[Effects of leaf damage and sediment type on compensatory growth of submerged macrophyte Vallisneria spiralis].

Through a 2 x 2 factorial outdoor experiment, the effects of leaf damage and sediment type on the compensatory growth of submerged macrophyte Vallisneria spiralis were examined. The results showed that leaf damage and sediment type had significant effects on the cumulative biomass, biomass allocation, and ramet number of V. spiralis. Compared with undamaged plant, the strongly damaged one had a decrease of cumulative biomass and ramet number and an increase of biomass allocation, but no evident difference was observed between weakly damaged and undamaged plants. The cumulative biomass of undamaged and strongly damaged plants was lower in infertile sediments (bank sediment) than in fertile sediments (lake sediment), but that of weakly damaged plant was almost the same in the two sediments. The biomass allocation and ramet number of V. spiralis were higher in bank sediment than in lake sediment. Leaf damage and sediment type also affected the relative growth rate (RGR) of V. spiralis. Leaf damage resulted in an increase of RGR, but the difference of RGR between weak damage and strong damage was not evident. The RGR of undamaged and strongly damaged plants was significantly higher in lake sediment than in bank sediment, but that of weakly damaged plant was almost the same in the two sediments. The mechanisms of the compensatory growth of V. spiralis were discussed.