si) is the second most common element in the soil. In reducing both biotic stress (e.g., plant diseases and pest damage) and abiotic ... Read More Introduction Drought is a restriction in crop production in arid and semiarid regions. It is forecast that climate change may cause droughts shortly. After oxygen, silicon (Si) is the second most common element in the soil. In reducing both biotic stress (e.g., plant diseases and pest damage) and abiotic stresses such as salinity, drought, aluminum toxicity, heavy metal toxicity, nutrient imbalance, lodging, radiation, high temperature, wounding, and freezing. Materials and Methods In order to study the effects of terminal drought stress and foliar application of potassium silicate on yield and canola spring genotypes components, a factorial split-plot test was conducted in Karaj, Iran in a full randomized block configuration with three replications for two years of cultivation (2016-2018). The irrigation was performed at two levels in this study, including routine irrigation (control) and interruption of irrigation from the pod formation stage. Potassium silicate foliar application at two levels comprised of 0 and 4 g liter-1 in factorial status in main plots and five Brassica napus L. genotypes including OG × AL, RGS × SLM, DALGAN, RGS003 and RGS × Okapi in subplots. SAS Ver 9.1 statistical analysis was used for variance analysis. Results Combined variance analysis showed that the impact of the year on some characteristics seed number in silique, silique length and seed yield was significant. Also, the effect of irrigation was significant on seed yield. The eﬀect of genotype on plant height was signiﬁcant indicating that the genotypes had diﬀerent reactions. The interaction eﬀect of irrigation × genotype on Harvest index was signiﬁcant. The interaction eﬀect of Irrigation × Potassium Silicate × Genotype on branch number, silique number, silique length, seed number in silique, seed weight, biological yield, seed yield, oil content and oil yield was signiﬁcant. The mean comparison of irrigation and Potassium silicate interaction demonstrated that the most grain yield was observed in normal irrigation and the least value related to cut off irrigation at pod formation stage. The results indicated that, irrigation, foliar application of Potassium silicate and their interaction had significant effect on growth and agronomic traits and increased them. Conclusions Finally, our study showed the beneficial effects of Potassium Silicate in improving the drought tolerance of canola plants, especially at the end of the season. This can provide a basis for attempting new strategies to reduce the damage from drought and create a functional link between the role of silicon, physiological response and tolerance to drought stress in canola plants. According to the results, in the case of application of Potassium Silicate and normal irrigation, the promising genotype of OG×AL, with the highest seed and oil yield, is recommended as standard. Also, in the case of application of Potassium Silicate and late-season drought stress (restricted irrigation from the pod formation stages), RGS × SLM and DALGAN with the highest seed yield, is recommended.

The effect of silicon on phosphorus uptake and wheat growth under drought stress in a calcareous soil

Zohreh Zandi Gouharrizi; Reza Khorassani; Akram Halajnia

Volume 14, Issue 3 , September 2021, Pages 665-673

https://doi.org/10.22077/escs.2020.2805.1728

Abstract

Introduction Drought stress is one of the major physical stresses that have adverse effects on plant growth and metabolic processes such as nutrient uptake. Some researchers reported that silicon can improve plant growth and regulation of phosphorus uptake under drought stress; But Gao et al. (2004) ... Read More Introduction Drought stress is one of the major physical stresses that have adverse effects on plant growth and metabolic processes such as nutrient uptake. Some researchers reported that silicon can improve plant growth and regulation of phosphorus uptake under drought stress; But Gao et al. (2004) did not observe a significant increase in fresh and dry weight under water-deficit stress induced by polyethylene glycol in maize. On the other hand, silicon did not have a significant effect on shoot dry matter and phosphorus concentration in wheat flag leaves under non-stressed condition (Sarto et al., 2014). Therefore, due to the increase in consumption of silicon fertilizer in our country to cope with drought stress, this experiment was conducted to investigate the influence of silicon on phosphorus uptake and wheat growth under water deficient conditions. Materials and methods A three-factor experiment was carried out in a completely randomized design with three replications in research greenhouse of ferdowsi university of Mashhad. The experiment factors were three levels of silicon (0, 50 and 150 mg kg-1), three levels of phosphorus (0, 25 and 50 mg kg-1) and two levels of moisture stress (45 and 100% of field capacity). Soil samples were taken from 0-30 cm depth. The pots were filled with 5 kg of soil. Silicon and phosphorus were added to the soil in the form of sodium silicate (Na2SiO3) and calcium phosphate (Ca(H2PO4)2.H2O) respectively. Ten seeds of wheat were sown in each pot and then thinned to 3 plants per pot after seedling establishment. Soil moisture was kept at about level of field capacity for two weeks. Moisture stress treatments were imposed by weighing the pots every day. The plants were irrigated with distilled water for 50 days after sowing. Then, harvested, oven-dried and grinded. Soil samples were air-dried and passed through a 2 mm sieve. Shoot fresh and dry weights, silicon and phosphorus concentrations in shoots and silicon concentration in soil samples were measured. Minitab 17 software was used for data analysis. The comparison of means was performed by using Tukey test at 5% probability level. Results and discussion According to the results, shoot fresh and dry weights were decreased by 55.4% and 41.5% under moisture stress. Also, concentration and uptake of phosphorus reduced by 13.6% and 49.8% under water deficient conditions. Moreover, application of 25 mg kg-1 phosphorus increased the plant fresh and dry weights in both stress and non-stressed conditions. Shoot fresh and dry weights did not change significantly with increasing silicon supply under different soil moisture levels. Silicon application decreased shoot phosphorus cocentration and uptake at field capacity, however, phosphorus concentration and uptake were not significantly affected by silicon at the 45% FC level. The interaction of silicon and moisture stress factors indicated that by increasing silicon concentration in the soil, no significant changes were observed in silicon uptake under stress conditions. Also, silicon concentration and availability in the soil were increased by solubility of soil silicates after plant cultivation. As a result, the effect of silicon on fresh and dry weights, shoot phosphorus concentration and uptake was not significant. Thus, further studies are needed to use silicon in calcareous soils for wheat under moisture stress. Conclusions The results showed that moisture stress significantly reduced shoot fresh and dry weights, silicon and phosphorus concentration of shoot and uptake of silicon and phosphorus. But, silicon addition did not alter the silicon uptake. It appears that the concentration of plant-available silicon in soil was increased by solubility of soil silicates after plant cultivation. Thus, plant did not respond to silicon fertilization and application of silicon in soil could not reduce the negative effects of moisture stress. Therefore, the initial concentration of silicon should be considered for silicon fertilizer recommendation to overcome moisture stress constraints in wheat cultivation in calcareous soils.

Effect of nitrogen and phosphorus fertilizers on yield and nutrient efficiency indices in maize under drought stress

Sadegh Bahamin; Alireza Koocheki; Mahdi Nassiri Mahallati; Seyed Alireza Behashti

Volume 14, Issue 3 , September 2021, Pages 675-690

https://doi.org/10.22077/escs.2020.3095.1793

Abstract

Introduction Reduced use efficiency of important elements such as phosphorus and nitrogen has led to higher costs for corn production, reduced economic efficiency of fertilizers and greater environmental impacts due to increased use of these fertilizers. The use of nitrogen-stabilizing biological fertilizers ... Read More Introduction Reduced use efficiency of important elements such as phosphorus and nitrogen has led to higher costs for corn production, reduced economic efficiency of fertilizers and greater environmental impacts due to increased use of these fertilizers. The use of nitrogen-stabilizing biological fertilizers is a potential alternative that can minimize these negative effects. Materials and methods For this purpose, a split factorial layout with 4 replications based on randomized complete block design was conducted two consecutive years (2016 and 2017) at the Agricultural Research Station of Mehran in East of Ilam province. The studied factors included irrigation in 3 levels including non-stress, drought stress based on 75% and 50% field capacity. In sub-plots, two factors were factorial. The first sub-factor included nitrogen fertilizer at 100% fertilizer requirement (Net nitrogen) through urea, control and Azotobacter biological fertilizer. Another sub-factor included 100% phosphorus fertilizer (Net phosphorus) in the form of triple superphosphate, control and Pseudomonas biological fertilizer applied. Results The results of this study showed that interaction of stress, nitrogen and phosphorus on seed yield were significant. The highest seed yield (11932 kg ha-1) was obtained in irrigation with Azotobacter and Pseudomonas. However, there was a significant difference at the same level of stress associated with Azotobacter and triple superphosphate (11873 kg ha-1) and irrigation treatment with Pseudomonas and urea (11318 kg ha-1). Furthermore, at all levels of stress and consumption of Azotobacter and triple superphosphate, grain yield increased compared to control treatment. The interaction of stress, nitrogen and Phosphorus had significant effect on nitrogen productivity. The highest nitrogen productivity was obtained in non-stress treatment and inoculation of Azotobacter and Pseudomonas with 54.04 kg kg -1. At all irrigation levels, Azotobacter inoculation along with Pseudomonas aeruginosa increased nitrogen productivity. Conclusion The results of this study showed that Pseudomonas and Azotobacter bacteria, both low (100% capacity) and severe (50% capacity) water stress conditions, possibly by increasing food absorption caused to increased the quantitative and qualitative yield of maize.

