Abbas Nameni; Alireza Abbasi; Manizhe Sabokdast
Abstract
Drought stress is one of the most destructive abiotic stresses. Expansins are one of the cell wall expandable proteins that can expand the cell wall under a pH-dependent pathway. Stomatal opening rate Due to the expression of AtEXPA1 gene in transgenic plants has been observed. In this study, second ...
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Drought stress is one of the most destructive abiotic stresses. Expansins are one of the cell wall expandable proteins that can expand the cell wall under a pH-dependent pathway. Stomatal opening rate Due to the expression of AtEXPA1 gene in transgenic plants has been observed. In this study, second generation (T2) of three transgenic tobacco lines with AtEXPA1 gene were studied for some physiological and biochemical traits under drought stress. Transgenic lines includes 2, 4 and 7 and Non-transgenic commercial cultivar Samson as control were cultivated. RWCL and leaf chlorophyll content has been reduced under drought stress, and ELIL, Lipid peroxidation as MDAL and leaf proline content has been increase. The activity of antioxidant enzymes such as, catalase (CAT), guaiacol peroxidase (GPOX), ascorbate peroxidase (APOX) and polyphenol oxidase (PPO) was increased in leaves under drought stress. In this study, according to biochemical traits Line 2 and Line 7 and according to physiological traits Line4 in Compared to the control cultivar, could cope with stress and introduce as tolerate cultivars.
Mojtaba Rouhi; Mohammad Banayan Aval; Amir Hossein Shirani Rad
Abstract
Introduction Rapeseed (Brassica napus L.) is one of the most important oilseed plants that has been ranked third in the oil production after soybeans and oil palm (Oil World, 2012). Drought stress is the most important limiting factor in the production of agricultural products in arid and semiarid regions ...
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Introduction Rapeseed (Brassica napus L.) is one of the most important oilseed plants that has been ranked third in the oil production after soybeans and oil palm (Oil World, 2012). Drought stress is the most important limiting factor in the production of agricultural products in arid and semiarid regions (Debaeke and Aboudrare, 2004). Although water shortage in many developmental stages reduces the yield of rapeseed, the negative effects of stress during flowering and growth stages are much more pronounced (Sinaki et al, 2007). Materials and methods In order to study the ecophysiology of new winter varieties of rapeseed (six lines ready for introduction and Ahmadi's native species as control), the drought stress of the end of the season was observed in two latent cultivation conditions including the usual sowing date (11th of October) and the latent planting date (26th of October) and Irrigation was carried out in two levels including irrigation (control) and irrigation cut off from stepping stage to a factorial split plot design in a randomized complete block design with three replications in two years of cultivars 2015-2016 and 2016-2017 at the Research Institute for Correction And planting seedlings and seeds of Karaj. Planting dates and irrigation will be the main factor and the cultivars of the sub-cultivar. Data analysis was performed using SAS software. First, the Bartlett test is performed and then the combined analysis of the two-year data is tested. Comparison of mean of main effects by LSD method at 5% level and in the case of meaningful interactions, cutting and comparing the meanings were done using L.S.Means test. The results showed that the main effect of cultivar, and the effects of year on planting date and cultivar, were significant on planting date on seed oil. Results and discussion Results showed that in the first year and sowing date of 11th of October, the highest seed oil was obtained in the amount of 24.31%. The lowest amount was obtained in the second year and the sowing date of October 26th. In general, the seeding date of Oct. 11, in both years, had more seed oil yields. Regarding the interaction between sowing date and cultivar, results showed that the highest seed oil at the planting date of 11th of October and L72 was 54.44 percent. The lowest values were obtained on the 26th of October and the HW3 cultivar. In general, L72 had more seed oil in both dates. The results showed that the main effect of year, main effect of irrigation, main effect of cultivar, main effect of sowing date and interaction effects of planting date on cultivar on seed yield was significant. In the second year, oil yields more than the first year. In irrigation, the yield of oil was 231.2 kg/ha, which was 21% more than irrigation treatment. The results of interaction between sowing date and cultivar showed that the highest yield of seed oil (2576.6 kg/ha) was obtained on the 20th of September and L72 cultivars. The lowest values were obtained on the 5th of November and the HW3 cultivar. In general, the L72 had more seed oil yields on both dates. The results showed that the main effect of year, main effect of irrigation, main effect of cultivar, main effect of planting date and interaction effects of planting date on cultivar was significant on grain yield. In the second year, grain yield was more than the first year. In irrigation, grain yield was 4444.72 kg/ha, which was 30% more than irrigation treatment. The results of interaction between sowing date and cultivar showed that the highest grain yield was obtained at 4231.2 kg / ha in sowing date of 11th of October and L72 cultivar. The lowest values were obtained on the 26th of October and the HW3 cultivar. In general, the L72 had more seed yield on both dates.
Mohamad Sadegh Azadi; Ali Reza Shokoohfar; Mani Mojadam; Shahram Lak; Mojtaba Alavifazel
Abstract
IntroductionNowadays, corn is recognized as a nutrition seed for human, birds and some animals. Corn is considered as an energetic nutrition. It will be graded after wheat and rice among whole the cereal according to the significance and the rate of cultivation. Breeding for environmental stress is one ...
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IntroductionNowadays, corn is recognized as a nutrition seed for human, birds and some animals. Corn is considered as an energetic nutrition. It will be graded after wheat and rice among whole the cereal according to the significance and the rate of cultivation. Breeding for environmental stress is one of the most important goals in plant breeding. Among stresses, drought stress has high influencing on limitation of maize production. potash management under water limitation condition is an important factor to obtain high grain yield of maize. . All the plants are in contact with biological fertilizer. One of the most important effects of such a biological fertilizer is the operation enhancement in the lands which are low fertility, confronting with different land disease, and strengthening the plant against drough. In general, Plants are exposed to environmental stresses. Water and Potassium availability are two major factors for crop production under different conditions In this study, correlation and stepwise regression of biochemical traits with grain yield of corn hybrids under drought stress conditions and application of potassium chemical and biological fertilizers are investigated. Materials and methods This study was performed to evaluate the effects of chemical and biological potash fertilizers and drought stress Biochemical characteristics and Grain yield of Zea mays varieties in 2014 - 2015 in Dehloran, Iran. The experiment was conducted as split split plots in randomized complete blocks design with three replications. The treatments included drought stress (normal irrigation, cutting irrigation at 12 leaf stage and at tassel emergence) as main factor, potassium sulfate application in three levels (100% potassium sulfate, 70% potassium sulfate fertilizer with 30% fertile-2 fertilizer, and 50% potassium sulfate fertilizer with 50% fertile-2 fertilizer) as sub plots and three corn hybrids (AS71, NS640 and CORDONA) as sub sub plots. Finally, the data was analyzed by the MSTAT-C. Results and discussion The results of data analysis showed that the occurrence of stress had a negative effect on Some biochemical traitsand and corn yield. Creating stress in the emergence stage of coronal grass compared with the stress in the 12 leaf stage, had more impact on the evaluated indicators. Consumption of biological and chemical fertilizers of potash by modifying the effects of drought stress had a positive effect on biochemical traits and grain yield. Application of 50% chemical potash+ 50 % seed incubation by Fertil-2 led to 10% increasing of kernel yield, Between studied genotypes, AS71 and NS640 showed highest (10717 kg/ha) and lowest (5887 kg/ha) means, respectively. According to interaction between treatments, it was founded that highest kernel yield (12130 kg/ha) was obtained by AS71 under optimum irrigation conditions + 50% urea fertilizer with 50% fertile-2 fertilizer treatment. Grain yield with proline content, chlorophyll a and b had a positive and significant correlation. The results of stepwise regression showed that the effects of chlorophyll a, proline content and catalase and superoxide dismutase enzymes activity on grain yield had a significant . ConclusionsAccording to the results of this research and due to the extreme sensitivity of the biochemical characteristics in water stress conditions, and the relationship of these traits with grain yield, it is necessary to prevent the occurrence of water stress at critical stages of plant growth.Combined use of biological potash fertilizers with chemical potash fertilizers were more effective than chemical fertilizers and significantly increased grain yield. In general, due to the changes in the traits, supplying 50% of needed fertilizer in form of potash fertilizer combined with Barvar-2 fertilizer and AS71 in optimal irrigation conditions were selected as the best experimental treatments.
Ali Khoshnam; Ebrahim Mamnoie
Abstract
Introduction Safflower (Carthamus tinctorius L.) is one of the world’s oldest cultivated crops. It is traditionally grown for its seeds and used for coloring and flavoring foods and for making red and yellow dyes. The total area of safflower harvested in Iran was 490 thousand ha, and in South Kerman ...
