外源褪黑素对盐碱胁迫下盛花期大豆花器官脱落及产量构成的影响OA

Soil salinization seriously affects the growth and development of soybean.As a plant growth regulator,melatonin can significantly improve plant resistance to various abiotic stresses.In this study,two soybean varieties(Heihe 49 and Henong 95)were used as experimental materials,and salt-alkali stress treat-ment was carried out.Based on the soil mass in the culture buckets,102.2 g Na2SO4,60.5 g NaHCO3,4.7 g NaCl and 8.5 g Na2CO3 were applied to each bucket.The effects of exogenous melatonin(300 μmol·L-1)on flowering morphogenesis,out-of-zone structure,cell wall degrading enzyme,photosynthetic capacity,carbohy-drate metabolism and yield traits of soybean were analyzed under saline-alkali stress.The results showed that compared with the control,salt-alkali stress significantly reduced chlorophyll content,photosynthesis,carbo-hydrate accumulation and metabolic capacity of soybean leaves,so caused a decrease in dry matter accumula-tion.Melatonin treatment significantly increased the chlorophyll content in soybean leaves under salt-alkali stress,improved the photosynthetic capacity,and increased the sucrose and starch contents and activities of related enzymes in leaves,flowers and stalks.In addition,melatonin treatment significantly reduced the activi-ties of cellulase and cell wall degrading enzymes in the flower stalk,increased the number of cells in the cortex and pulp of the flower stalk,reduced the number of vascular bundle in the flower stalk,and reduced the de-gree of lignification,which was conducive to enhancing the structural stability and flexibility of the flower stalk,thereby reducing flower shedding,and ultimately increasing the pod number per plant,kernel number per plant,100-kernel weight and kernel weight per plant of soybean.