Analysis of polysomaty in plants and its evaluation for genetics and plant breeding

用流式细胞术分析了重要经济植物中多倍体的分布，并根据分析数据分析了多倍体植物的共同特征。结果表明，多体现象广泛存在于具肉质器官的植物中，但也存在于石竹目等一些非肉质植物中。此外，木本植物很少有多胞体。这些结果表明，多体是在进化过程的不同方面独立获得的。除茎和根顶端分生组织外，其余器官均有多体现象，且倍性水平较高的细胞有随年龄增长的趋势。在人工诱导的四倍体中，多倍体模式向更高的水平移动，但最高倍性细胞的比例有下降的趋势。此外，还探讨了植物微繁过程中体细胞无性系变异与多倍体自发产生的关系。结果表明，从多倍体组织诱导的细胞悬浮培养具有与原始组织几乎相同的多体形态，表明倍性水平较高的细胞具有与基础二倍体细胞相同的细胞分裂能力。由于植物生长调节剂的种类和浓度改变了多倍体的形态，因此植物生长调节剂被认为是导致培养细胞多倍化的主要因素。本文揭示了DNA含量是区分不同类群的有用指标。此外，DNA含量的流式细胞仪分析对于确认DNA含量不同的种间杂交获得的植株的杂交性，以及鉴定由相同性质的种间杂交产生的种间多倍体杂种的母本是有效的。

Flowcytometric analysis was conducted on the distribution of polysomaty in economically important plants and common features of the plants with polysomaty were investigated based on the data of the analysis. As the results, polysomaty was widely found in the plants with succulent organs, but it was also found in some non-succulent plants belonging to some taxons such as Caryophyllales. Moreover, woody plants rarely have polysomaty. These results suggest that polysomaty have been acquired independently at different aspects of evolutionary processes. Polysomaty was found in all organs except for shoot and root apical meristems and the cells with higher ploidy levels tended to increase with aging. In the artificially induced tetraploids, polysomaty pattern shifted to the one-step higher level but the proportion of the highest ploidy cells tended to decrease. Relationship between polysomaty and the spontaneous production of polyploids as a somaclonal variation during the micropropagation of plants was also examined. As a result, cell suspension culture induced from the tissue with polysomaty had almost the same pattern of polysomaty as the original tissue, suggesting that the cells with higher ploidy levels had the same ability for cell division as the basal diploid cells. Since the polysomaty pattern changed by the kind and concentration of plant growth regulators added to the culture medium, plant growth regulators are considered to be a major factor for the polyploidization of the cultured cells. In the present stydy, it was revealed that DNA content is a useful index for discriminating the different taxons, . Moreover, flow cytometric analysis of DNA contents was effective for confirming the hybridity of the plants obtained by the cross between the species which have different DNA contents, and for identifying the maternal parent of the interspecific polyploid hybrid produced by the cross between the species with the same nature.