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Introduction Safflower (Carthamus tinctorius L.) is one of the world’s oldest cultivated crops. It is traditionally grown for its seeds and used for coloring and flavoring foods and for making red and yellow dyes. The total area of safflower harvested in Iran was 490 thousand ha, and in South Kerman was 7000 ha in 2017. Safflower is an oilseed crop, from the Asteraceae family, not very popular compared to other oil crops such as soybean, sunflower and peanut because it is not widely cultivated around the world. Safflower is a C3 plant tolerant to drought, salinity stress and highly adaptable to various environmental conditions because of having deep rooting ability, water uptake from soil, and different osmolyte accumulation. Drought stress is one of the most limiting factors in agricultural productivity because of its highly negative effect on photosynthesis, growth of plants and productivity worldwide. Water deficiency usually promotes the degradation of chlorophyll, caused by photo-inhibition, reduction of photosynthetic efficiency or other processes, such as cell division and expansion. Fernanda et al., (2017) reported that water stress decreased photosynthetic pigments, chlorophyll a, chlorophyll b, grain yield, oil content, oil yield, and increased electrolyte leakage. Nabipour et al., 2007. Water stress decreased 1000 seed weight, seed in capitul, capitul in plant, seed yield and oil content in safflower. Also, plant density is an important crop management that affects the seed yield. However, increasing plant density can be decreased grain yield, due to the competition for water and nutrients between the roots of the neighboring plants. The purpose of the present study was to investigate the response of safflower yield and yield component to water deficit and plant density. Materials and methods In other to study the effect of plant density and water stress on grain yield, yield components and oil content safflower. An experiment was conducted in Agricultural Research and Education Center Jiroft, Iran during 2012- 2013. This experiment was carried out as strip plot based on randomized complete blocks design with three replications. Treatments were water stress as vertical factor in four levels including normal irrigation (control), cut-off irrigation in capitul emergence stage before flowering (code 50 BBCH-scale), cut-off irrigation in 50 percent flowering (code 65 BBCH-scale), cut-off irrigation at the end of flowering and begins to expand as fruits develop (code 71 BBCH-scale), and density plant as horizontally factor in four levels including 30, 35, 40 and 45 plant/ m2. Traits were measured including plant height, 1000 seed weight, capitul number in plant, grain number in capitul, grain yield and oil content. The data were statistically analyzed using combined variance of analysis and the differences among mean values of the treatments were compared by LSD test (p≤0.05) using SAS 9.1 software. Results and discussion The results showed that water stress, plant density and water stress × plant density had significant (p < 0.05) effect on 1000 seed weight, capitul number in plant, grain number in capitul, grain yield and oil content. Plant density had not significant effect on plant height, while water stress had significant effect on plant height. Water stress decreased plant height, 1000 seed weight, capitul number in plant, grain number in capitul, grain yield and oil content significantly. The highest grain yield and oil content were obtained when applied treatment of cutoff irrigation in capitul emergence stage plus 40 plant/ m2, by 2852 and 884 kg ha-1 respectively. The lowest grain yield and oil content achieved when applied treatment of cut-off irrigation in the end of flowering plus 45 plan/m2, by 718 and 204 kg ha-1 respectively. Also, application of treatment normal irrigation (control) plus 40 plant/ m2 had the highest grain yield and oil yield by 4101 and 1239 kg ha-1 respectively. Conclusions The result of our study showed that there is a strong relationship between time cut-off irrigation and reduce of seed yield and yield component. The highest seed yield under water stress condition achieved when applied cut-off irrigation at the end of flowering, cut-off irrigation in 50 percent flowering and cut-off irrigation in capitul emergence respectively.
Maryam Niazi; Vahid Barati; Ehsan Bijanzadeh
Abstract
IntroductionGrain yield of cereals significantly affects by assimilate remobilization in arid zones. Many factors including N fertilizer application affects assimilate remobilization in cereals (Ercoli et al., 2008). Many researches have been done aboat the effects of chemical N fertilizer under normal ...
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IntroductionGrain yield of cereals significantly affects by assimilate remobilization in arid zones. Many factors including N fertilizer application affects assimilate remobilization in cereals (Ercoli et al., 2008). Many researches have been done aboat the effects of chemical N fertilizer under normal and water stress conditions on assimilate remobilization in arid environments (Ercoli et al., 2008; Barati and Ghadiri, 2017; Bahrani and Tahmasbi-sarvestani, 2006). However, the effects of other N sources such as crop ressidues and N fixing bacteria alone or in combination with chemical N fertilizers on assimilate remobilization and consequently grain yield was very scarce specially in arid zones. Therefore, there are two main questions; 1. Can using of Azospirillum brasilense as a N fixing bacteria instead of chemical N fertilizers or in combination with them in bio-agriculture boost the assimilate remobilization and consequently grain yield of barley under water stress conditions?, and 2. Can applying plant residues increase Azospirilum activity and consequently increase assimilate remobilization and grain yield in dry areas by improving water storage capacity or another mechanisms? For answering the above questions, the effects of application of N fixing bacteria (Azospirillum brasilense) and wheat residues on dry matter remobilization and barley yield under water stress after anthesis stage was evaluated in an arid zone of Southern Iran (Fars province). Materials and methodsThis research was conducted at the experimental farm of the Darab Agricultural College of Shiraz University. A split factorial experiment in a randomized complete block design with three replications were carried out in 2017 - 2018 growing season. Treatments included: two levels of irrigation as the main plots [normal irrigation (IRN): irrigation based on the plant's water requirement up to the physiological maturity and another factor was deficit irrigation (IRDI): irrigation based on the plant's water requirement up to the anthesis stage (cutting of irrigation after anthesis)]. Also, sub plots were two levels of wheat residues [1. without residue, 2. returning 30% of wheat residues to soil] and four fertilizer sources [N0, no nitrogen fertilizer (control); N100, 100 kg N ha-1; Bio + N50, Biofertilizer (Azospirillum brasilense) + 50 kg N ha-1 and Bio, Biofertilizer (Azospirillum brasilense)]. Finally, at the anthesis stage, dry matter of shoot samples were measured. Also, at the end of growing season, grain yield, dry matter of vegetative parts of shoot were measured. Then, assimilate remobilization, assimilate remobilization efficiency and contribution of pre-anthesis assimilate to grain were calculated by Ercoli et al., 2008 methods. Data were analyzed using SAS 9.1 software (SAS Institute, 2004). Results and discussionOverall, combined N fertilizer (Bio + N50) significantly increased grain yield (53%) in normal irrigation. Similarly, the grain yield was improved up to 12% under water stress conditions by Bio + N50. Water stress increased assimilate remobilization and contribution of pre-anthesis assimilate to grain in Bio + N50 treatment by 37 % and 148%, respectively, as compared with the normal irrigation treatment. The application of plant residues decreased the amount of assimilate remobilization, assimilate remobilization efficiency and contribution of pre-anthesis assimilate to grain in all fertilizer treatments. However, it did not significantly affect the grain yield. ConclusionGenerally, considering the economic aspects and moving towards the sustainable agriculture, using of combined N fertilizer [Biofertilizer (Azospirillum brasilense) + 50 kg N ha-1] in optimal irrigation conditions is recommended for farmers of Southern Iran. Furthermore, if cutting of irrigation after anthesis is considered because of irrigation water resource shortage, this fertilizer regime is recommended as compared with the other N sources due to the significant increase in assimilate remobilization (37%) and contribution of pre-anthesis assimilate to grain (148%) and lower grain yield reduction as compared with the normal irrigation conditions.
Somayeh Ghafari; Afshin Tavakoli; Ali Reza Yousefi; Jaefar Nikbakht; Hadi Salek Mearaji
Abstract
Introduction Bean (Phaseolus vulgaris L.) is one of the most important food sources of human. It has a high nutritional value due to its protein, vitamins and fiber supply. Abiotic stresses are most important limiting factors to crop productivity that among these, drought stress is known to be the main ...
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Introduction Bean (Phaseolus vulgaris L.) is one of the most important food sources of human. It has a high nutritional value due to its protein, vitamins and fiber supply. Abiotic stresses are most important limiting factors to crop productivity that among these, drought stress is known to be the main limiting factor of bean production in worldwide. The bean has a low tolerance to water stress, while about 60% of the bean crop is obtained in areas under low water stress. It has been reported that about 25% reduction of yield bean is due to drought stress conditions. The use of modern irrigation methods in addition raise grain yield, because saves of water consumption. Materials and methods In order to investigate the effect of different irrigation regimes on gas exchanges and agronomy traits related to yield in bean, a field experiment was carried out at the Research Farm of the Faculty of Agriculture, Zanjan University, Zanjan, Iran (36410N, 48290E) in spring 2012 years. The experiment was conducted at complete randomized block design with four replications. Experimental treatments included five level of irrigation (Traditional Irrigation with 100 % supply water requirement (I1), drip tape irrigation with 100 (I2), 80 (I3), 60 (I4) and 40 % (I5) supply water requirement. Each plot consisted of four rows, each measuring six meter long, distance of each rows and plants was 50 and 10 cm, respectively. Crop Evapotranspiration (ETc) of bean determined through calculation the evapotranspiration of the refrence crop (ETo) evaluated by FAO-Penman-Montith method and Crop Evapotranspiration (ETc) of plant. For of photosynthesis and other gas exchange parameters use IRGA Lci meter. At the physiological maturity stage, plants in an area of 1 m2 to measuring of length of plant, number pod in plan, number seed in pod, weight of thousand seeds, grain yield, biological yield and harvest index (HI) were harvested, then all aboveground dry matter were determined. Results and discussion The irrigation regimes have significant effect all traits investigate except plant length and intercellular CO2 concentration (Ci). Reducing the amount of available water had adverse effects on the yield and yield components. The maximum of Stomatal conductance to water vapour (gs) observed in I1 and net CO2 assimilation rate (ACO2), mesophyll conductance (gm) in I1 and I2 treatment. The intercellular CO2 concentration (Ci) was not affected by the irrigation regimes. The maximum of grain yield (945.6 kg/h), number of pod in plant (10.95) and harvest index (23.87 %) observed in I2 treatment and the highest of stomatal conductance to water vapour (gs) with 0.43 mmol.m-2s-1 was in I1 treatment. There was no difference in other traits investigate between I1 and I2 treatments. The intercellular CO2 concentration (Ci) not significant in different irrigation regimes. The grain yield, number of pod in plant and harvest index in I2 treatment was more than I1 treatment to the amount 31.29, 59 and 18.93 percent, respectively. Conclusions According to this study, results showed that the physiological and agronomical traits that affected the growth and development of common bean disturbed whit reducing the available water content and ultimately the yield reduced. Since the no significant difference between more eco-physiological traits, in order to reducing of water consumption, suggested that in the field of bean culture, instead of traditional (leakage) irrigation, to use from of drip irrigation method with 100 percent supply water requirement. Result showed that the use of drip tape irrigation with 100 % water requirement was better than traditional irrigation with 100 percent supply water requirement, because in addition raise grain yield, cause saves of water consumption and reduces of hardness of work in farm conditions.
