太湖环棱螺对两种常见沉水植物生长的影响

环棱螺(Bellamya sp.)是太湖常见的一类软体动物.本研究通过室内实验,探讨环棱螺对轮叶黑藻(Hydrilla verticillata Royle)和伊乐藻(Elodea nuttalli ST John)生长的影响及水体营养盐含量的变化.结果表明,三种处理情况下,单位质量伊乐藻增加的数量分别为:H组0.475 g,L组0.106 g,C组0.021 g,单位质量轮叶黑藻增加的数量分别为:H组0.704 g,L组0.663 g,C组0.478 g.从实验前后两种沉水植物的长度和分蘖数变化来看,H组最高,L组与C组分别次之,所以不论生物量、长度还是分蘖数的变化量,与环棱螺共存的伊乐藻和轮叶黑藻的变化都高于对照组中两种沉水植物的变化.环棱螺新陈代谢促进水体中溶解态氮磷含量增加,三种情况下水生植物的初级生产力都相当,由此可推测环棱螺通过新陈代谢,一定程度上促进了两种沉水植物的生长.

The effects of Bellamya sp. on the growth of two submerged macrophytes in Lake Taihu

Bellamya sp.snails are very common in Lake Taihu.The effects of snail(Bellamya sp.) on the growth of Hydrilla verticillata Royle and Elodea nuttalli ST John and dissolved nutrition elements were examined in a labo- ratory.After a week of exposure of snail and aquatic plant in a experiment,increments of the per unit of Hydrilla verticillata Royle in three groups were:H:0.475 g,L:0.106 g,C:0.021 g and increments of the per unit of Elode- a nuttalli ST John were H:0.704 g,L:0.663 g,C:0.478 g respectively.In addition,the change of length and node of Hydrilla verticiUata Royle and Elodea nuttalli ST John with snail were higher than those without snail,It could be concluded that the increase of nutrition by snail in water could stimulate the growth of HydriUa verticiUata Royle and Elodea nuttalli ST John,because the metabolism of Bellamya sp.increased the nutrition of water and the primary productivity of aquatic plant were similar in three situations with the same experiment environment.