Abstract

Seed morphogenesis of Orobanchaceae was not completely investigated previously. Here, we observed seed development of Orobanchaceous species in Taiwan using light and scanning electron microscopies. Results indicated that seeds of Aeginetia indica, Boschniakia himalaica, and Orobanche caerulescens all consisted of embryo, endosperm and testa. Ontogeny of the embryo in A. indica was Solanad type, while in both B. himalaica and O. caerulescens was Onagrad type. The mature embryos of the three species lacked embryonic organs, and their endosperm development was the cellular type and, at maturity, appeared as several cell layers of storage tissue. Ontogeny of the testa was all non-multiplicative, with the residues of the outermost cell layer and reticulately-thickened secondary walls of its cells at maturity. Mature seeds of A. indica and O. caerulescens were ovate whereas those of B. himalaica were oblate. As for Christisonia hookeri, due to lack of samples, only the cellular-typed endosperm was determined. The comparative development of Orobanchaceous seeds was discussed.

中文摘要

列當科種子之形態形成於先前未有完整的研究。於此，我們以光學與掃描式電子顯微鏡對臺灣產列當科植物進行種子發育之解析。結果顯示野菰、丁座草與列當之種子皆由胚、胚乳與種皮組成。於胚的層面，野菰之發育屬於茄型，而丁座草與列當屬於柳葉菜型；成熟的胚皆未分化。關於胚乳，所有種類之發育皆屬於細胞型；成熟時則由數層儲藏組織之細胞所構成。在種皮方面，所有種類之發育皆為非複分裂型；最終只剩最外層細胞，並具有網狀加厚之次生壁。野菰與列當之成熟種子呈現卵圓形，而丁座草則為扁圓形。至於假野菰則因材料不足，僅判定其胚乳發育屬於細胞型。列當科之種子發育比較於此討論之。

Keyword: Embryo, endosperm, Orobanchaceae, seed development, testa. 胚、胚乳、列當科、種子發育、種皮。