Seyed Reza Amiri; Khaled Salimi; Seyed Masoud Ziaei
Abstract
Introduction Lack of water resources and drought stress is one of the most important characteristics of arid areas. Therefore, selecting the resistant plant and appropriate irrigation method is the best approach to manage water resources in these areas. Furthermore, lentil (Lens culinaris Med) as a cold ...
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Introduction Lack of water resources and drought stress is one of the most important characteristics of arid areas. Therefore, selecting the resistant plant and appropriate irrigation method is the best approach to manage water resources in these areas. Furthermore, lentil (Lens culinaris Med) as a cold spring legume is one of the most suitable plant under these conditions. The deficit irrigation method is one of the most important options for decreasing water losses and maximize water use efficiency in arid areas. However, the purpose of this study was evaluation of managing drought stress using deficit irrigation and its effect on lentil production and water use efficiency in climatic condition of Saravan. Materials and methodsFor evaluation of deficit irrigation on lentil production a split plot experiment based on a randomized complete block design with four replications was conducted in the Agricultural Research Station, Higher Educational Complex of Saravan during the growing season of 2018-2019. Main plots were including four levels of irrigation (60, 80, 100 and 120%). Sub plots were two lentil landraces (Baluchestan and Kurdestan). Planting was done on November 30. Moreover, irrigation was carried out in control (full irrigation) whenever 35% of allowed water depletion was extracted at soil depth of 20 cm. At each irrigation interval, the soil moisture was returned to the field capacity point at depth of 60 cm. The amount of deficit moisture content of different layers of soil was calculated from the following equation:MDControl= (ƟFC- Ɵ10cm) + (ƟFC- Ɵ20cm) +…..+ (ƟFC- Ɵ60cm) (1) In this equation, MD was the amount of moisture deficiency based on mm, ƟFC was the volumetric moisture content of the soil in the field capacity of the field and Ɵ 10cm, 20cm, 30cm, 40cm, 50cm and 60cm were the volume of soil moisture at a depth of 10, 20, 30, 40, 50 and 60 cm, respectively.The amount of irrigation water for each plot in the control treatment was calculated based on the following equation:IControl= MDControl × A (2) In the equation of 2, I was the amount of irrigation water based on liter, MD was the amount of moisture deficiency (mm) calculated in equation 1 and A plot area (m2). Deficit irrigation was done at the same time as the control treatment, but irrigation was carried out at each irrigation interval according to different levels of deficit irrigation (60, 80).The amount of water at different levels of deficit irrigation was calculated as follows:I Deficit irrigation at 80 percentage= IControl ×0.80I Deficit irrigation at 60 percentage= IControl ×0.60Results and discussionsOverall, the results showed that the effect of deficit irrigation on grain yield, biological yield, harvest index, number of pods and seed per plant and water use efficiency was significant. The highest grain yield was obtained for Baluchestan cultivar in 120 and 100% water requirement with 680 and 643 kg ha-1, respectively. Furthermore, the highest harvest index was obtained in Baluchestan cultivar and 80% water treatment (0.24) treatments. Although, Baluchestan cultivar and 80% water requirement treatments encountered with 10% reduction in grain yield compared to 100% water requirement, its biological yield decreased 27% compared to 100% water requirement, which eventually led to an increase in harvest index. On the other hand, the greatest water use efficiency was observed in Balochistan cultivar and 80% water requirement treatment with 2.9 kg ha-1 mm-1. Although the yield of 80% water requirement was 58 kg ha-1 less than 100% water requirement, but its water use efficiency was 0.3 kg ha-1 mm-1 more than 100% water requirement. Conclusions Therefore, given that the area is considered as arid area, it is possible by reducing irrigation water and allocating it to critical stages especially flowering and pod filling stages and also other crops improve grain yield and the water use efficiency.
Roya Ghorbani; Ali Movafeghi; Ali Gangeali; Jafar Nabati
Abstract
Introduction Drought stress is one of the most important environmental stresses affecting plant growth and yield. Chickpeas are drought tolerant plant, but drought as a limiting factor affects their yield. Drought stress in chickpeas reduces the length of flowering period and decrees the growth period. ...
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Introduction Drought stress is one of the most important environmental stresses affecting plant growth and yield. Chickpeas are drought tolerant plant, but drought as a limiting factor affects their yield. Drought stress in chickpeas reduces the length of flowering period and decrees the growth period. There are various strategies for mitigating drought stress, in which nanotechnology has received special attention in plant sciences in recent years. The use of nanoparticles in various plant species indicates their positive effects on plant growth and development. Nanoparticles are atomic or molecular assemblies with dimensions of 1-100 nanometers. Highly permeable nanoparticles increase the water uptake of nutrients and ultimately improve growth. The use of nanoparticles can be effective as a way to mitigate the effects of drought stress. Materials and methods The experiment was carried out as a factorial experiment with three replications in a completely randomized design in a greenhouse. The morphological and physiological characteristics of the plant were assessed at different levels (40, 60 and 90 percentage) of field capacity (FC). FC was measured by calculating the amount of soil humidity. The titanium dioxide nanoparticles (TiO2-NPs) are used in five concentration including 0, 5, 20, 10 and 40 mg/L. Firstly characteristics of nanoparticles were investigated by measuring zeta potential, XRD and TEM. Secondly, a 100 mg/l mother solution was prepared in deionized water. TiO2-NPs were dispersed by ultrasonic bath for 40 min before spraying the solution on the plants. The plants completely were soaked by sprayed solution 4 times each 14 days .Finally after the growth duration some morphological and physiological parameters were measured. The data were analyzed using ANOVA with Statistical Analysis System (Minitab .17) software and the significance of difference between means was determined by Tuky test. Result and discussions The results showed that the leaf area of chickpea was significantly affected by the test factors and their interactions. A 35%-increase in leaf area was observed at the lowest level of irrigation after exposure to 20 mg/L of TiO2-NPs. Chlorophyll index of chickpea was significantly affected by the test factors and their interactions. The interaction of two test factors showed that with an increase in the concentration of TiO2-NPs to 20 mg/L, chlorophyll index of chickpea was increased in all levels of irrigation. At all levels of irrigation, using the concentration of 40 mg/L of TiO2-NPs, the chlorophyll index in chickpea leaves were reduced compared to the concentration of 20 mg/L. The highest osmotic potential was observed in 40% capacity after treatment with 5 and 10 mg/L titanium dioxide nanoparticles. There were no significant differences between 40 and 20 mg/L at this level of irrigation. At all irrigation levels, the application of the nanoparticle produced the highest osmotic potential, and thus, the use of nanoparticles increases the osmotic potential compared to control plants. Osmotic regulation under the water shortage conditions decreases cellular inflammation by maintaining water and collecting material in the cell. Also, the percentage of dry weight of the whole chickpea plants was significantly affected by the test factors and their interactions. The interaction of two factors showed that with the increasing concentration of TiO2-NPs to 20 mg/L, the dry weight of chickpea in the lowest irrigation level was increased by10% compared to control plants. Stomatal conductivity in all irrigation levels had an upward trend by using TiO2-NPs. Conclusion Generally, TiO2-NPs showed a positive effect on the total dry and fresh weight of the whole chickpea plants. The application of 20 mg/L TiO2-NPs at all levels of irrigation reduced drought stress and prevented further plant losses. The application of low concentration of nanoparticles promoted plant growth and at high levels showed inhibitory effects on growth. Taken all together, due to the increasing use of chemical fertilizers in agriculture, nano compounds can be used as an appropriate alternative that increases product quality.
Ebrahim Zarei; S. Ali Mohammad Modarres-Sanavy
Abstract
IntroductionThe chickpea is mainly cultivated in agricultural systems in arid and semi-arid regions and needs low input. Specifications such as the ability to fix nitrogen, deep rooting and the effective use of atmospheric depression have led the plant to play an important role in stabilizing crop production ...
