6－BA对低温下水稻幼苗细胞膜系统保护作用的研究

Protection of 6-Benzyladenine on Cell Membrane System of Rice Seedlings under Chilling Stress

在低温胁迫（３℃，４８ｈ）前后用６－苄基腺嘌呤（６－ＢＡ）（４４μｍｏｌ／Ｌ）处理水稻幼苗，可增强水稻幼苗的超氧化物歧化酶（ＳＯＤ）、过氧化氢酶（ＣＡＴ）活性，降低电解质渗漏率和丙二醛（ＭＤＡ）含量，同时也提高不饱和脂肪酸指数（ＩＵＦＡ）和叶绿素含量，但过氧化物酶（ＰＯＤ）活性无明显变化。在黑暗中处理效果优于在光照条件下的处理。亚细胞组分测定表明，ＳＯＤ活性对低温敏感的顺序是叶绿体＞线粒体＞细胞溶质，６－ＢＡ对低温下叶绿体的保护作用最明显。外源抗氧化剂抗坏血酸（Ｖｃ）（１ｍｍｏｌ／Ｌ）、苯甲酸钠（ＳＢ）（５ｍｍｏｌ／Ｌ）和二苯胺（ＤＰＡ）（５ｍｍｏｌ／Ｌ）与６－ＢＡ配合，比单独施用对膜系统保护作用的效果更佳。

Chilled (3℃, 48h) rice (Oryza sativa L. ) seedlings were sprayed with 44 μmol/L 6-benzyladenine (6-BA), the increases of superoxide dismutase (SOD) and catalase (CAT) activities and the decreases of malondialdehyde (MDA) and cell electrolyte leakage were observed. In the same time, 6-BA treatment also enhanced the index of unsaturated fatty acids (IUFA) and chlorophyll content. But no obvious change was found for peroxidase (POD) activity. The protective function of 6-BA to chilled rice seedlings in the dark was stronger than in the light.The sensitivity of SOD located in chloroplasts was higher than in mitochondria and in cytosol. And the result of raising SOD activity of 6-BA treatment to chloroplasts was more effective than to mitochondria and cytosol. When 6-BA was combined with antioxidants, such as 1 mmol/L ascorbic acid (Vc), 5 mmol/L sodium benzoate (SB) and 5mmol/L diphenylamine (DPA), the coordination for cell membrane system protection was observed.