Maryam Golabadi; Zahra Abbasi; Ahmad Reza Golparvar
Abstract
Drought stress as the most important abiotic stress has an important role in reducing crop production in arid and semi-arid regions of the world. The physiological traits related to drought stress are of utmost importance in this regard. In order to evaluate the effect of drought stress on physiological ...
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Drought stress as the most important abiotic stress has an important role in reducing crop production in arid and semi-arid regions of the world. The physiological traits related to drought stress are of utmost importance in this regard. In order to evaluate the effect of drought stress on physiological indices of bread wheat flag leaf, a split plot experiment was conducted based on randomized complete block design with three replications at the Faculty of Agriculture, Azad University of Khorasgan during 2008-2009 growing season. The three different irrigation conditions including normal irrigation, irrigation cease from 50% of head emergence to harvesting as well as irrigation cease from 50% of head emergence to harvesting with 30% increase in N fertilizer were assigned as the main plots and 7 genotypes of bread wheat were consisted as sub plots. The results of ANOVA showed that the physiological traits of relative water content, leaf water content, moisture retention capacity, cut leaves water retention, water loss ratio, as well as seed yield trait had significant differences under different environmental conditions. The amount of physiological traits under drought stress with extra N fertilizer was significantly greater than under drought stress without extra N fertilizer. In fact, extra N fertilizer increased plant tolerance to drought stress conditions through increasing the vegetative growth and leaf water content. Results showed that Pishtaz and Sepahan cultivars as well as line 11 which possessed the greatest grain yield, had the highest physiological traits and the lowest amount of water loss in different environments.
S. Mohammad Alavi Siney; Jalal Saba
Abstract
This study was conducted to investigate the associations between physiological and agronomicaltraits of different bread wheat genotypes in dryland conditions. 20 genotypes (including 18 lines and 2 cultivars) were investigated in one experiment using randomized complete block design with four replicates ...
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This study was conducted to investigate the associations between physiological and agronomicaltraits of different bread wheat genotypes in dryland conditions. 20 genotypes (including 18 lines and 2 cultivars) were investigated in one experiment using randomized complete block design with four replicates in dryland conditions during 2006- 2007. Traits measurements were carried out at the anthesis and physiological ripening stages. In this experiment 16 agronomical traits and 10 physiological traits were measured. According to the results of canonical correlation analysis, it can be concluded that selection for agronomical traits including lower height and percentage of leaf dry matter as well as higher percentage of spike and stem dry matter, spike length, 1000- grain weight and yield would result in the selection of effective physiological traits such as, higher chlorophyll content index, leaf area, specific leaf dry weight, relative water content and photosynthetic water use efficiency and lower stomatal conductance under drland conditions.
Kourush Shojaei Noferest; Hamid Reza Khazaei; Mohammad Kafi; Mohsen Khodadadi
Abstract
Drought is one of the most important factors that affect crop production in Iran. Potato is often assumed to be a drought sensitive crop and its exposure to even short periods of water stress from germination through tuber growth can cause significant reduction in tuber yield. In order to study the effect ...
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Drought is one of the most important factors that affect crop production in Iran. Potato is often assumed to be a drought sensitive crop and its exposure to even short periods of water stress from germination through tuber growth can cause significant reduction in tuber yield. In order to study the effect of drought stress at vegetative stage on root characteristics and allometric relationships between root and shoot of early and late maturing cultivars of potato, a split plot experiment was arranged in a randomized complete block design with three replications at the Research Greenhouse of Ferdowsi University of Mashhad in 2011. Experimental factors were two irrigation levels including drought stress and non- stressed as main plots and 20 potato cultivars in two groups of late and early ripening plants as sub plots. In stressed treatment, plants were exposed to stress based on 60% of potato water requirement to reach field capacity. Non-stressed plants were full watered based on 100% water requirements. Studied traits were root depth, root dry weight, total roots length, root area, root diameter, root to shoot weight ratio, root to leaf weight ratio and root to leaf area ratio. Results showed that all traits were affected by drought stress treatments. The responses of different cultivars in the early and late maturing groups were different to the above characteristics. Drought stress increased the translocation of assimilates to roots, which in turn enhanced root growth characters such as root dry matter, root depth, root area and total root length.
S. Majid Alimagham; Farshid Ghaderi-Far
Abstract
Germination is the first and most important developmental stage of plants which is influenced by genetic and environmental factors. Hydrotime model describes the relationship between water potential (ψ) and seed germination rate and percentage. This model quantifies the rate of germination progression ...