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IntroductionThe chickpea is mainly cultivated in agricultural systems in arid and semi-arid regions and needs low input. Specifications such as the ability to fix nitrogen, deep rooting and the effective use of atmospheric depression have led the plant to play an important role in stabilizing crop production systems. On average chickpea seed contain 23% protein is highly digestible. Water deficit stress is the most important factor limiting the growth and agricultural products in arid and semi-arid regions of the world. Drought stress is one of the most important factors in grain yield reduction of chickpea during pod formation and grain filling. Amino acids facilitate the transfer of food in the vascular system by improving the permeability of the cell membrane. In plants under drought stress or salinity, proline is widely used as an osmotic regulator. In fact, amino acids are the main chain in the protein structure, and in turn, are effective in plant growth. Increased proline in chickpea leaves is a mechanism for osmotic adjustment under water stress conditions. Using the priming method is one of the methods for improving seed function and increasing the quality of seeds in adverse environmental conditions, In fact, priming shortens the time from planting to emergence and protects seed of harmful biotic and abiotic factors in the critical stage of seedling establishment. These treatments also result in the emergence of uniformity, resulting in a uniform establishment and improved yield in the crop. Materials and methodsIn order to study the effect of Anti-stress materials priming and foliar application on quantitative and qualitative yield of chickpea (Cicer arietinum) Adel cultivar under Irrigation regime an experiment was conducted at the Research Farm of Agriculture of Tarbiat Modares University as randomized complete block design arrangement in split plot with three replications. The main plots were included 1- optimal irrigation 2- Moderate Irrigation 3- severe Irrigation as withholding irrigation until depletion of 20, 45 and 70 percent of soil available water at root development zone respectively and then the plots were irrigated to field capacity from flowering to plant harvest. Priming and foliar application of anti-stress materials including proline, valine, alanine, commercial combination of amino acids and distilled water together with without anti-stress materials were randomized to the subplot units.ResultsThe results showed that priming and foliar application of anti-stress materials and optimal irrigation incresed the number of primary branches to the 58.31% and 36.38%, plant fresh weight to the 108.25% and 36.16%, chlorophyll a to the 40.90% and 68.35%, number of seeds/plant to the 74.48% and 34.66%, pod per plant to the 48.13% and 45.12%, duration of ripening to the 9.53% and 8.65, yield forage to the 30.56% and 39.44%, biological yield to the 65.16% and 44.82% in chekpea in compring with using severe irrigation and without priming and anti-stress materials foliar application treatments repectively. Also 1000 kernel weight and harvest index were increased %20.67 and 27.82% in optimal irrigation related to severe irrigation. Interaction effects between irrigation regimes and anti-stress materials on chlorophyll b showed that the highest rate chlorophyll b related to optimal irrigation with using commercial amino acids to to the 80% and the least it related to severe irrigation without anti-stress materials to the 24%. Application of amino acids was significant in most traits such as number of primary branches, plant fresh weight, chlorophyll a, chlorophyll b, Number of seeds/plant, pod per plant, duration of ripening, yield forage, biological yield. ConclusionDrought stress reduced photosynthesis and limited the amount of assimilate and thus reduced the yield and yield components In this experiment. In most cases, the application of priming and foliar application of amino acids had a positive effect on the traits, including number of primary branches, plant fresh weight, chlorophyll a, chlorophyll b, number of seeds/plant, pod per plant, duration of ripening, yield forage, biological yield at drought stress condition. Therefore, the use of amino acids, especially its commercial combination or proline, is recommended to reduce the effects of water deficit stress in the chickpea Adel cultivar.
Seyed Ahmad Pourjamshid
Abstract
Introduction Wheat (Triticum aestivum L.) is considered as the major cereal crop in the world in respect of the cultivated area and total production. Drought is a polygenic stress and is considered as one of the most important factors limiting crop yields around the world. Most of the Iranian soils, ...
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Introduction Wheat (Triticum aestivum L.) is considered as the major cereal crop in the world in respect of the cultivated area and total production. Drought is a polygenic stress and is considered as one of the most important factors limiting crop yields around the world. Most of the Iranian soils, have a high pH and calcareous nature, and micronutrients solubility in these soils is low. Micronutrient deficiency is widespread in many Asian countries due to the calcareous nature of soils, high pH, low organic matter, salt stress, continuous drought, high bicarbonate content in irrigation water, and imbalanced application of NPK fertilizers. Micronutrients plays a critical role in increasing plant resistance to environmental stresses. Foliar nutrition is an option when nutrient deficiencies cannot be corrected by applications of nutrients to the soil. Foliar spraying of microelements is very helpful when the roots can not provide necessary nutrients. Iron as a micronutrient, is critical for chlorophyll formation and photosynthesis and is important in the enzyme systems and respiration of plants. Zinc is a ubiquitous micronutrient. It is required as a structural and functional component of many enzymes and proteins, and increases the yield and yield components of wheat. Manganese as a micronutrient, is necessary in photosynthesis, nitrogen metabolism and to form other compounds required for plant metabolism. Materials and methods To study the effect of iron, zinc and manganese foliar application on morphological and agronomic traits of bread wheat (Chamran cultivar) under irrigation regime, an experiment was conducted as split-plot with four replications in Ramhormoz city in the crop year 2016-2017. The experimental factors were included irrigation regime in two levels of complete irrigation (non-water stress) and irrigation cut from the beginning of tillering stage to the physiological ripening (water stress) as the main factor, and micronutrients foliar application in six levels of non-foliar application (control), foliar application by water, iron, zinc, manganese and iron + zinc + manganese (each 3 lit.h-1) in three times and at tillering, stemming and pollination stages as the sub factor. Solutions for foliar application were prepared by using Iron chelate (6%), Zinc chelate (7.5%) and Manganese chelate (7%). The measured traits included Peduncle length, spike length, plant height, number of tillers per m-2, number of spikes per m-2, number of grain per spike, 1000-seed weight and grain yield. At maturity, the inner two row of each plot unit were harvested to estimate grain yield, and sup sample of 1 m-2 was obtained for determining Peduncle length, spike length, plant height, number of tillers per m-2, number of spikes per m-2, number of grain per spike, 1000-seed weight. Analysis of variance was performed using general linear model (GLM) procedure of statistical analysis system (SAS version: 9.3). The means were analyzed using the least significant difference (LSD) method at P=0.05 (LSD 0.05). Results and discussion Results showed that the water stress decreased significantly (p < 0.01) traits of peduncle length (26.62%), spike length (12.87%), plant height (22.91%), number of tillers per m-2 (29.21%), number of spikes per m-2 (26.85%), number of grain per spike (13.43%), 1000-seed weight (17.37%) and grain yield (46.10%). However, the separate and combined application of iron, zinc and manganese increased the measured traits on average 15.20, 7.72, 7.32, 25.18, 23.24, 8.84, 8.76 and 32.63 percent under water stress, respectively. Meanwhile, zinc application showed the greatest effect in reducing the damage caused by water stress on measured traits. Conclusions In general, the use of micronutrients, especially zinc, as foliar application, can reduce the harmful effects caused by water stress and improve the morphological and agronomic traits of bread wheat in Ramhormoz region.
Abdollah Dorpoor Sorkhsaraei; Majid Jami Al-Ahmadi; Mohammad Hassan Sayyari Zahan; Mohammad Javad Babaie Zarch
Abstract
Introduction Many arid and semi-arid agricultural areas are facing with shortages of water and nutrients, especially micronutrients. Drought stress is one of the most important environmental stresses that seriously damage the growth and development of crops, limits the production and productivity of ...
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Introduction Many arid and semi-arid agricultural areas are facing with shortages of water and nutrients, especially micronutrients. Drought stress is one of the most important environmental stresses that seriously damage the growth and development of crops, limits the production and productivity of plants more than any other environmental factor. The use of micronutrients can partially alleviate the negative effects of this environmental stress on the growth and production of crops. Iron micronutrient plays an essential role in some biological and physiological processes such as respiration, photosynthesis and chlorophyll biosynthesis and is also effective in diastases as well as in chlorophyll production. According to the above, the main purpose of this experiment was to investigate the growth response of Roshan cultivar to applying iron sulfate fertilizer in different moisture conditions and to investigate changes in the content of some plant elements under these conditions. Materials and methods In order to evaluate the growth and uptake of iron and other nutrients by wheat, cv. Roshan, a two-factor factorial experiment was conducted in 2012 in the Research Greenhouse of the Faculty of Agriculture, University of Birjand. The first factor was consisted of four different levels of ferrous sulfate (0, 50, 100 and 150 mg.kg-1 soil) and the second factor included two soil moisture treatments including 50 and 100% soil field capacity. After preparing the pots and applying experimental treatments, the seeds were planted and after emergence, the plant density was set to 10 plants in the pot. Moisture levels were applied from the beginning of experiments and watering the pots was done daily based on the weight of the pots and taking into account 20% drainage of soil moisture (in each irrigation treatment). Sampling was done after 8 weeks (early stem elongation stage) and at this time some morphological traits (number of leaves, leaf area, number of tillers and plant height) and the SPAD index and relative water content of leaves were measured. The iron, potassium, nitrogen and protein contents of the plants were also determined for each pot separately. Analysis of variance was performed using SAS software and mean comparison was performed using FLSD test at a significant level of 5%. Results and discussion As soil moisture decreased from 100 to 50% of field capacity, plant height (5.8%), number of stems (37%), number of leaves (22%), stem diameter (15.8%), leaf area (33%), relative leaf water content (16.8%) and SPAD index (5.45%) decreased. The results also showed that in the control treatment (without iron fertilizer), the highest amount of SPAD index (38.8) was obtained, which with an increase of ferrus sulfate to 150 mg.kg-1 of soil, it decreased by 5.8%. Also, with the increase in soil water content to 100% of field capacity, the percentage of protein, nitrogen and potassium of wheat plants decreased by 9.2, 17.18 and 23.7%, respectively, compared to 50% of field capacity. The iron content of leaf in 100% of the field capacity was equal to 142.7 mg.kg-1 dry matter, which decreased by 27% by reducing the soil water content to 50% of the field capacity. Increasing the iron fertilizer from zero to 50, 100 and 150 mg.kg-1 soil caused the leaf nitrogen percentage to increase by 5, 9.5 and 7.2%, respectively. Leaf iron content in these levels of iron fertilizer was 35.8, 97.8 and 57.8% higher than the non-use of iron sulfate, respectively. Finally, biomass production was reduced by 31% compared to 100% of field capacity and finally water use efficiency was not affected by any of the experimental treatments. Finally, the watering at 50% of field capacity decreased the biomass production by 31%, compared to the 100% field capacity, and the water use efficiency was not affected by any treatments. Conclusion In general, the results of this experiment showed that with decreasing soil moisture level, a decrease occurs in the amount of plant dry matter. Increasing the level of ferrous sulfate only led to an increase in the leaf nitrogen and also a 100% increase in the iron content of the leaves, which in turn can play a role in improving drought resistance.
Mohammad reza Rafie; Mahmoud Sohi; Maryam Javadzadeh
Abstract
IntroductionWheat (Triticum aestivum L.) is one of the important crops in our country. this plant contains starch, protein, sugar and provides food for human population. In recent years, drought stress has become the main abiotic stress, and could decrease growth and yield of wheat. The application of ...
