Effects Of Drought On Physiological Characteristics And Rhizosphere Ecological Factors Of Peanut Under Salt Stress

To deal with the problem of double stress caused by uneven rainfall in peanut production,two varieties,HY22 and HY20,were selected for this experiment to investigate the physiological response of peanut to dry salt stress,to clarify the effects of dry salt stress on agronomic traits and physiological and biochemical characteristics of peanut,and to reveal the inter-root microecological changes of peanut under dry salt stress.To clarify the physiological mechanism of the change of inclusions in the process of seed germination under salt stress.To provide theoretical support for the planting process of peanut with full,strong and complete seedlings,thus providing theoretical guidance and technical technological support for high and stable yield of peanut in saline land.1.Salt stress slowed down the rate of fat decomposition during seed germination of peanut,and the lipase activity in the seeds was inhibited,and the lipase activity in HY20 was lower than that in HY22 seeds under salt stress;soluble protein content was similar between the two varieties,and the rate of soluble protein decomposition was inhibited under salt stress,and seed germination was inhibited.2.Salt stress and drought-salt interaction stress reduced the main stem height and lateral branch length of peanut,HY22 and HY20 showed the same performance,while the other treatments reduced the main stem height by 2.44%～59.15% and11.56%～58.54%,and the lateral branch length by 19.43%～72.23% and7.68%～80.00%,respectively,compared with the CK treatment.3.The photosynthesis of peanut was significantly inhibited under drought stress,salt stress and both stress treatments,and the net photosynthetic rate and single plant leaf area were significantly reduced under stress,but the effect on SPAD values was not significant.The drought reduction of HY20 at 0.3% salt concentration was significantly increased and reduced by 50.34%～70.83% compared to CK treatment,HY22 and HY20 performed similarly at harvest,CK and B1 treatments were significantly higher than other treatments,and other treatments of HY22 reduced by32.64%～58.58% compared to CK treatment.4.Three stress treatments decreased SOD and CAT activities and increased MDA content in peanut leaves.HY22 drought stress and salt stress decreased superoxide dismutase(SOD)activity by 3.78% to 59.57%;catalase(CAT)activity by 6.50% to61.76%;and malondialdehyde content by 8.41% to 66.19%.in HY20 superoxide dismutase(SOD)activity decreased by 3.40%～42.96%;catalase(CAT)activity decreased by 10.16%～62.72%;malondialdehyde(MDA)content increased by4.75%～77.18%.5.Both 100-fruit weight and 100-kernel weight were affected by drought stress and salt stress among different varieties,and both 100-fruit weight and 100-kernel weight of peanut decreased with increasing salt concentration under the same water application conditions.The pod weight of peanut single plant showed a decreasing trend under both drought and salt stress.6.The structure and changes of the soil bacterial community in the inter-rhizosphere of peanut were investigated by 16 Sr RNA gene sequencing.The results showed that the dominant bacterial phyla in drought stress,salt stress and both stress treatments were Proteobacteria,Actinobacteria,Acidobacteria,Chloroflexi and Gemmatimonadota.).The relative abundance of Proteobacteria and Acidobacteria decreased under both drought and salt stress,while the relative abundance of Cyanobacteria increased.Abiotic stress affects the inter-root soil microdomain environment and has a regulatory effect on the inter-root soil bacterial community structure of peanut.7.HY22 showed a trend of increasing and then decreasing inter-root soil alkaline nitrogen content throughout the reproductive period,and HY20 showed a gradual decrease,and both varieties showed a significant decrease in soil alkaline nitrogen content under dry salt cross-stress.The trend of fast-acting phosphorus in soil was similar between varieties,both showed a gradual decrease with the fertility process,and the content of fast-acting phosphorus in soil between the roots of both varieties decreased significantly with increasing salt concentration under normal water application conditions during the podding period of peanut.The cellulase activity in the soil reached its lowest value at the harvesting stage,with insignificant differences between treatments.Salt stress and drought inhibited CAT activity in the inter-root soil of peanut,and CAT activity in the inter-root soil of HY20 was lower than that of HY22 under salt stress.