中文摘要：

水位变化影响湿地水生植物群落的初级生产力、物种多样性及群落结构. 鄱阳湖作为我国最大的吞吐型、季节性浅水通江湖,其水位季节性变化显著. 通过对2009-2010年鄱阳湖3个水情期（丰水期、平水期、枯水期）的湖泊生态学调查,分析水位波动对鄱阳湖植物群落及植物的影响特征. 结果表明：丰水期鄱阳湖高水位导致草滩湿地植被被完全淹没,潜水型湿生植物受高水位胁迫,多采取休眠或耐受的生存策略度过不利时期. 该时期沉水和浮叶植物占优势,优势种为竹叶眼子菜、微齿眼子菜、苦草、轮叶黑藻、金鱼藻和荇菜.2009年枯水期鄱阳湖低水位创历史新低且提前近1个月到来,湖洲滩地的湿生植被也提前近1个月萌发,洲滩以虉草、灰化苔草、蒌蒿、水蓼、千金子和蓼子草占优势,中高位草滩以中生-湿生植物类群占优势. 平水期鄱阳湖洲滩部分被淹没,形成较明显水位梯度,优势湿生植物苔草属植物和虉草的地上部分生物量在水位梯度上变化显著.

英文摘要：

Water level can be used as an important ecological variable to indicate the growth and propagation of wetland plants. It has effects on the plant community composition and species biodiversity. Water level fluctuation is a crucial factor to shape the primary productivity, biodiversity and structure of aquatic macrophyte community in the wetland. Poyang Lake is the largest shallow river-connected lake in China, with significantly seasonal water-level fluctuation affected by the floods and drawdown of the Yangtze River and other inflowing rivers. This study explored how the water-level fluctuation affects the aquatic macrophytes in Poyang Lake. The adaption strategies in response to submergence and emergence were also investigated. The study was conducted through the lake investigation in three water regime periods （high-water period, normal-water period and low-water period） from 2009-2010. High water level gave rise to the complete submergence of wetland plant species such as phreatophytes, hygrophytes and hydrophytes, in Poyang Lake during the high-water period. The phreatophytes were stressed by high water-level mainly adopted either dormancy or tolerance （termed as quiescence） strategy to pass through this adverse time. Meanwhile, submersed and floating-leaved plants were rich in the wetland, and the dominant species were Potamogeton malaianus, P. maackianus, Vallisneria natans, Hydrilla verticillata, Ceratophyllum demersum and Nymphoides peltata. The records of the lowest water level had been broken in Poyang Lake during the low-water period, and drawdown was greatly brought forward within one month. Water level regime was broken markedly in low-water stage of Poyang Lake. The phreatophytes in bottomland also germinated early about one month. Phalaris arundinacea, Carex cinerascens, Artemisia selengensis, Polygonum hydropiper, Leptochloa chinensis and P. criopolitanum dominated in the bottomlands, and meso-hygrophyte species were dominant in middle-and high-level grasslands. The bottomlands of Poyang