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IntroductionWheat (Triticum aestivum L.) is one of the important crops in our country. this plant contains starch, protein, sugar and provides food for human population. In recent years, drought stress has become the main abiotic stress, and could decrease growth and yield of wheat. The application of biostimulants, i.e. amino acids, fulvic acid or seaweed extract were found to positive effect on plant growth which overcomes the harmful effect of some environmental stress such as drought. In recent years, the favorable effects of these substances on vegetative characteristics, yield and grain quality of wheat have been reported. Many studies have shown that the application of biostimulants can increase plant tolerance during abiotic stresses, especially water deficit. Little research have been done about the effects of biostimulants on wheat in Khuzestan yet. Therefore, this experiment was conducted to evaluate the effect of amini acid, fulvic acid and seaweed extract in drought stress on quantitative and qualitative characteristics of wheat. Materials and methodsThis experiment was conducted as split-plot in randomized complete block design with three replications at Behbahan Agricultural Research Station for one year (2017-2018). Irrigation interval considered as main factor in two levels: (70 mm and 130 mm evaporation from class A pan) and the sub factor was growth biostimulants in four levels :control (application of chemical fertilizers according to soil test), amino acid, fulvic acid and seaweed extract. Foliar application of amino ccid, fulvic acid and seaweed extract was done at a concentration of 0.5 % at two stages, tillering and heading. During experiment: plant height, number of spikes per m2, number of grain per spike, 1000- grain weight, grain yield, nitrogen, phosphorus, potassium, zinc, manganes and iron were recorded. Varince analysis were done by MSTATC statistical software and meanes were compared using Duncan,s Multiple Range Test. Results and discussionThe results showed a significant increase in grain yield in plants treated with biostimulants compared with control. The highest plant height, number of spikes per m2, number of grain per spike, 1000-grain weight and grain yield were recorded in amino acid treatment. The highest increase in N, K and grain Fe was achieved by amino acid while the highest increase in P, Zn and Mn of grain was obtained by seaweed extract compared with control. The results indicated that water deficit stress significantly reduced plant height, number of spikes per m-2, 1000 seed weight, grain yield and nutrients. Also, drought stress significantly reduced grain nutrient uptake. Intreraction of the irrigation levels and biostimulants on grain yield indicated that all biostimulants significantly increased the yield in drought stress. The application of amino acids and seaweeds significantly increased grain yield in compared with both controls (under water deficit stress and under water normal conditions) while the use of fulvic acid significantly increased grain yield in comparison to control under water deficit stress. Therefore, the application of amino acid and seaweed extract reduced the effects of water deficit stress. ConclusionsThe results of this study showed that increasing water deficit stress caused significant reduction of all studied traits. However, the application of amino acid and seaweed extract reduced the effects of water deficit stress and increased these traits compared with control under favorable irrigation condition. According to the results, the application of amino acid or seaweed extract is recommended in normal and drought stress condition for wheat cv brat.
Naeimeh Bayatian; Sepideh Nikoumaram; Omid Ansari
Abstract
Introduction One of the most important stages in the life cycle is germination, which is controlled by various environmental and genetic factors. Temperature and water potential are the most important factors in germination control. Different models for quantization of germination response to temperature ...
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Introduction One of the most important stages in the life cycle is germination, which is controlled by various environmental and genetic factors. Temperature and water potential are the most important factors in germination control. Different models for quantization of germination response to temperature and osmotic potential have been used. Quantification of germination response to osmotic potential and temperature is possible using non-liner regression models. Therefore, this research was carried out to determine the cardinal temperature of germination (base temperature, optimum and maximum germination) of safflower of Sofeh cultivar under different osmotic stress (drought stress) conditions and seed deterioration. Material and methods In this study germination response to water potential in different temperature were studied. Treatments included osmotic levels (0, -0.4 and -0.8 MPa), temperature (5, 10, 15, 20, 30, 35 and 40 °C) and seed deterioration (0 and 5 days). Ccumulative germination response of seeds to differential water potential and temperature were quantified using three-parameter sigmoidal model. For quantifying response of germination rate to temperature for different osmotic potential were used of 3 non-linear regression models (segmented, dent-like and beta). The root mean square of errors (RMSE), coefficient of determination (R2), CV and SE for relationship between the observed and the predicted germination percentage were used to select the superior model from among the employed methods. Germination percentage and time to 50% maximum seed germination of safflower were calculated for the different temperatures and osmotic potential by fitting 3-parameter sigmoidal functions to cumulative germination data. Results Results indicated that temperature in addition to germination percentage also on germination rate was effective. Also results showed that germination percentage and germination rate increased with increasing temperature, while germination percentage and germination rate reduced as a result of water potential increment. Results indicated that under different osmotic potential as 0, -0.4 and -0.8 MPa, the segmented model estimated base temperature as 2.23, 3.67 and 4.33 °C, the dent model estimated base temperature as 3, 3.96 and 4.33 °C, the beta model estimated base temperature as -1.22, -1.28 and -2.28 °C, the segmented model estimated optimum temperature as 23.05, 25.44 and 24.19 °C, the optimum temperature using beta model as 28.89, 28.99 and 26.46 °C, the dent-like model estimated lower limit of optimum temperature and upper limit of optimum temperature as 21.12, 21.92 and 20.16 and 30.07, 25 and 23.27 °C, ceiling temperature using segmented model were 40, 40 and 35 °C, using dent-like model were 40, 39.83 and 35 °C, using beta model were 40, 35 and 34.82 °C, the segmented model estimated fo as 23.02, 69.51 and 84.17 h, the dent-like model estimated as 27, 75.99 and 83.87 h and using beta model were 26.09, 75.09 and 103.41 h, respectively. In compared 3 models according to the root mean square of errors (RMSE) of germination time, the coefficient of determination (R2), CV and SE the best model for determination of cardinal temperatures of seed control of safflower for 0 MPa was dent-like model and for -0.4 and -0.8 MPa was segmented model and for seed deterioration of safflower in all osmotic potential was segmented model. In general, results indicated that lower limit of optimum temperature and upper limit of optimum temperature and ceiling temperature reduced but fo increased as a result of water potential increment. Conclusion Germination of safflower response to different temperatures and osmotic potentials, led to acceptable results. Utilizing the output of non-liner models at different temperatures can be useful in prediction of germination rate in different water potential.
Shokofeh Gholami; Tayebe Rostami; Khadigeh Ahmadi; Majid Amini Dehaghi; Mahmoud Bagheri
Abstract
IntroductionDrought is one of the most common environmental stresses that contributes to the growth and development of plants and is a major factor in reducing the production of products. Priming is a simple technique that improves seedling establishment and plant efficiency in farms. Seed priming has ...
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IntroductionDrought is one of the most common environmental stresses that contributes to the growth and development of plants and is a major factor in reducing the production of products. Priming is a simple technique that improves seedling establishment and plant efficiency in farms. Seed priming has proved beneficial in improving the germination metabolism and early stand establishment of crops under normal and stress conditions .Salicylic acid (SA) plays an important role in abiotic stress tolerance, and more interests have been focused on SA due to its ability to induce a protective effect on plants under adverse environmental conditions. salicylic acid (SA), an endogenous plant growth regulator has been found to generate a wide range of metabolic and physiological responses in plants thereby affecting their growth and development. Quinoa is a grain-like plant with high nutritional value and tolerance to abiotic stresses such as heat, cold and drought stress. Food quinoa importance due to the perfect combination of amino acids, calcium, phosphorus, iron and sodium low. Materials and methodsThus in order to investigate the effect of Salicylic acid pre-treatment on germination indices of quinoa plant under drought stress, a factorial experiment was conducted in a completely randomized design with three replications in Seed Technology Laboratory, Faculty of Agricultural Sciences, Shahed University in 1397.The experimental factors Includes salicylic acid at four levels (0, 50, 100 and 150 mM) and drought stress caused by polyethylene glycol at four levels (0, -4-, 8-, -12 bar) and the quinoa plant varieties (cultivars and varieties Giza1 Titicaca). The measured traits including germination percentage (GP), mean germination time (MGT), germination speed (GR), and germination coefficient (GC), SVI: seedling longitudinal index, SVI: weight index of seedling bud, root length, stem length, stem fresh weight, stem fresh root and seedling dry weight, and changes in the amount of photosynthetic pigments. Statistical analysis of the data included analysis of variance using AS 9.1 software and comparison of mean of traits evaluated by LSD test at 5% probability level. Results Analysis of variance showed that salicylic acid pre-treatment, drought stress and their interaction had a significant effect on germination indices and photosynthetic pigmentation and medicinal plant varieties quinoa. With increasing drought stress, the germination characteristics of quinoa plants decreased and the use of salicylic acid improved the seed germination properties of quinoa seeds and salicylic acid application improved germination characteristics of quinoa seeds. The highest germination percentage (98 percent) and its effective traits were obtained from seed soaking with salicylic acid with maximum concentration (1.5 mM) and low levels of drought stress. Longitudinal index and weight of seedling vigor was decreased at high concentrations of salicylic acid and high levels of drought stress. On the other hand, consumption of one and one and a half mM of salicylic acid increased the amount of chlorophyll and carotenoids and increased tolerance of this plant to drought stress. The highest amounts of chlorophyll a, chlorophyll b and total chlorophyll were observed under drought stress conditions and 1.5 mol / mol of salicylic acid and Titicaca cultivar.
Hossein Ahmadi; Alireza Abbasi; Alireza Taleei; Valiollah Mohammadi
Abstract
Salinity stress is one of the most important of abiotic stress that affects the yield of oilseed rape. In order to study some physiological and biochemical changes and BnaCDPK14 transcript expression in rapeseed (Brassica napus L.), two tolerant cultivars (Slm046 and Zarfam) and two susceptible cultivars ...
