Three Pteris Species (Pteridaceae: Pteridophyta) Reproduce by Apogamy

本研究確認大葉鳳尾蕨、闊葉鳳尾蕨及烏來鳳尾蕨的倍體數、配子體與幼孢子體形態及其生殖模式。大葉鳳尾蕨及烏來鳳尾蕨是二倍體，而闊葉鳳尾蕨則是三倍體。三倍體的闊葉鳳尾蕨孢子顯著大於其它兩種二倍體的孢子，但闊葉鳳尾蕨的正常孢子比例(73%)則較其它兩種的正常孢子比例(95%~98%)低。大葉鳳尾蕨與闊葉鳳尾蕨的配子體產生正常的藏精器，但沒有藏卵器。雖然烏來鳳尾蕨具藏卵器，但卻失去了功能。這三種鳳尾蕨的每一個藏精器都長有32顆精子，都行無配生殖。幼孢子體自配子體上直接產生而沒有受精的過程發生。第一片葉子大多數具中肋，僅少數不具中肋。這些與生殖有關之特徵雖然提供了辨認生殖模式的參考資訊，但最可信賴的生殖模式辨別方法仍為檢視「胚」是否形成自配子體上的營養細胞。

關鍵字

無配生殖；染色體；配子體；形態；倍體數；大葉鳳尾蕨；闊葉鳳尾蕨；烏來鳳尾蕨

並列摘要

The ploidy levels, morphologies of gametophytes and young sporophytes, and reproductive modes of Pteris cretica, P. pellucidifolia, and P. wulaiensis were determined in this study. Pteris cretica and P. wulaiensis were diploid while P. pellucidifolia was triploid. Sporophytes of all three species produced 32-spored sporangia. Spore sizes of the triploid P. pellucidifolia were significantly larger than those of the other two diploid species. However, the frequencies of normal spores were lower in P. pellucidifolia (73%) than those of the other two species (95%-98%). Gametophytes of P. cretica and P. pellucidifolia produced normal antheridia but no archegonium. Although P. wulaiensis produced archegonia, those archegonia had lost their function. Every antheridium of these three species produced 32 active sperms. All of these three species apogamously produced sporophytes. Young sporophytes were produced directly on the gametophytes without fertilization. The first fronds of young sporophytes predominantly possessed midribs, with only a few of them lacking midribs. This study also suggests that the best way to infer the reproductive mode of ferns is to detect whether the embryo formed from the vegetative cells of gametophytes, although those other reproduction-nrelated traits may provide useful indicators.

並列關鍵字

Apogamy ； Chromosome ； Gametophyte ； Morphology ； Ploidy ； Pteris cretica ； Pteris pellucidifolia ； Pteris wulaiensis

國際替代計量

Three Pteris Species (Pteridaceae: Pteridophyta) Reproduce by Apogamy

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