太湖水生植物氮磷与湖水和沉积物氮磷含量的关系

 分析了太湖沉水植物、浮叶植物组织及生长环境中的N、P含量，结果表明：太湖沉水植物组织N、P含量一般要高于浮叶植物组织，5月的N、P含量(以干重计)一般高于9月。5月以沉水植物微齿眼子菜(Potamogeton maackianus)的N(28.452 mg?g－1)、轮叶黑藻(Hydrilla verticillata)的P(4.552 mg&;#8226;g^－1)含量最高，浮叶植物荇菜(Nymphoides peltatum)的N(14.363 mg&;#8226;g^－1)、P(1.792 mg&;#8226;g^－1)含量均为最低；9月以沉水植物苦草(Vallisneria natans)的N(25.206 mg&;#8226;g^－1)、P(2.727 mg&;#8226;g^－1)含量最高，浮叶植物荇菜的N(17.245 mg&;#8226;g^－1) 、P(1.519 mg&;#8226;g^－1)含量均最低。沉水和浮叶植物的N、P含量与水体N、P浓度的相关性较为显著；与沉积物N、P的相关性不明显。此外，植物体内的N、P含量亦与植物物种的特性、生长发育阶段和生长状况等内在因素密切相关。

RELATIONSHIP BETWEEN N AND P CONTENTS IN AQUATIC MACROPHYTES,WATER AND SEDIMENT IN TAIHU LAKE, CHINA

Aims Our objectives were to 1) examine relationships between N and P contents in aquatic macrophytes, water and sediment in Taihu Lake, a eutrophic ecosystem, and 2) explore factors controlling N and P contents in plants in relation to plant characters, such as growth status and developmental stage.  Methods We selected 32 sampling sites in the emerging-plants-free water zone of Taihu Lake and collected plant samples twice with the quadrat method, sampled sediment with column-shaped samplers at different depths, and measured relevant parameters. Concentrations of total phosphorus and total nitrogen of sediment samples with and without macrophytes were measured with the Kjeldahl method and ICP-AES atomic absorption spectrometry, respectively, and those in tissues of aquatic plants were measured by Kjeldahl automatic N analyzer and molybdate-ascorbic colorimetric determination, respectively.  Important findings The N and P contents of tissues of submerged macrophytes were higher than floating-leaved macrophytes, and the nutrient contents were higher in May than in September. Significant correlations were found between the concentrations of N and P in plants and in water, but not in sediments. The N and P contents in plants were highly dependent on plant growth status and developmental stage. Our study provides the insight for the restoration of the eutrophic Taihu Lake ecosystem.