不同水分梯度下三江平原湿地漂筏苔草无性系株高生长特性

Ecological Attributes of Carex pseudocuraica over Different water Depth in the Sanjiang Plain

取三江平原沼泽湿地漂筏苔草（Carex pSeudocuraica）无性系种群在生长季（5—9月）进行桶栽实验，设计了6个水分梯度，即持续干旱（土壤含水量S1和S2分别为20％和50％）和持续淹水（S3、S4、S5、和S6的淹水深度分别为0cm、10cm、30cm和50cm）6个水分处理水平，研究了漂筏苔草株高生长变化规律。结果表明：在6月末以前，各水分处理（S1-S6）下株高呈单峰曲线变化，高峰值分别出现在S3、S4和S5处理下。从7月份开始直到生长季末，随着生长时期的延续、土壤湿度的增大和水位的加深株高值不断增加，即株高在S6处理下最大，S1处理下最小。到8月末以后，深水处理S6的株高远远高于其它处理。生长季各水分处理下（S1-S5）的株高增长量均呈单峰曲线变化；在S6状态下株高增长量呈双峰曲线变化。处理S1、S2、S3和S4的植株高度绝对增长速率（HAGR）随着植物生长呈逐渐降低趋势；S5和S6状态下HAGR呈单峰曲线变化。随着水分含量的增加和水位的提高（6—9月），植株高度相对增长速率（HRGR）不断增加，S1处理下最小，S6处理下最大；5月份的HRGR值呈单峰曲线变化。随着植物的生长各水分处理下植株HRGR 5月时最大，6—9月依次减小。综合分析认为，漂筏苔草对水分条件的适应性较强，无论是缺水（土壤20％含水量）或淹水环境下均可生长，淹水50cm时更有利于株高的增长，不同水分条件下株高及增长速率变化幅度较大。

Carex pseudocuraica were bucked -cultured under different water contents and depths in the Sanjiang Plain. The water gradients were designed as continuous draught （S1 -20% of soil water content; S2 -50% of soil water content）, continuous flooding （ S3 -0cm of water depth; S4 - 10cm of water depth; S1 -30cm of water depth ; S6 -50 cm of water depth）. The triangular prism - shaped stems, whose bases slanted towards flow direction, could be separated into rhizomes and stems fractions, both of which were composed with nodes and intemodes. The stem height increased with different water content and depth （ S1 - S6 ） showing unimodal curves with the peak in S3, S4 and S5 before end of June, compared with that showing a linear trend, the largest in S6, then decreased gradually in S5, S4 ,S3 ,S2 ,the smallest in Sl, showing the greatest height （ 160 cm） in deep water （ S6 ） scenario from July to the end of the growing season. The stem height increment （ S1 - S5 ） showed unimodal curves with the peak in June, while that of S6 showed bimodal curve with the first peak （35cm） in June and the second （60 cm） in August. The Height Absolute Growth Rate （HAGR） decreased gradually with the sedges＇ growth in S1 to S4, while that of S5 and S6 showed unimodal curves from June to the end. The Height Relative Growth Rate （HRGR） of stem height increased with water contents and depths. As far as specific month, the HRGR （S1 -S6） in May, showed unimodal curves with the peak in S5 of May, was greater than other months and decreased with time from then on.. In conclusion, Carex pseudocuraica could grow in either arid （20% water content in soil） or flooded conditions under artificial simulation and performed better in the latter, showing significant adaptability.