干旱对不同玉米品种苗期根系生理生化特性的影响

以抗旱性不同的23个玉米品种为试材，用20％PEG溶液对幼苗进行模拟水分胁迫，研究了干旱胁迫下苗期根系生理生化特性的变化及其与品种抗旱性的关系。结果表明：苗期干旱导致根冠比和根系活力呈升高趋势，耐旱性品种升高幅度最大。苗期干旱，根系超氧化物歧化酶（SOD）活性升高，且耐旱性品种升高幅度大于中等耐旱和不耐旱品种；根系中MDA含量均增加，且耐旱玉米品种丙二醛（MDA）含量增量最小。本研究认为耐旱型玉米品种苗期根系在干旱胁迫下优势的内在机制是根系活力和清除活性氧的能力较强。

Effect of Drought on Root Physiological and Biochemical Characters of Different Maize Cultivars during Seedling Stage

23 maize varieties with different drought resistance were used as materials and 20%PEG solution was used to induce drought stress in this experiment.The changes of root physiological and biochemical characters and their relationship with drought resistance were studied under drought stress.The results showed that the drought stress during seedling stage could increase the ratio of root to shoot and root activity.The increasing amplitude of drought-tolerant maize hybrids was the largest.Under drought condition,the activity of superoxide dismutase(SOD) increased and the increasing extent of droughttolerant hybrids was the highest.The MDA content in roots of different maize hybrids increased and the lowest gradient of MDA content changes in the drought-tolerant maize varieties.The drought-tolerant maize hybrids had advantage under drought stress during seedling stage,because of the stronger root activity and the ability against active oxygen in root system.