Difperent sensitiorty UVB radiation of rice cultioors based on UVB-caused CPDs Frequencies

我们先前发现，中波紫外线降低了水稻的分蘖数和生物量，降低了叶片中可溶性蛋白质、Rubisco等的含量。不同类型水稻品种对UVB辐射抑制效应的敏感性存在品种差异。在日本水稻品种中，Sasanishiki对UVB表现出较强的抗性，Norin 1对UVB表现出较弱的抗性。在这项工作中，我们研究了中波紫外线引起的环丁基嘧啶二聚体频率(CPD、S)的差异是否与紫外线敏感和抗紫外线的CVS有关。Norin 1和Sasanishiki。我们还研究了在无UVB的可见光辐射下生长的水稻不同时期叶片中UVB诱导的CPD的变化。我们利用Sutherland等人(1987)设计的单向脉冲场凝胶电泳法改进了碱性琼脂糖凝胶电泳法。利用该装置，我们首次发现Norin-1比Sasanishiki更缺乏光复活和切除CPDS的修复能力。将不同发育阶段的叶片从植株上剥离，暴露在UVB(9KJ/m~2)下：在叶片充分展开的第2、3、4叶产生的CPDS最高。此外，还检测了从出叶到展开结束的6叶不同年龄叶片中UVB诱导的CPDS的变化。出叶后1、4、7和15天生长的叶片接受上述剂量的UVB照射，6叶在出叶后7天完全展开。生长4d的叶片产生的CPDS最高。由此可见，紫外光对CPDS的敏感性随生长进程和叶龄的变化而发生显著变化。

We previously fornd that UVB reduced tiller number and biomass, and the amounts of soluble protein, Rubisco and so on in leaves of rice. There were cultivar differences in the sensitivity to the inhibitory effects of UVB among indica, javanica and japonica rice cultivars. Among Japanese rice cultivars, Sasanishiki exhibited more resistance to UVB,while Norin 1 was less resistant. In this work, we examined if differences in cyclobutyl pyrimidine dimer frequencies (CPD^S) caused by UVB were involved in UV-sensitive and UV-resistant cvs. Norin 1 and Sasanishiki. We also investigated the changes in UVB-caused CPDs in leaf developed at the different stages in rice grown in visible radiation without UVB.We improved an alkaline agarose gel electrophoresis using unidirectional pulse field gel electrophoresis devised by Sutherland et al.(1987). Using this apparatus, we first found that Norin 1 was more deficient in the repair ability of CPDs by photoreactivation and excision than Sasanishiki. The leaf fully expanded at the different stages was detache from plant, and exposed to UVB (9KJ/m2) : the highest CPDs were shown to be produced in the 2,3 and 4th fully expanded leaf. Furthemore, the changes of UVB-caused CPDs were examined in the different aged-leaf of the 6th leaf from leaf emergence through completion of expansion.The leaf grown for 1,4,7 and 15 days after leaf emergence was exposed to the above mentioned dose of UVB.The 6th leaf was fully expanded 7 days after emergence. The highest CPDs were found to be produced in the 4 days-grown leaf. It was thus indicated that the sensitivity to UVB caused CPDs dramatically changed in the progress of growth and leaf age.