苹果叶片离体培养中秋水仙素加倍效应的研究

用不同浓度的秋水仙素溶液处理苹果的栽培品种嘎拉试管苗的离体叶片，发现以０．５％的秋水仙素溶液处理４ｄ效果最佳，诱变频率达５６．１％。诱变后获得的四倍体植株在形态学和细胞学上均发生了明显变异。与对照株比较，变异株茎矮、粗壮、节间短、叶片厚、叶色浓绿；叶背面的气孔体积增大，单位面积气孔数目减少、茸毛数量增加；染色体数目加倍，２ｎ＝４ｘ＝６８（对照２ｎ＝２ｘ＝３４），细胞核核仁数目增加。梢端组织学切片证明，变异株中同质突变体的频率达７３％。

Study on the Doubling Effect of Colchicine on the Chromosome Number of in vitro Cultured Apple Leaves

Study was conducted with the leaves of diploid apple cultivar and treated them with fif-ferent concentration of colchicine solution. Results showed the best result was received by treatedwith 0. 5 % colchicine for 4 days, it's variation frequency was 56. 1 %. Obvious changes have taken place on the induced tetraploid plants. In comparison with normal plants, variant plants expressed the following features :the stem became dwarf, thick and shortened. The leaf appeared tobe darken green. The stomatal cell size is larger than that of diploid. The number of stomata in aunit area of the leaf in variant plants sharply reduced. The chromsome number were determined tobe 2n = 2x = 34 for diploid plants and 2n = 4x = 68 for variant plants. The nucleolus number ofvariant plants increased. By means of paraffin-embeded shoot apices,73. 3 % variant plants havebeen identified as solid tetraploid.