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Salinity stress is one of the most important of abiotic stress that affects the yield of oilseed rape. In order to study some physiological and biochemical changes and BnaCDPK14 transcript expression in rapeseed (Brassica napus L.), two tolerant cultivars (Slm046 and Zarfam) and two susceptible cultivars (Okapi and Sarigol) were planted in a growth chamber and were irrigated by water including 100 and 200 mM NaCl and normal water. Relative water content, electrolyte leakage, antioxidant enzyme guaiacol peroxidase (GPOX), antioxidant enzyme catalase (CAT) and the expression of calcium-dependent protein kinase 14 (BnaCDPK14) were measured. The results indicated the relative water content and electrolyte leakage (200 mM NaCl) decreased and increased under stress respectively. The antioxidant enzyme guaiacol peroxidase (GPOX), catalase (CAT) and BnaCDPK14 increased by salinity stress, tolerant cultivars showing more increase. Negative correlation was observed between the relative water content of leaves and electrolyte leakage. There was a high positive correlation between the guaiacol peroxidase and catalase contents and the expression of BnaCDPK14, indicating that by increasing the reactive oxygen species under stress, the plant enzymic antioxidant system helps the plant to cope with it. Salinity stress is one of the most important of abiotic stress that affects the yield of oilseed rape. In order to study some physiological and biochemical changes and BnaCDPK14 transcript expression in rapeseed (Brassica napus L.), two tolerant cultivars (Slm046 and Zarfam) and two susceptible cultivars (Okapi and Sarigol) were planted in a growth chamber and were irrigated by water including 100 and 200 mM NaCl and normal water. Relative water content, electrolyte leakage, antioxidant enzyme guaiacol peroxidase (GPOX), antioxidant enzyme catalase (CAT) and the expression of calcium-dependent protein kinase 14 (BnaCDPK14) were measured. The results indicated the relative water content and electrolyte leakage (200 mM NaCl) decreased and increased under stress respectively. The antioxidant enzyme guaiacol peroxidase (GPOX), catalase (CAT) and BnaCDPK14 increased by salinity stress, tolerant cultivars showing more increase. Negative correlation was observed between the relative water content of leaves and electrolyte leakage. There was a high positive correlation between the guaiacol peroxidase and catalase contents and the expression of BnaCDPK14, indicating that by increasing the reactive oxygen species under stress, the plant enzymic antioxidant system helps the plant to cope with it. Salinity stress is one of the most important of abiotic stress that affects the yield of oilseed rape. In order to study some physiological and biochemical changes and BnaCDPK14 transcript expression in rapeseed (Brassica napus L.), two tolerant cultivars (Slm046 and Zarfam) and two susceptible cultivars (Okapi and Sarigol) were planted in a growth chamber and were irrigated by water including 100 and 200 mM NaCl and normal water. Relative water content, electrolyte leakage, antioxidant enzyme guaiacol peroxidase (GPOX), antioxidant enzyme catalase (CAT) and the expression of calcium-dependent protein kinase 14 (BnaCDPK14) were measured. The results indicated the relative water content and electrolyte leakage (200 mM NaCl) decreased and increased under stress respectively. The antioxidant enzyme guaiacol peroxidase (GPOX), catalase (CAT) and BnaCDPK14 increased by salinity stress, tolerant cultivars showing more increase. Negative correlation was observed between the relative water content of leaves and electrolyte leakage. There was a high positive correlation between the guaiacol peroxidase and catalase contents and the expression of BnaCDPK14, indicating that by increasing the reactive oxygen species under stress, the plant enzymic antioxidant system helps the plant to cope with it.
Parvin Jarideh; Reza Amiri Fahliani; Asad Masoumi Asl; Ali Moradi; Maryam Hosseini Chaleshtory
Abstract
IntroductionSalinity stress greatly affects crop yields especially in arid and semi-arid climates. The reaction of rice plants; with a special situation among other crops for supplying human nutrition, to salinity varies in different growth stages. Salinity tolerance in plants is a complex process in ...
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IntroductionSalinity stress greatly affects crop yields especially in arid and semi-arid climates. The reaction of rice plants; with a special situation among other crops for supplying human nutrition, to salinity varies in different growth stages. Salinity tolerance in plants is a complex process in which morphological changes, physiological and biochemical processes are involved. In order to study the reaction of rice plants to salinity conditions and identification of tolerant genotypes, it is recommended to evaluate the salinity effects at salinity sensitive stages such as germination stage. The use of genetic diversity in crops is one of the most important interests of breeders in understanding the strategies for crops improvements. The aim of this research was to, estimate the genetic diversity of evaluated traits, study the effect of salinity on various morphological and physiological characteristics in the rice germination stage, determine the relationship between traits, and to identify the traits that affect the indirect selection of tolerant genotypes to salinity. Materials and methodsOne hundred seventeen F2:4 generation lines; obtained from the cross between Mousa Tarom and 304 rice genotypes, were cultured in two separate experiments; with and without salinity stress, in a randomized complete block design at the Faculty of Agriculture, Yasouj University. The seeds were placed in petri dishes in germinator at 25 ± 3 ° C. The number of germinated seeds of each genotype was counted during 14 days, and the seed length and weight vigor, germination percentage, seed germination rate, as well as the morpho- physiological characteristics of rootlet and shootlet length, rootlet fresh and dry weight, shootlet fresh and dry weight, Leaf proline, total soluble sugars and leaf protein content were evaluated. Results and discussionIn both the salinity stress and non-stress conditions, the phenotypic coefficient of variation (CVp) was larger than the genetic coefficient of variation (CVg) for all measured traits. Leaf proline, total protein and soluble sugars had the highest CVg in both the stress and non-stress conditions, indicating a wide diversity of the evaluated genotypes. The genotypes showed the lowest CVg and CVp under both the conditions for germination percentage. So, it can be claimed that the genotypes were not significantly different in their reaction to environmental variations.Proline heritability was 98% in both the salinity conditions. The heritability of protein content in stress condition (86%) was about 13 percentage points lower than non-stress (99%). Salinity stress increased 6 percentage points of soluble sugars (98%) compared to non-stress condition. Salinity stress also increased the heritability of germination percentage, shootlet length, shootlet fresh weight, rootlet fresh weight, and shootlet dry weight and Seedling length vigor index compared to non-stress condition. In non-stress condition, the highest positive and significant correlation was found between rootlet and Seedling length vigor index, and between shootlet dry weight and weight vigor index. In stress conditions, the highest correlation was observed between rootlet length and rootlet dry weight. Also, a significant correlation was observed between the characteristics of the Seedling length vigor index with rootlet dry weight, rootlet and shootlet fresh weight, germination percentage and rate in salinity stress condition. Rootlet dry weight with germination percentage, rootlet length and shootlet length showed a positive and highly significant correlations. No significant correlation was seen between soluble proline, total protein content and soluble sugars in germination stage.On the basis of principal component analysis, in non-stress, and salinity stress conditions 5 and 6 factors were identified, respectively, which explained 74% and 78% of the diversity of the total data. In non-stress conditions, the first factor explained 33.92% of the variation, in that, traits such as shootlet length, shootlet fresh and dry weight and seedling weight vigor index had the highest effect with the positive direction. In stress condition, the first factor explained 32.2% of the total variation in which the shootlet fresh weight and length, germination percentage and germination rate, and Seedling length vigor index had the highest positive effect. ConclusionDifferent lines and varieties of rice show different responses to different environmental stresses, which evaluation of such a reactions are of particular importance for breeders. Leaf soluble proline, protein and soluble sugars had the highest genetic variation in both the stress and non-stress conditions. These conditions indicated that selection for soluble sugars, proline, and leaf total protein was promising, and their high heritability suggests that the traits in question are more likely to be transmitted to the offspring. Therefore, they can be used in breeding programs for creation of genetic diversity, hybridization and selection. Based on the results of factor analysis, shootlet fresh weight and length can be used as an effective feature in the selection of salt tolerant genotypes in both stress and non-stress conditions at germination stage.
Reza Saeidi; Hadi Ramezani Etedali; Abbas Sotoodehnia; Bijan Nazari; Abbas Kaviani
Abstract
IntroductionIn the presence of environmental stresses such as salinity and fertility stresses, water and nutrients less absorbed by the plant. Despite the stresses of salinity and nitrogen deficiency (fertility stress), the determination of the actual water requirement of plants with the AquaCrop model, ...
