Studies on Chromosomal Translocation in Haworthia

Abstract

The normal karyotype of most species of the tribe Aloineae comprises 8 long and 6 short chromosomes. It was observed that in a diploid plant of Haworthia attenuata var. britteniana f. V. Poelln., there occured a simple translocation between the L4 and L2 chromosomes . The detailed description is K = 2n = 8L + 6S = 2L1 + 1L2 + 1LT + 2L3 + 1L4 + 1LD + 2S1 + 2S2 + 2S3. Among the 337 cells examined at meiosis, the quadrivalent chromosomes involving translocation in the form of ( 1L2 + 1LT ) and ( 1L4 + 1LD ) was observed in 285 cells , pairings of either ( 1L2 + 1LT ) or ( 1L4＋1LD ) to form bivalents were found in 48 cells, and other chromosome pairings were observed in 4 cells. Pollen grains appeared to be 50% viable. 百合科Aloineae族植物之染色體為典型之”Bimodal”核型，即有8個大型染色體與6個小型染色體（8L + 6S） Haworthia屬中之H. attenuata var. britteniana f. V. Poelln. 為2倍體，核型分析結果，在L2與L4染色體上產生單轉座現象，其核型為K = 2n = 8L + 6S = 2L1 + 1L2 + 1LT + 2L3 + 1L4 + 1LD + 2S1 + 2S2 + 2S3，減數分裂顯示，在337個細胞中，兩組相同染色體各相配對且其單向轉座部份之染色體對合成IV價者，有285個細胞；相同染色體配對成II價，而轉座部分不相對合者，有48個細胞；其他者有4個細胞，花粉稔性僅50%。