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与２％二甲基亚砜的复合溶液处理苹果栽培品种嗄拉和千秋的试管苗离体叶片，结果表明，以０．５％秋水仙素溶液处理４天的效果最佳，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，与对照相比，变异株茎矮、粗壮、节间短、叶色浓厚，单位面积气孔数目减少，气孔体积增大，染色体数目加倍，２ｎ＝４ｘ＝６８，核仁数目增加，梢端组织学切片证实，获得的同质四倍体频率为８６

STUDY ON THE DOUBLING EFFECT OF COLCHICINE ON LEAVES in vitro OF APPLE SEEDLINGS

Leaves in vitro of two diploid apple cultivars were treated with different concentrations of colchicine and 2% DMSO solution. Among all treatments, 0.5% of colchicine treating for 4 days showed the best effect with variation frequency of 56.1%. Obvious changes occured in the morphological and cytological aspects of the induced tetraploid apple plants. In comparison with normal plants, variant plants showed the following features:the stem became dwarf and think; node was shorten; the leaves' colour appeared dark green. The stomatal cell size was larger than that of diploid plants. The number of the stomata per unit area of the leaves in variant plants distinctly reduced. The chromosome number were determined to be 2n=2x=34 for diploid plants and 2n=4x=68 for variant plants. The nucleolus number of variant plants increased. By the means of section of paraffin embeded shoot apices, 86% of variant plants have been identified as solid tetraploid.