Impact Of C、N、P Ecological Stoichiometry And Growth Of Submerged Plant By Eutrophication Water

Shanghai is leading the urbanization of China, thus the environmental problems are serious. This research studied the ecology of submerged plants under different urbanization gradient, ie the central urban area, the developing urban area and the suburb area. Water and submerged plants in 20 parks were sampled to survey the water quality and morphological, physiology and stoichiometric traits. The main research results are as followings:(1)The N and P contents of landscape water were most polluted in the developing urban area followed by the suburb area the central urban area:In winter, the TN content in the central urban is 475.1-4758.3ug/L, TP is 13.3-320.9ug/L; the TN content in the suburb is 738.3-4738.9ug/L, TP is 36.6-2815.3ug/L; the TN content in the outer suburbs is 484.6-4848.3ug/L, TP is 23.8-542.3ug/L. In summer.the TN content in the central urban is 1358.2-3607.9ug/L, TP is 18.9-267.0ug/L; the TN content in the suburb is 1729.9-4971.1ug/L, TP is 49.4-205.9ug/L; the TN content in the outer suburbs is 1729.9-4971.lug/L, TP is 49.4-904.6ug/L.(2)The internode length is different among species, The moisture content did not show significant differences. In winter, the internode length of Potamogeton crispus is 1.1-3.6cm; in summer the internode length of Hydrilla verticillata is 0.6-2.2cm, Ceratophyllum demersum L. Is 0.7-5.6cm, Cabomba caroliniana is 2.4-5.6cm, Myriophyllum verticillatum is 1.2-2.7cm. In winter, the Potamogeton crispus’s content of chla is 6.7-16.2mg/L, the content of MDA is 0.03-1.67umol/L; in summer, the Hydrilla verticillata’s content of chla is 3.9-9.8mg/L, the content of MDA is 0.76-2.33umol/L; the Ceratophyllum demersum L.’s content of chla is 3.7-8.2mg/L, the content of MDA is 0.18-1.04umol/L; the Cabomba caroliniana’s content of chla is 7.6-10.4mg/L, the content of MDA is 0.40-0.95umol/L; the Myriophyllum verticillatum’s content of chla is 4.3-9.9mg/L, the content of MDA is 0.63-1.62umol/L. In winter, the Potamogeton crispus’s content of TC is 247.9-400.0g/kg, the content of TN is 41.8-66.3g/kg, the contnet of TP is 0.16-0.18g/kg. In summer, the Hydrilla verticillata’s content of TC is 276.0-377.0g/kg, the content of TN is 13.8-41.2g/kg, the contnet of TP is 0.49-0.79g/kg; the Ceratophyllum demersum L.’s content of TC is 273.8-401.6g/kg, the content of TN is 115.7-47.2g/kg, the contnet of TP is 0.42-0.64g/kg; the Cabomba caroliniana’s content of TC is 326.1-390.7g/kg, the content of TN is 8.4-69.4g/kg, the contnet of TP is 0.17-0.76g/kg; the Myriophyllum verticillatum’s content of TC is 272.5-379.0g/kg, the content of TN is 3.5-29.5g/kg, the contnet of TP is 0.04-0.53g/kg.The results indicated that, the internode length and content of MDA were increased with the eutrophication degree, while the content of chlorophyll was decreased; Eutrophication resulted in the decrease of TC、TN、C/N and the increase of TP、/P、N/P. Among the different submerged plant species, Potamogeton crispus and Cabomba caroliniana could grow very well in high nutritional conditions, Hydrilla verticillata and Ceratophyllum demersum L. were found to grow well in varied nutrition conditions. Additionally, the plant physiological, biochemical indexes and ecological stoichiometry characteristics were correlated with water N and P contentions.