Abstract: To identify effective approaches for alleviating drought stress in flax and improve its drought resistance，the flax cultivar Jinya 10 was used as the experimental material. At the seedling stage，three treatments were established：normal control（CK），drought stress after spraying with water（DS），and drought stress after spraying with 0.1 mg/L brassinolide（BD）. After the drought treatment reduced the relative soil water content to 50%，water physiological traits，antioxidant enzyme activities，antioxidant substances，malondialdehyde（MDA），osmotic adjustment substances，endogenous hormone contents，yield，and yield components were determined under each treatment. The results showed that drought stress at the seedling stage significantly affected the physiology and yield of flax，resulting in a significant reduction of 26.01% in seed yield.Exogenous brassinolide alleviated the adverse effects of drought stress on flax.Seed yield in the BD treatment was 15.59% higher than that in the DS treatment，mainly because of the significant increases in capsules per plant and seeds per capsule.Exogenous brassinolide significantly increased the relative water content and water use efficiency of flax leaves under drought stress.Compared with the DS treatment，the activities of superoxide dismutase（SOD），peroxidase（POD），and catalase（CAT）in the BD treatment increased significantly by 9.26%，12.37%，and 9.14%，respectively，whereas MDA content decreased significantly by 17.33%. Exogenous brassinolide also significantly increased the contents of ascorbic acid（AsA），glutathione，soluble sugars，soluble proteins，proline，indole‐3‐acetic acid（IAA），gibberellin（GA），and zeatin（ZA）in flax leaves under drought stress，whereas starch content decreased significantly by 4.73%，thereby further enhancing drought resistance.These results indicate that exogenous brassinolide effectively mitigates the adverse effects of seedling‐stage drought stress on the physiology and yield of flax by increasing leaf relative water content and water use efficiency，enhancing antioxidant enzyme activities and antioxidant substance contents，reducing MDA and starch contents，and regulating the balance of key endogenous hormones.

Key words: Flax, Brassinolide, Drought stress, Yield, Physiological characteristics

摘要： 为探究胡麻干旱胁迫的缓解方法以提高胡麻抗旱性，以胡麻品种晋亚10号为供试材料，待植株生长至苗期，设置正常对照（CK）、喷施清水后干旱胁迫（DS）和喷施0.1 mg/L油菜素内酯后干旱胁迫（BD）3个处理，干旱处理使土壤相对含水量降至50%后，测定各处理胡麻的水分生理特性，抗氧化酶活性，抗氧化物质、丙二醛（MDA）、渗透调节物质、内源激素含量以及产量与产量构成。结果表明，苗期干旱胁迫显著抑制胡麻的生理特性和产量，使胡麻籽粒产量显著减少26.01%，外源油菜素内酯缓解了干旱胁迫对胡麻的不利影响。BD处理籽粒产量比DS处理显著提高15.59%，这主要归因于单株果数和每果粒数的显著增加。外源油菜素内酯显著增加了干旱胁迫下胡麻叶片的相对含水量和水分利用率，BD处理超氧化物歧化酶（SOD）、过氧化物酶（POD）和过氧化氢酶（CAT）活性较DS 处理分别显著增加9.26%、12.37%和9.14%，MDA含量较DS处理显著降低17.33%。外源油菜素内酯还显著增加了干旱胁迫下胡麻叶片的抗坏血酸（AsA）、谷胱甘肽（GSH）、可溶性糖、可溶性蛋白、脯氨酸、吲哚乙酸（IAA）、赤霉素（GA）、玉米素（ZA）含量，而淀粉含量则显著降低4.73%，进一步增强了胡麻的抗旱性。综上，外源油菜素内酯通过提高胡麻叶片相对含水量和水分利用率、增强抗氧化酶活性与抗氧化物质含量、降低MDA和淀粉含量、调节关键内源激素的平衡，有效缓解了苗期干旱对胡麻生理特性及产量的不利影响。

关键词: 胡麻, 油菜素内酯, 干旱胁迫, 产量, 生理特性