土壤环境变化对杉木生态化学计量特征及化感特性的干扰机制

The seedlings and young trees of Chinese fir plantation from southern China are used as research materials in our study. The young trees in first and second generation plantations are selected for the field investigations, and the seedlings were used for the controlled environment experiments to determine the effects of soil pH, N&P ferterlization and allelochemicals enrichment. We detected the soil physical and chemical properties, analysis of C, N, P, K elements concentrations in different tissues, and ecological stability index of different organs were calculated. And we also detected the morphology, water and element use efficiency, allelochemicals release rate in Chinese fir seedlings under different soil conditions and the combination treatments. Our aim is to elucidate the different roles of the various soil environmental factors that affect plant ecological stability, allelochemicals and consequently to predicate the dynamics of Chinese fir plantations under the changing soil environment. Our results could be very useful for forest conservation and management under soil environment changing, and the results about allelochemicals enrichment could also provide theoretical basis and scientific instructions for the degradation and restoration of Chinese fir plantation.

本项目以我国人工林主要用材树种杉木的幼树与幼苗为研究材料，通过整体调查—局部控制的研究方式，采用野外数据调查与控制实验相结合的研究思路，以受我国酸雨危害程度为依据，在湖南会同、江西千烟洲、重庆乐村及四川洪雅等主要人工林产区选取一代、二代杉木幼林，测定所选林分土壤理化性质，分析杉木各组织器官元素含量及有效性，检测化感物质含量及释放速率，建立土壤环境因子与杉木器官内稳性及化感特性的初步关系。在四川洪雅实验基地，采用精确控制土壤环境因子的交互设计实验，精确控制土壤pH、NP肥力、化感物质浓度等环境因子，从杉木幼苗内稳性、生长速率及化感特性多水平去研究杉木幼苗在不同土壤环境因子交互作用下的适应对策及其内稳性指数的响应差异，揭示杉木人工林的化感自毒性的产生与土壤环境因子的相互关系，进而预测未来酸雨污染、肥料乱施及化感物质沉积条件下杉木内稳性的变化趋势，为杉木人工林的退化与修复提供理论依据与科学指导。