Effect of Exogenous Hydrogen Peroxide on the Physiological Characteristics of Cotton Seedlings under Salt Stress
In order to investigate the physiological regulation mechanism of exogenous H2O2 on the cotton seedlings under NaCl stress,the cotton variety Xinluzao 48 was used as the test material in an outdoor potting meth-od.Two-factor random combinations of salt stress(NaCl,concentration gradients of 0,100,200 mmol/L)and H2O2(concentration gradients of 0,0.005,0.010,0.020,0.050 mmol/L)were set,to study the change rule of fresh weight,dry weight,chlorophyll content,chlorophyll fluorescence parameters,photosynthetic gas parameters,antioxi-dant enzyme activities and osmotic regulation system of cotton seedlings.The results showed that exogenous H2O2 ef-fectively alleviated the inhibitory effect of salt stress on the growth of cotton seedlings,increased chlorophyll con-tent,photosynthetic gas parameters and chlorophyll fluorescence parameters of cotton seedlings,maintained the nor-mal operation of photosynthesis of cotton seedlings and ensured the accumulation of dry matter.Meanwhile,exoge-nous H2O2 could increase the activity of antioxidant enzymes(POD,APX,CAT),accelerated the removal of ROS from cotton seedlings.Exogenous H2O2 reduced the electrolyte leakage rate,MDA content,the content of osmoregu-lation substances such as pro,free amino acid and SS,and improved the salt resistance of cotton seedlings.Among all treatment,0.020 mmol/L exogenous H2O2 had the best effect in alleviating the salt stress suffered by cotton seedlings.In summary,exogenous H2O2 improves the adaptation of cotton seedlings to salt stress by improving photo-synthetic performance,keeping stable photosynthesis in cotton seedlings,and maintaining the dynamic balance be-tween ROS production and elimination in cotton seedlings.
Cotton seedlingsSalt stressExogenous H2O2Photosynthetic performanceAntioxidant enzyme system
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