亚精胺预处理对渗透胁迫下小麦幼苗抗氧化能力的影响

以小麦绵农4号幼苗叶片为试材，以－0.6 MPa聚乙二醇-6000(PEG-6000)处理造成渗透胁迫，研究了外源亚精胺（Spd）预处理对小麦相对含水量(RWC)、H₂O₂含量、丙二醛(MDA)含量、电解质渗漏以及超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)和抗坏血酸过氧化物酶(APX)活性的影响。在渗透胁迫处理

The Effects of Spermidine Pretreatment on Antioxidative Capacity in Wheat Seedlings under Osmotic Stress

The effects of spermidine(Spd) pretreatment on relative water content(RWC),H_2O_2 content,malonyldialdehyde(MDA) level,electrolyte leakage and activities of superoxide dismutase(SOD),peroxidase(POD),catalase(CAT) and ascorbate peroxidese(APX) in wheat seedlings(Triticum aestivum L.cv.Miannong 4) were investigated under osmotic dehydration by-0.6 MPa polyethylene glycol 6000(PEG-6000).Half of eight-day-old seedlings(control) were daily sprayed with distilled water( 0.02%)(V/V) Tween-80 and irrigated with half-strength Hoagland's nutrient solution,and the other half seedlings(Spd pretreatment) were daily sprayed with 0.2 mmol/L Spd( 0.02 %)(V/V) Tween-80 and irrigated with 0.2 mmol/L Spd half-strength Hoagland's nutrient solution for 2 days before osmotic stress.The results showed that the RWC decreased,lipid peroxidated,as well as H_2O_2 content and electrolyte leakage increased in seedling leaves of control under osmotic stress,while these changes deferred in Spd pretreatment.Under osmotic stress,the activities of SOD,POD and APX increased,but CAT activity decreased in control.Spd pretreatment increased the activities of SOD and POD.Moreover,the activities of POD,CAT and APX,especially SOD in seedling leaves of Spd pretreated were higher than those of control during the throughout osmotic stress period.It suggested that Spd could induce and maintain the higher level of antioxidant enzyme activities,and decrease the concentration of H_2O_2,therefore alleviate oxidative damages by osmotic stress,and promote antioxidant capacity of wheat seedlings under osmotic stress.