Proximal aperture in Cephalanthera longifolia (L.) Fritsch (Orchidaceae) pollen: a rare germination site for angiosperms

Author(s)
Carola Purgina, Fridgeir Grimsson, Silvia Ulrich
Abstract

The pollen dispersal unit of the epidendroid species, Cephalanthera longifolia, is a soft pollinium consisting of loosely connected tetrads that are agglutinated by elastoviscin. With scanning electron microscopy, the reticulate exine is visible on the outer pollen grains of outer tetrads of a pollinium. The pollen grains are mostly arranged in planar-tetragonal tetrads or decussate tetrads and easily disintegrate into monads. Contrary to the inaperturate pollen in members of subfamily Epidendroideae known so far, C. longifolia exhibits ulcerate pollen. When pollen grains are attached in tetrads within a pollinium the apertures are obscured, as they are located on the proximal side of the pollen grains. The ulcus can only be observed when tetrads disintegrate, freeing the monads and exposing the proximal side of pollen grains for investigation by light and scanning electron microscopy. Proximal aperture configurations are rare among angiosperms and currently known only from few other species of flowering plants. This is the first report of an ulcerate proximal aperture within Orchidaceae.

Organisation(s)
Department of Botany and Biodiversity Research
External organisation(s)
Österreichische Akademie der Wissenschaften (ÖAW)
Journal
Botanical studies
Volume
65
No. of pages
11
ISSN
1817-406X
DOI
https://doi.org/10.1186/s40529-024-00439-7
Publication date
2024
Peer reviewed
Yes
Austrian Fields of Science 2012
106008 Botany, 106049 Ultrastructure research
Keywords
Portal url
https://ucrisportal.univie.ac.at/en/publications/proximal-aperture-in-cephalanthera-longifolia-l-fritsch-orchidaceae-pollen-a-rare-germination-site-for-angiosperms(6807c562-0495-408e-b6a2-e32214342232).html