【摘要】 两个耐盐力不同的籼稻品种80-85(耐盐)和83-51(不耐盐),经0.5％NaCl溶液处理后,质膜透性和膜脂过氧化产物—丙二醛的含量均有不同程度的增加,与此同时,叶组织内过氧化物酶活性因盐刺激而上升。质膜透性的增加和丙二醛的积累呈极显著的正相关。上述变化在尚未出现可见伤害症状的幼叶内作用较小,在外部症状明显的老叶内表现严重,不耐盐品种受影响的程度远远超过耐盐品种。进一步的试验发现,在同一叶片中,丙二醛的积累明显早于质膜透性的增加。结果提示,水稻盐渍伤害的主要部位可能在膜上,而细胞内膜脂过氧化作用水平的增强是膜系统受损伤的重要原因之一。更多还原

【Abstract】 The relationship between plasmalemma permeability, membrane lipid peroxida-tion, peroxidase activity and salt tolerance in rice was investigated, using 30 days old seedlings of two rice varieties, "80-85" (salt-tolerant) and "83-51" (non-tolerant), irrigated with 0.5% NaCl solution in pots under natural conditions. The results are summarized as follows:1. Salinity imposed a slight effect on the plasmalemma permeability of the first leaf (from the top) with invisible symptoms of injury, while the effect was rather severe for the third leaf with visible symptoms. The maximum relative conductivity was about 93.9% in the non-tolerant variety and 42.2% in the tolerant one, indicating the relation between plasmalemma permeability and salt-tolerance in the rice plants.2. Malondialdehyde (MDA) concentration in the third leaf was higher than that in the first one under normal conditions, increasing with the age of leaves. Lipid peroxide of membrane was increased markedly by salinity treatment. MDA accumulated before the appearance of visible symptoms in younger leaf and much more in the non-tolerant variety than in the tolerant, showing the relation between the level of membrane lipid peroxidation and salt-tolerance.3. The regression equation for the salt-tolerant variety is Y=-6.5488+0.8929x (r=0.7703**)and that for the non-tolerant one is Y=4.5959+1.1298x(r=0.9244**), where Y and X stand for plasmalemma permeability and MDA content respectively.In addition, the authors found in another experiment that the increase in MDA concentration took place prior to the damage of plasmalemma permeability in youngerleaves, which suggests that the increase in membrane lipid peroxides might be one of the causes of injury to plasmalemma permeability.4. That the activity of peroxidase was enhanced by salt stimulation and much higher in the non-tolerant variety is an indirect evidence of the accelerated peroxidation in the cell system. However, the increase in activity of peroxidase was not proportional to the increase in plasmalemma permeability and MDA accumulation. The complex process of growth in peroxidase activity and its function in cell peroxidation should be further studied.更多还原