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IntroductionIn the presence of environmental stresses such as salinity and fertility stresses, water and nutrients less absorbed by the plant. Despite the stresses of salinity and nitrogen deficiency (fertility stress), the determination of the actual water requirement of plants with the AquaCrop model, will be important. Therefore, the aim of this research was to evaluate the AquaCrop model for estimating the soil moisture, evapotranspiration and yield of maize, under the salinity and fertility stresses.Materials and methodsIn this research, two treatments of water salinity and nitrogen deficity in four levels and three replications, with a control plot, were implemented as a factorial experiment in a randomized complete of block design. The studied plant was maize with cultivar of 704 Sc and was planted in plots with dimensions of 3 × 3 meters and 1.5 meters apart. In this plan, fertility stress was in the form of nitrogen fertilizer consumption and at four levels. Treatments of N_0، N_1، N_2 and N_3consisted of consumption of 100, 75, 50 and 25% of nitrogen fertilizer based on fertilizer recommendation, respectively. Salinity stress has been applied by irrigation of the plant with saline water. Water salinity treatments were selected based on yield potential of maize at four levels of 100, 90, 75 and 50% (3). According to the above four performance levels, treatments of S_0، S_1، S_2 and S_3 were included; irrigation water with electric conductivity of 0.5, 1.2, 3.5 and 7.5 (ds/m) respectively. Determining the irrigation time, was the same as the moisture content reached the RAW (Readily Available Water) level. Between the two irrigation intervals, the stomatal resistance of maize leaf, was measured by the AP4 prometer device. At the same time as increasing stomatal resistance, RAW was calculated and plots were irrigated. In the days of between two irrigation, was measured the soil moisture content of the plots at the depth of root development. The daily evapotranspiration of the plant, was calculated based on the amount of daily water depletion. For optimal calibration of parameters in the AquaCrop model, was used the method of Generalized Likelihood Uncertainty Estimation (GLUE). Among 16 treatments, 8 treatments were randomly selected for calibration and the rest were selected for validation. Results and discussionResults were obtained for evaluating the AquaCrop model at the validation stage. The root mean square error (RMSE) of soil moisture simulation, varied from 1.43 to 2.6%. The normalized error value (NRMSE) ranged from 4 to 6 percent. The AquaCrop model showed a similar trend in the evapotranspiration simulation. The root mean square error (RMSE) of evapotranspiration simulation, varied from 1.85 to 2.35 mm. The normalized error value (NRMSE) ranged from 3.5 to 4.5 percent. For yield simulation, RMSE was 0.34 ton. ha-1 and NRMSE was 0.65%. The value of the R^2, EF, and d statistics showed a good correlation between the data and the optimal efficiency of the modeling. Therefore, the results showed that the performance of the model was good in estimating the parameters. ConclusionsEvaluating the capability of the models is a great help to the agricultural sector planners, in estimation the parameters. In this research, evaluated the estimation of soil moisture content, evapotranspiration and yield of maize, under salinity and fertility stresses with AquaCrop model. The purpose of the model calibration was to nearing the simulated data to the real data (measured in the region). The obtained amounts for NRMSE and R^2 were less than 10% and greater than 0.9, respectively, which indicated the optimal performance of the model in this regard.
Roya Nezamivand Chegini; Fatemeh Benakashani; Iraj Alahdadi; Elias Soltani
Abstract
Introduction Environmental stresses, especially drought and salinity stresses are considered as inhibitors of plant growth and development. The salinity stress cause delay in germination, decrease in the rate and percentage of germination and delay in the emergence of roots and stems in the germination ...
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Introduction Environmental stresses, especially drought and salinity stresses are considered as inhibitors of plant growth and development. The salinity stress cause delay in germination, decrease in the rate and percentage of germination and delay in the emergence of roots and stems in the germination stage. It seems that if seed could pass through the germination stage under stress conditions, the seedling will have more opportunity to grow and develop, and will have the higher ability to tolerate and overcome adverse environmental conditions. This greatly depends on the biochemical and physiological structures of the seedlings. The response is also species and genotypes dependent and depends on the length and severity of the salinity, the age, and stage of development. Differences in the salt tolerance have variation among species within a genus, and of genotypes within a species. black caraway (Nigella sativa L.) is an annual plant with valuable medicinal properties belong to Ranunculaceae family. Because Black caraway growth is slow at the beginning of the season, and on the other hand, salinity and drought are some limiting and effective factors on germination and other stages of plant growth, the aim of this study was to evaluate different N. sativa ecotypes in terms of tolerance to salinity and drought. Materials and methods In order to investigate the effects of salinity and drought stress on seed germination factors of fourteen black caraway, two separate experiments were carried out in a completely randomized design in the Seed Technology Laboratory of the University of Tehran in 2018. The treatments consisted of fourteen black caraway ecotypes (Ashkzar, Arak, Isfahan, Eqlid, Bejestan, Khaf, Khomeini Shahr, Razan, Zabol 1, Zabol 2, Sarayan, Semirum, Gardmiran, Hamedan), six salinity stress levels (0 , 40, 80, 120, 160 and 200 mM) and four levels of drought stress (0, 0.3, -0.6 and -0.9 MPa) with four replicates in each level. Salinity stress levels were due to different concentrations of sodium chloride and levels of drought stress were due to different concentrations of polyethylene glycol 6000. Distilled water was used to create a zero stress level (control treatment) in both experiments. To conduct the experiments, 50 seeds were placed on filter paper in 8 cm diameter Petri dishes containing 7 mL of each solution. Petri dishes were kept in the growth chamber at a constant temperature of 20°C. The number of seeds germinated was recorded daily until no germination was observed for two consecutive days. The Germin program was used to calculate germination percentage and rate of germination. In addition, to illustrate the germination response to drought stress, the hydrotime model was used. Results and discussion salinity experiment; The highest Ymax (germination percentage) was found in Razan, Arak, and Ashkzar ecotypes (99.5, 99.33 and 99.16% respectively) and the lowest in Khomeini-e-Shahr ecotype (85.83%). The highest salinity tolerance threshold (X0) was detected in Semirum ecotype (37.17 mM). Arak ecotype had the highest rate of germination (0.013 per hour) in salinity conditions. Thus, Semirom ecotype was the most tolerance ecotype due to the higher salinity tolerance threshold. Drought experiment; The minimum hydrotime constant (θH= 284.040 MPa h) was related to the Bejestan ecotype, and the lowest water potential (Ψb(50)= -0.563 MP ) was observed in the Isfahan ecotype. Since there is a positive correlation between the less water potential )Ψb(50) ( and the emergence percentage and rate of seedling emergence, the Isfahan ecotype was the most tolerant among biotypes that were studied. Conclusion In general, the results of these experiments showed that salinity and drought stresses reduced the percentage and rate of germination. Germination percentage response shape and germination rate were different between various ecotypes. Hydrotime model and salinity regression have high ability in separating ecotypes for germination components. The Bejestan and the Isfahan ecotypes are recommended for cultivation in drought conditions. In salt stress conditions, the Semirom ecotype was the most tolerant ecotype among ecotypes.
Touraj Mir Mahmoodi; Keywan Fotohi; Hamze Hamze; Heydar Azizi
Abstract
IntroductionSalt stress is one of the most important abiotic stresses, which decreases crop yields and limits the land use. Three hectares of agricultural land are being destroyed in each minute by salinity In Iran, salinity is one of the most important factors which limit the agriculture. Salt stress ...
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IntroductionSalt stress is one of the most important abiotic stresses, which decreases crop yields and limits the land use. Three hectares of agricultural land are being destroyed in each minute by salinity In Iran, salinity is one of the most important factors which limit the agriculture. Salt stress studies were very important in the most sugar beet planting regions of Iran based on sugar beet experts and farmers opinions producing sugar beet salt tolerant varieties, improving planting methods, irrigation and fertilizer use are the most Sugar Beet Seed Institute (SBSI) strategies for optimizing the production in saline lands. Materials and methodsIn order to investigate the effect of salinity stress on quantitative and qualitative characteristics of sugar beet genotypes in normal and salinity stress conditions an experiment was conducted in a completely randomized block design with three replications in Miandoab Agricultural and Natural Resources Research Station at 2016-17 Crop seasons. In this research, 16 sugar beet genotypes were tested under two normal conditions and saline conditions with salinity of 12.1 dS/m. In this research, root yield, sugar content, white sugar content, sugar yield, the amount of sodium, nitrogen, and potassium of root, white sugar yield percent of sugar extraction was measured.Data was analyzed by using SAS 9.2 software.Results and discussionThe results showed that the effect of the environment on all studied traits wasn’t significant. Differences between genotypes were significant for all traits except for white sugar content, also the interaction of genotype in environment on all traits except the white sugar content was significant. Results showed that the highest root yield, white sugar yield and sugar yield in normal and salinity conditions were allocated to genotypes 14 and 15. Based on the results of correlation analysis in both environmental conditions, white sugar yield had positively and significantly correlated with root yield, white sugar content and sugar yield. Based on the results of stepwise regression analysis, root yield, percent of sugar extraction and sugar yield in normal conditions with justified 93 percent of white sugar yield variation and in salt stress condition with justified 84 percent of the total white sugar yield variation were identified as the most effective traits on white sugar yield. ConclusionsIn the present study, there was no significant difference between two years in term of studied traits. It can be concluded that climate conditions in the two years studied did not have a significant difference in terms of effect on the studied traits. In the present study, there wasn’t significant difference between normal and salinity stress conditions in terms of all traits and salinity Therefore, it can be said that sugar beet genotypes were resistant to salinity. In both environmental conditions, genotypes number 14 and 15 had the highest root yield, white sugar yield and sugar yield, Selection of these genotypes is recommended for future breeding programs. In both normal and salinity conditions root yield, percent of sugar extraction and sugar yield recommended as Criteria for selecting high-yielding genotypes.
Samar Khayamim; Hamid Noshad; Abazar Rajabi; Ruhollah Jafari
Abstract
Introduction Nowadays it is focused on sugar beet monogerm varieties because of mechanization improvement In Iran, but it couldn't be said that monogerm root and sugar yields are more than multigerm varieties. In some experiments, root yield of monogerm sugar beet varieties are more, equal or even less ...