Drought stress

Effect of tillage, irrigation and nitrogen fertilizer on crop yield of forage maize (Zea mays L.)

Esmaeil Afshoon; Hossein Moghadam; Mohammad Reza Jahansooz; Mostafa Oveisi

Volume 14, Issue 3 , September 2021, Pages 691-702

https://doi.org/10.22077/escs.2020.3111.1798

Abstract

Introduction Corn (Zea mays L.) for its high potential in the production of yield is critical. Given Iran's position in the arid and semiarid belt of the world, the issue of drought, salinity, and their effects on crops should be considered more than any other non-biological stress. Drought stress is ... Read More Introduction Corn (Zea mays L.) for its high potential in the production of yield is critical. Given Iran's position in the arid and semiarid belt of the world, the issue of drought, salinity, and their effects on crops should be considered more than any other non-biological stress. Drought stress is a global problem that threatens the growth of crops and food security (Jaleel et al., 2009). Drought stress affects biomass and eventually, yield losses by affecting physiological processes, growth and development of plant tissues (Orfanou et al., 2019). Irrigation and nitrogen mismanagement have been considered as the most critical factors in reducing maize yield (Norwood, 2000). Although nitrogen is critical for the growth of plants, the negative growth response to the excess of nitrogen fertilizer under drought stress (Cabrera, 2004) must be considered. Conservation tillage due to improved water, carbon and nitrogen resources in the soil has the remarkable ability to optimize crop production in arid and semiarid regions of the world (Husnjak et al., 2002). Optimal leaf aria deployment is crucial for photosynthesis performance and dry matter production (Aslam et al., 2013). Decrease in leaf area index following drought stress (Karam, 2005) and a decrease in plant height and grain weight following reduction of nitrogen levels and increase in drought intensity (Kalamian et al., 2006) have been reported previously. It has been suggested that no-3tillage under drought stress and conventional tillage under normal water demand, will cause increased yield (Ruisi et al., 2014). The results of different researches on the application of tillage methods on maize crop varied, with no significant differences in plant traits (height, leaf area index and dry weight) as a result of long-term application of different tillage methods (Ram et al. 2010), no significant effect of tillage on plant growth and yield (Jat et al., 2006) and improved growth and yield enhancement in non-tillage under compacted soils due to improved aeration And increased seedling emergence (Morrison et al., 1990). This study was conducted to study the effects of different tillage methods, different nitrogen fertilizer levels and drought stress on forage maize yield. Materials and methods This study was carried out to study the effect of irrigation and nitrogen fertilizer on crop yield of forage maize cultivated under conventional and conservation tillage systems, an experiment was conducted in 2018 and 2019 in split -split plots on randomized complete block design with three replications in farm of University of Tehran. Tillage systems as the main -plot in two factors was including conversation and conventional tillage, Water stress as the subplot in three levels by 30, 60 and 90 Percent of moisture requirement and nitrogen urea as the sub-sub plot at three levels by 0, 50 and 100 Percent of the recommended rate. Results The combined variance analyses indicated that the highest stem diameter (19.8 mm) was obtained from the interaction of water slightly stress and conventional tillage. the highest leaf aria index (6.08), leaf dry weight (441.58 g m-2), stem dry weight (1478.2 g m-2), total dry weight (1919.93 -2) and total fresh weight (6732.6 -2) was obtained from the interaction of conventional tillage, 90 and 100 percent water and nitrogen demand, respectively. The effect of drought stress on stem diameter reduction in conservation tillage compared to conventional tillage can be due to decreased root penetration and consequently reduced nutrient uptake by the plant. Decrease of leaf area index due to drought stress (Ur-Rahman et al., 2004) and increase of leaf area index with increased irrigation levels and supply of required amounts of nitrogen fertilizer (Lack et al., 2008), previously has been reported. Loss of leaf dry weight following water stress can be attributed to decreased water uptake and, most likely disruption of plant photosynthetic processes and sap production. Conclusions According to the results of two years of study, it is concluded that the interaction between drought stress and nitrogen fertilizer in conventional tillage with severe drought stress will decrease yield. Nitrogen fertilizer management is critical under these conditions.

Drought stress

Effect of foliar application of iron, zinc and manganese nano-chelate on some quantitative and qualitative characteristics of soybean (Glycine max L.) under water deficit stress

Mohammad Saeed Vaghar; Saeed Sayfzadeh; Hamid Reza Zakerin; Soheil Kobraee; Ali Reza Valadabady

Volume 14, Issue 3 , September 2021, Pages 703-718

https://doi.org/10.22077/escs.2020.3197.1816

Abstract

Introduction The country's food security and economy are certainly dependent on agricultural production. Today, however, water scarcity causes the agricultural product facing a serious threat. Drought stress disrupts the balance of uptake of micro nutrients and also the transfer of nutrients from roots ... Read More Introduction The country's food security and economy are certainly dependent on agricultural production. Today, however, water scarcity causes the agricultural product facing a serious threat. Drought stress disrupts the balance of uptake of micro nutrients and also the transfer of nutrients from roots to plant shoots. In addition, deficiency of micro nutrients can reduce the resistance of soybean to drought, as the life cycle and production of vegetable crops suffer from irreparable problems, it is therefore essential to maintain food security and provide plant protein in the human food basket. Due to the importance and role of micro nutrients in reducing the effects of drought stress, this experiment was conducted to investigate the effect of foliar application of Fe, Zn, and Mn fertilizers on soybean in irrigation interruption at different stages of plant productivity. Materials and methods This experiment was conducted as split plot in a randomized complete block design with three replications on soybean cultivar M9 at Agricultural Research Farm of Islamic Azad University, Kermanshah Branch during two consecutive years (2016-2017). The climate of the area is the semi-arid cold to temperate. According to the meteorological statistics, the mean annual precipitation and temperature in the region were 480.7 mm and 15.8 °C, respectively. Fertilizer recommendation was applied on the basis of soil test results (50 kg urea and 100 kg superphosphate). Irrigation treatments were applied at four levels including complete irrigation, an interruption irrigation turn at flowering stage, podding start, seed filling period as main plots and foliar application was performed at eight levels including foliar application with Fe, Zn, Mn, Fe+Zn, Fe+Mn, Zn+Mn, Fe+Zn+Mn Nano-chelates and distilled water (control) in sub-plots. In order to foliar application of micronutrients, chemical fertilizers with the brand name of Fe (9%), Zn (12%) and Mn (12%) nano chelate in powder form that was completely soluble in water with 6.5 pH which was prepared by Khezra Company. Each experimental plot consisted of 6 rows that are 6 m length and the distance among rows was 50 cm. The seeds were impregnated with a symbiotic bacterium (Rhizobium japonicum) and were cultured manually at the depth of 5 cm and the distance of 5 cm on May 10, 2015 and 2016. Nano chelate foliar spraying was performed at a concentration of three in one thousand at two time points, stage V4 (formation of the fourth leaf on the stem) and one week after spraying the first time. The studied traits were seed yield, biomass yield, harvest index, number of pods per plant, number of pods per pod, number of seeds per plant, 1000-seed weight, oil percentage, oil yield, protein percentage and protein yield of soybean. Results and discussion The results of combined analysis of variance showed that the main effects of drought stress, foliar application, and interaction between irrigation and foliar application on the studied traits was significant. The interaction of drought stress at podding stage and non-foliar application of nano chelate further reduced 1000-seed weight (30%), seed yield (34.9%), biomass yield (29.5%) and harvest index (7.6%) rather than control treatment in complete irrigation. In contrast Fe+Zn foliar application increased these traits 22.9%, 61.6% 46.5% and 10% respectively and was superior to other treatments. Oil loss percentage was more severe due to irrigation interruption at seed filling stage, and the lowest oil percentage (17.47) was obtained from combination of irrigation interruption at seed filling stage and non-foliar application and the most related to combination of complete irrigation and Zn+Mn foliar application (23.73). While the highest seed protein (39.57%) was obtained from irrigation interruption at seed filling stage and Zn+Mn foliar application. Overall, the results showed that the effect of drought stress in podding and seed filling stages on soybean yield and yield components was higher. Fe+Zn foliar application had the highest seed yield by better adjusting the stress effect. Treatments of Zn+Mn and Fe+Mn were the next priorities. Conclusions Overall, the results showed that foliar application with each of the elements Fe, Zn and Mn is an applied method to increase the micro nutrients content in plants and yield and yield components of the plant can be increased by reducing the effect of drought, under water deficit conditions, combined use of these elements was more effective. The combined treatments of complete irrigation and Zn+Mn foliar application had the highest seed yield with an average of 3704.6 kg.ha-1.

