Study On The Alleviating Effect Of Exogenous Glutathione On Maize Seedlings Under Low Temperature Stress

Low temperature is a common form of adversity stress.Low temperature cold damage often occurs in Heilongjiang province,which is prone to spring cold phenomenon,which affects crop growth and thus reduces crop quality and yield.Corn is an important grain crop in China,and low temperature will have adverse effects on corn growth.Glutathione is a widely studied antioxidant and plays an important role in plant stress resistance,which can promote plant growth under low temperature stress.In this experiment,maize hybrid’Zhengdan 958’was used as the test material,and the low temperature condition was set at 10℃,the concentration of glutathione was 0.5 g/L.Four treatment groups were set:CK,CK1,LT,LT1,to investigate the effects of exogenous glutathione on the germination,growth and physiological characteristics of maize seedlings under low temperature stress,in order to investigate the the mitigating effect of glutathione on low temperature.The study findings obtained are as follows:1.Exogenous injection of glutathione alleviated the inhibitory effect of low temperature on maize seed germination.In the germination test,germination and growth of maize seeds were inhibited by low-temperature stress and reduced germination potential,germination rate and germination index.The effect of low temperature on the germination period was alleviated by glutathione immersion treatment,and the germination potential and germination rate of seeds increased by 22.01%and 11.84%,respectively.The activity of SOD,POD and APX in maize seeds,roots and buds under low temperature stress increased,the content of soluble protein,soluble sugar,proline,and MDA increased.The antioxidant enzyme activities increased after glutathione application,POD activities increased by 2.23%,0.40%,and 9.98%,SOD activities increased by 23.40%,5.65%,and 16.62%,APX activities increased by 15.27%,28.67%,and 9.94%,osmoregulatory substances content increased,and malondialdehyde content decreased by 35.19%,22.07%,and 33.33%.2.Exogenous glutathione injection alleviated the inhibitory effect of low temperature on the growth of maize seedlings.In the soil cultivation test,maize seedlings grew slowly under low temperature stress,with high seedlings,leaf area and aboveground dry（fresh）weight reduced,which inhibited the elongation growth of roots.After 3 d,5 d and 7 d of exogenous glutathione spraying,seedling height increased by 3.38%,5.56%and 7.23%,leaf area increased by 1.80%,9.52%and11.29%,leaf water content increased by 1.24%,0.42%and 2.43%compared with low temperature,which promoted shoot dry（fresh）weight content and low temperature stress damage was improved.The root growth of maize seedlings under low temperature was slow and the root dry（fresh）weight was reduced.After 7 d of exogenous glutathione spraying,the root length and dry（fresh）weight increased by 9.33%,10.22%and 17.31%compared with low temperature LT,indicating that glutathione had a promoting effect on root growth under low temperature.3.Antioxidant enzyme activities increased under low temperature stress,malondialdehyde content increased,and relative conductivity became larger.After exogenous spraying of glutathione for 3 d,5 d,and 7 d,antioxidant enzyme activities increased significantly,and LT1 treatment increased POD activity by 7.05%,37.04%,and 0.90%,SOD activity by 16.12%,24.43%,and 1.80%,CAT activity increased by64.72%,64.82%,115.90%,and APX activity increased by 18.29%,28.13%,35.51%.Low temperature stress caused the photosynthesis of maize seedlings to be affected,with lower SPAD values,faster chlorophy decomposition,less synthesis,and decreased Pn,Gs,Ci,and Tr.After exogenous glutathione treatment,SPAD values increased,chlorophyll synthesis was accelerated,Pn,Gs,Ci,and Tr increased,and photosynthetic capacity was improved.Soluble protein content increased by 23.67%,10.42%and 11.89%,soluble sugar content increased by 42.02%,56.05%and 35.81%,and proline content increased by 77.42%,13.24%and 31.73%after exogenous application of glutathione for 3 d,5 d and 7 d,which alleviated the damage caused by low temperature stress to the cells.4.As A and GSH contents decreased under low temperature stress,and external application of glutathione was able to increase GSH and As A contents.After 3 d,5 d,and 7 d of glutathione treatment,GSH contents increased by 40.00%,64.29%,and73.33%,and As A contents increased by 31.37%,63.54%,and 46.24%,respectively,indicating that exogenous glutathione treatment could make maize After DAB,NBT and Taipan blue staining,leaf spots increased and H₂O₂ and superoxide anion over-accumulated under low temperature,and after exogenous spraying of 0.5 g/L glutathione,it could alleviate the degree of oxidative damage to maize seedlings by low temperature stress and maintain the integrity of cell membrane.In conclusion,exogenous 0.5 g/L glutathione were alleviated maize seed germination and seedling growth under cold stress,improved seed germination potential,germination rate and seed germination index,promoted the growth of maize seedlings,and improve the influence of low temperature stress on the relevant indexes of maize seedlings.