杜仲四倍体的诱导与鉴定

Induction and Identification of Tetraploids in Eucommia ulmoides Oliv.

以杜仲籽苗为材料，采用秋水仙素溶液处理生长点的诱变方法和茎尖细胞染色体数检测及DNA相对含量测定的倍性鉴定方法，研究了秋水仙素浓度和处理时间的诱变效果。结果表明，除0．05％秋水仙素处理48h外，其它浓度（0．1％，0．2％，0．4％）均以处理12h效果最好，变异株率在43．3％～63．3％，最佳处理组合为0．1％秋水仙素处理生长点12h，变异株率和四倍体株率分别为63．3％和36．7％。在获得的148个变异株中，染色体计数表明47株为四倍体（2n=4x=68），占31．76％；染色体计数结果进一步被流式细胞仪分析验证。四倍体植株表现出多倍体特征，叶片变厚，叶面积增大，叶形指数减小，保卫细胞增大，单位面积气孔数减少，叶绿体数明显增多。

Stem primodia of Eucommia ulmoides Oliv. seedlings were treated with different concentrations of colchicine solution at different stages in order to figure out the best inducing method and obtain tetraploids. The results showed that, apart from 0.05% colchicine solution for 48 h, the treatments （0. 1%, 0.2% or 0. 4% ） were all suitable for 12 h, in which the rates of mutants with morphological characteristics varied from 43.3% to 63.3%, the optimum treatment combination was 0. 1% colchicine solution for 12 h, and the rates of variant plants and tetraploid plants were 63.3% and 36. 7% , respectively. The results of chromosome counts indicated that 47 plants were tetraploid plants （2n = 4x = 68） , taking up about 31.76% among the 148 variant plants. This result was consistent with that analyzed with the ‘Flow Cytometry＇ method. The plants showed the general characteristics of tetraploids, such as thicker leaf, smaller leaf index, larger guard cells, less stomata per unit area and more chloroplasts in guard cells.