喀斯特干旱-复水下不同地理种源构树根系有机酸分泌特征及其根际效应

干旱是喀斯特地区植物生长的重要限制因子。构树由于其重要的生态和经济价值在该区域广泛栽植，受特殊地理环境和气候变化的影响面临造林成活率和保存率低的问题，抗旱品种的筛选是维持构树可持续经营的重要途经。干旱胁迫下根系有机酸对根际微环境的调控是植物干旱适应的重要策略，目前针对干旱及复水过程中构树根系有机酸分泌特征及其根际效应的研究十分缺乏。本项目以不同地理种源构树为研究对象，通过盆栽水分控制和有机酸添加培养试验，结合高效液相色谱和高通量测序技术，研究干旱及复水过程中构树根系有机酸分泌组成和浓度的动态特征，揭示有机酸分泌对土壤微生物群落组成和养分有效性的调控机制，探究有机酸分泌在植物干旱适应及复水恢复中的作用，明确不同种源构树有机酸的根际效应差异。研究结果对深入认识喀斯特地区树木干旱适应机制具有重要意义，也为构树抗旱品种筛选及可持续经营管理提供理论依据。

Drought is an important limiting factor for plant growth in the karst area. Broussonetia papyrifera is widely planted in this area due to its important ecological and economic value. Due to the impacts of special geographical environment and climate change, Broussonetia papyrifera has a low survival rate and preservation rate. Thus the selection of drought-resistant varieties is an important way to maintain its sustainable and management. The regulation of root organic acid on the rhizosphere microenvironment under drought stress is an important strategy for plant drought adaptation, and there is a lack of research on the characteristics of organic acid secretion and rhizospheric effects during drought and rewatering process. In this study, taking trees from different geographic provenances as the research object, through potted water control and organic acid addition, combining with high performance liquid chromatography and high throughput sequencing technology, we aim are (1) to study the composition and concentration of organic acid secretion in the roots of Broussonetia papyrifera during drought and rewatering process; (2) to reveal the regulation mechanism of organic acid secretion on soil microbial community composition and nutrient availability; (3) to explore the role of organic acid secretion in plant drought adaptation and rewatering restoration; (4) to identify the differences in rhizosphere effects of organic acids among different provenances. The research results are significance to the study of drought adaptation mechanism of trees in the karst area, and also provide a theoretical basis for the selection of drought-resistant varieties and sustainable management.