茶树特异成分对辐照诱导自由基的作用

研究了茶树体内特异成分对辐照诱导自由基的作用。结果表明，辐照茶籽内自由基的增长趋势表现为乔木型大叶品种大于灌木型中、小叶品种，１０个品种茶籽内自由基的耗照剂量效应模型为ｙ＝ａｅ（－ｂ／ｘ）。茶树体内儿茶素、茶多酚、黄酮苷、咖啡碱等特异成分与其辐射敏感性及自由基含量变化密切相关。影响辐照茶树体内自由基消长的主要因子是儿茶素，其中（－）－没食子儿茶素没食子酸酯（ＥＧＣＧ）与自由基反应有浓度效应，在低浓度条件下，具有诱发产生自由基的作用，而在高浓度条件下，则有消除自由基的作用

EFFECTS OF THE PECULIAR COMPOSITIONS IN TEA PLANT ON FREE RADICALS INDUCED BY RADIATION

Effects of the peculiar compositions in tea plant on free radical s induced by radiationwas investigated.Results showed that the contents of free radicals in aborescence large-leafvarieties were more than that in shrubby middle-small leaf varieties under the same irradia- tion dose.Dose-effect curve for free radical contents in tea varieties could be discribed withan exponential equation y=9.04-5.35/x.The contents of free radical and the radioseusi- tivities were related to the contents of catechin,tea polyphenols,flavone glycoside and caf- feine. Tbe main factor that affected free radical content in tea plant was catechin. Resultsalso showed that there was a quantitative effect between(-)- EGCG and free radical :(-)-EGCG could induce the incrcase of free radical contents in tea at low concentration but scav-enge free radicals at high concentration.