内陆河湿地芦苇叶功能性状特征及其对土壤环境因子的响应

植物功能性状是连接植物与外界环境的重要桥梁，其在不同环境梯度下的变化表现出了对异质环境的适应机制。本文以敦煌西湖国家级自然保护区克隆植物芦苇（Phragmites australis）为研究对象，设置了未退化、轻度退化、中度退化和重度退化4个梯度样地，研究环境异质条件下芦苇叶功能性状特征及其对土壤环境因子的响应。结果表明：① 各环境梯度下，芦苇叶功能性状特征变化显著（P<0.05），叶长、叶宽、叶面积、叶干重随环境梯度退化呈下降趋势，比叶面积随梯度退化呈上升趋势；② 芦苇各叶功能性状间呈协同变化的特征，叶长、叶宽、叶面积、叶干重之间呈极显著正相关（P<0.01），比叶面积与叶长、叶干重呈显著负相关（P<0.05）；③ 叶长、叶宽、叶面积、叶干重与土壤表层（0~30 cm）、中层（30~60 cm）水分呈显著正相关（P<0.05），而与土壤表层、中层含盐量呈显著负相关（P<0.05），说明土壤表层与中层的水分与盐分是芦苇叶功能性状最主要的驱动力。研究结果对干旱区内陆河湿地的保护、生态恢复及管理具有重要的指导意义。

Functional Traits of Phragmites australis Leaves and Response to Soil Environmental Factors in Inland River Wetland

Phragmites australis in Dunhuang West Lake National Nature Reserve was taken as the research object. The undegraded, mild degraded, moderately degraded and severely degraded plots were delimited so as to analyze the functional traits of P. australis leaves and the response to soil environmental factors under the heterogenetic environment conditions. The results showed that:① The change of functional traits of P. australis leaves was significant under the environmental gradients (P<0.05), the leaf length, width, area and dry weight were decreased with the environmental degradation, and the specific leaf area was increased with the gradient degradation; ② The coevolution of functional traits of P. australis leaves was observed, there were the extremely significant positive correlations among the leaf functional traits including the leaf length, width, area and dry weight (P<0.01), but the significant negative ones among the specific leaf area and the leaf length and dry weight (P<0.05); ③ Leaf length, width, area and dry weight were significantly positively correlated with the moisture content in topsoil (0-30 cm in depth) and middle soil layer (30-60 cm) (P<0.05), and negatively correlated with salt content in these two soil layers (P<0.05). These revealed that the soil moisture content and salt content in topsoil and middle soil layer were the most important driving forces for the functional traits of P. australis leaves. The results of this study are of the important guiding significance for the ecological conservation and restoration in the inland river wetland in arid area.