The Protective Mechanism Of Hydrogen On Oxidative Damage Of The Salt-tailed Iris In Salt Stress

Soil salinity is a major abiotic stress in the world especially in arid and semi-arid regions and irrigation areas,salt resistance of plants is a complex progress which based on multiple mechanisms.Iris halophile Pall.is a perennial herbaceous plant growing in grasslands,hillsides,salty soils in Xinjiang,Gansu and other regions in China.Hydrogen(H2),as a new signal molecule that regulates the physiological processes of plants,can regulate plant growth and development by influencing plant hormones,transporters that regulate ion balance and transcription factors,antioxidant enzymes,rhizosphere microorganisms.We have explored whether it can enhance the tolerance of salt to I.halophila and provide the theoretical basis for further enhancing the tolerance of salt tolerant plants.Our main results are as follows:1.Callus of I.halophila has a certain stress tolerance under low salt stress2.Hydrogen-rich water through the regulation of antioxidant defense system and Na+ outflow enhancement I.halophila salt tolerance.After the treatment of 50,100,500 mmol/L NaCl and 25%,50%and 100%hydrogen-rich water(HRW)on the callus of I.halophila,HRW can alleviate the damage caused by salt stress on I.halophila,100%HRW is the best.3.HRW treatment can inhibit the ROS burst by increasing the activity of antioxidant enzymes,thus alleviating the increase of MDA content,that is,to reduce the degree of lipid peroxidation.4.HRW could significantly increase the expression level of Na+/H+exchanger protein(NHX)gene to improve its ability to adapt salt stress to reduce the ionic toxicity of salt treatment to callus cytoplasm.5.100%HRW could increase the contents of endogenous NO in I.halophila,and it was involved in the salt-tolerant of I.halophila.In this study,HRW could increase antioxidant enzymes activity,the relative expression of NHX gene,decrease Na+/K+,enhance the content of endogenous NO,which suggesting that HRW may reduce the damage of salt stress by reducing the content of intracellular Na+,regulating Na+transport and improving the antioxidant activity,which provides a solid foundation for further exploration of hydrogen stress protection.