莫莫格湿地芦苇对水盐变化的生理生态响应

认识湿地植物对不同水盐环境的生理生态响应特征和规律,是确定湿地生态需水阈值的关键,为湿地生态需水量计算及生态恢复提供科学依据.通过对莫莫格湿地水盐环境因子与芦苇生理生态特征指标进行调查研究,并利用国际通用植被数量分析软件CANOCO4.5对其关系进行了冗余度分析(RDA).结果表明:湿地水深、Na+,HCO(3)含量3个环境因子组合对芦苇生理生态特征变异的解释量达到54.7％,说明这3个变量是影响芦苇生理生态特征变异的重要因子,水深是关键驱动因子.水深与芦苇株高、生物量、叶绿素含量、最大光化学效率Fv/FM以及光化学性能指数PIABS成显著正相关,随着水深的增加,芦苇株高、生物量以及叶绿素含量等逐渐增加.Na+含量、HCO(3)含量与芦苇生理生态特征的相关性没有达到显著水平.因此,中轻度盐碱湿地生态恢复需要重点考虑水深条件对湿地生态的影响,其次是水质( Na+/HCO(3))因素的影响作用,确保适宜生态水位,满足生态恢复需要.

Eco-physiological responses of Phragmites australis to different water-salt conditions in Momoge Wetland

Understanding the eco-physiological response characteristics of Phragmites australis to water-salt condition is the key of determining the threshold of wetland ecological water requirement, in order to supply a feasible method for calculating the wetland ecological water requirement and scientific base for wetland restoration. By field investigation of Phragmites australis in Momoge wetland, we analyzed the relationship between eco-physiological characteristics of Phragmites australis and water-salt gradient with method of redundancy analysis (RDA) by using CANOCO software in Version 4.5. The results showed that the combination of three environmental factors including water depth, Na and HCO3-, explained 54.7% of the variation of eco-physiological responses of Phragmites australis, suggesting that the three environmental factors led to great changes in eco-physiological responses of Phragmites australis. Water depth was the key environmental factor influencing the growth of Phragmites australis. There was a significant positive correlationship between water depth and the eco-physiological characteristics including plant height, biomass, chlorophyll content, maximum photosynthesis efficient (FV/FM) and maximum photosynthesis performance index (PIABS). There was no significant correlationship between Na /HCO3- and the characteristics of Phragmites australis. The results suggested that it is the key point in the process of wetland restoration in mild or moderate saline-alkaline wetland to consider the influence of water depth on the growth of Phragmites australis, and secondly consider the effect of Na /HCO3- , and determining the ecological water depth and fulfilling the ecological water requirement.