Effect of iron and zinc chelates on quantitative characteristics and amount of grain nutrients of corn (Zea mays L.) under different irrigation regimes

Khoshnaz Payandeh; Mani Mojaddam

Volume 14, Issue 3 , September 2021, Pages 719-729

https://doi.org/10.22077/escs.2019.2929.1754

Abstract

Introduction Maize (Zea mays L.) is an annual monocotyledonous plant of the poaceaae family. The corn is C4 and is native to the tropical region. The breadth of its degree of adaptation and adaptation makes it possible to cultivate it in temperate and cold regions. The corn is the third highest cereal ... Read More Introduction Maize (Zea mays L.) is an annual monocotyledonous plant of the poaceaae family. The corn is C4 and is native to the tropical region. The breadth of its degree of adaptation and adaptation makes it possible to cultivate it in temperate and cold regions. The corn is the third highest cereal after wheat and rice production, but its production is equal to the production volume of each of the world's two grains. The agricultural sector and its systems, with more than 90 percent of the country's water consumption, are the largest water consumer, wasting 80 percent of its traditional irrigation systems. Therefore, by reducing water resources, the reform of consumption patterns is the only way to overcome the depleted crisis. About 70% of the Earth's surface is covered by water, but unfortunately, the water crisis in many countries of the world, including the countries of the dry belt of the earth, such as Iran, is a concern. Iranian soils have difficulty absorbing elements such as iron and zinc due to high pH. Therefore, chelate fertilizers, while retaining the elements for a long time, reduce the possibility of water leaching of these elements into the soil. Chelated fertilizers stabilize the material in the soil and do not eliminate it quickly. So that fluctuations in pH range from high acid to alkaline cannot have a negative effect on them. Zinc is one of the essential nutrients needed for optimal plant growth. It plays an important role in many biochemical reactions within the plant. Therefore, study of agronomic traits and nutrient content of maize in Hamidiyeh region to identify sensitive growth stages of water deficit and to investigate the role of zinc and iron chelate were necessary. Materials and methods This research was carried out in 2018-19 in a farm located in Hamidieh with a longitude of 48 degrees and 10 minutes east and 31 degrees and 33 degrees north latitude and 13 meters above sea level. This study was carried out as split split plot in a randomized complete block design with three replications. The treatments included three levels of irrigation regimes: 60, 90 and 120 mm evaporation from class A evaporation pan in the main plots and spraying iron and zinc in three levels (non-spraying, foliar spray of 2 per thousand and 5 per thousand) in the sub plots. Results Analysis of variance showed that the effect of different irrigation regimes and foliar application of iron and zinc had significant effect on number of grains per ear, number of grains per row, grain yield, zinc percent, iron percent, protein percentage and biological yield. Iron and zinc foliar application at 5 per thousand treatments significantly increased yield, grain yield components, plant height, ear length, leaf area index, Fe and Zn concentration of corn, which was not significantly different from 2 per thousand treatments. Interaction between different irrigation regimes and foliar application of iron and zinc had significant effect on grain number per ear, grain yield and biological yield. The highest grain yield (6400.49 kg.ha-1) was obtained by irrigating 95 mm evaporation from the pan and spraying of iron and zinc at 5 per thousand. According to the results of this study, foliar application of iron and zinc at 5 per thousand in 95 mm evaporation of pan caused to increase quantitative and qualitative characteristics of spring maize in Hamidiyeh region which was economically effective. Conclusion Overall, the results of this study indicate that soils in most of the southern parts of the country are low-pH calcareous and low in organic matter and lack of micronutrients such as zinc and iron. Therefore, in order to achieve maximum quantitative yield and nutrient content, cultivation of maize with foliar application of 5 to 1000 micronutrients is recommended in appropriate moisture conditions because soils of Khuzestan province are deficient in micro elements so foliar application the micronutrients in the irrigation conditions were able to compensate for the deficiency of these elements. Although, as expected, the highest grain yield was obtained in the irrigation treatment with micronutrients foliar application, but under conditions of water resources limitation, mild moisture stress, ie 95 mm evaporation from the pan with the foliar application of iron and zinc at a concentration of 5 in a thousand can be recommended.

Determination of drought stress indices in corn (Case study: Behbahan)

Nader Salamati; Amirkhosro Danaie

Volume 14, Issue 3 , September 2021, Pages 731-745

https://doi.org/10.22077/escs.2020.3057.1785

Abstract

Introduction Drought stress is the most important factor limiting the growth and grain yield of maize (Zea mays L.). Drought stress is one of the most important abiotic stresses that can seriously reduce crop yields depending on the season and the time it occurs. In arid and semi-arid regions, the plant ... Read More Introduction Drought stress is the most important factor limiting the growth and grain yield of maize (Zea mays L.). Drought stress is one of the most important abiotic stresses that can seriously reduce crop yields depending on the season and the time it occurs. In arid and semi-arid regions, the plant undergoes periods of dehydration during its growth and must be able to tolerate these periods to produce proper yield (Emam and Niknejad, 2004). Cooper et al. (2006) reported that the capacity and ability to produce different maize genotypes under drought stress varied according to their morphological and physiological characteristics. Corn at different stages of development requires different amounts of water. The effect of dehydration on maize plants is marked by certain symptoms. These symptoms are seen as decreasing plant height and root length, delay in plant growth, leaf area depletion, seed production and biomass (Cakir 2004). The results of correlations indicate a significant positive relationship between potential yield (without stress) with MP, GMP, STI, TOL and HARM indices. The most positive and significant correlation between indices was related to GMP and STI (0.99) (Alipour et al, 2014). Due to the importance of maize as one of the important cereals in Iran, using irrigation method can be adapted to water shortage during drought. The purpose of this study was to investigate the effect of drought stress through different irrigation intervals and identify superior cultivar based on stress indices. Materials and Methods In order to investigate the response of new maize cultivars to water stress, an experiment was conducted at Behbahan Agricultural Research Station with latitude 50°:14´ east and 30°:36´ north latitude as a split plot in a randomized complete block design with four replications. It was implemented in two years (2014 - 2015). Drought stress including irrigation after 100 and 200 mm evaporation from Class A pan in main plots and three maize cultivars (S.C. 704, PH3 and PH4) were compared in sub plots. Results Comparison of mean water use efficiency in irrigation and cultivar interactions showed that 100 mm evaporation from Class A pan and V2 cultivar with yield of 1.299 kg maize per 1 m3 of water was in the first rank and position. The 100 mm evaporation treatment of Class A pan and cultivar V2 was ranked second with production of 1.155 kg of maize grain per cubic meter of water. Pearson correlation coefficient results showed that the highest correlation of grain yield with water use efficiency and 1000-grain weight were calculated as 0.8761 and 0.8478, respectively, indicating the effective role of 1000-grain weight in increasing maize yield. The highest values of SSI, STI, MP, TOL, GMP, HM and YI were for V2 and the lowest for V3. The lowest YSI index belonged to V2. In other words, the accuracy of the stress and non-stress treatments in V2 indicates that the above indexes are classified as ascending and descending, respectively. Therefore, higher values of SSI, STI, MP, TOL, GMP, HM and YI in each cultivar showed that the cultivar is resistant to drought stress or deficit irrigation. Therefore, the drought tolerant cultivar identification criterion can be high values of SSI, STI, MP, TOL, GMP, HM and YI. Thus, the values of the above indices and their use in selection of drought tolerant cultivars indicate an increase in grain yield under stress and non-stress conditions and can be recommended together to identify suitable cultivars for each condition. Conclusion Comparison of mean interaction effects between irrigation and cultivar in terms of water use efficiency showed that water use reduction in stress treatment decreased water yield in this treatment compared to non-stress treatment. The effect of reducing water use was even to the extent that it failed to cover the continuous decrease in yield in return for water consumption, and the treatment of 100 mm evaporation from Class A pan despite still consuming more water than the 200 mm evaporation treatment from Class A pan. Due to the increase in performance, water consumption was the most efficient. Positive and significant correlations of yield components with important traits of 1000-grain weight on one hand and highly significant correlation of 1000-grain weight with yields on the other hand indicate that the trend of increasing yield components with grain yield increased. Drought stress tolerance index was higher than other cultivars for SSI, STI, MP, GMP, HM and YI indices. Acknowledgements We would like to thank the Khuzestan Agricultural and Natural Resources Research and Education Research Center for their financial support and spiritual support for this research.

