DOI
10.5642/aliso.20062201.15
First Page
191
Last Page
196
Abstract
Within monocotyledons, monosulcate pollen is the predominant type and probably represents the plesiomorphic condition, but considerable variation occurs in sulcus morphology. An operculum is an exine thickening that covers most of an aperture. Monocot opercula are usually associated with sulci, although they can occur in ulcerate apertures, as in Poaceae. There are several other aperture types closely related to the monosulcate-operculate type, and confusion occurs in the palynological literature between monosulcate-operculate, pontoperculate, disulculate, disulcate, and zona-aperturate (zonasulculate or zonasulcate) pollen. Transmission electron microscopy (TEM) was used to determine the distribution of the thick apertural intine and to accurately identify these aperture types. Operculate pollen most frequently was present in Asparagales (particularly Agavaceae, Doryanthaceae, lridaceae, and Tecophilaeaceae), Liliales (particularly Liliaceae, Melanthiaceae, and Uvulariaceae), and relatively infrequently among commelinid monocots, except for some Arecaceae, Dasypogonaceae, and Poales. Thus, we conclude that opercula have probably evolved several times independently within monocots, particularly in taxa from dry or seasonally dry habitats, and that this adaptation may be related to their function in protecting the aperture. Two transformation series of related aperture types are proposed, one of which involves monosulcate-operculate pollen, although further testing will be required.
Recommended Citation
Furness, Carol A. and Rudall, Paula J.
(2006)
"The Operculum in Pollen of Monocotyledons,"
Aliso: A Journal of Systematic and Floristic Botany:
Vol. 22:
Iss.
1, Article 15.
Available at:
https://scholarship.claremont.edu/aliso/vol22/iss1/15
Rights Information
© 2006 Carol A. Furness, Paula J. Rudall
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.