黄河三角洲芦苇功能性状对不同水分生境的适应性

Adaptation of Functional Traits of Phragmites australis to Different Water Habitats in the Yellow River Delta

植物功能性状反映植物对环境变化的适应对策,对揭示植物的环境适应机制具有重要意义。以黄河三角洲不同水分生境(草地、河岸)的优势植物芦苇(Phragmites australis)为研究对象,分析了2种不同水分生境条件下芦苇功能性状变化特征、功能性状之间的关系、土壤含水率与芦苇功能性状之间的关系。结果表明:草地生境的芦苇株高、叶长、叶面积、比叶面积显著小于河岸生境,而叶片厚度显著大于河岸生境(P<0.05),说明芦苇对生境变化的适应策略发生了改变,其在草地生境下表现为保守的生存策略。芦苇株高与叶长、叶面积呈极显著正相关(P<0.01),叶片厚度与株高、叶长呈极显著负相关(P<0.01),叶片厚度与比叶面积呈显著负相关(P<0.05),株高、叶长、叶面积与土壤含水率呈显著正相关,叶片厚度与土壤含水率呈显著负相关。逐步回归分析表明,土壤深度(h)为10 cm<h≤20 cm土层土壤含水率对芦苇株高、叶长、叶面积、叶片厚度、比叶面积影响最大。黄河三角洲芦苇对不同水分生境适应策略存在差异,其通过调整个体大小与主要叶性状适应水分生境条件变化。

Plant functional traits play an important role in revealing the mechanisms of plant adaptation to specific environmental conditions.We chose the dominant specie Phragmites australis in the grassland and river bank habitats of the Yellow River Delta as the research object.The characteristics of functional traits and trade-offs of P.australis was investigated,and the relationship between soil moisture content and functional traits was analyzed.The result showed that plant height,leaf length,leaf area and SLA were significantly lower in the grassland than that in river bank habitat,while leaf thickness was significantly higher in the grassland than that in river bank habitat(P<0.05).The adaptive strategies of P.australis changed due to the habitat changes,and the result reflected the conservative survival strategy of P.australis in grassland.Plant height was positively correlated with leaf length and leaf area(P<0.01),while leaf thickness was negatively correlated with plant height and leaf length(P<0.01),and positively correlated with SLA(P<0.05).Soil moisture content was positively and significantly correlated with plant height,leaf length and leaf area,while the significant and negative correlation between soil moisture content and leaf thickness was observed.The stepwise regression analysis showed that soil moisture content(10 cm<h≤20 cm)has highest impact on plant height,leaf length,leaf area,leaf thickness and SLA.Our results suggested that the adaptation strategies of P.australis were different in the grassland and river bank habitats,and plant size and key leaf traits of P.australis varied with habitat changes in the Yellow River Delta.