Zn诱导的菹草叶抗氧化酶活性的变化和超微结构损伤

本文以培养在不同浓度梯度Zn 溶液中的菹草为材料, 研究Zn 对植物的影响。培养第5天, 测定叶内抗氧化酶系统活性等指标的变化, 并用透射电镜观察对细胞超微结构的损伤。结果表明:低浓度(<20mg/L)在短期内(5d)未对菹草产生影响, 各生理指标呈上升趋势。当培养浓度为50mg/L 时SOD 和CAT 活性达到峰值, 而其他指标则下降:其中POD 活性和叶绿素含量高于对照, 而可溶性蛋白含量则比对照低。100mg/L 培养浓度各指标均明显降低。同时电镜观察发现过量Zn 损伤了细胞的超微结构。当培养浓度大于50mg/L 时, 叶绿体被膜断裂, 叶绿体解体。线粒体脊突膨大, 线粒体空泡化。细胞核核膜断裂, 核仁散开。这说明过量Zn 削弱了细胞抗氧化酶的活性, 同时对细胞超微结构产生致死性损伤, 从而导致细胞死亡。

ANTIXIDANT ENZYMES ACTIVITY CHANGES AND ULTRASTRUCTURAL DAMAGE WERE CAUSED BY ZINC IN POTAMOGETON CRISPUS LINN. LEAVES

Potamogeton crispus Linn.was cultivated in solution with different Zinc gradient concentration for 5 days for studying the effect of Zn excess on plants. Changes of SOD, POD, CAT and other indicators were analyzed and ultra structural damage was observed using electron microscope. The conclusion showed that: None toxic effect was caused by low Zn concentration (<20mg/L), all in indicators had an increment tendency. Activity of SOD and CAT reached maximum at 50mg/L, while the other four indicators decreased, but activity of POD and chlorophyll content remain higher than that of the control, soluble protein content was lower than that of the control. All indicators decreased obviously at 100mg/L. Meanwhile ultra structural damage was caused by on excess of Zn. Such as disrupted chloroplast membrane, disintegration of chloroplasts; swelling of cristae of mitochondria and vesiculation of mitochondria at last; disrupted nuclear membrane, break of nucleolus into several small nucleoli and eventually cell death. So we could come to the conclusion that serious injury was caused by on excess of Zn.