城市湖泊富营养化对水生植物叶片C、N、P化学计量特征的影响

Influences of Urban Lakes Eutrophication on the C,N and P Stoichiometric Characteristics in Leaves of Aquatic Macrophytes

为研究城市湖泊富营养化对水生植物叶片元素组成的影响,在植物生长季,对南京3个湖泊的6种常见水生植物进行碳(C)、氮(N)、磷(P)生态化学计量学研究,并分析驱动水生植物叶片元素变化的关键环境因子。结果表明:(1)水生植物叶片C、N、P含量变化范围分别为397.03~672.70、10.63~39.16及1.15~13.30 mg/g,叶片C/N、C/P及N/P变化范围分别为13.15~50.36、31.39~458.60及1.88~19.06,其中叶片P含量变异最大,叶片C含量变异最小;(2)Spearman相关性分析表明,芦苇(Phragmites australis)、睡莲(Nymphaea tetragona)和金鱼藻(Ceratophyllum demersum)叶片元素组成与湖泊富营养化综合指数具有显著相关性,叶片P含量随湖泊富营养指数升高而增加,叶片C/P及N/P随之减小;(3)RDA分析表明,春季水生植物叶片C、N、P含量及C/N/P变化主要受水体高锰酸盐指数(CODMn)和底泥总有机碳(SOC)含量的共同影响,夏季主要受水体总磷(TPW)浓度的影响,秋季主要受底泥总磷(TPS)含量的影响。

In order to study the influences of urban lakes eutrophication on the elemental compositions of aquatic macrophytes,carbon(C),nitrogen(N),and phosphorus(P)ecological stoichiometry studies were conducted on six common aquatic macrophytes in three lakes during the growing season,and key environmental factors that driving the changes of the leaf elements were explored.The results showed that:(1)The changing ranges of C,N,P contents in leaves of aquatic macrophytes in different lakes were respectively from 397.03 to 672.70 mg/g,10.63 to 39.16 mg/g and 1.15 to 13.30 mg/g;the ranges of C/N,C/P and N/P were respectively from 13.15 to 50.36,31.39 to 458.60 and 1.88 to 19.06,among which P contents in leaves varied the greatest and C contents varied the smallest.(2)Spearman’s correlation analysis suggested that the elemental compositions of leaves of Phragmites australis,Nymphaea tetragona and Ceratophyllum demersum had significant correlations with the eutrophication index of water bodies;P contents in leaves increased with the rise of the lake eutrophication index,but C/P and N/P in leaves decreased accordingly.(3)RDA analysis showed that the changes of C,N,P contents and C/N/P in leaves of aquatic macrophytes in spring were mainly affected jointly by the permanganate index(CODMn)of the water and the total organic carbon contents of sediment(SOC);while in summer they were affected mainly by the concentrations of total phosphorus in water(TPW),and in autumn by the contents of the total phosphorus in sediment(TPS).