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

Abstract

: 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 buckwheat 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, seedling 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 buckwheat by improving the protective enzyme activity of buckwheat seeds, reducing the accumulation of reactive oxygen species, and increasing the content of osmotic regulation substances.