Drought stress

Evaluation of drought tolerance indices of hybrids from potato commercial cultivars

Mohammad Reza Vesali; Reza Baradaran; Davood Hassanpanah; Mohammad Javad Soqa al-Islami

Volume 14, Issue 3 , September 2021, Pages 747-758

https://doi.org/10.22077/escs.2020.3123.1801

Abstract

Introduction‌Potato (Solanum tuberosum L.) is one of the most important crop plants in the world. Different indices have been introduced to determine stress tolerance, but in general, indices that are highly correlated with yield under both stress and non-stress conditions are considered as the best ... Read More Introduction‌Potato (Solanum tuberosum L.) is one of the most important crop plants in the world. Different indices have been introduced to determine stress tolerance, but in general, indices that are highly correlated with yield under both stress and non-stress conditions are considered as the best indices. Because these indices are capable of identifying high yield genotypes in both stress and non-stress environments, they can be used to estimate yield stability. Therefore, the purpose of this study was to compare different drought tolerance and susceptibility indices and group hybrids from potato cultivars in Ardabil province based on these indices. Materials and methods In order to study drought tolerance indices of 12 hybrids obtained from crossover of experimental potato cultivars in a randomized complete block design with three replications at two irrigation levels (100 and 65% of plant water requirement) in Zareh Agricultural Company greenhouse Gostar Arta was performed. The first year was for genetic variation, and the second year was for greenhouse cultivation. Drought tolerance indices were also calculated for the studied genotypes in order to determine the tolerance of cultivars to different water deficit conditions. The susceptibility and stress tolerance indices (GMP, MP, STI, SSI and TOL) were used to evaluate drought tolerance and drought resistance of potato genotypes.Drought tolerance indices were calculated and after computing the indices, these indices were analyzed and compared with 100% and 65% water requirement using SPSS-22 software. Relationship between gland function in two environments and calculated tolerance indices were performed and three-dimensional graphs were plotted using SPSS-22 software. Minitab15 software was used for better evaluation of relationships by principal component analysis and biplot charts. Also, WARD method was used to select the desired hybrids for hybridization and the obtained results were obtained. A dendrogram chart form was provided. The dendrogram was plotted by Minitab15 software. Results and discussion Results of analysis of variance of yield under normal conditions and 65% water use and stress tolerance indices showed variation among 12 hybrids from crosses. Under normal conditions (100% plant water requirement) the highest yield of tuber with average of 53.55 ton /h belonged to R12 hybrid (♀Luca×Esprit♂). The highest tuber yield under drought stress conditions (65% plant water requirement) was observed in S13 (♂Luca×Esprit♀) and S14 (♂Luca × Esprit♀) hybrids with 34.41 and 35.47 ton / ha, respectively. In stress conditions (65% plant water requirement) the highest tuber yield and the highest harmonic mean, geometric mean yield and stress tolerance index belonged to hybrid R14 (♀Luca × Esprit♂). The results of correlation analysis showed tuber yield under normal and stress conditions (65% of available water) and drought tolerance index, Geometric mean productivity index and average productivity index are the most appropriate indices for determining potato-tolerant hybrids. Multivariate biplot charts showed that the two hybrids R14 (♀Luca × Esprit♂) and S13 (♂Luca × Esprit♀) were adjacent to vectors related to important drought tolerance indices namely productivity mean, geometric mean productivity And stress tolerance. Also distribution of hybrids in biplot showed genetic variation among hybrids relative to drought stress. Cluster analysis showed that the highest genetic distance was between R14 (♀Luca × Esprit♂) and R12 (♀Luca×Esprit♂) hybrids and S12 (♂Luca × Esprit♀) susceptible hybrids. Conclusions Based on the results, it can be concluded that the ability of separation of drought tolerant hybrids from potato cultivars by geometric mean productivity and average productivity index and tolerance index is more appropriate and two hybrids R14 and S13 can be used as stress tolerant hybrids.

Modeling the effect of moisture stress on the shift in optimal and maximum temperatures for germination of Malva parviflora L. seeds: Introducing a new hydrothermal time model

Mohammad Reza Moradi Telavat; Seyed Ataollah Siadat; Abolfazl Derakhshan; Samad Safarkhanzadeh

Volume 14, Issue 3 , September 2021, Pages 759-770

https://doi.org/10.22077/escs.2020.2806.1732

Abstract

Introduction Seed germination is largely controlled by the temperature and moisture content of the seedbed. Therefore, hydrothermal time models have been widely used to describe seed germination patterns in response to temperature and water potential (Ψ) of the seedbed. The majority of these models ... Read More Introduction Seed germination is largely controlled by the temperature and moisture content of the seedbed. Therefore, hydrothermal time models have been widely used to describe seed germination patterns in response to temperature and water potential (Ψ) of the seedbed. The majority of these models assume a Normal distribution for base water potential (Ψb(g)) to describe the variation in time to germination. In some of these models, it is assumed that the thermoinhibition of germination induced by the shift in Ψb(g) to more positive values occur only at temperatures above the optimum (To) and that the To is independent of drought stress levels. In this study, the Weibull hydrothermal time was used to quantify the Ψb(g) changes in response to temperature and to model the effect of drought stress on the shift in the optimal (To(g)) and maximum (Tm(g)) temperatures for different germination fractions of malva parviflora seeds. Materials and methods The experiment was conducted at the Seed Technology Laboratory of Agricultural Sciences and Natural Resources University of Khuzestan in 2016. Germination test was performed at eight constant temperatures of 8, 12, 16, 20, 24, 28, 32 and 36 (± 0.2) °C in light/dark conditions (12 h/12 h). In each of the above temperature regimes, seed germination response to different levels of drought stress, i.e. osmotic solutions with concentrations of 0, -0.2, -0.4, -0.6, -0.8 and -0.1 MPa was evaluated. Germination test was performed with four replications (each Petri dish as one replicate). In each replicate, 50 seeds were placed on a layer of Whatman No 1 filter paper in a 9 cm glass Petri dish, and then moistened with 7 ml distilled water or other osmotic solutions. The number of germinated seeds was counted twice every day until germination stopped at each temperature regime (when no germination occurred for 5 consecutive days). All models, having been formulated into the hydrotime and then hydrothermal models, were fitted to data using PROC NLMIXED procedure of SAS software version 9.4. Results and discussion While Ψb(g) showed a linear increase in the temperature range between Tb (base temperature) and Tm(g), the hydrotime constant (θH) decreased nonlinearly in response to increasing temperature. Based on the relationship between Ψb(g) and θH, the shape of the germination rate (GR(g)) response to temperature in the hydrothermal time model was curvilinear. The model estimated the values of θHT (hydrothermal time constant), Tb, Ψbase (base water potential at Tb), and KT (slope of the Ψb(g) response to temperature) as 1800.04 MPa °C h, 4.20 °C, -2.46 MPa, and 0.064 MPa °C-1, respectively. Both To(g) and Tm(g) decreased proportionally with increasing drought intensity and became cooler for higher germination percentiles. For example, the estimated To(50) (optimal temperature for the median) for M. parviflora seeds germinated under no water stress (Ψ=0 MPa) was 23.38 °C but dropped to 15.59 °C as water availability became minimum (Ψ=-1.0 MPa). Similarly, it was estimated that 50% of seeds would be able to germination at (or below) 42.55 °C form zero osmotic potential (Tm(50) at Ψ=0 MPa) but to attain the same germination level at -1.0 MPa, temperature should never exceed 26.99 °C (Tm(50) at Ψ=-1.0 MPa). Conclusion The hydrothermal time model not only gave good fits to germination data but also showed some adaptive properties of M. parviflora seeds to different temperature and moisture environments. With the increasing severity drought, the To(g) and Tm(g) shifted to cooler values, which mean that the seeds were able to germinate at a narrower temperature range under drought conditions.

