巨桉人工林主效水溶酚类化感物质筛选及生理生态作用研究

Large scale development of Eucalyptus plantations bring about a series of ecological environment problems controversy, among which eucalyptus allelopathy is mostly concerned. In natural conditions, the release of allelochemicals and the active concentrations are influenced by plant traits and other environmental factors. The exiting studies of allelopathy focused on its physiological effects on target plants germination and seedling growth, however, which were lack of the research on its ecological effects. Compared with the volatile organic compounds, phenol compounds might play particularly critical role in plant’s allelopathy. Among the phenol compounds, the allelopathy of non-phenolic acids has rarely received more attentions, which might be stronger than the effects of phenolic acids. Based on the identification of volatile and phenol organic compounds and their dynamic changes with plantation ages, depending on the long-term monitoring fields, the density and site types Eucalyptus grandis plantations with 4 and 8 year-old age were selected, the phenolic acids and flavonoids will be identified through UPLC-MS. The field control experiment will be used to evaluate the ecological factors influencing the allelochemicals. The physiological effects of allelopathy will be measured through ecotoxicology experiments including seed germination, soil animal separation etc. Finally, the main effective phenol compounds will be screened and identified, the physio-ecological effects of water-soluble phenol compounds in E. grandis will be revealed. The present study will provide scientific recommendations for the scientific management and sustainable development of Eucalyptus plantations.

桉树人工林在为区域经济做出巨大贡献的同时在生态环境方面也引起了一系列争议，其中化感作用是主要争议之一。化感物质产生和作用表达受到植物特性和环境因子等诸多因素影响。而现有桉树人工林化感作用研究多关注生理作用机制，缺乏生态作用机制研究。植物水溶性酚类化感物质具有强烈的化感效应，其中非酚酸类可能较酚酸类物质化感作用更强但尚未受到关注。本项目在前期挥发性和水溶性酚类化感物质林龄效应研究基础上，依托年龄序列长期监测样地，拟选择不同密度和不同立地类型4年和8年生巨桉人工林为研究对象，通过UPLC-MS代谢组分析鉴定水溶性酚类化感潜力物质，通过野外控制实验确定巨桉人工林化感物质的生态影响因素，通过植物萌发、土壤动物分离等生态毒理实验揭示化感物质生理作用；筛选出巨桉人工林主效酚类化感物质，分析作用特点，认识水溶性酚类物质导致的巨桉人工林化感效应的生理生态作用，为巨桉人工林科学经营及可持续发展提供理论支撑。

桉树在为区域经济做出巨大贡献的同时也存在一系列生态环境问题，其中化感作用是主要争议之一。化感物质产生和作用的表达受植物特性和环境因子等诸多因素的影响。现有桉树人工林化感作用研究多关注生理作用机制，缺乏生态作用机制研究。本项目在前期水溶性酚类化感物质林龄效应研究基础上，依托年龄序列长期监测样地，选择不同密度和不同立地类型的4年和8年生巨桉人工林，通过代谢组学分析鉴定了巨桉产生的水溶酚类化感物质，通过野外控制实验确定了巨桉化感物质的生态影响因素，通过对植物和土壤生物生态毒理实验揭示化感物质的生理作用。结果显示：1）巨桉人工林根、凋落物和根际土壤中共分离和鉴定出阿魏酸、没食子酸等9种酚酸和槲皮黄酮等8种黄酮类酚类化感潜力物质。其中根分泌是巨桉化感物质释放的最主要途径；2) 轮伐期前（4-6年生）根和凋落物化感物质释放较多，8年时其含量也有所升高。酚类化感物质在巨桉根区土壤中含量显著低于根和凋落物中的化感物质含量, 且随林龄升高无。3）通过毒理实验发现酚酸类物质对植物和土壤生物作用强于黄酮类，筛选出了没食子酸、羟基苯基乳酸和鞣花酸等3种巨桉主效酚类化感物质。4）不同林分密度和立地类型控制对巨桉人工林生物多样性和土壤肥力有显著影响，轻中壤立地类型和低密度控制（883 ind hm-2）能够通过对环境因子的改变减少巨桉化感物质释放，削弱其化感作用的表达。研究深入揭示了巨桉人工林酚类化感作用机制，为我国西南巨桉人工林科学经营和管理提供了科学依据。