不同水体浊度对鳗草存活、生长和生理的影响

Effects of different water turbidity levels on the survival, growth and physiology of the eelgrass Zostera marina

中文关键词: 鳗草  浊度  存活  生产力  生长速率  碳水化合物

英文关键词: Zostera marina  Turbidity  Survival  Productivity  Growth rate  Carbohydrate

中文摘要:

      海水浊度升高是导致海草床退化的主要因素之一。通过3个月的室内实验，研究了不同水体浊度[2 (对照)、10、20、30和40 NTU]对鳗草存活、生长和生理的影响。结果显示，3个月后，鳗草植株的存活率随水体浊度升高呈现逐渐降低趋势，10~40 NTU处理组植株存活均显著低于对照组(P<0.05)，至40 NTU处理组，植株存活率仅为对照组的56.1%；随水体浊度升高，植株的生长速率和生产力亦呈现下降趋势，至40 NTU处理组，植株茎节延伸速率和叶片延伸速率达到最小值，分别下降至对照组的48.9%和61.6%，地上生产力和地下生产力与对照组相比下降了64.6%和78.8%；相关性分析表明，长期浊度胁迫主要是通过影响植株非结构性碳水化合物含量，进而对植株生长存活产生负面影响。植株非结构性碳水化合物含量随水体浊度增加而逐渐下降，10~40 NTU处理组植株碳水化合物含量均显著低于对照组(P<0.05)，各浊度升高处理组植株地上组织可溶性糖含量相比对照组降低了20.2%~74.7%。研究表明，水体浊度长期升高导致鳗草植株非结构性碳水化合物显著下降，对鳗草的生长存活不利。本研究为阐明鳗草海草床退化机理和选划适宜修复区等提供了理论依据。

英文摘要:

      An increase in water turbidity is one of the main factors underlying seagrass meadow degradation. The effect of different water turbidity levels [2 (control), 10, 20, 30, and 40 NTU] on the survival, growth and physiology of eelgrass (Zostera marina) was studied through a 3-month indoor experiment. The results showed that the survival rate of eelgrass decreased gradually with an increase of water turbidity, and the survival rate under 10–40 NTU conditions was significantly lower than that of the control group (P<0.05). In particular, the survival rate of eelgrass exposed to 40 NTU was only 56.1% that of the control group. With an increase of water turbidity, the growth rate and productivity of eelgrass also showed a decreasing trend. In the 40 NTU treatment group, the internode elongation rate and leaf elongation rate of eelgrass reached minimum values, which decreased to 48.9% and 61.6% of that of the control group, respectively. Compared to the productivity of the control group, aboveground and underground productivity decreased by 64.6% and 78.8%, respectively. Correlation analysis showed that the increase of water turbidity mainly affected the growth and survival of eelgrass by affecting the content of nonstructural carbohydrates. The content of nonstructural carbohydrates in eelgrass decreased gradually with an increase of water turbidity, and the content of carbohydrates in plants exposed to 10~40 NTU was significantly lower than that in the control group (P<0.05). The aboveground soluble sugar content in eelgrass exposed to 10–40 NTU was 20.2%–74.7% lower than that in the control group. The results showed that a long-term increase of water turbidity led to a significant decrease in the nonstructural carbohydrates of eelgrass, which was not conducive to its growth and survival. The results provide a theoretical basis for clarifying the degradation mechanism of Z. marina seagrass meadows and selecting suitable restoration areas.