Taxanes介导的喜树-南方红豆杉人工混交林种间促进作用研究

Allelopathy plays an important effect on artificial mixed forest cultivation successfully. Camptotheca acuminata, as a national emphasis protection wild plant, its resource crisis has risen. Nowadays, the growth of C. acuminata artificial pure forest is poor; therefore, it is urgent to select the appropriate species cultivated with C. acuminata. The preliminary study of project team showed that the mixed forest of C. acuminata and Taxus chinensis var. mairei has an advantage over the growth of C. acuminate and proved that taxanes, the allelochemicals in T. chinensis var. mairei root significantly promoted the C. acuminata seedling growth. In the study, the artificial mixed forest of C. acuminate and T. chinensis var. mairei are used as research subject, first, the degradation process of taxanes in the soils of woodland are established and then the contents of taxanes and their degradation products in the soils of woodland are real-time determined by LC / MS / MS analysis. The recovery rate and retention equation of allelochemicals in woodland soil are built using soil chromatographic techniques. Microbial diversity and community structure in woodland soil are determined using PLFAs and EcoPlate analysis. Mycorrhizal infection rate and infection intensity are assayed by Trypan blue staining. In the study, our aim is to discuss the effect of taxanes in C. acuminate / T. chinensis var. mairei rhizosphere and illustrate an important mechanism of C. acuminate / T. chinensis var. mairei artificial mixed forest productivity improvement from the perspective of the allelopathic effects of inter-mixed species trees, thus, providing a basis reference for creating a C. acuminate artificial mixed forest of reasonable interspecific relationships.

化感作用是影响人工混交林培育成功与否的重要因素之一。喜树是国家重点保护野生植物，其人工纯林生长较差，选择合适树种进行喜树混交林培育具有重要意义。项目组前期研究表明：喜树与南方红豆杉混交对喜树生长有利，南方红豆杉根系紫杉烷类(taxanes)化感物质可显著促进喜树幼苗生长。本项目拟以喜树-南方红豆杉人工混交林为研究对象，在明确林地土壤中taxanes降解过程的基础上，采用LC/MS/MS分析技术，实时监测林地土壤中taxanes及其降解产物含量；采用土壤层析技术，建立各化感物质在林地土壤中的恢复率及滞留方程；PLFAs与EcoPlate分析法相结合，测定林地土壤微生物多样性和群落结构；采用台盼蓝染色法测定喜树菌根侵染状况。探讨taxanes在喜树-南方红豆杉根际作用中的效应，从混交树木种间化感作用角度，探明南方红豆杉对喜树生长的促进作用机制，从而为营造种间关系合理的喜树混交林提供理论依据。

化感作用是影响人工混交林培育成功与否的重要因素之一。喜树是国家重点保护野生植物，其人工纯林生长较差，选择合适树种进行喜树混交林培育具有重要意义。项目组前期研究表明：喜树与南方红豆杉混交对喜树生长有利，南方红豆杉根系紫杉烷类(taxanes)化感物质可显著促进喜树幼苗生长。本项目拟喜树-南方红豆杉人工混交林为研究对象，在明确林地土壤中taxanes降解过程的基础上，采用微透析采样-LC/MS/MS分析技术，实时监测林地土壤中taxanes及其降解产物含量；采用土壤层析技术，明析了各化感物质在林地土壤中的迁移性；土壤可培养微生物法与高能量分析法相结合，分析林地土壤微生物总量和多样性，探讨taxanes在喜树-南方红豆杉根际作用中的效应。证明南方红豆杉对喜树的化感促进作用主要是通过根系分泌的紫杉烷类成分改善喜树根际微生物群落结构以及提高土壤酶活性并进一步提高土壤养分的可利用性来实现。项目从混交树木种间化感作用角度，探明了南方红豆杉对喜树生长的促进机制，为营造种间关系合理的喜树混交林提供了理论依据。项目发表论文5篇，其中SCI收录4篇；获得国家发明专利1项；培养研究生4名，其中硕士研究生3人、博士研究生1人。