中文摘要：

【目的】针对长江流域特别是长江上游近几年春季降水偏少易导致干旱的特点，研究水分胁迫对油菜蕾薹期生理特性及农艺性状的影响，为揭示油菜蕾薹期抗旱机制及抗早品种选育提供理论依据。【方法】采用盆栽的方式，在遮雨网室对两种抗旱性不同的油菜品种中双10号（抗旱性弱）和94005（抗旱性强）蕾薹期进行干旱胁迫，以各性状的抗旱系数研究油菜相关生理指标及农艺性状的变化，在此基础上筛选出适用于该区域油菜蕾薹期抗旱性鉴定的指标。【结果】随着干旱时间的延长，两种油菜的叶片净光合速率、气孔导度、蒸腾速率、胞间二氧化碳浓度、RWC、叶绿素含量、RuBP羧化酶活性、株高、茎粗、一次分枝数以及单株产量抗旱系数均呈下降趋势，下降幅度与胁迫时间成正相关。其中，气孔导度、蒸腾速率抗旱系数下降幅度与材料抗旱性成正相关，其余指标则与材料抗旱性成负相关。抗旱性弱的材料气孔限制值、水分利用率抗旱系数分别呈现出上升-下降与一直下降的趋势，抗旱性强的材料则均为上升趋势。POD、SOD、CAT活性、可溶性糖以及可溶性蛋白相对值随着干旱胁迫时间的延长先升高后下降，抗旱性强的材料增加幅度高于抗旱性弱的材料；细胞膜透性、丙二醛（MDA）含量和脯氨酸相对值随干旱胁迫时间的延长呈上升趋势。对干旱胁迫下的油菜蕾薹期和复水后的成熟期相关指标之间的关系进行分析表明，干旱胁迫下，产量与净光合速率、RWC、叶绿素含量和一次分枝数抗旱系数呈极显著正相关，与细胞膜透性、MDA含量抗旱系数呈显著负相关。主成分分析将单株产量、净光合速率、胞间二氧化碳浓度、气孔限制值、水分利用率、Rwc、叶绿素、RuBP羧化酶、SOD、POD、CAT、细胞膜透性、MDA、可溶性糖、株高、茎粗及一次分枝数划分?

英文摘要：

[ Objective ] Against the characteristics of less precipitation which easily lead to drought in the Yangtze River Basin, especially in the upper reaches of the Yangtze River in the spring in recent years, the effects of water stress on physiological characters and agronomic traits at bud stage of rapeseed were studied, the aims were to reveal the drought resistance mechanism of rapeseed at bud stage, and to provide a theoretical basis for drought-resistant breeding. [Method] The changes of associated physiological indicators and agronomic traits of rapeseed were studied by drought resistance coefficients of each character using two different drought resistance rapeseed varieties at bud stage （zhongshuangl0 with low drought resistance and 94005 with high drought resistance） with drought stress experiment in pot. And filter out some indicators that apply to the local area, which can be used to identify drought resistance at bud stage of rapeseed. [Result] The results showed that the drought resistance coefficients of net photosynthetic rate, stomatal conductance, transpiration rate, intercellular CO2 concentration, leaf relative water content, content of chlorophyll, RuBP carboxylase activity, height per plant, stem diameter, primary branches number and seed yield per plant tended to decrease with the extension of drought stress time, and the decrease range was positively related to the time of drought stress, the decrease range of the drought resistance coefficients of stomata conductance and transpiration rate was positively related to the drought resistant ability of rapeseed, the rest of the indicators were negatively related to the drought resistance coefficients of materials. The drought resistance coefficients of stomata limitation value and water use efficiency of low drought resistance variety presented an upward to downward and downward trend, respectively, but both of that showed an increase trend in high drought resistance variety. With the lasting of drought stress, the relative values of POD, SOD,