河岸带植物水蓼对水淹环境的适应可塑性研究

植物的表型可塑性在自然界普遍存在，但并非所有的可塑性都具有适应性，只有能显著提高物种适合度的表型可塑性被称为适应可塑性（adaptive plasticity）。然而，目前对植物适应可塑性的研究还较为缺乏。水淹是影响河岸带植物生存和进化的重要环境因子，水淹耐受能力强的物种往往对水淹具有较高的表型可塑性，然而其是否具有适应性并不清楚。本研究以三峡库区长期经历自然水淹的消落带为研究区域，研究典型河岸带植物水蓼（Polygonum hydropiper）对水淹的表型可塑性在种群内和种群间的差异，揭示产生可塑性差异的生理生态学机制，分析植株的表型可塑性与其母代所在生境环境因子的相关性，分析异质水淹胁迫下不同基因型植株的表型可塑性的成本和效益，进而探讨河岸带植物对水淹环境的适应可塑性。本研究将进一步完善河岸带植物对水淹胁迫适应进化的基础理论研究，并为退化河岸带植被的恢复与重建提供理论基础和科学依据。

Phenotypic plasticity of plants is a ubiquitous phenomenon in natural ecosystems, while it does not necessarily imply that plasticity is adaptive. Adaptive plasticity refers to the phenotypic plasticity which can greatly improve species fitness. Up till now, there have been very few studies on adaptive plasticity of plants to environmental stress, which still needs to be greatly advanced. Flooding is one of the most important factors limiting survival and evolution of riparian plants. However, flood-tolerant plants always possess high phenotypic plasticity, whether it is adaptive is not clear, upon flooding. This study will research on the typical riparian plant Polygonum hydropiper, which is naturally distributed at the water-level fluctuation zones of the Three Gorges Reservoir Region and subjected to long-term natural flooding. The plasticity variations of P. hydropiper within and between populations upon flooding and the related eco-physiological mechanism will be studied. The correlation between phenotypic plasticity and environmental factors of mother plants will be analyzed. The costs and benefits of phenotypic plasticity of different genotypes to heterogeneous flooding stress will be investigated. Finally，the adaptive plasticity of riparian plants to flooding will be elicited. This study will further advance the researches on the basic theory of adaptive evolution of riparian plants and re-vegetation in degraded riparian areas.