60Co-γ射线辐照对不同千粒重紫苏品种种子萌发及酶活性的影响OA

[Objective]The effects of different gamma radiation doses(60Co-γ)on germination and physicochemical indexes of Perilla frutescens seeds were investigated to confirm the appropriate radiation dose for seed germination of different P.frutescens varieties,and to provide a theoretical basis for radiation breeding of P.frutescens breeding.[Method]The P.frutescens seeds of Qisu 2(thousand-kernel weight=2.3 g),Qishu 3(thousand-kernel weight=1.5 g),M478(thousand-kernel weight=0.9 g)and M626(thousand-kernel weight=0.5 g)were exposed to various level of 60Co-γ radiation with 0 Gy(CK),50 Gy,100 Gy,150 Gy,200 Gy,250 Gy,and 300 Gy.The changes in germination capacity and leaf physicochemical indexes(SOD,POD,CAT,MDA)of the treated seeds were analyzed.[Result]Low-dose irradiation could improve seed germination rate and germination potential of Qisu 3,but reduce the relevant germination indexes of M626 with the minimum thousand kernel weight.The bud and root length of all tested P.frutescens varieties shortened with increase of irradiation dose.The optimal irradiation doses for the good mutagenic effects of Qisu 3,Qisu 2,M478 and M626 were 338.81-363.64 Gy,269.94-287.84 Gy,124.75-138.67 Gy and 36.31-52.35 Gy,respectively.There was a significant difference in SOD activity among 4 P.frutescens varieties.The SOD activity of Qisu 2 reached the peak at 100 Gy level.The SOD activity of Qisu 3 at 50 Gy and 100 Gy level was significantly lower than CK.The SOD activity of M478 reached the highest at 150 Gy level and lowest at 100 Gy level.The SOD activity of M626 at 100 Gy and 150 Gy level was lower than CK significantly.The POD activity of Qisu 2 and Qisu 3 showed a decrease-increase-decrease-increase trend with increase of radiation dose.The POD activity of Qisu 2 and Qisu 3 was the highest at 0 Gy,150 Gy level.The POD activity of M478 at 100 Gy level was significantly higher than other treatments.The POD activity of M626 continuously decreased and then increased with increase of irradiation dose.There was a variety specific response to CAT activity overall.The CAT activity of Qisu 2 and Qisu 3 showed a decrease-increase-decrease trend with increase of irradiation dose.The CAT activity of M478 at 100 Gy level was significantly higher than CK only.The CAT activity of M626 at 50 Gy-150 Gy level was significantly higher than CK.The MDA content of Qisu 3 at 50 Gy,150 Gy,200 Gy,250 Gy,300 Gy level was significantly higher than CK.There was no significant difference in MDA content between different treatments of M626 at different irradiation dose levels.There was a significant difference in the response mode of antioxidant system between different P.frutescens varieties.[Conclusion]The P.frutescens seeds with a higher thousand kernel weight have a greater tolerance to 60Co-γ irradiation dose and their cytomembrane structure is stable relatively.The appropriate irradiation dose can promote seed germination of Qisu 3 and M478,but an excessively high irradiation dose will inhibit their bud and root growth.