材料，对比了不同条件下野生型和 fas1突变体拟南芥的发芽势和发芽率、根长以及根尖分生区有丝分裂细胞的末期，结果表明在正常生长条件下WT和 fas1 突变体的发芽势和发芽率、根长以及根尖分生区细胞在有丝分裂末期的形态都没有显著差异。而在 UV-B 辐射条件下，对比不同组之间的发芽势和发芽率、根长，结果表明，WT+UV-B 组低于 WT 组，fas1+UV-B 组低于fas1组，fas1+UV-B 组低于 WT+UV-B 组，且差异均达到显著水平。此外，在UV-B 辐射条件下，观察到在 fas1+UV-B 组中，有丝分裂也表现出一定的异常现象。这些结果表明，fas1基因功能的缺失可能是导致fas1 突变体对 UV-B 胁迫敏感的诱因之一。
关键词 UV-B;fas1;拟南芥
中图分类号 Q947.9 文献标识码 A
文章编号 0517-6611（2019）17-0001-04
Abstract With the thinning of the ozone layer and the emergence of ozone holes， the UVB radiation reaching the Earth’s surface is significantly increased， which has a certain impact on the growth and development of organisms. The knockout of the fas1 homolog in Arabidopsis thaliana did not cause a lethal phenotype， and the plant was still alive， only when the postembryonic organ developed defects， such as activation of the silencing gene at its apical meristem， resulting in stem wide and flat， the corresponding leaf order and inflorescence structure were disordered. Therefore， fas1 was able to stabilize heterochromatin and kept the genes in silent. In this paper， the wildtype and fas1 mutants A.thaliana were used as experimental materials to compare the germination potential and germination rate， root length and the terminal phase of mitotic cells in the wildtype and fas1 mutant A.thaliana under different conditions. The results showed that there was no significant difference in germination potential，germination rate， root length and morphology of apical meristem cells at the end of mitosis under normal growth conditions. Under UVB radiation conditions， the germination potential，germination rate and root length between different groups were compared. The results showed that the WT+UVB group was lower than the WT group， the fas1+UVB group was lower than the fas1 group，the fas1+UVB group was lower than the WT+UVB group，the differences reached a significant level. In addition， under UVB radiation conditions， it was observed that mitosis also showed some anomalies in the fas1+UVB group. These results suggested that the loss of fas1 gene function may be one of the incentives for fas1 mutants to be sensitive to UVB stress.
Key words UVB;fas1;Arabidopsis thaliana
太陽光是地球能量的主要来源，而大气平流层中的臭氧层可以吸收太阳光中的紫外线。20世纪以来，由于排放到大气中的氯氟烃以及其他氮化物（如N2O等）增加，引起臭氧层的破坏，已成为人类面临的重大环境问题之一。臭氧层变薄及臭氧空洞的出现[1]，导致到达地面的太阳紫外线辐射增强;且平流层中O3每减少1%，到达地面的太阳紫外线辐射增加2%[2]。太阳紫外线（ultraviolet，UV）按波长大小分为3种：UV-A（315～400 nm）、UV-B（280～315 nm）以及UV-C（100～280 nm）。由于臭氧层变薄，因而到达地面的UV-B辐射增强，会危害陆地植物。尽管UV-B是太阳光中最少的成分，其在到达地表的光中占不到0.5%，但它是太阳光光谱中能量最高的，对生物有十分重要的影响[3]。