【摘要】 采用室内培养液培养的方法,研究了重金属对水稻呼吸速率及相关同功酶的影响。结果表明,较高浓度(≥0.1m m ol·L-1)的重金属C u2+、C d2+和H g2+显著抑制扬稻6号和武运粳8号叶片的呼吸速率;供试浓度(0.025～1.0m m ol·L-1)的Cu2+、C d2+和H g2+强烈抑制上述两水稻品种根系的呼吸速率。对呼吸作用相关的几个重要酶同功酶的电泳分析表明,C u2+、C d2+、H g2+可通过影响水稻叶片和根系中的淀粉酶、苹果酸脱氢酶及细胞色素氧化酶同功酶来表达对水稻呼吸作用产生的影响,其中高浓度(≥0.5m m ol·L-1)C u2+、C d2+、H g2+抑制水稻叶片和根系呼吸作用的最主要原因与细胞色素氧化酶同功酶表达受到C u2+、C d2+、H g2+的抑制相关。更多还原

【Abstract】 The ions Cu2+, Cd2+and Hg2+were selected to determine theeffects of heavy metals on respiratory metabolism of rice plants. Rice plants from the indica variety Yangdao No.6 and the japonica variety Wuyungen No.8 were cultivated with the modified Kimura B nutrient solution, and were treated for 7 days starting from the eight day after flowering with 0.025, 0.05, 0.1, 0.5, 1.0and 2.0 mmol·L-1 of Cu2+, Cd2+and Hg2, respectively. The respiratory rate in the leaves of the indica variety (measured with an oxygen electrode method) was enhanced at lower concentrations (0.025～0.1 mmol·L-1) and inhibitedat higher concentrations (>0.1mmol·L-1) of these ions, respectively, while,the respiratory rate of leaves in the japonica variety was inhibited by 0.025～1.0 mmol·L-1 of these ions. The root respiratory rate was strongly inhibited by 0.025～1.0 mmol·L-1 of the three ions in the two varieties. The activities of isozymes related to respiration were analyzed using a polyacrylamide concentration gradient gel electrophoresis technique. The expression of amylase isozymes in the leaves of the two varieties was inhibited by a high concentration (0.1 and 0.5mmol·L-1) of the ions. The expression of malate dehydrogenase(MDH) isozymes in the leaves of the two varieties were induced by 0.05 mmol·L-1 Cu2+and 0.05～0.5 mmol·L-1 Cd2+and Hg2+, but that in the roots was induced by 0.05 mmol·L-1, and inhibited by 0.1 and 0.5 mmol·L-1 of the three ions. The expression of cytochrome oxidase(COD) isozymes in leaves was inhibited by 0.05 mmol·L-1 Cu2+in Yangdao No.6, and by 0.05～0.5 mmol·L-1 of the three ions in Wuyungen No.8; the COD expression in roots was also strongly inhibited by 0.1 and 0.5 mmol·L-1 Cu2+and Cd2+and 0.05～0.5 mmol·L-1 Hg2+in the two varieties. These results indicated that the effects of heavy metals on respiration varied with organs, genotypes and the concentrations of the ions in the rice plants, and suggested that changes of respiration rate in the leaves and/or roots might arise from the changes of expression levels of the isozymes under the stress.更多还原