Salinity stress

Mapping of genes controlling secondry metabolits in barley (Hordeum vulgare L.) under salinity stress

Somayyeh Makhtoum; Hossein Sabouri; Abdolatif Gholizadeh; Layila Ahangar; Mahnaz Katouzi; Ebrahim Gholamalipour Alamdari

Volume 14, Issue 3 , September 2021, Pages 771-781

https://doi.org/10.22077/escs.2020.3163.1808

Abstract

Introduction Barley (Hordeum vulgare L.) is one of the four important cereals in the world. Soil salinity is one of the major barriers to the production of important agricultural products. Crops are one of the most important factors affecting the level of secondary metabolites present in plants under ... Read More Introduction Barley (Hordeum vulgare L.) is one of the four important cereals in the world. Soil salinity is one of the major barriers to the production of important agricultural products. Crops are one of the most important factors affecting the level of secondary metabolites present in plants under protective conditions. Secondary metabolites help plants to survive and survive external disturbances (such as pests and pathogens) and stress environmental conditions (such as drought or unfavorable soil conditions). Many agriculturally important traits are controlled by many genes and are known as quantitative. The regions within genomes that related to genes associated with a particular quantitative trait are known as quantitative trait loci (QTLs). The identification of QTLs based only on classic phenotypic evaluation is not possible. A major breakthrough in the characterization of quantitative traits that created opportunities to select for QTLs was initiated by the development of DNA markers. One of the main uses of DNA markers in research has been in the providing of linkage maps. Linkage maps have been used for identifying chromosomal regions that contain genes controlling simple traits and quantitative traits using QTL analysis. Materials and methods In order to locate secondrey metabolits of salinity tolerant genes in barley in vegetative and reproductive stages, 106 F8 lines caused Badia and Kavir crosses was used and cultivated as augumented design.This research was conducted in the research greenhouse of Gonbad Kavous University in 2019 and 2020. The seeds of 106 lines as well as were parents planted in the pot. For salinity stress, the lines were kept normal until the end of the vegetative phase and then irrigated with 16 dS.m-1 in the reproductive stage. At the end of grain filling period, leaf samples were taken from flag leaf and secondary metabolites of sugar, phenol, catalase and peroxidase were measured. The linkage map was provided with markers with clear and consistent Mendelian segregation markers (152 SSR markers, 72 ISSR alleles, 7 IRAP alleles, 29 CAAT alleles, 27 Scot alleles and 15 iPBS alleles). Four methods of mapping CIM, ICIM, STMIM and STPLM were used to identify the control QTLs and estimate the effect genetic of one of them. Results Gene loci were detected for the sugar content using CIM, ICIM and STPLME in the region of chromosome 1 at 26 cM and near the Bmaq0211. Also, for the peroxidase effective loci on chromosome 3 were identified in 44 cM flanked Bmac0067 and HVM33. The SMIM method was identified at position 118 cM between ISSR13-1 and ISSR16-4 for the sugar content, phenol, peroxidase of a gene locus on chromosome 4. Conclusions qSUG-4 QTLs (sugar content on chromosome 4) with a coefficient of 20.2 as well as qPHE-1 and qPHE-2 QTLs (phenol content on chromosomes 1 and 2) with coefficients of determination of 21.3, 29.21 and qPER-1, qPER-4b, qPER-5, qPER-7 (peroxidase on chromosomes 1, 4, 5 and 7) are a siutable candidate for marker-assisted selection programs in the barley recombinant line population

Salinity stress

Evaluation of activity of antioxidant enzymes and grain yield in barley (Hordeum vulgare L.) cultivars under salinity stress

Jamal Rahimi Darabad; Varahram Rashidi; Hossein Shahbazi; Mohammad Moghaddam vahed; Ebrahim Khalilvand Behrouzyar

Volume 14, Issue 3 , September 2021, Pages 783-791

https://doi.org/10.22077/escs.2020.3176.1811

Abstract

Introduction Drought, cold, high-salinity and heat are major abiotic stresses that severely reduce the yield of food crops worldwide (Mantri et al., 2012). Iran with 6.8 million hectares of the state after India and Pakistan is considered in the first rank for threats of salinity stress (Moameni, 2010). ... Read More Introduction Drought, cold, high-salinity and heat are major abiotic stresses that severely reduce the yield of food crops worldwide (Mantri et al., 2012). Iran with 6.8 million hectares of the state after India and Pakistan is considered in the first rank for threats of salinity stress (Moameni, 2010). High salinity can cause ionic toxicity, osmotic stress and oxidative stress, leading to gradual lipid peroxidation, protein oxidation and inactivation of antioxidant enzymes (Tanou et al 2009). Ascorbate peroxidase has several basic roles in plant physiological processes such as growth, development and metabolism and acts as a regenerative agent for many free radicals, especially hydrogen peroxide. Therefore, the damage caused by oxidative stress is minimized (Kocsy et al 2005). The superoxide dismutase enzyme converts free oxygen radical (O2-) into hydrogen peroxide (H2O2) and oxygen (O2), which is the first reaction to detoxify ROS. In the next step, hydrogen peroxide produced by the catalase enzyme and several other peroxides are eliminated (DaCosta & Huang 2007). Most results have shown that antioxidant enzymes system activity in barely acts to reduce the caused oxidative stress by salinity and reducing the cellular damage degree (Kim et al 2005). The aim of this study was to evaluate salt tolerant and susceptible varieties of barley cultivars through grain yield and to evaluate the activity of some antioxidant enzymes to evaluate their potential in breeding programs as an indirect selection tool. Materials and methods In this research, a factorial experiment was conducted in a randomized complete block design with three replications. The first factor consisted of 7 barley cultivars (Afzal, Kavir, Valfajr and Nosrat as tolerant; Yoosef, Sahara and Reihan as susceptible) and the second factor was different salinity levels (0, 8 and 12 dS.m-1). This research cultivated in vases in greenhouse of Islamic Azad University, Ardabil, Iran during 2016-17. Ascorbate peroxidase enzyme activity was measured by Nakano & Asada (1981), Catalase enzyme activity was measured by Chance and Maehly (1955) and Superoxide dismutase enzyme activity was measured by Gianopulotis and Reis (1977) methods. MSTATC, SPSS, and Excel softwares were used for statistical analyses. Results Analysis of variance showed significant differences among cultivars and salinity levels and interaction of genotype × salinity on activity of ascorbate peroxidase, catalase, superoxide dismutase enzymes and grain yield in plant. Investigation of changes in activity of antioxidant enzymes at different salinity levels showed that their activity increased significantly with increasing salinity level from 0 to 8 and 12 dS and it was higher in tolerant and semi-tolerant cultivars. Evaluation of changes in grain yield at different salinity levels showed that their grain yield decreased significantly with increasing salinity level from 0 to 8 and 12 dS.m-1 and it was higher in susceptible cultivars. Correlation of ascorbate peroxidase enzyme with grain yield was positive and significant. Results showed that Nosrat and Kavir cultivars had the highest tolerance index (STI) and in terms of other traits studied, they were in better condition and they can be used in barley breeding programs. Conclusions The results of this study showed that salt tolerant cultivars were superior to other cultivars in terms of studied traits. Also, Nosrat and Kavir cultivars had higher antioxidant enzymes activity and yield under salinity stress, which could be considered in barley breeding programs for salinity tolerance.

