摘要
聚乙二醇溶液处理玉米（Ｚｅａ ｍ ｅｙｓ Ｌ．）幼苗根系，引起叶片电解质渗漏，丙二醛含量增加，叶绿素降解，水分耗失加快，光合速率、光合电子传递活性减少和暗呼吸速率增高。叶面喷施６－苄基氨基嘌呤及２，６－二丁基甲酚、没食子酸丙酯和抗坏血酸等抗氧化剂，可缓解渗透胁迫引起的膜损伤，具有一定的保护作用。
Osmotic stress of root system of maize seedling was induced by treatment with different concentrations of polyethyleneglycol solution.After 1—3 h of treatment, obvious physiological changes were observed in leaves.The leaf water potential decreased with the increase of PEG concentration and time of stress.An increase of malondialdehyde content was associated with the higher electrolyte leakage through cell membrane.Osmotic stress of root system caused degradation of chlorophyll, reduction of photosysthetic rates and photosynthetic electron transport, as well as the increase of respiration/photosynthesis ratio.The inhibition of electron transport was more severs in PS Ⅱ than in PS Ⅰ.Pretreatment by leaf spraying with 6 BA and the three kinds of antioxidants (propyl gallate, dibutyl hydroxytoluene and ascorbic acid) before the roots were submited to osmotic stress in -0 41 MPa PEG solution for 3 h improved all of the above parameters significantly.The results indicated that antioxidart possessed definite protective regulative and adaptative effects on photosysthetic membrane under water stress of root.As the damage of water stress to plant may volve the free radical mechanism.
