模拟水深和氮添加对三江平原湿地植物功能性状的影响

水深和氮素是影响湿地植物生长的关键因素,研究两者对功能性状的影响有助于预测未来环境变化下湿地植物的生长与分布趋势.以三江平原沼泽湿地3种优势植物(漂筏苔草Carex pseudocuraica、毛苔草Carex lasiocarpa和燕子花lris laevigata)为研究对象,设置3个水深(0、5、15 cm)和3...

Effects of simulated water depth and nitrogen addition on functional traits of wetland plants in Sanjiang Plain

Water depth and nitrogen are the key factors affecting the growth of wetland plants. The studies, which examined their combined effects, can help predict the growth and distribution of wetland plants under future environmental changes. Three dominant plants(Carex pseudocuraica, Carex lasiocarpa, and Iris laevigata) in the marsh wetland of the Sanjiang Plain were used as the experimental organisms. We conducted a two-factor control experiment with three levels of water depth(0, 5, and 15 cm) and three levels of nitrogen concentration(0, 12, and 36 mmol/L) to explore their effects on the functional traits of the three types of wetland plants. Water depth and nitrogen addition have interactive effects on the root : shoot ratio of C. pseudocuraica;and the height, belowground and above-ground biomass, and root : shoot ratio of I. laevigata. At 0 mmol/L nitrogen concentration, the root : shoot ratio of C. pseudocuraica decreased, and the root : shoot ratio of I. laevigata decreased first and then increased with increasing water depth. At a nitrogen concentration of 12 mmol/L, the below-ground and aboveground biomass of I. laevigata decreased, and the root : shoot ratio increased with increasing water depth. With the increase in nitrogen concentration, the height of I. laevigata decreased at water depths of 0 and 5 cm, and increased at a water depth of 15 cm. Water depth has a significant effect on the leaf area, below-ground and above-ground biomass of C. pseudocuraica, and the leaf area of I. laevigata. With increasing water depth, the leaf area, below-ground and above-ground biomass of C. pseudocuraica increased at first and then decreased;the leaf area of I. laevigata decreased. Nitrogen addition has a significant effect on the height, leaf area, and root : shoot ratio of C. lasiocarpa. With increasing nitrogen concentration, the height and leaf area of C. lasiocarpa decreased, and the root : shoot ratio of C. lasiocarpa decreased at first and then increased. The response of wetland plants to water depth and nitrogen addition depended on particular species and their functional traits. Future studies should strengthen the research on the below-ground traits of wetland plants.