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Germination is the first and most important developmental stage of plants which is influenced by genetic and environmental factors. Hydrotime model describes the relationship between water potential (ψ) and seed germination rate and percentage. This model quantifies the rate of germination progression (θH), the stress tolerance of germination (ψb(50)) and the uniformity of germination (σψb). This indicators can be used to show seed lots or varieties vigor and evaluation of dormancy in seed and some treatments effects (e.g. priming, ABA or GA) on seeds vigor. Hydrotime model is not well known amongst Iranian researchers. This study aims at introducing the application of hydrotime model in germination data analysis. To achieve this, germination data of three plants (sweet clover: Melilotus officinalis, rye: Secale cereael and wheat: Triticum aestivum) in response to drought stress were used. The θH value quantifies the inherent rate of germination,which can vary among species and different physiological stages. The ψb(50) value is an indication of theaverage stress tolerance of the population. A population with a high ψb(50)value (less negative) will be inhibited germination at higher ψ (less stress) than will a population with a lower ψb(50) value. The value of ψb(50) for a seed population can be shifted to higher or lower values by the induction and release of dormancy.The σψb value is a quantitative estimate of the uniformity in germination in the population as greater σψb means a wider variation between the first and last seeds to germinate.
Ehsan Rabieyan; Majid Jiriaie; Amir Ayneband
Abstract
Selenium is of micronutrients which beside its effective role on increment of endurance of plants such as rice against undesirable environmental effects, plays an important role in human health, due to its anti-oxidant and anti-cancer characteristics. Thus, to evaluate the influence of selenium on diminishing ...
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Selenium is of micronutrients which beside its effective role on increment of endurance of plants such as rice against undesirable environmental effects, plays an important role in human health, due to its anti-oxidant and anti-cancer characteristics. Thus, to evaluate the influence of selenium on diminishing the negative effect of salinity and low seed storage in germination of Shafagh rice cultivar (CV. Shafagh) a factorial experiment was carried out based on completely randomized factorial design (CRFD) with three replications at the Physiology Lab of Shahid Chamran University in 2012. Testing factors included pretreatment of seeds with selenium in 0 and 16 mg/l, salinity in three levels including 0, 6, and 12 dS/m, and seed grain weight of 22, 24, and 26 gr. Results showed that salinity stress caused drastic and significant damage on measured properties of rice germination as much as 32 to 59 % in germination indices and 30-60% in germination characteristics. Priming with selenium rectified the salinity damage (1-23%) and low seed grain weight (32-47%) significantly, so that the germination rate in control treatment was classified in the same statistical group with selenium treatments and seed grain weight of 24 gr and also rice primed with selenium and salinity of 6 dS/m. Accordingly, salinity value and low seed weight had a drastic negative effect on all measured properties, but selenium pretreatment rectified the damages on germination through the increment of anti-oxidant enzymes.
Seyyed Fazel Fazeli Kakhki; Mohammad Ghiasabadi; Morteza Goldani
Abstract
Salicylic acid reduces the effects of oxidative stress as a secondary stress in dry condition. In order to study mitigation effects of salicylic acid (SA) on drought stress conditions in mustard plant, a factorial experiment was conducted based on completely randomized design with three replications ...
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Salicylic acid reduces the effects of oxidative stress as a secondary stress in dry condition. In order to study mitigation effects of salicylic acid (SA) on drought stress conditions in mustard plant, a factorial experiment was conducted based on completely randomized design with three replications at the Research Greenhouse of Ferdowsi University of Mashhad Iran, in 2012. The first factor was three levels (0, 100 and 200 ppm) of salicylic acid (SA) and the second factor was three levels of drought stress (%25, %50 and %75 of field capacity (FC)). Foliar spraying of salicylic acid started one week before the initiation of drought stress and continued in seven- day intervals until three weeks after drought stress The results showed that the effects of salicylic acid (SA) and drought stress on all morphophysiological, seed weight per plant and its components were significant. The greatest plant height was obtained from application of 200 ppm SA and %75 FC drought stress treatment. The maximum photosynthetic amount and membrane stability index (MSI) were observed where 100 ppm of SA was applied at %75 FC drought stress. The highest seed weight per plant with 1.43 g was also acquired with application of 100 ppm SA and %75 FC drought stress treatment. The results of the correlation coefficients showed that the greatest significant positive correlations were observed between seed weight per plant and number of seeds per pod (r=0.93**), number of pod per plant (r=0.84**) and 100-seed weight (r=0.84**). Amongst physiological traits the greatest significant positive correlation was observed between seeds per plant and photosynthesis (r=0.53**). Overall, it seems that application of 100 ppm SA may reduce harmful effects of water deficit and enhance growth and production of mustard plant through improving some physiolological traits.
Yaaghoub Hosseini; Mehdi Homaei; Najafali Karimian; Saeid Saadat
Abstract
Seed germination and the following growth of young seedlings are important stages of plant development particularly under stress conditions and plant survival depends on these two influential stages. The effects of salinity and boron on seed germination and seedling emergence of canola (Brassica napus ...
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Seed germination and the following growth of young seedlings are important stages of plant development particularly under stress conditions and plant survival depends on these two influential stages. The effects of salinity and boron on seed germination and seedling emergence of canola (Brassica napus L.) were examined in this research. Results showed that the seed germination were significantly (P≤0.001) decreased and delay in seed germination increased by increasing the salinity. The percentage of germination in natural saline water was less than that of NaCl + CaCl2 solution when measured in high salinity levels. When using natural saline water, minimum germination was observed in 30 dS m-1 i.e., 75% compared to control. Also, increased delay in germination was observed with increasing salinity levels; as delaying in germination at 30 dS m-1 (through application of NaCl + CaCl2 solution ), compared to non-saline conditions was nearly doubled. On the other hand, in the first and second experiments, boron application reduced germination significantly (P≤0.001) and increased delay in germination. Combination of salinity and boron further reduced germination and caused more delay in germination. In the third experiment, the percentage of emerged plantlets decreased from 57% in the control to about two percent in salinity of 9 dS m-1. Inclusion of boron in soil significantly reduced emerging seed of canola. The results suggest when using saline waters, besides its osmotic effect, the boron concentration should also be considered.
