干旱处理迫对花生品种叶片保护酶活性和渗透物质含量的影响

以花育22和花育25为试验材料，利用防雨棚池栽人工模拟干旱胁迫逆境试验，调查苗期、花针期和结荚期水分胁迫对花生叶片膜脂过氧化、渗透调节物质含量和保护酶活性的影响。结果表明，干旱处理初期，两品种抗氧化系统和渗透调节物质各成分的反应并不完全一致，超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性、可溶性蛋白质(Pr)、游离氨基酸(AA)、脯氨酸含量(Pro)显著升高，但随干旱处理进行，其活性明显降低，保护酶活性与渗透调节物质降低时间基本同步，POD活性对水分胁迫的响应较弱, 丙二醛(MDA)含量显著升高，随干旱处理历时延长，含量降低，其降低时间滞后于保护酶活性，花育22 MDA含量高于花育25；各生育期干旱处理结束后，SOD、CAT、Pr、AA、Pro含量明显升高，且在水分敏感的花针期升幅均较大；苗期干旱对生育后期保护酶及渗透调节能力的影响较小; SOD和CAT是花生适应抗旱胁迫的主要抗氧化酶，各渗透调节物质调节能力表现为可溶性蛋白质>可溶性糖>游离氨基酸>脯氨酸；花育25抗旱适应能力较强。

Effect of Drought Stresses at Different Growth Stages on Peanut Leaf Protective Enzyme Activities and Osmoregulation Substances Content

UsingHuayu 22 and Huayu 25 as experimental materials, the physiological and biochemical parameters at seedling stage, flowering-pining stage, and podding stage in peanut leaf were investigated under drought stress in pool cultivation with rainproof. The result showed that, the changes of antioxidant systems and the components of osmoregulation substances of two varieties were not entirely consistent during early drought stress stage. Leaf superoxide dismutase (SOD) and catalase (CAT) activities, soluble protein (Pr), free amino acid (AA) and proline (Pro) contents were significantly increased and then decreased under drought stress. With the prolonged stress, the protective enzyme activities and osmoregulation substances content decreased at the same time. The POD activity and soluble sugar content weakly responded to drought stress. The content of malondialdehyde (MDA) was significantly increased and then decreased with the stress prolonged, but its time lagged behind those of the protective enzyme activities. The MDA content in Huayu 22 leaf was higher than that in Huayu 25. After the drought stress, the activities of SOD, CAT, and soluble protein, free amino acid and proline contents were obviously increased at the end of drought stress at different growth stages. Among those stages, all the parameters were markedly increased at the flowering-pining stage, which is sensitive to water supply. The effects of drought stress on protective enzyme activities and osmoregulation substances of peanuts were weaker at seedling stage than at late growth stages. SOD and CAT were the key antioxidant enzymes to adapt dr ought stress in peanut. The ability of osmoregulation substances contributed to the regulation of drought stress in turn was: soluble sucrose > free amino acid > soluble protein > proline. The drought tolerance of Huayu 25 was higher than that of Huayu 22.