Development of pollinium and associated changes in anther of Calanthe tricarinata Lindl., an epidendroid orchid

Ravi KANT

《TAIWANIA》 64卷3期 (2019/09) Pp. 269-279

https://doi.org/10.6165/tai.2019.64.269

摘要

In Calanthe tricarinata Lindl., anther primordium develops two thecae each with a mass of densely cytoplasmic archesporial cells surrounded by the protoderm. A six-layered anther wall develops from the archesporial cells of hypodermal layer. Cells in the tapetum are binucleate, only reported in a few primitive orchids. Formation of two septa in each theca results into eight microsporangia which is a primitive character. Pollen mother cells undergo simultaneous cytokinesis and form tetrahedral, rhomboidal, decussate, T-shaped, square and linear type of microspore tetrads. Pollen grains unite to form eight pollinia, which is a primitive feature in the family Orchidaceae. Pollinia unite to the viscidium through long caudicles to form a structure called the pollinarium unit. Pollen grains are monoaperturate with smooth exine. Present observations contribute significantly in the taxonomy and understanding character evolution in the family Orchidaceae.

關鍵字

Anther wall ； Binucleate tapetum ； Calanthe tricarinata ； Caudicle ； Orchid ； Pollinium ； Septum

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