Hasan Monirifar; Mohammad Ebrahim Sadegzadeh
Abstract
Survival and profitability of alfalfa fields in cold regions is affected by winter injury and parts of alfalfa fields are subject to damage or destruction due to winter conditions every year. In this study eleven alfalfa ecotypes with two international cultivars were evaluated as check in 'Tikmadash ...
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Survival and profitability of alfalfa fields in cold regions is affected by winter injury and parts of alfalfa fields are subject to damage or destruction due to winter conditions every year. In this study eleven alfalfa ecotypes with two international cultivars were evaluated as check in 'Tikmadash station', Tabriz, Iran with an ultra-cold climate from 2008 to 2011. Seeds were first planted individually in pots and seedlings were transplanted to the field based on a randomized complete block design with five replications. Various traits were measured for 3 years in the field. After each snowfall, the farm was completely shoveled for to remove the protective influence of snow and plants were exposed to the cold of winter. First year was considered as the estblishment year and data recording was taken place from the second year. ANOVA results for the survival percentage showed that there were significant differences in plants survival percentages amongst ecotypes and cultivars in the second and third years compared to the first year, but this trait was not significantly different between second and third years. This indicates that the most damages and plants death accrued at the first year. Ranger and Moapa cultivars showed the most winter damage and the most winter survival was belong to Joshin ecotype. To gain a better conclusion, the mean of adjusted yields of ecotypes and cultivars for three years were calculated and based on obtained results ‘Bahraman’, ‘Joshin’, ‘Horand’, ‘Dizaj-Safarali’ and ‘Alhord’ ecotypes were determined as the best ecotypes of this study.
Saeed Mahmoodi; Gholamreza Savaghebi; Babak Motesharezadeh
Abstract
One of the most important problems of calcareous soils in arid and semi-arid areas is the reduction of iron and zinc uptake. There are different ways to resolve this deficiency in the soil which the most effective and economic way is to use efficient varieties. This study was conducted to evaluate the ...
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One of the most important problems of calcareous soils in arid and semi-arid areas is the reduction of iron and zinc uptake. There are different ways to resolve this deficiency in the soil which the most effective and economic way is to use efficient varieties. This study was conducted to evaluate the effect of iron deficiency on the concentration, uptake and relative transport of iron, zinc, copper and manganese in 12 commercial bean cultivars (red, white and wax) as a factorial experiment based on CRD with three replications under greenhouse conditions and in a calcareous soil with deficiency of uptakable iron (1.67 mg/kg). Iron was added at planting to the pots in two levels including without fertilizer (Fe0) and optimum usage (5mg/kg). Plants were harvested after six weeks at late vegatative growth period. The most tolerant and sensitive cultivars to iron deficiency were Dorsa (108.9%) and Derakhshan (76.14%), respectively. There was a significant and positive correlation in root and shoot in terms of the amount of iron uptake amongst studied cultivars under iron deficiency stress conditions. Results showed that Dorsa, Mahali Khomin, Daneshkade, Naz, and Goli cultivars had the greatest amount of uptake and translocation ratio of Fe, Zn, Cu and Mn. Increasing micronutrients uptake and translocation from root to shoot in different plant cultivars is one of the important aspects of enrichment programs aiming to improve the quality of products.
Fatemeh Taati; Hajar Talebi; Mohammad Taghi Ebadi; Asghar Khoshnood Yazdi; Alireza Dadkhah
Abstract
Indigo (Indigofera tinctoria) is one of the legume family which its flowers because of producing a blue color and having wound healing properties is widely used in traditional medicine and cosmetics industries. Due to reduction of water resources and agricultural lands salinization, evaluation of tolerance ...
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Indigo (Indigofera tinctoria) is one of the legume family which its flowers because of producing a blue color and having wound healing properties is widely used in traditional medicine and cosmetics industries. Due to reduction of water resources and agricultural lands salinization, evaluation of tolerance of this plant to drought and salinity stress conditions at germination stage was investigated. In order to investigate the effects of drought stress caused by PEG 6000 (0, -2, -4, -6 and -8 bar) and salinity stress induced by NaCl (0, 100, 200, 300, 400 and 500 mM), two separate experiments were carried out. According to the results, different levels of drought and salinity had significant effects on all germination indices, so that germination percentage in control treatments was highest in both experiments (90.1 and 90 percent respectively) and was lowest at -8 bar and 500 mM treatments (17.7 and 72.5 percent, respectively). According to the results, it seems that this plant has a good tolerance to drought and salinity stresses at germination stage.
