咖啡因Na_2─EDTA对辐照大豆和油菜幼苗DNA合成的影响

本文研究了咖啡固和Ｎａ２一ＥＤＴＡ后处理对不同辐照敏感性作物幼苗ＤＮＡ、ＲＮＡ含量和修复能力的影响。结果表明，随着辐照剂量的增大，大豆（对辐射敏感）和油菜（抗辐射）７天龄幼苗下胚轴内ＤＮＡ，ＲＮＡ含量随之增大，且大豆的ＤＮＡ含量比油菜高２倍多。咖啡固和Ｎａ２一ＥＤＴＡ后处理，均高于对照。放射性３Ｈ─ＴｄＲ标记６渗入法证实，种子辐照后，７日龄幼苗体内仍存在着非按期的ＤＮＡ合成，且油菜的非按期ＤＮＡ合成能力强于大豆。咖啡固、Ｎａ２─ＥＤＴＡ和二者复合作用的后处理，抑制了ＤＮＡ的非按期修复合成，加重了辐射损伤，其抑制程度，咖啡因＋Ｎ８２－ＥＤＴＡ＞咖啡固＞Ｎ８２─ＥＤＴＡ。

INFLUENCE OF THE CAF AND EDTA ON DNA SYNTHESIS OF DIFFERENT CROPS

Post-treatment of radiation and radiation damage repair inhibitor had substan-tial effect on the DNA and RNA content and DNA self-reparing synthesis. The resuItsshowed that the content of DNA and RNA in soyhean and Rape seedlings hypocotyl in-creased with increasing radiation doses,Caf and EDTA post-treatment made them higherthan that of H2O-treatment in respective doses. In the different treatment,the content ofDNA and RNA in soybean seedlings hypocotyl was two times more than that in Rape. Ra-diative 3H-TdR experiment confirmed that the unscheduled DNA synthesis existing in twokinds of different radiosensitive crops seedlings and indicated that the damaged DNA self-repairing took a long time,this self-repairing DNA synthesis was inhibited by Caf,EDTAand C E post-treatment in the order of C E>Caf>EDTA,C E complex post-treat-ment had acollaboration effect.