جستجوی مقالات مرتبط با کلیدواژه "پایداری غشاء سلولی" در نشریات گروه "زراعت"

Selenium (Se) is a beneficial element with anti-oxidant and anti-viral properties that strengthens the defense system and increases plant adaptability under environmental stress conditions. In present study we examined the effect of Se on alleviating adverse effect of Cd, Pb and Ni alone and in combination together in cucumber (Cucumis sativus cv. Super Dominus). The research was conducted using a completely randomized design with factorial arrangement in three replications for two germination tests. The first experiment was carried out to determine the optimal effectiveness of Se and heavy metal toxicity threshold levels, which contain levels of Se (0, 4, 6, 8, 10 mg.L -1 ), cadmium (0, 10, 15, 20, 25 µM), nickel (0, 50, 100, 150, 200 µM) e and lead (0, 20, 40, 60, 100 µM). The second experiment were consisted of two levels of Se (0 and 8 mgL-1) and toxicity threshold levels of heavy metals, including cadmium (0, 25 µM), nickel (0, 200 µM) and lead (0, 100 µM) treatments. The result showed that the germination percentage and germination rate significantly reduced at all heavy metal stress and Se has beneficial effect in alleviation of toxicity of heavy metal. Heavy metals stress increased electron leakage (EL) malondialdehyde (MDA) and Se supplementation enhance EL and MDA under heavy metal stress. Cd, Pb and Ni alone or in combination together significantly reduced enzyme activity such as catalase (CAT), glutathione peroxidase (GPX) and ascorbate peroxidases (APX) in cucumber leaves and Se increased enzyme activity in stress condition in comparison with non-Se application. In general, Se has beneficial effect in alleviation of heavy metals stress in cucumber during germination by preventing oxidative damages.

This research was carried out to identify drought tolerant genotypes on the basis of physiological, phonological and morphological traits and drought tolerance indices in bread wheat. Twenty wheat genotypes were assessed in two field experiments based on randomized complete block design with three replications under non-stress and drought stress conditions in Dryland Agricultural Research Sub-Institute, Sararood, Kermanshah. The studied traits were number of grains per spike, peduncle length, spike length, plant height, 1000-grain weight, days to heading, days to physiological maturity, grain yield, flag leaf area, relative water content, a, b and total chlorophyll, proline content, water retained in cut leaves, cell membrane stability and leaf water potential. Futhermore, drought tolerance indices based on grain yield under stress and non-stress conditions were also evaluated. The results showed that there is significant genetic variation among the studied genotypes for improving drought tolerance. Results of the yield index (YI), yield tolerance index (YTI), mean productivity (MP), geometric mean productivity (GMP), tolerance index (TOL), stability tolerance index (STI) and stress susceptibility index (SSI) identified relatively similar genotypes as the drought tolerant genotypes, but according to the high and significant correlation coefficients among MP, GMP, HMP and STI indices with grain yield under both stress and non-stress conditions, these indices were suitable to identify the high yielding genotypes under both conditions. According to these indices, the genotypes 72YRRGP, T179, T189, 914GB, MARAGHEH(1379-80) and Sardari were detected as the drought tolerant genotypes. Correlation coefficient analysis also revealed that among the evaluated traits, proline content of flag leaf, cell membrane stability and spike length had the stronger relationship with stress tolerance index (STI) and are introduced as the most important traits for selecting drought tolerant genotypes in this research.

Cold is one of the most important abiotic stresses in some regions of Iran. To Investigate of some tolerance related traits to cold condition, 22 bread wheat genotypes planted in Ardabil region in 1980. After plants passed winter cold condition (135 freezing days), cell membrane stability, chlorophyll content of leaf and crown depth and grain yield of genotypes were measured. ANOVA analysis showed significant differences between genotypes for grain yield, cell membrane stability and chlorophyll content of leaf at 5%. While there was none significant differences between genotypes for crown depth. Mean comparison showed that, Aug//gt/…, Navid, C-73-8, sardari and C-70-3 genotypes with 3.52, 3.41, 3.34, 3.26 and 3.24 ton/ha respectively had the highest and 4213 genotype with 1.59 tn/ha had the least grain yield in experiment condition. Correlation coefficients showed negative significant correlation between grain yield and cell membrane Stability, and positive correlation between grain yield and chlorophyll content of leaf. Overall it seems these methods can be used as simple and quick tools for evaluating and screening wheat genotypes in winter cold condition.