咖啡因和EDTA对大麦辐射效应的影响

INFLUENCE OF CAFFEINE AND EDTA ON IRRADIATION EFFECTS IN BARLEY

研究了咖啡因和 EDTA 后处理对辐照大麦种子幼根 DNA 合成及幼苗酶活性的影响。结果表明,辐照大麦种子萌发初期根尖的 DNA 合成率较对照高10%～28%,咖啡固、EDTA 及咖啡因+EDTA 后处理,使非按期 DNA 合成受到抑制。DNA 合成率随辐照剂量的加大而降低,并与苗高呈极显著的正相关。咖啡因后处理降低了超氧化物歧化酶(SOD)活性,增加了过氧化氢酶(CAT)及过氧化物酶(POD)的活性。EDTA 提高了除240GY 处理外的所有辐射处理的 SOD 活性和60GY 以下辐射处理的 CAT 活性及300GY 辐照处理的 POD 活性,而降低了150GY 以上辐射处理的 CAT 活性。咖啡因+EDTA 后处理,提高了 SOD 和 POD 活性,而对 CAT 活性无明显影响。咖啡因、EDTA后处理,导致苗高下降,下降幅度为:γ+咖啡固+EDTA>γ+咖啡因>γ+EDTA。

DNA synthesis in primary roots and the activity of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) in the seedlings of irradiated barley seeds post-treat- ed with caffeine and/or EDTA were investigated. DNA synthesis rate was 10%～20% higher than in the control.Unscheduled DNA synthesis was inhibited and DNA synthesis rate decreased with irradiation doses.SOD ac- tivity was lowered and POD and CAT activity was enhanced in caffeine post-treatment. EDTA post-treatment increased the acitivity of SOD for all dose treatments except 240GY,the acitivity of CAT when the irradiation dose was lower than 60 GY and the activ- ity of POD when an irradiation dose of 300 GY was used.EDTA lowered CAT activity when the irradiation dose was higher than 150 GY.Caffeine+EDTA post-treatment in- creased the activity of SOD and POD,but showed no great effect on CAT activity.Seedling height was lowered by caffeine and/or EDTA post-treatments in the order of caffeine+ EDTA>caffeine>EDTA.