二氧化碳浓度升高对太湖沉水植物马来眼子菜生长的影响

通过室外培养试验，研究不同CO₂浓度条件下沉水植物马来眼子菜的生长及生理变化.结果表明：CO₂浓度升高(1000 μmol·mol^-1)条件下，马来眼子菜单株的平均生物量增加了44.3%(P<0.01)，茎生物量比重下降了5.5%(P<0.05)；根和叶中氮含量分别下降了18.1%和6.4%(P<0.05)，而茎中氮含量变化不明显(P>0.05)；根、茎、叶中磷含量分别增加了22.2%(P<0.05)、26.6%(P>0.05)和38.8%(P<0.05)；可溶性糖含量增加了27.3%、18.3%和37.5%(P<0.05)；根、茎和叶中全碳含量增加了4.6%、5.3%和2.0%；CO₂浓度升高使水体中氮、磷含量分别下降了7.9%和5.1%(P<0.05)，但对底泥中氮、磷的含量影响不明显.CO₂浓度升高将对沉水植物生长及其生境有一定影响.

Effects of elevated CO2 concentration on the growth of submerged macrophyte Potamogeton malaianus in Taihu Lake.

An outdoor culture experiment was conducted to study the growth and nutrient con tents of submerged macrophyte Potamogeton malaianus in Taihu Lake unde r different CO2 concentrations. As affected by elevated CO2 concentration (1 000 μmol·mol-1), the biomass per plant increased by 443% (P<001) , but the shoot biomass decreased by 55% (P<0.05). The N content in root a nd leaf decreased by 181% (P<005) and 64% (P<005), respectively, but that in stem was less affected (P>005). The P content in root, shoot, and leaf increased by 222% (P<005), 266% (P>005) and 388% ( P<005), soluble sugar content increased by 273%, 183% and 375% (P< 005), and total C content increased by 46%, 53% and 20%, respectively. E levated CO2 concentration decreased the N and P concentrations in w ater body by 79% and 51% (P<005), respectively, but had less effects o n the N and P contents in sediment. It was suggested that elevated CO2 concent ration had definite effects on the growth and habitat of submerged macrophytes.