茶树染色体G带与大螺旋的结构转化

CONFigURATIONAL TRANSFORMATION IN CHROMOSOME G─BANDS AND MACROCOILS OF CAMELLIA SINENSIS

对云南大叶茶（Ｃａｍｅｌｌｉｓｓｉｎｅｎｓｉｓ）进行染色体Ｇ带和大螺旋结构的高温原位诱导表明。其Ｇ带带纹丰富而清晰，部分晚前期染色体带数接近人类高分辨带的水平。当Ｇ带原位诱导超过一定范围时，常出现染色体大螺旋结构。晚前期和早中期是观察统计和分析大螺纹的最适时期。本文首次观察到木本植物染色体由Ｇ带向大螺旋转化的现象。在Ｇ带带纹中常有大螺旋的雏形或典型的螺纹结构，螺纹数目，大小及相对位置大致对应于带纹。初步推测Ｇ带的诱导是染色体大螺旋结构上的特异染色体组分丢失后，固有结构的显示。

The chromosomes of Camellia sinensis var.' Yunnan' were subjected to in situ induction of G─bands and macrocoils at hig tempera─turcs. The bands obtained were numerous and clear and thenumber of G─bands chromosomes at the late prophase was close to that of the high─resolution G─banded chromosomes of man, When in situ induction periods lasted beyond the critieal time for G─banding , macrocoiling structures were often revcealed. Late prophase and early metaphase werethe optimum periods for the observation and analysis of gyres. The present paper is the first reportthat configurational transformation in chromosomes from G─bands to macro─cils was successfullyobserved in any woody plant. Among the G─bands , the embryonic forms of macrocoils or thetypical gyre struc─nearly corresponded to those of the G─bands. The results suggest that the G─banding treatmen ts induce specific structru ral alterations in chromoomes which contribute to thedisclosure of the ingerent structures based on the macrocoiling structures,removing the char─acteristic chromosomal complements.