水体营养水平对3种沉水植物生长及抗氧化酶活性的影响

Effects of different nutritional condition on the growth and antioxidant enzyme activity of three submerged macrophytes

模拟研究了沉水植物狐尾藻 Myriophyllum spicatum L、轮叶黑藻 Hydrilla verticillata L 和金鱼藻 Ceratophyllum demersum L 在中、富两种营养水平下的生长及生理特性。研究结果表明,在 45 d 的培养过程中,狐尾藻、轮叶黑藻和金鱼藻在中营养(TN1.86 mg·L-1;TP0.087 mg·L-1)和富营养(TN2.47 mg·L-1;TP0.16 mg·L-1)水平下的单株最大生物量分别是 0.92、0.27、1.11、0.56、0.41 和 0.87 g,狐尾藻和金鱼藻在中营养水平下单株最大生物量分别较富营养水平下高出 39%和 22%,而黑藻在中营养水平下单株最大生物量较富营养水平下低了 51%,表明狐尾藻和金鱼藻在中营养水平下的生长较黑藻好。通过对 3种沉水植物可溶性蛋白和叶绿素质量分数的分析发现,黑藻在中富两种营养水平下,质量分数较低且波动平稳,金鱼藻和狐尾藻可溶性蛋白和叶绿素质量分数持续升高,表明这两种沉水植物对水体中营养盐的耐受能力较黑藻强。金鱼藻超氧歧化酶(SOD)活性、过氧化物酶(peroxidase)活性和丙二醛(MDA)含量在试验后期上升速度加快,且富营养水平下金鱼藻 MDA质量分数的最大值是中营养水平下最大值的 5 倍,表明在中营养水平下金鱼藻已经受到明显胁迫,而在富营养水平下受到胁迫更为显著。在本试验条件下,黑藻生物量小,而金鱼藻 SOD 活性、POD 活性和 MDA 质量分数变化幅度大,在试验后期急速上升,表明这两种沉水植物受到的营养盐胁迫较狐尾藻大,而狐尾藻在中营养水平下的耐营养盐胁迫能力较强。

The effects of different nutritional condition on the growth and antioxidant enzyme activity of submerged macrophytes Myriophyllum spicatum L, Hydrilla verticillata L and Ceratophyllum demersum L. were investigated in this study. The results showed that during the 45 days experimental time the fresh weigh of Myriophyllum spicatum L, Hydrilla verticillata L and Ceratophyllum demersum L were 0.92 g, 0.27 g, 1.11 g and 0.56 g,0.41 g, 0.87 g in medium nutritional condition （ TN 1.86 mg·L-1,TP 0.087 mg·L-1 ） and eutrophic condition （ TN 2.47 mg·L-1,TP0.16 mg·L-1 ）, respectively. The largest single plant biomass of Myriophyllum spicatum L and Ceratophyllum demersum L in in middle nutritional condition were over 39% and 22% higher than those in eutrophicated condition, but that of Hydrilla verticillata L was less than 51%, which shown that Myriophyllum spicatum L and Ceratophyllum demersum L grow better than Hydrilla verticillata L in middle nutritional condition. The contents of protein and chlorophyll of Hydrilla verticillata.L is lower, but those of Myriophyllum spicatum L and Ceratophyllum demersum L raised steadily in the same condition, which indicated that those two submerged macrophytes have the stronger tolerance for nutrition than Hydrilla verticillata L. The activitys of Super Oxide Dismutase （SOD）, peroxidase （POD） and Multiple Displacement Amplification （MDA） of Ceratophyllum demersum L raised rapidly in the late of experiment, and the maximum value of MDA of Ceratophyllum demersum L in the eutrophic condition was 5 time higher than that in the medium nutritional condition, implied that Ceratophyllum demersum L has been stressed in the middle nutritional condition. During the experimental conditions, the activitys of SOD, POD and MDA of Ceratophyllum demersum L changed greatly, and raised rapidly in the late of experiment, which indicated that those two submerged macrophytes got more nutrient stress than Myriophyllum spicatum L, and the nutritional stress-resistant ability of Myriophyllum spicatum L was higher than those two submerged macrophytes in the medium nutritional condition