Comparison of some physiological root traits of bread and durum wheat cultivars under salt conditions

Vahid Atlassi Pak; Omid Bahmani

Volume 14, Issue 3 , September 2021, Pages 793-804

https://doi.org/10.22077/escs.2020.3097.1794

Abstract

Introduction Faster and more extensive root growth is important for good plant growth and such a root system is expected to extract more available soil water in salt conditions. In order to examine root system and some physiological characteristics of four bread wheat contrasting in salt tolerance (Arg, ... Read More Introduction Faster and more extensive root growth is important for good plant growth and such a root system is expected to extract more available soil water in salt conditions. In order to examine root system and some physiological characteristics of four bread wheat contrasting in salt tolerance (Arg, Ofoq, Tajan and Morvarid) and two durum wheat cultivars (Behrang and Shabrang), a greenhouse experiment was conducted with two salinity levels (0 and 13.5 dS/m NaCl) growing in PVC tube. Salt stress decreased root dry weight, shoot dry weight, seminal root length, total root length, root and shoot K+, shoot K+/Na+, root K+/Na+ and tillers and increased root Na+,shoot K+ leaf temperature and chlorophyll content compared to control. Seminal root growth did not affect by salinity stress in Arg andno significant differences was observed between Arg and Shabrang in this aspect. Although, reduction in seminal root length was less in Arg (5%) and Shabrang (32%), but these cultivars had more reduction in total root length by 64% and 68% respectively under saline conditions. Root growth reduction in cultivars was due to osmotic stress of salt solution out of the roots and the values for total root length in bread wheat cultivars was more under salt stress. Finding of this study on root lentgh identify it as one of the valuable index for improved adaptation to osmotic stress in wheat. Materials and methods In order to examine root system and some physiological characteristics of four bread wheat contrasting in salt tolerance (Arg, Ofoq, Tajan and Morvarid) and two durum wheat cultivars (Behrang and Shabrang), a greenhouse experiment was conducted with two salinity levels (0 and 150mM NaCl) growing in PVC tube. Treatments were imposed when the leaf 2 was fully expanded. Leaf temperature of plants was acquired in the greenhouse 5 days after imposing the salt treatments. At 21 days after salt treatment plants were harvested and traits were measured. Seminal root length, total root length, Chlorophyll content, K+ and Na+ root, root and shoot dry weight in all cultivars were investigated. Results Salt stress decreased root dry weight, shoot dry weight, seminal root length, total root length and increased root Na+, leaf temperature and chlorophyll content compared to control. Seminal root growth did not affect by salinity stress in Arg and no significant differences was observed between Arg and Shabrang in this aspect. Although, reduction in seminal root length was less in Arg (5%) and Shabrang (32%), but these cultivars had more reduction in total root length by 64% and 68% respectively under saline conditions. Differences in root Na+ concentration between some wheat cultivars were less obvious in 21 days after salt treatments and it seems the roots exposed to salinity were reduced in growth mainly because of the osmotic effect of the salt, rather than a salt-specific or toxic effect. Seminal root length reduction in cultivars was due to osmotic stress of salt solution out of the roots and the values for total root length in bread wheat cultivars was more under salt stress. Shabrang showed the highest and significant increase in leaf temperature among cultivars and the most reduction in shoot dry weigh was observed in this cultivar under salt conditions. In more extended studies, shoot growth was more inhibited than root growth in saline and dry soils, however, in this study, there was little effect on shoot growth. Thus, assimilate supply was not limiting root growth. Conclusions The ability of wheat to retain seminal and total root length improved osmotic tolerance and extending root system in salt tolerant cultivars would allow water acquisition from deeper in the soil profile, thus helping to overcome osmotic stress. Results showed that osmotic tolerance may be in bread wheat to the same extent as in durum wheat cultivars and the finding of this study on root traits identify it as one of the valuable index for improved adaptation to osmotic stress in wheat. Under salt conditions or in some wheat cultivars, modification of root water uptake capacity plays a more important role compared with stomatal closure in avoiding stress-induced growth reduction.

Salinity stress

The effect of salinity stress on the amount of proline, chlorophyll and sodium and potassium ions in different rice cultivars in hydroponic environment

Somayeh Kamrava; Nadali Babaeaian Jelodar; Nadali Bagheri

Volume 14, Issue 3 , September 2021, Pages 805-821

https://doi.org/10.22077/escs.2020.3078.1791

Abstract

Introduction Among the cereals, rice is the most important human food source after wheat and has a major place in human nutrition in terms of production and cultivation. This plant is susceptible to salt stress and its response to salt stress varies with growth stages, concentration and duration of impact. ... Read More Introduction Among the cereals, rice is the most important human food source after wheat and has a major place in human nutrition in terms of production and cultivation. This plant is susceptible to salt stress and its response to salt stress varies with growth stages, concentration and duration of impact. Materials and methods This study was carried out in factorial experiment in a completely randomized design with three replications in the research greenhouse of Sari University of Agricultural Sciences and Natural Resources in 1977-98. The first factor was 71 rice genotypes and the second factor was salinity stress with 4 levels. The germinated seeds were transferred to hydroponic medium to prepare the culture medium from Yoshida nutrient solution (Yoshida et al., 1994). Chlorophyll extraction of rice leaf by Arnon method (1997), Proline amino acid extraction from leaf tissue by Bets et al. (1973) and for determination of sodium and potassium ions from leaf by Hamada and Elnai method (1994) used. The data obtained from these traits were analyzed by SAS and SPSS statistical software and compared by means of Duncan's multiple range test and clustering of genotypes by cluster analysis of tolerant cultivars based on this. Attributes were identified. Results and discussion Results of analysis of variance for different physiological traits under salinity stress showed that genotype, salinity and their interaction effects were statistically significant at the 5% probability level for all measured traits. Comparison of mean salinity levels in all measured traits was significant at 5% probability level. It showed that proline amino acid content and leaf tissue sodium content increased with increasing salinity and zero (normal) level with minimum and salinity level 9 The highest Ds was obtained and the chlorophyll pigment and potassium content of leaf tissue decreased with increasing salinity level and the highest (zero) level and the lowest salinity level was 9 dS / m. Within plant cells, proline acts as an osmotic preserving agent between the cytoplasm and the cell vacuole, and proline protects the plant against free radical damage. In the present experiment, proline content increased significantly with increasing salinity dose. This increase was higher in tolerant cultivars than in susceptible cultivars. An important effect of increasing salinity is leaf senescence and the main factor causing leaf senescence is the decrease in chlorophyll content under salinity stress. In this study, total chlorophyll a, chlorophyll a and chlorophyll b also decreased significantly under salinity stress, which was in line with the results of Bori Boncast et al. (2013) and (Wijita et al., 2018). Higher concentrations of potassium ions in the leaves of tolerant cultivars exposed to salinity can be a adaptive response to high potassium ion storage in stomach cells in salinity stress (Fallah 2015). Aerial is one of the mechanisms of plant tolerance against salinity stress. The results of this study are in line with the results of Hong et al. (2012).Conclusions The results of this study showed that salinity stress significantly decreased chlorophyll pigment and leaf potassium ion content and significantly increased proline amino acid and sodium ion content of leaf. Mean comparison between cultivars under salinity stress showed that Shastak Mohammadi, Nemat, Tarom Ghali, GASMAL, Neda, Roshan, NONABOKRA, FL478, Dilmani and Barley at 9 dS m-1 were the most tolerant cultivars to salinity and salinity stress. Saleh, Rashti Cold, IRBLZFU, IR39595, IR29, Black tip and Dorfak at 9 dSm-1 were the most susceptible cultivars to salinity stress. Acknowledgements Thanks to Sari University of Agriculture and Natural Resources and the Genetics and Plant Breeding Laboratory for providing some of the cost of this research as well as for providing plant specimens.

