不同湿地植物对外源氮输入的响应

通过半人为控制模拟试验研究了土壤含氮量及黄花鸢尾、睡莲、芦苇、杞柳4种湿地植物含氮量不同月份的差异及土壤含氮量对植物含氮量和生物量的影响,分析了土壤含氮量与植物含氮量、生物量之间的相关关系.结果表明:当土壤施氮量为80g·m-2时,黄花鸢尾和睡莲含氮量达到最大,分别为(19.93±4.63)、(60.49±7.75)g·kg-1;种植黄花鸢尾和睡莲筛选池内土壤含氮量整体呈下降的变化趋势,杞柳和芦苇筛选池内土壤含氮量先降低后升高,9月份达最低值,分别为(0.89±0.14)、(0.82±0.15)g·kg-1;4种湿地植物生物量的变化存在一定的时间差异;湿地土壤含氮量对不同植物生物量的影响不同,睡莲和杞柳生物量与土壤含氮量之间呈线性相关.4种湿地植物含氮量与土壤含氮量之间存在一定的相关性,其中,杞柳、芦苇含氮量与土壤氮含量之间呈线性相关.

Responses of Wetland Plants to Exogenous Nitrogen Inputs

Semi-artificial control simulation was used to study the seasonal variation of nitrogen in soil and four types of wetland plants. The effects of different soil nitrogen contents on plant biomass were analyzed, the relationships between soil nitrogen and the nitrogen in wetland plants, and between soil nitrogen and plant biomass were analyzed. The results showed that the total nitrogen (TN) in Nymphaea tetragona and Phragmites australis had an inverse fluctuation after September while the TN in Iris wilsonii and Nymphaea tetragona reached the values of (19.93±4.63) g·kg^-1and (60.49±7.75) g·kg^-1 at a maximum soil nitrogen input of 80 g·m^-2. The soil nitrogen, with the plants of Iris wilsonii and Nymphaea tetragona, changed downward in overall, while the soil nitrogen, with the plants of Phragmites australis and Salix purpurea, declined to the minimum value at September (Phragmites australis: (0.89±0.14) g·kg^-1; Salix purpurea: (0.82±0.15) g·kg^-1) and then increased. The seasonal variations in the biomass existed for the four types of wetland plants. The effects of soil nitrogen on plant biomass changed among different types of wetland plants. Exponential relationships were found between the soil nitrogen and plant biomass of Nymphaea tetragona and Salix purpurea. The soil nitrogen was related to the nitrogen in the four types of wetland plants, and a linear relationship was found between the soil nitrogen and the nitrogen in Phragmites australis, while the nitrogen in Salix purpurea changed quadratically with the soil nitrogen.