太湖湖滨湿地沉积物氮磷与2种挺水植物氮磷的关系

Relationship between N and P contents in sediments and two emerged plants in Taihu Lakeside wetland

在无锡太湖湖滨带布设3条样带、36个样点进行了调查,分析了表层沉积物（0~15 cm）和芦苇（Phragmites australis（Cav.）Trin.）、茭白（Zizania latifolia（Griseb.）Turcz.）2种挺水植物w（N）、w（P）的变化,揭示了沉积物N、P的空间分布以及与2种挺水植物N、P的关系。结果表明：（1）表层沉积物w（N）自上而下分别为7.89~4.24 mg.g-1（0~5 cm）、7.56~3.81 mg.g-1（0~10 cm）、7.61~3.77 mg.g-1（0~15 cm）,w（P）分别为1.293~0.532 mg.g-1（0~5 cm）、1.112~0.497 mg.g-1（0~10 cm）、0.952~0.471 mg.g-1（0~15 cm）。（2）生态修复区表层沉积物N、P的水平变化规律一致,按陆向辐射区-水位变幅区-水向辐射区依次递减,而从垂直变化来看,w（N）、w（P）均以表层最高,并依次向下层递减;硬质护坡区P的变化与之一致,但N的水平分布却按陆向辐射区-水位变幅区-水向辐射区依次递增,垂直分布呈现表层最低,并依次向下层递增变化。（3）2种挺水植物w（N）、w（P）不同,芦苇对N、P的吸收明显高于茭白（芦苇地上部分w（N）31.75~42.61 mg.g-1,地下部分w（N）13.57~18.21 mg.g-1;茭白地上w（N）14.78~23.57 mg.g-1,地下部分w（N）13.57~18.21 mg.g-1,而芦苇地上部分w（P）3.62~5.08 mg.g-1,茭白地上部分w（P）1.42~1.93 mg.g-1,地下部分w（P）0.35~0.57 mg.g-1）。2种挺水植物地上部分N、P吸收量远远大于地下部分吸收量。（4）相关分析表明,2种植物地下部分w（TP）与沉积物w（TP）呈正相关,而芦苇地下部分w（TP）与沉积物w（TP）相关性显著（P〈0.05）,说明芦苇根系对沉积物中的P具有强烈吸附作用。（5）2种植物对太湖中沉积物N、P分配有显著影响,生态恢复区沉积物中w（N）显著高于硬质护坡,而w（P）较硬质护坡显著降低,适度恢复水生植被可有效缓解湖泊水体的富营养化。

Three sample lines and 36 surface sediments（0~15 cm） were surveyed and sampled from various sections in riparian zone of Tai Lake Wu Xi,N and P mass fraction in sediments and two emerged plants（Phragmites australis and Zizania latifolia）were analyzed,relationship between them were discussed too.The results showed that：（1）N contents in surface sediments were from top to bottom 7.89-4.24 mg？g-1（0-5 cm）、7.56-3.81 mg？g-1（0-10 cm）、7.61-3.77 mg？g-1（0-15 cm）;P were 1.293-0.532 mg？g-1（0-5 cm）、1.112-0.497 mg？g-1（0-10 cm）、0.952-0.471 mg？g-1（0-15 cm）.（2）Horizontal change pattern of N and P of sediments in ecological restoration area（ⅠandⅡ） were consistent,that was declined according to the order,the terrestrial area,the transition area of water and terrene,the water area,while that of N and P in vertical direction was that the N and P contents was the most in surface sur-face（0-5cm）,and it declined to the low.The change of P in cement slope area（Ⅲ）were so,but that of N reversed.（3） N and P contents of two emerged plants were different,absorption of N and P of P.australis was higher than Z.latifolia.According to the analyzed results,N contents of P.australis was 31.75-42.61 mg？g-1 in overground part（OP）,13.57-18.21 mg？g-1in underground parts（UP）;that of Z.latifolia was 14.78-23.57 mg？g-1（OP） and 13.57-18.21 mg？g-1（UP）.P absorption of P.australis was 3.62~5.08 mg？g-1（OP）,and that of Z.latifolia was 1.42-1.93 mg？g-1（OP）,0.35~0.57 mg？g-1（UP）.Their absorption of both N and P in OP was bigger than tha in UP.（4）The correlation analyze showed TP in UP of two emerged plants and TP in sediments has a positive correlation,and the corre-lation of P.australis was obvious（p0.05）,so sorption of P.australis roots to P in sediments was very strong.（5）Two emerged plants has important effects on the distribution of N and P in sediments,N contents in ecological restoration area was higher than that in cement slope area,but P contents chang reversed,so the reasonable restoration emerged plants in lakeside wetland was one of the effective measures to relieve the eutrophication.