Effects of snail herbivory and sediment type on the growth of Vallisneria spiralis
螺类牧食与沉积物类型对苦草生长的影响

An outdoor experiment was conducted to investigate effects of the herbivory of snail Radix swinhoei and sediment type on the growth of submerged macrophyte Vallisneria spiralis from June to August in 2006.Results showed that snail herbivory on plant tissue suppressed V.spiralis growth.Furthermore,herbivory damage resulted in a decrease in tuber number and weight.Plant growth was affected by sediment type.The relative growth rate of V.spiralis was much higher in fertile lake sediment treatment than that in infertile soil treatment.Besides,root number and tuber weight were significantly lower in lake sediment treatment than that in soil treatment.However,the interactive effects of both snail herbivory and sediment type on the growth of V.spiralis were not significant.