Salinity stress

Study of millet (Panicum miliaceum) response to humic acid, silicon and mycorrhiza application under saline-sodic irrigation water stress

Mohammad Ahmadi; Alireza Astaraei; Amir Lakzian; Hojat Emami

Volume 14, Issue 3 , September 2021, Pages 823-836

https://doi.org/10.22077/escs.2020.2842.1782

Abstract

IntroductionSalinity and sodicity stresses are the major problems in the production of crops under arid and semi-arid regions. Sustainable management by using water and soil resources, under conditions of salinity and sodicity, is considered as a management strategies, also application of mycorrhizal ... Read More IntroductionSalinity and sodicity stresses are the major problems in the production of crops under arid and semi-arid regions. Sustainable management by using water and soil resources, under conditions of salinity and sodicity, is considered as a management strategies, also application of mycorrhizal fungi along/or organic matter such as humic acid addition are the major causes in reclamation of the environment and also increases the stability of agro-systems by reducing the use of chemical fertilizers. Among other ways to overcome the negative effects of salinity on the growth and yield of the plant, application of ordinary silicon and silicon nanoparticles have prior importance. This research was conducted to evaluate the effect of humic acid, mycorrhiza and silicon (ordinary and nano) on yield and nutrient content of millet under saline-sodic irrigation water. Materials and methodsA field experiment was conducted as split plot factorial in a randomized complete block design with three replications in summer 2015. The study area is located in Tabas city, South Khorasan province (Iran) with longitude 56o 53' and latitude 33o 34'. The main plots consisted of saline-sodic irrigation water (S) at two levels (S1= EC: 2.1 dSm-1, SAR:11.5 and S2= EC: 5.04 dSm-1, SAR: 20.8) and a combination of sub factors including three treatments of silicon salts (SI): (control (Si0), silicon nanoparticles, 10KgSiha-1 (NSi) and ordinary silicon (by using sodium silicate salt) 10KgSiha-1 (Si)) and three levels of mycorrhiza and Humic acid (MH): (control (MH0), inoculation with Glomus mosseae mycorrhizal fungi (M) and humic acid 10Kgha-1 (H)) as The factorial was placed in the main plots. Results and discussion The results showed that increasing salinity-sodicity of irrigation water decreased grain yield, straw yield, number of panicles per square meter and plant height and its effect on 1000 seed weight and grain number per spike were not significant. Increasing salinity-sodicity of irrigation water decreased the grain yield by reducing the number of panicles per square meter, reduction of the straw yield due to its negative impact in plant height. The application of silicon nanoparticles treatment increased the grain yield compared to non-silicon treatment, but ordinary silicon (sodium silicate) had no effect. Mycorrhizal inoculation increased grain yield, straw yield and panicle per square meter and application of humic acid also increased grain yield, number of panicles per square meter. Mean grain yield at S1 level increased with the use of humic acid and mycorrhiza and in S2 level, mean grain yield increased only with the use of humic acid. Saline-Sodic irrigation water reduced the concentrations of nitrogen, phosphorus, potassium and K/Na ratio, and increased sodium concentration in millet. Application of silicon had no significant effect on nitrogen, phosphorus, potassium, sodium and K/Na ratio in the plant, but mycorrhiza and humic acid increased plant phosphorus and K/Na ratio and decreased sodium content of the plant. ConclusionsAccording to our results, it can be concluded that the use of silicon nanoparticles in comparison with ordinary silicon (sodium silicate) could increase the yield of millet. Also the application of humic acid or mycorrhiza can be improved the yield of millet by increasing the amount of phosphorus and K/Na ratio and decreasing sodium content in millet and thus the enhancement of resistance of the plant and the reduction of the effects of salinity-sodicity of water irrigation, and in this regard, the effect of humic acid was much superior to mycorrhiza impact.

Heavy metals

Effect of different salinity levels on germination indices of 20 new quinoa genotypes

Mehrzad Tavoosi; Zeynab Anafjeh; Javad Mahdavi Majd

Volume 14, Issue 3 , September 2021, Pages 837-847

https://doi.org/10.22077/escs.2020.2987.1772

Abstract

Introduction Iran's climate change to hot and dry, and the gradual salinization of arable soils on the one hand, and the good tolerance of the quinoa to drought, salinity and frost on the other hand, makes the use of quinoa as a suitable plant reasonable. This study was carried out with the aim of investigating ... Read More Introduction Iran's climate change to hot and dry, and the gradual salinization of arable soils on the one hand, and the good tolerance of the quinoa to drought, salinity and frost on the other hand, makes the use of quinoa as a suitable plant reasonable. This study was carried out with the aim of investigating 20 new cultivars of quinoa in vitro and also evaluating salinity tolerant cultivars for introduction and development in field preliminary experiments. Materials and methods In order to obtain tolerant cultivars of quinoa to salinity for field experiment conditions, as well as to study the effect of different salinity levels on seed germination indices of quinoa, a factorial experiment with four replications in a randomized complete block design with four replications in 2017 The Khuzestan Agricultural and Natural Resources Research Center was designed and implemented. Treatments included a combination of four salinity levels of zero, low, medium and high (0, 100, 200 and 300 mM NaCl, respectively) and 20 quinoa cultivars. Results Results showed that different salinity values had a significant effect on germination percentage, germination rate index, germination rate coefficient, mean germination time and seedling vigor index of different cultivars (P <0.001). At zero salinity levels: Santamaria, Titicaca, Red carina, Q12, Q22, Q31, Q102 and 882051, at low and medium salinity levels: Santamaria, Titicaca, Red carina, Q12, Q22, Q31, Q101, Q102 and 882051, and at high levels: Santamaria, Titicaca, Q102, Q12 and 882051 showed superiority in all germination indices. In general, Santamaria, Titicaca, Q102, Q12, Q31, and 882051 cultivars were in the medium to strong group at different salinity levels. This indicates the stability of germination components of these cultivars under different environmental conditions. Therefore, this group of cultivars can be considered as promising cultivars for field experiments. Conclusions The results showed that the salinity stress affected the measured indices in this experiment and reduced these indices. Also, among the cultivars studied, Santamaria, Titicaca, Q102, Q12, Q31 and 882051 showed a good response among all the traits tested. And in response to salinity stress, they showed the lowest decrease among most of the traits, indicating the ability of these cultivars to withstand adverse salinity conditions and the ability to be introduced in early field trials.

QTL mapping for physiological traits affecting lead tolerance in the Hordeum vulgare L.

