作 者 ：刘伟龙,胡维平,谷孝鸿
期 刊 ：生态学报 2007年 27卷 8期 页码：3324~3333
关键词：马来眼子菜；生物量；水深；氮磷比；透明度；底泥；太湖；
Keywords:Potamogeton malaianus, biomass, water depth, N-P ratio, transparency, sediment characteristics, Lake Taihu,
摘 要 ：2006年5月和10月在太湖马来眼子菜分布区进行了定点采样，分析了马来眼子菜的生物量在不同水域变化特征及影响其生物量主要因素。结果表明：不同水环境中，马来眼子菜的生物量变化较大，介于526~4843 g/m2，个体植株生物量依次为叶>根>茎，其中叶的生物量占总生物量的55%~80%。水深增加能促进植株高度和生物量的增加，但单位面积生物量变化不明显。群落的自疏效应使马来眼子菜生物量与资源供应维持在一个动态平衡的水平上。马来眼子菜的生物量与水体中TN呈显著正相关，P是影响其生物量变化的间接限制因子，根、茎、叶的N/P介于16.92~59.88之间，叶片的N/P达到42.33。马来眼子菜对水环境的形态可塑性响应是其在水环境长期变化中逐步成为幸存者和优势种的重要原因之一。底泥的深度和营养含量对其分布和生物量具有显著影响。围网捕捞、养殖以及航运的发展是造成局部地区马来眼子菜生物量急剧下降的主要人为因素。不同水域的生物量的差异是水深、水体营养盐、底质特征、水体透明度、人类活动等因素综合作用的结果。同时，对水环境变化在形态上较强的可塑性响应，也是马来眼子菜生物量变化的重要原因之一。
Abstract:The biomass is a quantitative descriptor of the growth form of submerged macrophytes. Biomass indicates an important ecological characteristic of macrophytes communities because it is closely related to the influence of plants on the extinction of light within stands. Biomass also influences the communities of benthic invertebrates in vegetated sediment and fish abundance in weed beds. Biomass reflects the growth form of the dominant species in the stand, because stands of species with similar growth forms also have similar biomass. Biomass has important implications for light capture and light competition with neighboring plants. Thus, biomass should be a useful index in the quantitative analysis of submerged macrophytes community structure.
Potamogeton malaianus Miq. is one of the dominant species in Lake Taihu, whose ecosystem has been deteriorating due to the increasing amount of pollutants discharged into the water body since the 1980s. P. malaianus forms a monotypic stand in many water zones in Lake Taihu. In order to have a better understanding of the biomass of P. malaianus and why it is becoming the dominant species in Lake Taihu, two investigations of the biomass of P. malaianus, along with water quality and sediment, were performed in different sites in May and October, 2006. The results show that, (1)The biomass of P. malaianus varies greatly (526-4843 g m-2 )in the different sites and Bleaf > Broot > Bstem per individual P. malaianus. The Bleaf is 55%~80% per individual P. malaianus. (2) Stem height and biomass are directly proportional to water depth. P. malaianus can regulate its biomass via the self thinning effect to meet the resource supply and light availability. (3) There is positive correlation between biomass and TN content in water. N-P ratio in different component is all beyond 16, ranging from 16.92 to 59.88. The mean value of N-P ratio of the leaf is 42.33. Phosphorous is the main indirect influential factor on the growth of P. malaianus. (4) Water transparency is the main limiting factor of the survival ability and biomass variation of P. malaianus in Lake Taihu. The high phenotypic plasticity enhances the survival ability of P.malaianus in the adverse transparency environment. (5)The sediment depth shows a prominent effect on the distribution and BD of P. malaianus. The decomposed P. malaianus contributes to the organic matter in sediment and releases toxins to limit plant growth. The morphological adaptive ability of the structure of P. malaianus helps the plant to survive the adverse effect. Fishing activities and water transportation cause great damage to the BD of P. malaianus.