不同浓度藻类水华对两种沉水植物的影响

为了研究藻类水华对沉水植被恢复的影响，通过模拟不同浓度的藻类水华，开展了篦齿眼子菜（Potamogeton pectinatus）和伊乐藻（Elodea nuttallii）在不同浓度藻类水华下（0，6.25×10⁸，2.5×10⁹，10¹⁰cell/L）的生长和生理试验.结果表明，低浓度（6.25×10⁸cell/L）处理组中伊乐藻的干重显著低于对照组，而藻浓度达到10¹⁰cell/L时，篦齿眼子菜的干重才显著低于对照组.与其它处理组相比，在藻浓度为10¹⁰cell/L的情况下，篦齿眼子菜的株高最矮，而伊乐藻的株高最高.叶绿素荧光特性表明藻浓度为10¹⁰cell/L的情况下，篦齿眼子菜的光合活性从0.77降低至0.50，而伊乐藻的光合活性无显著性变化，在0.72～0.79之间波动.沉水植物的抗氧化酶活性在藻类水华胁迫环境下先增加后降低.这表明，藻类水华对水生植物的生长影响有差异性；水体中过高的藻浓度会影响植物的抗性生理.沉水植物能忍耐短期低浓度的藻类水华胁迫，但是长期高浓度的藻类水华会严重影响沉水植物的生长，进而影响水生植被的恢复.

The effects of different concentrations of algal blooms on the two submerged macrophytes

In order to examine the effects of the amount of algal blooms on the restoration of submerged vegetations, we carried out the simulated experiments to study the growth and physiological responses of Potamogeton pectinatus and Elodea nuttallii to different concentrations (0, 6.25×10⁸, 2.5×10⁹, 10¹⁰cell/L) of algal blooms. The results showed that the dry weight of E. nuttallii at the low concentration (6.25×10⁸cell/L) of algal blooms was less than that of the control group, whereas the dry weight of P. pectinatus was not less than that of control group until the concentration of algal blooms reaches 10¹⁰cell/L. Compared with other treatments, the height of P. pectinatus was the shortest, while the height of E. nuttallii was the highest at the high concentration (10¹⁰cell/L) of algal blooms. It was showed that the photosynthetic activity of P. pectinatus decreased from 0.77 to 0.50 at the high concentration (10¹⁰cell/L) of algal blooms. However, the change of photosynthetic activity of E. nuttallii was not significant, ranging from 0.72 to 0.79. The antioxidant enzymes activity of submerged macrophytes decreased with increasing amount of algal blooms. These studies suggest that the effect of algal blooms on the growth of aquatic plants is dose-dependent. Although submerged plants can tolerate short-term stress of low concentrations of algal blooms, the high concentrations of algal blooms affect the resistance physiology of submerged macrophytes. The high concentrations of algal blooms greatly affect the growth of submerged plants over a long time, thereby affecting the restoration of submerged vegetations.