Physiological Response To Cd²⁺ Stress Induced By Different Exogenous Materials In Creeping Agrostis

The effect of heavy metal cadmium-tolerant(Cd²⁺)on the physiological and biochemical characteristics of six cultivars of Agrostis was studied through the seedling tray test.The cadmium-tolerant cultivars and susceptible varieties of cadmium in the genus Agrostis were screened by observing the morphology of the plants.The above-ground biomass,chlorophyll content,plant height,plant stress resistance indicators,and active oxygen defense enzyme and other related contents of Agrostis were measured.The related changes and physiological responses of two kinds of Agrostis plants,which were tolerant and sensitive to heavy metal cadmium stress,were studied.The cadmium-tolerant cultivar‘PennA-4’and‘Highland’sensitive cadmium‘Highland’were used as materials.Salicylic acid（SA）,nitric oxide（NO,provided by SNP）,glycine betaine（GB）and 2,3-butanediol（2,3-BD）were used as foliar sprays.Root injections are treated in two different ways.To study the changes of protective enzyme activity,malondialdehyde（MDA）,free proline（Pro）and soluble sugar content in Agrostis leaves under different concentrations of Cd²⁺stress.To explore the physiological responses of Agrostis to cadmium resistance by SA,NO,GB and 2,3-BD.1.Under the sand culture conditions,different concentrations of Cd²⁺treatment inhibited the growth of the six trial Agrostis,Cd²⁺600 mg/L is its tolerance limit.‘PennA-4’was the most resistant to Cd²⁺stress,and‘Highland’was the weakest.Under 0-100 mg/L Cd²⁺stress,the SOD,POD and CAT activities of Highland and PennA-4 increased with the increase of Cd²⁺concentration.At 100-600 mg/L,it decreases with increasing Cd²⁺concentration.‘PennA-4’in the genus Agrostis is more resistant to cadmium than‘Highland’.2.Under Cd²⁺stress,10-30 mmol/LSA,50-200μmol/LSNP,100-400μmol/L 2,3-BD,and5-50 mol/LGB pretreatment significantly relieved the stress of the two species of Agrostis.Foliage spraying with 10 mmol/LSA and 100μmol/LSNP and root injection of 400μmol/L 2,3-BD and 50 mol/L GB had the best effect on Highland.PennA-4 showed the best effect when foliar spraying of 20 mmol/LSA and 200μmol/LSNP and root injection of 200μmol/L 2,3-BD and 25 mol/L GB.3.Pretreatment with SA,SNP,2,3-BD and GB significantly increased the activities of SOD,POD and CAT in the leaves of two species of Agrostis,and increased the content of Pro and soluble sugar.The two species of Agrostis under Cd²⁺stress still had strong ROS scavenging capacity,reduced MDA content,and finally alleviated the oxidative damage caused by Cd²⁺stress.