2,4-表油菜素内酯对盐胁迫下紫花苜蓿种子萌发及幼苗生长的影响

为明确外源2,4-表油菜素内酯(24-epibrassinolide,EBR)对盐胁迫下紫花苜蓿幼苗伤害的缓解作用,以中苜3号和陇中苜蓿为材料,在150mmol/L NaCl胁迫下,研究不同浓度EBR处理对紫花苜蓿种子萌发及幼苗生长的影响。结果表明:(1)150mmol/L NaCl胁迫显著抑制了苜蓿种子萌发、幼苗生长及根系活力,降低了幼苗的地上、地下生物量;(2)外源EBR可有效的缓解NaCl胁迫对苜蓿种子萌发、幼苗生长及根系活力的抑制作用,并具有明显的浓度效应;(3)综合发芽试验、幼苗生长试验,在150mmol/L NaCl胁迫下,10-1μmol/L EBR处理显著地提高了苜蓿种子的发芽势、发芽率、发芽指数、活力指数和胚芽长、胚根长、萌发期幼苗干重,并显著增加了苜蓿幼苗的叶片数、茎粗、株高、主根长、侧根数和地上、地下生物量,提高了苜蓿萌发期、幼苗期的根系活力水平,对盐胁迫下苜蓿幼苗的缓解效果最好。说明外源EBR能够促进NaCl胁迫下紫花苜蓿种子的萌发及幼苗的生长发育,EBR在诱导植物抗盐性上具有积极作用。

Effect of 2,4-epibrassinolide on seed germination and seedling growth of Medicago sativa under salt stress

In order to figure out the mitigating effects of exogenous 2,4-epibrassinolide on seedling damage of Medicago sativa under salt stress,Medicago sativa cv.Zhongmu No.3 and Longzhong treated with 150 mmol/L NaCl solution were used to study the effect of EBR with different concentrations on seed germination and seedling growth.The results indicated that 1 )seed germination,seedling growth and root vigor of alfalfa were restrained significantly under 150 mmol/L NaCl stress,aboveground and underground biomass were re-duced as well.2)exogenous EBR mitigated the suppression effects of NaCl stress on seed germination,seedling growth and root vigor effectively,and showed an obvious concentration effect.3 )under 150 mmol/L NaCl stress,10 -1 μmol/L EBR treatment had the best mitigating effect on alfalfa seedling,when the root vigor level in germination and seedling stage were enhanced,germination potential,germination rate,germination velocity,vig-or index,sprout length,radical length and germination seedling dry weight were facilitated significantly,as well as the seedling leaf number,stem diameter,plant height,main root length,branch root number,aboveground and underground biomass.It suggested that exogenous 2,4-Epibrassinolide promoted seed germination and seedling growth of Medicago sativa under salt stress and EBR had positive impacts on inducing plant salt resistance.