模拟积水深度下若尔盖高原木里薹草叶片的生理生态特征

为了研究不同积水深度下若尔盖高原木里薹草(Carex muliensis)叶片的生理生态特征,于2016年4月23日,在若尔盖县喀哈尔乔县级湿地自然保护区内,将生长着木里薹草的原状土柱移栽至若尔盖湿地国家级自然保护区管理局实验场的木箱内,使木里薹草继续生长;设置3种模拟积水深度,分别为20 cm、10 cm和0 cm(无积水),于2019年6月30日、7月16日和8月1日,测定各积水深度下木里薹草叶片的光合气体交换参数、叶绿素荧光参数和生长指标。研究结果表明,随着积水变浅至无积水,3个观测日的木里薹草叶片的净光合速率、气孔导度和蒸腾速率都显著减小(n=5,p<0.05),而胞间CO2浓度显著增大(n=5,p<0.05);积水深度变化对木里薹草叶片的最小荧光产量、PSⅡ反应中心最大光化学效率和碳稳定同位素δ13C值无显著影响;随着积水变浅至无积水,木里薹草叶片的光化学猝灭系数和电子传递量子效率也减小,非光化学猝灭系数增大;随着积水变浅至无积水,木里薹草的株高变矮,叶长变短。

Physiological and Ecological Characteristics of Carex muliensis Leaves in Zoige Plateau under Simulated Ponding Depths

In order to study the physiological and ecological characteristics of Carex muliensis marsh in Zoigêplateau under different water depths, soil cores containing Carex muliensis in Kahaer Wetland Nature Reserve in Zoigê county were transplanted in situ to the experiment field in Zoigê Wetland National Nature Reserve Administration on April 23, 2016. In the experiment, the water ponding depths of 20 cm, 10 cm and 0 cm(no ponding) were set. The parameters of photosynthetic gas exchange and chlorophyll fluorescence of the leaves of Carex muliensis under different ponding depths were measured on June 30, July 16 and August 1, 2019.The results showed that compared with the ponding depth decreased until no ponding, the values of net photosynthetic rate, stomatal conductance and transpiration rate of Carex muliensis leaves decreased significantly on the 3 observe days(n=5, p<0.05), and intercellular CO2 concentration increased significantly(n=5, p<0.05). The changes of ponding depths had no significant effect on the minimum fluorescence yield and the maximum photochemical efficiency of the reaction center of photosystem II(PSII) of the leaves of Carex muliensis. Similarly, the values of stable carbon isotope(δ13 C) of Carex muliensis leaves displayed no significant difference under different ponding depths, suggesting the change of ponding depths did not cause water stress on the growth of Carex muliensis. With the ponding depth decreased until no ponding, the photochemical quenching coefficient and electron transfer rate of the Carex muliensis leaves significantly decreased, whereas the non-photochemical quenching coefficient dramatically increased, indicating that the decrease of ponding depth leads to the increase of heat dissipation and the decrease of photoelectron transfer rate, which results in the height and leaf size decreased.