Ecophysiological response of a wetland plant (<i>Carex cinerascens</i>) to different groundwater depths in Lake Poyang wetland

Abstract

地下水位在非淹水期对湿地植物的生长影响较大，但目前相关研究十分缺乏.本文选择鄱阳湖典型植被灰化薹草（Carex cinerascens）为研究对象，研究不同地下水位（地下水位埋深10、20、40、80和120 cm）对灰化薹草形态指标、地上生物量和生理指标的影响.结果表明，随着地下水位埋深的增加，灰化薹草的株高、叶长和生物量均显著降低，地下水位10 cm处理组的灰化薹草生物量为0.371±0.017 g，为地下水位120 cm处理组（0.084±0.004 g）的4.4倍；处理组间灰化薹草叶片中超氧化物歧化酶活性、过氧化物酶活性、游离脯氨酸含量和叶绿素含量均存在显著差异，其中游离脯氨酸含量由地下水位10 cm处理组的6.29±0.70 μg/g增加到地下水位120 cm处理组的8.54±1.37 μg/g，表明随着地下水位埋深的增加，灰化薹草面临一定程度的干旱胁迫.灰化薹草的生理生态响应综合表明，地下水位埋深20 cm以内适宜灰化薹草的生长，地下水位埋深80 cm以上的干旱胁迫会阻碍灰化薹草的生长.;Groundwater depth is important to wetland vegetation during non-inundation. However, the relationship between groundwater and wetland plants is still scarce. In this study, we investigated the effects of groundwater depth on the growth of Carex cinerascens, one of the dominant species in the Lake Poyang wetland based on controlled experiments. The experiment includes five groundwater depth treatments (10, 20, 40, 80 and 120 cm). Morphological and physiological characteristics of C. cinerascens as well as aboveground biomass were monitored. The results showed that the plant height, leaf length and aboveground biomass decreased with increasing groundwater depth. The biomass in 10 cm treatment (0.371±0.017 g) is 4.4 times of that in 120 cm treatment (0.084±0.004 g). The groundwater depth has significant effect on the enzyme activities, proline and chlorophyll. The proline content increased from 6.29±0.70 μg/g in 10 cm treatment to 8.54±1.37 μg/g in 120 cm treatment. These physiological differences among treatments suggested C. cinerascens would encounter some drought stress along with increased groundwater depth. All the results indicated areas with groundwater depth of less than 20 cm were suitable for C. cinerascens growth, but the growth of C. cinerascens would be impeded when the groundwater depth was below 80 cm.