N^(7+)重离子注入和贯穿后小麦种胚的期外DNA合成效应

EFFECT OF UNSCHEDULED DNA SYNTHESTS IN SEED EMBRYOS OF WHEAT INJECTED AND PENETRATED BY N^(7+) HEAVY ION

用3H－TdR掺入法研究了经N7＋重离子往入和贯穿处理的82579小麦和8812小麦种胚的DNA合成动态。结果发现，未经N7＋重离子任何处理的两个小麦品种的对照种胚，在萌发早期（20h内）仅存在一个DNA合成峰（于萌发的第14h），而经过N7＋重离子注入和贯穿处理的小麦种胚则存在两个DNA合成峰（分别于萌发的8－10h和14－16h），该种子经DNA修复合成的抑制剂咖啡因处理后，第一个DNA合成峰（8－10h）消失。表明经N7＋重离子注入和贯穿处理的小麦种胚内存在着DNA修复合成，即期外DNA合成。N7＋重离子注入处理的期外DNA合成效应低于贯穿处理，本文对其产生的可能原因进行了讨论。

The effect of unscheduled DNA synthesis (UDS) in seed embryos of wheat afterN7+ heavy ion injection and penetration hase been studied by 3H-TdR incorporationmethods. The experimental materials are dry seeds of cultivar 8812 and 82579 of wheat (Triticum aestivum L, ). The untreated normal seed embryos of two strains of wheat all show a peak of DNA synthesis during early germination (within 20 h) of them,the peak is at the 8th hour of germination of seed embryos. Whereas the seed embryos with N7+heavy ion injection and penetration show two peaks of DNA synthesis,the peaks are at 8- 10th and 14- 16th hour of germination of the seed embryos, respectively. When theseeds treated with N7+ heavy ion are futher treated by caffeine which is inhibitor of DNA repair synthesis,the peak of DNA synthesis occurred at 8- 10th hour of the seeds ger-mination disapear. It indicat that there is a effect of DNA synthesis or UDS during early germination in seed embryos of wheat injected and penetrated by N7+ heavy ion. TheUDS effect of seed embryos injected by N7+ heavy ion is lower than that of penetrated byN7+. The possible reason is discussed in the paper.