弱干旱下H2O2稳态调控大豆抗旱性的信号作用研究

研究弱干旱胁迫下H₂O₂稳态调控大豆抗旱性的信号作用，为大豆抗旱栽培提供理论依据。以大豆科丰1号为材料，用0.5%和5%的PEG-6000模拟不同程度的干旱，测定干旱胁迫下大豆叶片中相对含水量、膜脂过氧化程度、活性氧水平、抗氧化酶活性以及抗坏血酸-谷胱甘肽（AsA-GSH）循环中抗氧化剂含量及相关酶活性。结果表明：干旱胁迫增加了大豆叶片中活性氧的含量，促进了叶片膜脂过氧化，降低了叶片相对含水量；弱干旱胁迫下叶片H₂O₂积累并在抗氧化酶和抗氧化剂的共同作用下形成持续的稳态，产生信号作用，诱导植株在更强干旱胁迫下抗氧化酶活性以及AsA含量的进一步提高，显著降低了丙二醛和H₂O₂含量，提高了抗旱性，维持了叶片相对含水量的稳定。该信号作用同时具备时效性，会随着弱胁迫时间的延长而减弱。

Regulation of signaling of H2O2 homeostasis under mild drought on drought resistance of soybean

This study was carried out to explore signaling effects of H₂O₂ homeostasis on soybean （Glycine max） drought resistance and provide theoretical basis for soybean drought resistance cultivation. ‘Kefeng 1’ was used as material and treated in 0.5% and 5% PEG-6000 solution to simulate different drought levels. The relative water content, degree of membrane lipid peroxidation, level of reactive oxygen species, activity of antioxidant enzymes, content of antioxidants and activity of related enzymes in ascorbic ascorbate-glutathione （ASA-GSH） cycle of soybean leaves were determined under different stress conditions. The results showed that drought increased the content of active oxygen, promoted the membrane lipid peroxidation and decreased the relative water content of soybean leaves. Under mild drought stress, H₂O₂ accumulated in leaves and formed a continuous homeostasis by the regulation of antioxidant enzymes and antioxidants, which produced signal effect to induce the further increase of antioxidant enzyme activity and AsA content in plants under stronger drought stress, significantly reduction in MDA and H₂O₂ content, improved drought resistance, and maintained stability of relative water content in leaves. The effect of the signal is time-dependent and would be weakened with the lasting of mild drought stress.