Floral structure and development of Apostasia and Neuwiedia (Apostasioideae) and their relationships to other Orchidaceae
Floral structure and development of Apostasia and Neuwiedia (Apostasioideae) and their relationships to other Orchidaceae
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DOI：
10.1086/320781
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发表时间：
2001-07-01
影响因子：
2.3
通讯作者：
Endress, PK
中科院分区：
文献类型：
--
作者：
Kocyan, A;Endress, PK
本文研究了近缘兰亚科Apostasioideae的Apostasia和Neuwiedia两个种的花发育、结构和传粉生物学。花被器官起源于环状原基。两个正面的萼片首先出现，然后是花瓣原基。这与单雄蕊的兰花形成对比，其中中央花瓣原基是内花被轮的第一个器官发育。雄蕊只在花的背面形成。然而，在Neuwiedia veratrifolia和Apostasia nuda中，雄蕊原基的遗迹存在于花的近轴侧。只有在Apostasia中，侧生雄蕊发育完全，而中间器官是退化雄蕊; nuda退化雄蕊被抑制。在开花期，Neuwiedia的花药是游离的，但Apostasia的花药是后生殖连接的。在这两个属中，雄蕊和花柱在基部先天融合。下位卵巢最初是单室的，然后通过卵巢隔的生殖后融合和一个短的合囊带的发育而变成三室的。这两个属的三个心皮从一开始就相等，但在A.只有裸心皮，中心皮在早期发育中占主导地位。柱头凸出，具乳突。显著的针晶异细胞积累发生在退化雄蕊和花柱以及花药和花丝的顶端。与所有其他兰花不同的是，这两个属都提供花粉作为奖励。Neuwiedia有唇花，由Trigona蜜蜂授粉; Apostasia有“Solpendi型”花，花被下弯，花药联合。我们的研究支持这样的观点，Apostasia和Neuwiedia是密切相关的，Apostasioideae是在基础的兰花分支，共享字符与兰花和较低的芦笋。
Floral development, structure, and pollination biology of species of Apostasia and Neuwiedia constituting the basalmost orchid subfamily Apostasioideae were studied. The perianth organs arise from a ring primordium. The two adaxial sepals appear first, followed by the petal primordia. This contrasts with monandrous orchids, in which the median petal primordium is the first organ of the inner perianth whorl to develop. Stamens are only formed on the abaxial side of the flower. However, in Neuwiedia veratrifolia and Apostasia nuda, vestiges of stamen primordia are present on the adaxial side of the flower. In Apostasia only, the lateral stamens are fully developed, whereas the median organ is a staminode; in A. nuda the staminode is suppressed. At anthesis the anthers are free in Neuwiedia, but they are postgenitally connected in Apostasia. In both genera, stamens and style are congenitally fused at the base. The inferior ovary is at first unilocular and then becomes trilocular by postgenital fusion of the ovary septa and the development of a short synascidiate zone. The three carpels of both genera are equal from the beginning, but in A. nuda only, the median carpel dominates during early development. The stigma is convex and papillate. Conspicuous raphide idioblast accumulations occur in staminode and style and in the tips of anthers and filaments. In contrast to all other orchids, both genera offer pollen as a reward. Neuwiedia has lip flowers, which are pollinated by Trigona bees; Apostasia has "Solanum-type" flowers with recurved perianth and united anthers. Our study supports the view that Apostasia and Neuwiedia are closely related and that Apostasioideae are at the base of the orchid clade, sharing characters with orchids and lower Asparagales.