Azadeh Rahmani; Ali Asghari; Hosein Jafari; Omid Sofalian

Volume 14, Issue 3 , September 2021, Pages 849-860

https://doi.org/10.22077/escs.2019.2731.1717

Abstract

IntroductionHuman activities such as mining and industrials activities have increasingly affected soil contamination through the sedimentation of heavy metals. This issue is concerned as a global problem. All heavy metals are potentially poisonous, which vary based on their biologic available concentrations ... Read More IntroductionHuman activities such as mining and industrials activities have increasingly affected soil contamination through the sedimentation of heavy metals. This issue is concerned as a global problem. All heavy metals are potentially poisonous, which vary based on their biologic available concentrations and the sensitivity of organisms which are exposed to the heavy metal. One of the main heavy metals is Lead. lead is a potential pollutant that readily accumulates in soils and sediments. Pb is considered a major troublesome poison, crop productivity sharply declines in soils contaminated by Pb. The poisonous characteristics of lead on plants are attributed to chlorosis, declined growth, blackening of root system, upsets mineral nutrition and water balance, changes in hormone status, and the effects on the structure and permeability of membrane. In recent years, many plants have been destroyed due to the increased pollution of the earth by heavy metals, and which has led researchers are interested in soil improvement, the production and use of resistan. Most of the important agricultural traits, such as yield, grain quality and resistance, or tolerance of live and non-live stresses in nature, are complex qualitative traits. These traits are usually controlled by multiple quantitative traits (QTLs), which are strongly influenced by the genetic context of the creaturet plants, and the identification of mechanisms and genes associated with heavy metal tolerance. This research was carried to identification of QTL traits related to lead toxicity tolerance in barley. Materials and methodsIn this study, we used 94 double haploid from Dom and Rec parents that were planted in a completely randomized design with three replications in twenty-cm diameter pots. Then at 2- to 3-leaves stage, seedlings were treated by 0 (control) and 2000 ppm density lead nitrate. Physiological traits such as sub-stomatal CO2, transpiration rate, photosynthesis rate, stomatal concentration and plant greenness after 24 under stress, were measured at the beginning heading stage. In order to investigate the frequency distribution of data and their variation under stress and normal conditions, Spss program version 23 was used. After observing the continuous and quantitative variation among progenies to studied traits, in order to locate the lead-tolerance genes, Using Mapchart2.32 and MapQTLs Software, chromosomal regions associated physiological traits were identified on seven chromosome of barley. ResultsThe phenotypic Analysis of the studied traits showed a quantitative and continuous variation. the studied traits showed normal distribution in both non stress and stress conditions The genetic which is lead tolerance is controlled depending on the physiological indices of different parts in the genome of the barely. In this study No QTL was observed for the studied traits under normal conditions. among the traits sub-stomatal CO2, transpiration rate, plant greenness after 24 under stress, stomatal concentration, photosynthesis rate, QTL was observed Under stress conditions with lead, two QTL discovered for sub-stomatal CO2 on chromosome 6, two QTL for transpiration rate on chromosome 3, four QTL for Stomatal Conduction on chromosomes 1 and 3, four QTL for photosynthesis rate on chromosomes 3 and 2, four QTL for plant greenness after 24 under stress on chromosomes 1 , 4 and 5. Phenotypic variation justified by these QTLs varied 10.5% to 19.10%.ConclusionThe results of this study showed that the OWB mass mapping can be used as a proper mass mapping and as a model for studying the genetic of lead tolerance in plants. The results of this study also showed that various physiological traits of barely under lead stress conditions are manipulated by different genes. Precisely locating lead resistant QTL is the most important step in cloning and finding the function of the genes involved in lead resistance. In order to use QTL detection methods for understanding the attributes related to lead resistance, it is necessary to divide lead toxicity resistance into smaller traits. This task is achieved through considering the events occurring in lead poisoning and the determining the reason why some plants are tolerate.

Heavy metals

Effect of putrescine foliar application on growth and tolerance of iberica dragon’s head (Lallemantia iberica) to lead stress

Aida Ansari; Babak Andalibi; Mehdi Zarei; Farid Shekari

Volume 14, Issue 3 , September 2021, Pages 861-871

https://doi.org/10.22077/escs.2020.3018.1779

Abstract

IntroductionIn the last two decades, soil contamination with heavy metals, including lead (Pb), has been increasing. Pb is the most important heavy metal that has polluted the environment and caused symptoms of plant toxicity such as limiting root and shoot growth, blackening of the root system and decreasing ... Read More IntroductionIn the last two decades, soil contamination with heavy metals, including lead (Pb), has been increasing. Pb is the most important heavy metal that has polluted the environment and caused symptoms of plant toxicity such as limiting root and shoot growth, blackening of the root system and decreasing photosynthesis and the quantity and quality of yield. In many agricultural areas of Iran, including Zanjan, the presence of heavy metals, especially Pb, is always associated with the growth stages of plants, including medicinal plants. Native medicinal plants of Iran, including Lallemantia iberica have an important role in the treatment and prevention of diseases. The seeds of this plant are reconstituent, stimulant, diuretic, and expectorant and have a high content of oil and omega-3 fatty acid alpha linolenic acid. The use of polyamines such as putrescine (Put) is one of the new strategies to reduce the harmful effects of environmental stresses such as heavy metals. Polyamines, as plant growth regulators, have a protective role against membrane damage and lipid peroxidation and are involved in regulating processes such as cell division, enzyme activity, vascular differentiation, flowering, fruit ripening, and root growth. Due to the contamination of agricultural soils near the industrial areas with heavy metals and the need for medicinal plants in the country, this study was conducted to investigate the effect of Put spraying on the growth and tolerance of L. iberica to Pb stress.Materials and methodsThe experiment was conducted as a factorial based on a randomized complete block design with six replications (three replications for grain yield and three replications for other traits) at the research greenhouse of the Faculty of Agriculture, the University of Zanjan in February 2018. The experimental factors were Pb stress in four levels (control, 300, 600 and 900 mg Pb/kg soil) from the source of Pb(NO3)2 and Put in two levels (0, and 0.5 mM). The Pb amount in the test soil was measured at the beginning of the experiment and considered as control. The Put spraying was performed before flowering begins (with the observation of the first flower bud) during 2 steps (half concentration at the 10-leaf stage and the other half 7 days later to prevent Put accumulation). Greenness index, proline content, leaf area, leaf, stem, and capsule dry weight, total shoot dry weight, root length and dry weight, and tolerance index at the flowering stage and grain yield at the harvest stage were measured. Analysis of variance was done by using SAS (9.1) software. Mean comparison was performed by Duncan multiple range test at 5% probability level.Results and discussionThe main effects of Pb stress and Put spraying on all the traits were significant. The interaction effect between them on greenness index, proline content, leaf, stem, and capsule dry weight, total shoot dry weight, root length, tolerance index, and grain yield was significant while its effect on leaf area and root dry weight was not. Pb stress, especially at 900 mg concentrations, decreased leaf area, greenness index, leaf, stem, and capsule dry weight, total shoot dry weight, root length and dry weight, tolerance index, and grain yield and increased proline content. The highest grain yield and tolerance index was obtained in the non-added Pb. Within each four Pb levels, Put spraying had the maximum amount of measured traits than the non-Put. Growth restriction and improper development of the root system under Pb stress reduced water and nutrient uptake and subsequently affected chlorophyll and photosynthesis, thereby reducing leaf area, shoot growth and plant yield, which the positive and significant correlation of root length with total shoot dry weight, leaf area, and greenness index (r=0.87***, r=0.61**, and r=0.9***, respectively) confirms the above content. The positive role of the Put can be due to its effect on increasing cell division, which ultimately improves plant growth. Positive and high correlations of leaf area with grain yield (r=0.69***) and greenness index with grain yield (r=0.87***) confirm that any factor which increases leaf area enhances producing and storing assimilate in the plant, leading to increased grain yield.ConclusionsOverall, measured traits affected by increasing Pb concentration in the soil, however, Put spraying had improvement effects on these traits and with an increasing root length, greenness index and leaf dry weight led to an increase in the tolerance index of L. iberica under Pb stress. Also, the highest grain yield was found in Put spraying under control. Therefore, given the crisis of the increasing concentration of heavy metals, especially Pb in the agricultural soils, Put application can be suggested to increase Pb tolerance in L. iberica and to use this plant in Pb-contaminated areas to restore lost vegetation.

Volume 17 (2024-2025)

Volume 16 (2023-2024)

Volume 15 (2022-2023)

Volume 14 (2021-2022)

Volume 13 (2020-2021)

Volume 12 (2019-2020)

Volume 11 (2018-2019)

Volume 10 (2017-2018)

Volume 9 (2016-2017)

Volume 8 (2015-2016)

Volume 7 (2014-2015)

Volume 6 (2013-2014)

Volume 5 (2012-2013)

Volume 4 (2011-2012)

Volume 3 (2010-2011)

Volume 2 (2009-2010)

Volume 1 (2009)

Volume & Issue: Volume 14, Issue 3, Open Access Policy, September 2021, Pages 569-872

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract