中国河湖岸带草本植物氮磷化学计量学及内稳性特征

Nitrogen and phosphorus stoichiometry and homeostasis characteristics of herbaceous plants in the riparian zone of rivers and lakes in China

河湖岸带是拦截净化氮磷等陆源污染物进入河湖水体的最后屏障,河湖岸带草本植物的稳定性影响着其对污染物的拦截净化能力,研究河湖岸带草本植物生态化学计量学及内稳性,可为河湖岸带草本植物群落恢复和构建提供基础数据。通过对中国河湖岸带草本植物地上部氮(N)、磷(P)含量及土壤或沉积物、水体进行数据收集,分析了植物氮磷化学计量学和内稳性特征及其与环境因子的关系。结果表明:青藏高原湖区草本植物具有较高的N含量(湿生植物:20.51 g·kg^(-1),水生植物:29.81 g·kg^(-1))和较低的P含量(湿生植物:1.39 g·kg^(-1),水生植物:0.99 g·kg^(-1)),N:P>14,表现为P限制,而其他湖区草本植物具有较高的P含量(2.73 g·kg^(-1)),N:P<14,表现为N限制。各湖区植物N、P含量及其比值在空间上具有一定差异,青藏高原湖区水生植物N含量最高,东北平原与山地湖区最低(P<0.05);东北平原与山地湖区湿生和水生植物P含量最高(P<0.05);青藏高原湖区湿生和水生植物N:P最高,东北平原与山地湖区最低(P<0.05)。植物N、P含量及N:P受环境中P含量影响最大,其次是环境中N:P和N含量。内稳性模型表明河湖岸带草本植物属于稳态型,其中湿生植物内稳性指数HN、HP及HN:P大于水生植物,表明水生植物受环境胁迫时响应较大,水生和湿生植物对环境中N、P含量变化响应的差异表明水生和湿生植物对环境中N、P不同的保守利用策略。

The riparian zone of river and lake is the ultimate barrier to intercept and purify N,P pollutants into rivers and lakes.Stability of herbaceous plants in riparian zone affects their ability to intercept and purify pollutants.Ecological stoichiometry and homeostasis characteristics of herbaceous plants were studied to provide basic data for the restoration and construction of herbaceous plant communities in riparian zone.The plant N,P stoichiometry and homeostasis characteristics and their relationships with environmental factors were analyzed by collecting data on the N,P contents in herbaceous plants above ground,soil or sediment and water in the riparian zones of rivers and lakes in China.The results showed that herbaceous plants in the lake area of Qinghai-Tibet Plateau had high N content(wetland plants:20.51 g.kg^(-1),aquatic plants:29.81 g·kg^(-1))and low P content(wetland plants:1.39 g·kg^(-1),aquatic plants:0.99 g·kg^(-1)),N:P>14,exhibiting P limitation,while herbaceous plants in other lake areas had high P content(2.73 g·kg^(-1)),N:P<14,showing N limitation.The N,P contents in plant and their ratios in different lake areas had certain spatial differences.The N content in aquatic plants was the highest in the lake area of Qinghai-Tibet Plateau,and the lowest in the lake area of Northeast Plain and Mountain(P<0.05).The P contents of wetland and aquatic plants were the highest in the lake area of Northeast Plain and Mountain(P<0.05).The N:P in wetland and aquatic plants were the highest in the lake area of the Qinghai-Tibet Plateau,and the lowest in the lake area of Northeast Plain and Mountain(P<0.05).The plant N,P contents,and N:P were most affected by P content in the environment,followed by N:P and N content in the environment.The homeostasis model showed that herbaceous plants in riparian zone belonged to the steady-state type,the homeostasis indices HN,HP,and HN:P of wetland plants were higher than those of aquatic plants,indicating that aquatic plants were more responsive to environmental stress.The differences in response of aquatic and wet plants to changes in N and P contents in the environment indicates that aquatic and wetland plants had different conservative utilization strategies for N and P in the environment.