Abstract

Antioxidative responses in faba bean plants subjected to different osmotic potentials induced by PEG-6000 were investigated. Drought stress significantly decreased photosynthetic gas exchange parameters (net CO₂ assimilation rate, transpiration rate, internal concentration of CO₂ and stomatal conductance) and leaf RWC in Bachar and Giza 3, while the magnitude of reduction in Bachar was relatively low. This could be due to its better antioxidant enzyme activities (catalase, superoxide dismutase and ascorbate peroxidase) and higher transcription levels of their respective genes. Moreover, the accumulation of proline and soluble sugars, combined with enhanced total phenolics content, total flavonoid content, and total antioxidant capacity may play important roles in drought tolerance in faba bean, thereby increasing osmotic adjustment and protection from free radicals. In agreement with this assumption, Bachar displayed lower MDA and H₂O₂ content and lower electrolyte leakage than Giza 3. Moreover, the detected increase in antioxidant enzyme activities appeared to be correlated with mRNA levels. Enzymatic and non-enzymatic (phenolic and non-phenolic) antioxidants may be useful as biochemical markers of oxidative stress responses to differentiate drought tolerant faba bean cultivars under drought stress. In the study, Bachar was found to be relatively tolerant to drought stress and Giza 3 was sensitive.

摘要

研究了PEG-6000诱导的不同渗透势作用下的蚕豆植物的抗氧化反应。干旱胁迫显着降低了光合气体交换参数（净CO ₂同化率，蒸腾速率，内部CO ₂浓度）和气孔导度）和Bachar和Giza 3的叶片RWC，而Bachar的减少幅度相对较低。这可能是由于其更好的抗氧化酶活性（过氧化氢酶，超氧化物歧化酶和抗坏血酸过氧化物酶）以及它们各自基因的更高转录水平。此外，脯氨酸和可溶性糖的积累，再加上总酚含量，总黄酮含量和总抗氧化能力的增强，可能在蚕豆的抗旱性中起着重要作用，从而增加了渗透调节和免受自由基的侵害。与该假设一致，Bachar显示较低的MDA和H ₂ O ₂含量和电解质泄漏量低于吉萨（Giza）3。此外，检测到的抗氧化酶活性的增加似乎与mRNA水平相关。酶促和非酶促（酚和非酚）抗氧化剂可用作氧化应激反应的生化标记，以区分干旱胁迫下的耐旱蚕豆品种。在该研究中，发现Bachar相对耐干旱，而Giza 3敏感。