黄河三角洲贝壳堤湿地不同类型盐生植物水分利用机制研究

Due to the impact of human and natural factors, Yellow River Delta shell dikes wetlands ecosystem were severely damaged, water is the main ecological limiting factor for vegetation restoration,the study will be carried out to reveal water use mechanisms of different types of halophytes, which has an important guiding significance for damaged shell dikes wetlands ecosystem revegetation.The temporal heterogeneity of potential water sources will be studied in the Yellow River shell dikes wetlands based on stable isotope techniques.The δ18O characteristics of potential sources and plant xylem water in three different types of halophytes will be analyzed in order to reveal different types of halophytes water niche differentiation patterns and drivers. Using δ13C stable isotope techniques combined with the use of time-domain techniques moisture determination , the coupling relationship will be determined of the different types of halophytes water use efficiency with potential sources distribution, soil water content, leaf water potential , gas exchange parameters , chlorophyll fluorescence parameters , and to clear the internal mechanisms of water use efficiency temporal dynamics changes.The results will enrich coastal zone of halophytes carbon-water relations theory, and provide the theory basis for the species configuration and water efficient use in the process of vegetation restoration of coastal zone ecosystem.

由于人为和自然因素的影响，黄河三角洲贝壳堤湿地植被退化严重，水分是限制植被恢复的主要限制因子，深入研究本地优势盐生植物的水分利用机制，对贝壳堤湿地生态系统的植被恢复具有重要的指导意义。本项目利用氢氧碳稳定同位素等技术，通过研究3种不同类型盐生植物茎木质部水分及潜在水源的稳定同位素特征，揭示不同类型盐生植物的水分生态位分化格局及驱动因素；通过研究不同类型盐生植物水分利用效率与潜在水源分布、土壤水分含量、叶片水势、气体交换参数、叶绿素荧光参数之间的耦合关系，明确不同类型盐生植物水分利用效率变异的内在机理。研究结果将丰富海岸带湿地植物的碳水关系理论，为海岸带湿地植被恢复过程中物种优化配置、水分高效利用提供理论依据。

黄河三角洲贝壳堤湿地植被退化严重，水分是限制植被恢复的主要限制因子，深入研究本地优势盐生植物的水分利用机制，对贝壳堤湿地生态系统的植被恢复具有重要的指导意义。本研究以黄河三角洲贝壳堤不同类型盐生植物碱蓬、芦苇、二色补血草为研究对象，利用稳定同位素技术来探讨其水分利用来源及水分利用效率差异。研究结果表明：贝壳堤土壤水的δ18O值随着土壤深度的增加，呈现先增加后减少的趋势，土壤水的δ18O值的范围约为-7.3%~-5.9%。3种不同类型盐生植物的木质部水的δ18O差异显著，芦苇的δ18O值最小，二色补血草的δ18O值最大，碱蓬次之。雨水对芦苇的贡献率为50.9%，各层土壤水的贡献率之和为49%；各层土壤水对碱蓬的贡献率之和为90.9%，雨水对碱蓬的贡献率为9%；雨水对二色补血草的贡献率为18.5%，土壤水对二色补血草的贡献率为81.4%。3种不同类型盐生植物相比较，芦苇具有较高的水分利用效率，其次是碱蓬，二色补血草水分利用效率最低。研究结果将为海岸带湿地植被恢复过程中物种优化配置、水分高效利用提供理论依据。