Germination characteristics of native Japanese dandelion autopolyploids and their putative diploid parent species

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• 作者：Akihiko Hoya ; Hiroyuki Shibaike ; Tatsuyoshi Morita and Motomi Ito
• 关键词：Genus Taraxacum ; Autopolyploid ; Seed ; germination characteristics ; Germination suppression
• 刊名：Journal of Plant Research
• 出版年：2007
• 出版时间：January, 2007
• 年：2007
• 卷：120
• 期：1
• 页码：139-147
• 全文大小：246 KB

文摘

Germination characteristics of native Japanese Taraxacum lineages of Taraxacum platycarpum (diploid), T. venustum (triploid and tetraploid), and T. albidum (pentaploid) have been studied at different temperatures. Taraxacum platycarpum ssp. hondoense is the putative diploid parent of T. venustum. Diploid T. platycarpum ssp. hondoense and the polyploids T. venustum and T. albidum are found in different areas of Japan, and distribution differences may reflect divergent ecological and physiological traits among ploidy levels. In this study, to prevent mixing of seeds of different polyploidy we used flow cytometry to examine the ploidy level of the plants from which seeds were collected. Results from seed-germination experiments showed that dependence on temperature of final percentage germination was qualitatively similar for both autopolyploids T. venustum and diploids T. platycarpum—germination was suppressed at high and low temperatures. It was also shown that seed germination of autopolyploids was suppressed more than that of the ancestral diploid at low temperatures and that seed germination for polyploids was higher than for the diploid. Threshold variations at low temperatures might affect the distribution of native dandelions. Taraxacum venustum, which occurs in cool climates, might have developed a distinctly lower germination threshold at low temperatures whereas T. albidum, which is native to warm climates, might have developed an adaptive threshold at high temperatures.