两种营养状态下pH对轮叶黑藻(Hydrilla verticillata)生长和抗氧化酶活性的影响

Bloom and strong photosynthesis of algae in eutrophic lake has increased the pH of lake water in summer. Accordingly, the research of the effect of changed ecological factors on the growth of submerged plant became the basis for the reestablishment of submerged vegetation and water ecological restoration. The effects of different pH (7, 8, 9 and 10) on the growth, chlorophyll contents, antioxidative enzymes and malondiadhyde (MDA) contents of Hydrilla verticillata under mesotrophic (TN 0.60 mg•L^(-1) and TP 0.04 mg•L^(-1)) and eutrophic (TN 4.20 mg•L^(-1) and TP 0.28 mg•L^(-1)) conditions were studied by the method of laboratory simulation. The results showed that plant growth was obviously inhibited at pH 10 after 21 days' culture, particularly under eutrophic condition. Chlorophyll contents of Hydrilla verticillata increased under eutrophic condition at pH 7 and pH 8, while the chlorophyll contents under eutrophic condition were lower than that under mesotrophic condition at pH 10. POD and SOD activities significantly increased at pH 8 and were inhibited at pH 9 under eutrophic condition, while the activities of two enzymes didn't increase until pH 9 under mesotrophic condition. CAT activitiy significantly increased at pH 9 under both nutritional conditions but inhibited at pH 10 under eutrophic condition. MDA contents increased linearly between pH 7 and 9 under eutrophic condition. The content of MDA was significantly higher under eutrophic condition than that under mesotrophic condition between pH 7 and 9, and the difference reached the maximum at pH 9. The research showed that the influence of pH on Hydrilla verticillata was relevant to the nutritional conditions. Hydrilla verticillata was stressed above pH 9 under both nutritional conditions and the stress was even greater under eutrophic condition.