Abstract: In order to elucidate the regulatory mechanism of exogenous 2,4-epibrassinolide (EBR) on seeds germination of Avena sativa L. under salt stress,we used A. sativa ‘Jiayan 2’ and ‘Qingyin 2’ as materials,and studied the effects of EBR (10^-5,10^-4,10^-3,0.01,0.10 and 1 μmol·L^-1) on seed germination and physiological characteristics of oat under 100 mmol·L^-1 NaCl stress. Results showed that 100 mmol·L^-1 NaCl significantly inhibited the seed germination and seedling growth of oat,inhibited starch hydrolysis by decreasing amylase activity,and significantly accelerated the hydrolysis of soluble protein by increasing the activity of proteolytic enzyme. By adding EBR under 100 mmol·L^-1 NaCl stress,the germination potential,germination rate,germination index and vigor index of oat seeds were significantly increased,the growth of seedling and root,as well as the root vigor and seedling dry weight,were enhanced. The activity of α- and β-amylase in the process of seeds germination was promoted,which improved starch hydrolysis. The activity of proteolytic enzyme was inhibited,which effectively restrained the hydrolysis of soluble protein and the accumulation of free amino acid. Among them,adding 0.01 and 0.10 μmol·L^-1 exogenous EBR had the most significant effect on seed germination and seedling growth of oat under NaCl stress. In conclusion,exogenous EBR can significantly alleviate the inhibitory effect of NaCl on oat seed germination,which was obviously affected by EBR concentrations. The treatment with 0.01 and 0.10 μmol·L^-1 EBR perform the best.

Key words: 2,4-Epibrassinolide, NaCl stress, Avena sativa L., Seed germination

摘要： 为探明外源油菜素内酯（Brassinosteroids，BRs）对盐胁迫下燕麦（Avena sativa L.）种子萌发的调控机理，本试验以‘加燕2号’和‘青引2号’燕麦为材料，在100 mmol·L^-1 NaCl胁迫下，采用不同浓度梯度（10^-5，10^-4，10^-3，0.01，0.10和1 μmol·L^-1）2，4-表油菜素内酯（2，4-Epibrassinolide，EBR）处理燕麦种子，研究外源EBR对NaCl胁迫下燕麦种子萌发和生理的影响。结果表明：100 mmol·L^-1 NaCl胁迫显著抑制了燕麦种子萌发和幼苗生长，降低了淀粉酶活性（P<0.05），提高了蛋白水解酶活性（P<0.05）；100 mmol·L^-1 NaCl胁迫下，添加外源EBR显著提高了燕麦种子的发芽势、发芽率、发芽指数和活力指数，促进了燕麦幼苗和根系的生长，提高了根系活力和幼苗干重及燕麦种子萌发过程中的α-淀粉酶和β-淀粉酶活性，降低了蛋白水解酶活性，有效抑制了可溶性蛋白水解和游离氨基酸的积累；其中，添加0.01 μmol·L^-1和0.10 μmol·L^-1外源EBR对NaCl胁迫下燕麦种子萌发和幼苗生长的促进效果最为明显。综上，本研究得出外源EBR能够明显缓解NaCl胁迫对燕麦种子萌发的抑制作用，且具有明显的浓度效应，以0.01 μmol·L^-1和0.10 μmol·L^-1外源EBR的处理效果最好。

关键词: 2, 4-表油菜素内酯, NaCl胁迫, 燕麦, 种子萌发