丹东蒲公英和斑叶蒲公英染色体变异初探

Preliminary Studies of Chromosome Mutation in Taraxacum antungense and Taraxacum variegatum

通过根尖染色法并结合流式细胞仪技术对丹东蒲公英(Taraxacum antungense)和斑叶蒲公英(Taraxacum variegatum)根尖和茎尖染色体进行观察,以确定丹东蒲公英和斑叶蒲公蒲染色体变异程度。结果发现,丹东蒲公英和斑叶蒲公英根和叶幼嫩组织中普遍存在多倍性、非整倍性以及混倍性现象,表明具有无融无生殖的蒲公英基因组存在不稳定特性,并且在分生组织中有不同表达。据此推测多倍体蒲公英是由杂交以及多倍化造成,基因组不稳定,表明这一过程新近发生,各种基因组处于进一步选择、融合的过程中。不同生态条件下不同细胞类型可能具有不同表达,以提高植物生态适应性。

Somatic chromosome numbers of Taraxacum antungense and Taraxacum variegatum had been determined by root tip squashing method and flow cytometry to confirm the variation degree. Results showed that gametophytic apomixis is naturally accompanied with phenomena of poly-, aneu-, and mixoploidy and apomicts had genome instability manifesting at the level of meristematic somatic cells. A hypothesis was substantiated that the phenomena in dandelions was caused by hybridogenesis and/or polyploidization. It was concluded that instability of the genome manifests not only the short period of time but also in the process of selection and fusion of the genome. Different kinds of cell types may have a different expression in different e- cological conditions so as to improve the plant ecological adaptability.