PEG模拟干旱胁迫对叶缘裂刻小白菜生理特性的影响

Effects of Drought Stress Simulated by PEG 6000 on Physiological Characteristics of Lobe-leafed Non-heading Chinese Cabbage(Brassica rapassp.chinensis)

研究PEG模拟干旱胁迫下小白菜近等基因系叶缘深裂(11H)和叶缘全缘(11B)幼苗萎蔫指数和生理特性的变化。结果表明,随着PEG胁迫质量浓度增大,2种材料幼苗叶片的萎蔫指数、失水率、相对电导率及丙二醛(MDA)含量均呈上升趋势,显著大于对照(CK),且11B较11H上升幅度大;二者叶片相对含水量随干旱胁迫加重而逐渐下降,11B的下降幅度大于11H。11B的超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性随着胁迫增强均呈先较大程度上升后大幅度下降趋势;11H的POD活性先上升再下降,最终持续维持在较高水平,11H的SOD和CAT活性表现为持续上升的趋势。在高质量浓度PEG胁迫下,11H的SOD和CAT活性较11B高。综合比较不同质量浓度PEG胁迫下11H和11B的生理特性变化,确定11H抗旱能力强于11B。

In order to evaluate drought resistance of non-heading Chinese cabbage NILs（near isogenic line）of 11Hlines characterized by leaf-lobed phenotype and 11Blines characterized by smooth margin phenotype,the leaf wilting index and physiological changes were examined in a hypertonic gradients created by PEG-6000.The results indicated that with the increase of PEG concentration,their leaf wilting index,water loss rate,relatively permeability of plasma membrane and content of malondialdehyde（MDA）increased gradually.All the indexes were significantly greater than the control（CK）, while there was a greater increase in 11Hcompared with 11B.The leaf relative water content of 11B and 11Hdecreased gradually with the increase of PEG concentration.As for 11B,with the drought stress intensity increasing,the activity of superoxide dismutase（SOD）,peroxidase（POD）and catalase（CAT）showed the trend of increasing initially and then decreasing.Compared with 11B,the POD activity of 11Hincreased primarily and then decreased,lastly maintain at a high level.The SOD and CAT activity of 11Hincreased gradually.At high concentration of PEG,the SOD and CAT activity of 11H were higher than that of 11B.After comparing the physiological characteristics between11Hand 11Bat the different concentrations of PEG stress,we draw the conclusion that the droughtresistant ability of 11H was greater than 11B.