Inflorescence and floral development in Astragalus lagopoides Lam. (Leguminosae: Papilionoideae: Galegeae)

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• 作者：Ali Movafeghi^a ; ^{movafeghi@tabrizu.ac.ir} ; Somayeh Naghiloo^a ; Mohammad Reza Dadpour^b
• 关键词：Astragalus ; Common primordia ; Epi-illumination light microscopy ; Floral development
• 刊名：Flora - Morphology, Distribution, Functional Ecology of Plants
• 出版年：2011
• 出版时间：March 2011
• 年：2011
• 卷：206
• 期：3
• 页码：219-226
• 全文大小：2292 K

文摘

Inflorescence and floral organogenesis and development of the bushy perennial legume Astragalus lagopoides of the section Hymenostegis were studied by means of epi-illumination light microscopy. Based on our observations, the primordia of lanceolate racemose inflorescences are born in the axils of leaves. Each inflorescence apex initiates acropetally bracts and floral apices for some time and then eventually ceases meristematic activity and forms an oblong-shaped terminal structure. The formation of such atypical terminal protrusion on the inflorescence meristem is judged to be a diagnostic feature for well-organized cessation of meristem morphogenesis. Pentamerous perfect flowers of the plant show strong zygomorphy and marked overlap in time of initiation among different organ primordia. Unexpectedly, sepal initiation is bidirectional starting from the lateral sides of the floral apex. Other significant developmental feature includes the existence of two types of common primordia, which are formed successively. From the primary common primordia there are produced antesepalous stamens and secondary common primordia. In comparison, the five secondary common primordia subdivide into a petal and an antepetalous stamen primordia. Initiation of two different types of common primordia is possibly the result of rising overlap in time of initiation of organs and demonstrates an advanced developmental style in the genus Astragalus.