东太湖四角菱（Trapa quadrispinosa）生长特性

通过室外受控实验,研究了在不同沉积物类型及不同水体营养水平条件下东太湖四角菱的生长特性.结果表明:沉积物类型对菱的各项生长指标均有显著影响.在营养相对丰富的湖泥中,菱的相对生长率、同化根与吸收根的生物量以及株高增长率分别为相对贫瘠的岸泥的4.3、2.4、7.3、2.5倍,菱盘直径增长率在湖泥中为16.5%,在岸泥中则为负增长(-13.2%).水体营养盐浓度升高在一定程度上也促进了菱的生长,而且营养盐浓度(尤其是磷)升高对菱生长的促进作用在岸泥中要比在湖泥中显著得多.探讨了沉积物类型与水体营养水平对菱生长的作用机理,并认为水体富营养化的加剧及湖泊沼泽化所造成的氮、磷等营养物质在沉积物中的大量积累是东太湖菱种群迅速扩张的重要原因之一.

The growth characteristics of floating\|leaved macrophyte Trapa quadrispinosa in East Taihu Lake

Effects of nutrient levels in sediments and water column on growth of floating\|leaved plant Trapa quadrispinosa were evaluated through a 2×2 factorial outdoor experiment. The results showed that nutrient levels of sediments had significant effects on the growth of T. quadrispinosa. For the relative growth rate (RGR), the percentage increase in plant height and rosette diameter, and the biomass of aquatic and anchoring roots, they were significantly greater in high\|nutrient sediments than in low\|nutrient sediments. Increased concentrations of nutrients in water could stimulate the growth of plant T. quadrispinosa. Nutrient addition (especially for phosphorus) in water resulted in a more significant plant growth in the low\|nutrient sediments than in the high\|nutrient sediments. The study suggests that eutrophication of water body and accumulated nutrients in sediments with swampy tendency may be causes that the stock biomass of floating\|leaved macrophyte Trapa quadrispinosa in East Taihu Lake has increased rapidly recently.