منابع مشابه
Polyamines in Pollen: From Microsporogenesis to Fertilization
The entire pollen life span is driven by polyamine (PA) homeostasis, achieved through fine regulation of their biosynthesis, oxidation, conjugation, compartmentalization, uptake, and release. The critical role of PAs, from microsporogenesis to pollen-pistil interaction during fertilization, is suggested by high and dynamic transcript levels of PA biosynthetic genes, as well as by the activities...
متن کاملPhylogenetic Analysis of Dioecy in Monocotyledons.
Surveys of plant breeding systems in angiosperm families have shown a significant association between monoecy and dioecy, and researchers have proposed that dioecy has tended to evolve from monoecy. We evaluated this hypothesis in the context of a phylogeny of 918 monocotyledons assembled from 19 published trees. Binary and multistate breeding system characters were mapped onto a set of composi...
متن کاملThe Operculum in Pollen of Monocotyledons
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 ...
متن کاملMolecular control of microsporogenesis in Arabidopsis.
Microsporogenesis is essential for male fertility and requires both the formation of somatic and reproductive cells in the anther and meiotic segregation of homologous chromosomes. Molecular genetic studies have uncovered signaling molecules and transcription factors that play crucial roles in determining the anther cell types and in controlling gene expression for microsporogenesis. At the sam...
متن کاملVegatative Architecture of Desiccation-tolerant Arborescent Monocotyledons
Within the monocotyledons the acquisition of the tree habit is enhanced by either primary growth of the axis or a distinctive mode of secondary growth. However, a few arborescent monocotyledons deviate from this pattern in developing trunks up to four meters high that resemble those of tree ferns, i.e., their "woody-fibrous" stems consist mainly of persistent leaf bases and adventitious roots. ...
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ژورنال
عنوان ژورنال: Annals of Botany
سال: 1999
ISSN: 0305-7364
DOI: 10.1006/anbo.1999.0942