Effects Of Salicylic Acid And Abscisic Acid On Physiological And Biochemical Indexes And DNA Methylation Of Maize Seedlings Under Sodium Chloride Stress

Soil salinization is one of the important environmental factors affecting plant growth.How to solve the problem of growth and development of plants in high salt areas has become one of the hotspots of research.In recent years,the use of exogenous salicylic acid(SA)and abscisic acid(ABA)to alleviate the salinized land on plant growth inhibition is of great significance.In this study,the effects of salicylic acid and abscisic acid on the physiological and biochemical indexes and DNA methylation of maize seedlings under chloride stress were studied by using the antagonistic effects of exogenous hormones SA and ABA and sodium chloride as explorers.To analyze the mechanism of corn resistance to sodium chloride to provide a theoretical basis.1、under different concentrations of Nacl stress,low concentration of 50 mmol / LNacl will promote the accumulation of biomass of maize seedlings,showing the plant height,dry fresh weight and root length increased.With the increase of Nacl concentration,the growth of maize began to be inhibited.When the concentration of Nacl reached 150 mmol / L,the inhibition of maize seedling growth began to increase obviously,and the plant became shorter,the stalk became thinner and the leaf became green.2、Under 150mmol/LNacl stress,the exogenous hormone application,low concentration(1~5mg/L)of SA on seedlings of Nacl stress relief effect is not obvious,high concentration(25~50mg/L)to ease the effect is good,and the best effect in 25mg/LSA stress on plant salt;ABA at low concentration(0.5~12.5mg/L)of salt stress relief effect is obvious.The 2.5mg/L optimal effect,high concentration of ABA(25mg/L)under the effect is not obvious.Applying 25mg/LSA and 2.5mg/LABA makes the activity of antioxidant enzymes in seedlings(CAT,POD,SOD)has been improved to varying degrees,including plant osmotic adjustment,increased soluble sugar and soluble protein and free proline content,MDA content and membrane lipid oxidation products significantly decreased,leaf conductance decreased,reduced the inhibitory effect of salt stress on the growth of plants.By applying exogenous hormones SA and ABA,25mg/LSA and 2.5mg/LABA increased the chlorophyll content of maize seedlings increased and improved net photosynthetic rate of Photosynthate accumulation increased,effectively enhance their ability to resist salt stress.3、Using the MSAP technology to detect the methylation level and variation pattern of leaf genome,we found that the methylation patterns of all treatments were mainly CG methylation,and the total methylation level of each treatment was lower than that of blank control.Detected by MSAP,found in maize seedlings and blank under 6 different treatments compared to the control,the variation pattern of methylation in CG,CHG,CG+CHG methylation was higher than CG,CHG,hypermethylation of CG+CHG,as long as the variation pattern of demethylation role.