褪黑素与2,4-表油菜素内酯浸种对盐胁迫下荞麦发芽与幼苗生长的促进效应

土壤盐渍化是影响农作物种子萌发出苗以及生长发育的重要限制因素,探究外源激素对盐胁迫条件下荞麦种子萌发与幼苗生长的缓解作用具有重要意义。本试验以荞麦品种西农9976为材料,采用培养皿萌发和盆栽发芽2种方法,研究褪黑素(MT)与2,4-表油菜素内酯(EBR)浸种对不同盐浓度胁迫下荞麦种子萌发、幼苗生长、抗氧化酶活性、渗透调节物质的影响。结果表明,盐胁迫增加了荞麦种子和幼苗叶片丙二醛(MDA)含量、可溶性糖含量和抗氧化酶(SOD、POD、CAT)活性,降低了荞麦种子发芽势、发芽率和成苗率,使荞麦种子胚芽长度、胚根长度和幼苗高度显著下降。MT、EBR浸种荞麦种子可有效缓解盐胁迫危害,使荞麦种子发芽势、发芽率和成苗率较对照分别增加14.9%～33.3%、11.5%～27.3%和20.0%～46.2%,显著提高荞麦种子胚根长度、胚芽长度、胚芽鲜重和干重、幼苗高度、幼苗鲜重和干重,并显著增加荞麦种子和幼苗叶片中可溶性糖含量和SOD、POD、CAT活性,降低MDA含量。综上所述, MT和EBR浸种均能通过提高荞麦种子保护酶活性、减少活性氧积累、增加渗透调节物质含量,促进盐胁迫条件下荞麦种子发芽及幼苗生...

Effects of soaking seeds with MT and EBR on germination and seedling growth in buckwheat under salt stress

Soil salinization is an important limiting factor affecting seed germination,emergence,and growth of crop seeds.It is of great significance to explore the relieving effect of exogenous hormones on buckwheat seed germination and seedling growth under salt stress.This experiment was conducted to study the effects of melatonin(MT)and 2,4-epbrassinolide(EBR)on seed germination,seedling growth,antioxidant enzyme activity,and osmotic regulation substances of buckwheat varieties Xinong 9976 under different salt concentration stress using petri dish germination and pot germination.The results showed that salt stress increased the malondialdehyde(MDA)content,soluble sugar content,and antioxidant enzyme(SOD,POD,CAT)activities of buckwheat seeds and seedling leaves,decreased the germination potential,germination rate,and seedling rate of buckwheat seeds,and significantly decreased the germ length,radicle length,and seedling height of buckwheat seeds.MT and EBR soaking buck-wheat seeds could effectively alleviate the harm of salt stress.Compared with the control,the germination potential,germination rate,and seedling formation rate of buckwheat seeds were increased by 14.9%–33.3%,11.5%–27.3%,and 20.0%–46.2%,respectively.It significantly increased the radicle length,embryo length,embryo fresh weight,dry weight,seedling height,seed-ling fresh weight,and dry weight of buckwheat seeds,and significantly increased the soluble sugar content and the activities of SOD,POD,and CAT in buckwheat seeds and seedling leaves,and decreased MDA content.In conclusion,MT and EBR soaking can promote the germination and seedling growth of buckwheat seeds under salt stress,and improve the salt resistance of buck-wheat by improving the protective enzyme activity of buckwheat seeds,reducing the accumulation of reactive oxygen species,and increasing the content of osmotic regulation substances.