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Introduction Nowadays it is focused on sugar beet monogerm varieties because of mechanization improvement In Iran, but it couldn't be said that monogerm root and sugar yields are more than multigerm varieties. In some experiments, root yield of monogerm sugar beet varieties are more, equal or even less than multigerm ones. Although sugar and white sugar yields of monogerm sugar beet varieties are similar to multi germ in most experiments and sugar beet seed germ based on mono or multi doesn't affect on sugar purity percentage. Beet production areas such as clay texture lands are still dedicated to multigerm varieties. It is recommended to use multigerm varieties to alleviate undesirable environmental effects such as drought and salinity stress to have better plant germination and establishment. Improvement of salt tolerant multigerm varieties could be very important to decrease the effect of this stress on sugar beet. Therefore, screening of sugar beet multigerm germplasm under saline condition to develop multigerm varieties is necessary. Materials and methods In this study, 20 sugar beet multigerm genotypes were evaluated under normal and saline conditions (EC=20 dS/m) in factorial experiment based on completely randomized design with four replications. Two seed germination methods including fast germination test in Erlen and between paper tests, used in laboratory. Then, the genotypes were compared under normal and saline (EC=16 dS/m) conditions in four replications in greenhouse. Samples took two months after stress initiation at establishment stage (8-10 leaves). Shoot and root fresh and dry weights, Na, K, K/Na and total soluble carbohydrate of leaves measured. Results and discussion 7233, AMP2 and PB13-S2-151-HSF-91genotypes had the highest field emergence potential (FEP) with 0.176, 0.09 and 0.05, respectively. Salinity decreased total, shoot, and root dry weights, K and soluble carbohydrate by 20, 24, 6 42 and 38 percent respectively and increased Na and P by 400 and 11 percent, respectively. Finally, the genotypes PB 13S2-151-HSF 915, 7233, S1–930882, S1–931008, Poly8823, S1–930770, Gazale, S1–930910, 5RR-87-HS-28 and S1–930792 were selected as tolerant materials based on fast germination and between paper germination tests, yield and biochemical traits. Some of selected genotypes were evaluated and been selected under drought or saline stress studied in field experiments but result of field experiments could be achieved after 7 months while the result of this experiment was taken after two months. So, the similarity of result of this experiment with field tests showed that fast genotype screening in green house could be useful for accelerating breeding of salt tolerant varieties. Aknowledgment This project was done in Sugar Beet Seed Institute (SBSI), Agricultural Research, Education and Extension Organization of Iran, Karaj. Writers would be appreciating SBSI for its support to conducting of this project.
Seyedeh Hadiseh Bahari saravi; Ahmad Gholami; Hemmatollah Pirdashti; Mehdi Baradaran Firouzabadi; Hamidreza Asghari
Abstract
Introduction Salinity is one of the environmental abiotic stresses and most important factors limiting the growth and production of plants around the world, which dramatically affect various aspects of plant growth and development through anatomical, morphological and physiological changes (Siringam ...
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Introduction Salinity is one of the environmental abiotic stresses and most important factors limiting the growth and production of plants around the world, which dramatically affect various aspects of plant growth and development through anatomical, morphological and physiological changes (Siringam et al., 2011). Saline environments decrease the growth and yield characteristics of plants and increase some physiological properties such as proline content and electrolyte leakage (Noreen et al, 2010). On the other hand, in the recent years, the role of symbiotic fungi and polyamines in plants tolerance to environmental stress such as saline conditions are pronounced. Morever, due to the importance of medicinal plants, many researches of plant sciences have focused on the various aspects of the application of these plants (Vafadar et al., 2018). Therefore, the present study was conducted to investigate the growth and physiological response of stevia (Stevia rebaudiana Bertoni) medicinal plant to inoculation with endophytic fungi and foliar application of spermidine polyamine under salt stress conditions. Materials and methods This experiment was conducted at research greenhouse of Genetics and Agricultural Biotechnology Institute of Tabarestan (GABIT) at Sari Agricultural Sciences and Natural Resources University using factorial arrangement based completely randomized design with three replicates in spring and summer of 2016. The treatment consisted of salinity in three levels (0, 6 and 12 dS/m), fungal symbiosis treatments including four levels [non-inoculated (control), inoculation with Piriformospora indica (Pi), inoculated with Trichoderma virens (Trich) and co-inoculation of two fungi (Pi+Trich)] and foliar application of spermidine in three levels (0, 0.75 and 1.5 mM). Seedlings of stevia after inoculation with fungi transfered to adaptation chamber for 40 days and then moved to the greenhouse. Plants were irrigated with tap water until the end of vegetative stage and then irrigated with saline water treatments containing mixture of distilled and Caspian sea water. The Spermidine was foliar applied one week before salinity stress. Two weeks after salinity stress, leaf samples were prepared to measure leaf relative water content (RWC), electrolyte leakage (EL), proline content and soluble sugars. Finally, the plants were removed from the pots and the growth and yield traits were measured. Results and disscusion The result showed that in saline conditions, endophytic symbiosis, especially Pi+Trich, increased the stem dry weight (40-64%) and leaf dry weight (44-50%), relative water content (5-30%) and proline content (40-64%), and reduced EL (11-20%). Also spraying 0.75 mM spermidine signiticantly increased both leaf dry weight and plant height. Fungal symbiosis, especially Pi+Trich, and spermidine 0.75 mM resulted in an increase in the RWC. Also, spraying with polyamine spermidine at both concentrations of 0.75 and 1.5 mM increased soluble sugars and inoculated with endophytic fungi, particularly co-inoculation of two fungi, led to a reduction in the content of sugar (17%) in the stevia leaf. At the most levels of salinity and fungal treatments, spermidine, especially at the rate of 0.75 mM, led to increase in stem diameter (10-35%) and leaf area (35-46%). Conclusion In general, the results of the present study indicated a negative effect of salinity on the growth and physiological characteristics of the stevia plants. However, inoculation of endophytic fungi, particularly co-inoculation of Pi and Trich, improved the growth and physiological parameters and ameliorated adverse effects of salinity in stevia plants. Morever, the spermidine (especially 0.75 mM) induced salt stress tolerance in stevia plants and showed a synergetic effects with endophytic fungi in terms of the mentioned parameters. Acknowledgements The authors wish to acknowledge Shahrood University of Technology (Shahrood, Iran), Genetics and Agricultural Biotechnology Institute of Tabarestan (GABIT), and Sari Agricultural Sciences and Natural Resources University (Sari, Iran) for financial support of this study.
Mohammad Javad Babaie Zarch; Sohrab Mahmoodi; Seyed Vahid Eslami; Gholam Reza Zamani
Abstract
Introduction Plants in arid and semi-arid regions are constantly exposed to environmental stresses such as salinity. The sensitivity of different plants to salinity stress at different growth stages is quite different. In many plants, perhaps the most sensitive stage of the plant growth cycle to salinity, ...
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Introduction Plants in arid and semi-arid regions are constantly exposed to environmental stresses such as salinity. The sensitivity of different plants to salinity stress at different growth stages is quite different. In many plants, perhaps the most sensitive stage of the plant growth cycle to salinity, is germination and emergence stages. Germination and emergence of seeds are the first important stages in plant establishment which is affected by most environmental stresses. In South Khorasan, which has saline soil and water, conventional millet cultivation is common, and it’s most important weeds are lambsquarters, tumble pigweed and purslane. Since the irrigation of millet fields in this region of the country is performed with saline water, this experiment was conducted out to investigate the emergence response of millet and lambsquarters, tumble pigweed and purslane weeds, under sodium chloride salinity in Hoagland solution. Materials and methods In order to evaluate the effect of salinity stress on quality and emergence rate of common millet, lambsquarters, tumble pigweed and purslane, four separate experiments were conducted out in a randomized complete block design with three replications in 2017 in the research greenhouse of agricultural faculty at Birjand University. Experimental treatments consisted of 10 salinity levels including Hoagland solution with 2 dS/m as control, 4, 6, 8, 10, 12, 14, 16, 18 and 20 dS/m (created sodium chloride in Hoagland solution). Hoagland formula was used for preparation of nutrient solution and sodium chloride was used for preparation of different salinity levels. After filling each pot with 1.5 liters of acid washed sand, 25 seeds from each species were placed at 1 cm depth from soil surface. Seedling emergence were counted daily. In order to investigate the response of each species to salinity stress, the emergence percentage in each species was analyzed in a randomized complete block design without considering treatments with zero emergence percentage. Data analysis was performed using SAS software. GLM procedure was used for analysis of variance and comparison of mean performed with protected LSD at 5% probability level. Results and discussion The results showed that common millet, purslane, tumble pigweed and lambsquarters seeds had the ability to germinate up to 20, 16, 12 and 12 dS/m, respectively. The start of emergence for common millet seeds up to 10 dS/m and tumble pigweed up to 8 dS/m was 3 days after sowing. Meanwhile, the seeds of lambsquarters emergence up to 6 dS/m on the fourth day, and purslane in 2 dS/m on the second day after sowing. Millet plants were emergence up to 18 dS/m salinity in the first five days after sowing. The results also showed that for common millet and tumble pigweed, no significant difference were observed for single seedling dry weight at 2 and 4 dS/m. Increasing salinity from 2 to 4 dS/m led to a significant decrease in purslane seedling dry weight but with increasing salinity stress from 4 to 8 dS/m, the reduction in seedling dry weight was not significant. In this study, with increasing salinity stress from 2 to 8 dS/m, dry weight of common millet, purslane, lambsquarter and tumble pigweed decreased by 55, 73.8, 80.7 and 79.5%, respectively. In this study, after ensuring that the seeds did not emerge, to determine the viability of non-emerged seeds, the pots were irrigated with distilled water. Under this condition, non-emerged millet seeds in the pots were not able to germinate at any levels of salinity stress. Purslane had no germination under salinity stress of 18 and 20 dS/m, but there were 34% and 62% emergence percentage respectively, when the salinity were terminated. Under mild stress, the percentage of germinated purslane seeds was 18% after recovery, which decreased with increasing salinity up to 12 dS/m and then increased. Conclusion In general, the results showed that salinity stress caused a change in the emergence behavior of millet and purslane, tumble pigweed and lambsquarters weeds. Common millet had the ability to germinate at all levels of salinity stress, but tumble pigweed and lambsquarters had the potential to emerge up to 12 dS/m and for the purslane up to 16 dS/m. Also, with increasing salinity stress from 8 to 16 dS/m, dry weight of seedling of common millet, purslane, tumble pigweed and lambsquarters decreased by 66, 82, 100 and 100 percent, respectively. At the end, the results showed that occurrence of salinity stress and its removal, the purslane seeds had a greater ability to keep their viability, whereas the common millet seeds completely lost their viability.
