Abstract: To investigate the ecological stoichiometric characteristics and their interrelationships of plants and soil that subjected to externally applying brassinosteroid (BR) under different drought conditions. In this study,Cassia glauca Lam. was used as the research object,and the pot-water control method was used by setting up well water,moderate drought and severe drought treatments (75%±5%,55%±5% and 35%±5% of the water holding capacity in the field) and four BR concentration treatments (0,0.05,0.2 and 0.5 mg·L^-1). Plant height,biomass,nutrient content and stoichiometric characteristics of plants and soil were determined after 90 days of drought treatment. It was found that drought stress caused plant height,above-ground and below-ground biomass to decrease. With the increase of BR application concentration,plant height and biomass showed an increase and then a decrease. 0.2 mg·L^-1 BR was beneficial to plant nutrient content,with a more significant effect on aboveground growth. The growth of Cassia glauca had a high demand for the supply of nitrogen element in the ecological restoration of arid areas. The application of BR can help to increase the plant height and biomass of Cassia glauca,regulate the nutrient allocation strategy,and alleviate the adverse effects of drought on plants. This study provides new ideas and methods for ecological restoration and revegetation in arid areas.

Key words: Ecological restoration, Drought stress, Brassinosteroid, Stoichiometry, Nutrient characteristics, Interal stability

摘要： 为探究施用油菜素内酯(Brassinosteroid，BR)对不同干旱条件下植物与土壤的生态化学计量特征及其相互关系，本研究以黄花决明(Cassia glauca Lam.)为研究对象，采用盆栽控水法，设置正常水分、中度胁迫、重度胁迫处理(田间持水量的75%±5%，55%±5%，35%±5%)及4种BR浓度处理(0，0.05，0.2和0.5 mg·L^-1)，在干旱90天后测定株高、生物量和植物、土壤的养分含量及化学计量特征。研究发现：干旱胁迫导致株高、地上和地下生物量降低；随着施用BR浓度的增加，株高、生物量表现为先上升后下降；0.2 mg·L^-1 BR有利于植物养分含量提升，地上部提升效果更好；干旱区生态修复中黄花决明的生长对N元素的供应需求较大；施用BR有助于提高黄花决明株高和生物量，调节养分分配策略，缓解干旱对植物的不利影响。本研究可为干旱地区的生态修复和植被重建提供新思路与新方法。

关键词: 生态修复, 干旱胁迫, 油菜素内酯, 化学计量, 养分特征, 内稳性