三江平原湿地退化对小叶章有性繁殖特征的影响

Effects of Wetland Degradation onSexual Reproduction Characteristics ofDeyeuxia angustifolia in Sanjiang Plain

植物在退化生境中采取不同的方式来扩展种群,了解退化生境中植物有性繁殖特征的变化是解释植物生态策略和管理生态系统的重要措施。本研究以三江平原三种不同退化阶段的小叶章种群为研究对象,测定了小叶章花序的数量特征和退化生境中的土壤理化性质,以探讨退化生境中小叶章花序特征的转变方式以及影响其变化的环境驱动因子。结果表明,沿着沼泽化草甸-典型草甸-杂类草草甸这一退化生境序列,小叶章花序长、花序生物量、种子千粒重和株高均呈显著增加趋势;当湿地退化,土壤含水量下降,土壤有机碳、硝态氮含量随之下降,而有机氮、铵态氮、p H值、全磷和速效钾含量随之上升;当湿地退化水位和有机碳含量下降时,对花序的影响主要是通过增加花序的小枝数量进而影响花序的生物量,小叶章通过这种方式来在不利的生境中增加种子的产量以拓展种群。

Plants take different ways to expand their populations in degraded habitats.Understanding the changes in sexual reproduction characteristics of plants in degraded habitats is an important measure to explain plant ecological strategies and manage ecosystems.In this study,the number of D.angustifolia’s inflorescence characteristics and soil physical and chemical properties in three degraded habitats were determined of D.angustifolia populations in Sanjiang Plain,to explore the transformation mode of D.angustifolia’s characteristics in degraded habitats and the environmental driving factors affecting its change.The results showed that along the degraded habitat sequence of swampy meadow,typical meadow,and miscellaneous grass meadow,the length of D.angustifolia’s inflorescence,inflorescence biomass,seed 1000-grain weight,and plant height increased significantly.When the wetland was degraded and the soil water content decreased,the contents of organic carbon and nitrate nitrogen decreased,while the contents of organic nitrogen,ammonium nitrogen,pH,total phosphorus and available potassium increased. When the wetland degraded water level and organiccarbon content decreased, the main effect on inflorescence was toincrease the number of branchlets in inflorescence, thus affecting thebiomass of inflorescence. In this way, the D.angustifolia increasedseed yield in the unfavorable habitat to expand the population.