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• 基金项目：

• 杨惠东
• 中国科学院上海植物生理研究所

• 谭常
• 中国科学院上海植物生理研究所

• 俞子文
• 中国科学院上海植物生理研究所

• 何鉴钢
• 中国科学院上海植物生理研究所

• 余叔文
• 中国科学院上海植物生理研究所

• 摘要：应用祝宗岭等（1982）改进的在稳流下测量植物组织电阻的中段电压降法,测定了小麦叶片在SO₂或HSO₃-引起伤害过程中的叶组织电阻变化,并与离子外渗的变化进行了比较。小麦接触不同浓度SO₂,如浓度在伤害阈值以下,组织电阻无明显变化.如以引起伤害的浓度处理,在出现伤害的初始症状前组织电阻就开始下降,而随着熏气时间的延长在出现初始症状时则有一急剧下降。浓度高,电阻下降也大。平行测定离子外渗的变化,它与组织电阻呈负相关,相关系数为0.936,回归方程为y=412.7-28.3x。 用不同浓度的HSO₃^-处理小麦离体叶,组织电阻也随浓度的增加而下降。 试验结果说明,测定叶组织的电阻可以比较灵敏地反映叶细胞质膜的结构和功能受损的程度。这方法可应用于原位叶或离体叶测定,也便于作动态观测。

• Abstract：SO₂ causes damage to differential permeability of plasma membrane, so ion leakage occurs. Measurement of conductivity of exosmosis fluid of leavesis commonly used to assess change of permeability, which serves to indicate the extent of injury or resistance of plants. However, this method is complicated, and a lot of leaves have to be consumed with the disadvantage that it cannot be done in situ and promptly.Damage of plasma membrane is accompanied by a drop in membrane electrical resistance, which is thought of contributing to a major part of the tissue electrical resistance. In order to show the extent of tissue damage in a direct way, it is more logical to determine tissue electrical resistance than conductivity of exosmosis fluid of leaves. Attempts of this kind have not been satisfactory so far as complexity of the plant tissue structure and lack of a proper method are concerned.The present investigation has made use of the newly improved method by Zhu (1982) to measure drop in electrical resistance of leaf tissue along the course of injury caused by SO₂ or HSO^3-. Ion leakage was also measured parallelly with the purpose of comparison.When wheat was exposed to SO₂ at various concentrations, no change in leaf tissue electrical resistance happened as SO₂ concentration was below injury threshold. In injury experiments with SO₂ at different concentrations, tissue electrical resistance started to decline before appearance of initial symptoms of injury. After the symptoms appeared, a further drastic drop of the tissue electrical resistance occured. The higher the concentration, the greater the decrease of the electrical resistance. Ion leakage was measured simultaneously and found changing inversely with change of tissue electrical resistance. Correlation coefficient was 0.936, regression equation y= 412.7 -28.3x.When detached leaves of wheat were treated with HSO^3- in a series of concentrations, tissue electrical resistance also decreased with increasing concentrations.Experimental results show that change of tissue electrical resistance may be an indication of the extent of damage to structure and function of the plasma membrane. This method is nondestructive and can be applied to leaves in situ as well as detached. It is also suitable for dynamic observation.

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