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Full-Text Articles in Life Sciences
Inflorescence Architecture And Floral Morphology Of Aratitiyopea Lopezii (Xyridaceae), Lisa M. Campbell, Dennis Wm. Stevenson
Inflorescence Architecture And Floral Morphology Of Aratitiyopea Lopezii (Xyridaceae), Lisa M. Campbell, Dennis Wm. Stevenson
Aliso: A Journal of Systematic and Floristic Botany
Aratitiyopea lopezii is a robust perennial species of Xyridaceae from seasonally saturated, mid- to high-elevation, sandstone and granite sites in northern South America. The species lacks the scapose inflorescence characteristic of Xyridaceae and, having the gestalt of a rhizomatous bromeliad, it is seemingly aberrant in the family. However, closer examination confirms features consistent with the family and the previously noted morphological similarities to Orectanthe. Details of inflorescence structure and floral morphology are presented and compared to other genera of Xyridaceae.
The Operculum In Pollen Of Monocotyledons, Carol A. Furness, Paula J. Rudall
The Operculum In Pollen Of Monocotyledons, Carol A. Furness, Paula J. Rudall
Aliso: A Journal of Systematic and Floristic Botany
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 Pattern And Microsporogenesis In Asparagales, Sophie Nadot, Laurent Penet, Leanne D. Dreyer, Arlette Forchioni, Adrienne Ressayre
Aperture Pattern And Microsporogenesis In Asparagales, Sophie Nadot, Laurent Penet, Leanne D. Dreyer, Arlette Forchioni, Adrienne Ressayre
Aliso: A Journal of Systematic and Floristic Botany
The aperture pattern of pollen grains is a character defined as the number, shape, and position of apertures. Although this character is highly variable in angiosperms, two states are particularly widespread. Pollen grains with one polar aperture occur frequently in basal angiosperms and monocots while tricolpate pollen is a synapomorphy of the eudicots. Many morphological characters are the result of a compromise between selective forces (acting on morphology) and developmental constraints (limiting the range of possible morphologies). To investigate what are the respective roles of development and selection in the determination of aperture pattern in angiosperms, we have chosen to …
Adaptability Of Scanning Electron Microscopy To Studies Of Pollen Morphology, John J. Skvarla, John R. Rowley, William F. Chissoe
Adaptability Of Scanning Electron Microscopy To Studies Of Pollen Morphology, John J. Skvarla, John R. Rowley, William F. Chissoe
Aliso: A Journal of Systematic and Floristic Botany
We have explored methods to achieve excellent results in study of the pollen grain wall by using only one electron microscope, the scanning electron microscope (SEM). While the secondary electron imaging mode, the most common in use, has great value in characterizing the exine surface it is possible to obtain a more comprehensive representation of pollen grain walls by expanding the capability of the secondary mode and making use of backscatter and transmission imaging detectors. In this way information is obtained about internal exine features that are likely to be more stable phylogenetically than the generally late-to-form surface structure. We …