نتایج جستجو برای: exine pattern
تعداد نتایج: 348496 فیلتر نتایج به سال:
The external pollen morphology of the family Sapotaceae in Thailand was examined using acetolysis method to determine its taxonomic significance. Pollen 39 specimens belonging 32 species investigated by means light and scanning electron microscopy. grains are found be monads, isopolar, colporate, lalongate, variable size, shape, aperture number, colpus length exine thickness. Exine ornamentatio...
Pollen grains of land plants have evolved remarkably strong outer walls referred to as exine that protect pollen and interact with female stigma cells. Exine is composed of sporopollenin, and while the composition and synthesis of this biopolymer are not well understood, both fatty acids and phenolics are likely components. Here, we describe mutations in the Arabidopsis (Arabidopsis thaliana) L...
Pollen ornamentation patterns are important in the study of plant genetic evolution and systematic taxonomy. However, they are normally difficult to quantify. Based on observations of pollen exine ornamentation characteristics of 128 flowering crabapple germplasms (44 natural species and 84 varieties), three qualitative variables with binary properties (Xi: regularity of pollen exine ornamentat...
Lipid transfer proteins (LTPs) are small secretory proteins in plants with defined lipid-binding structures for possible lipid exocytosis. Special groups of LTPs unique to the anther tapetum are abundant, but their functions are unclear. We studied a special group of LTPs, type III LTPs, in Arabidopsis (Arabidopsis thaliana). Their transcripts were restricted to the anther tapetum, with levels ...
In this article, we propose an automatic method for the segmentation of pollen grains from microscope images, followed by the automatic segmentation of their exine. The objective of exine segmentation is to separate the pollen grain in two regions of interest: exine and inner part. A coarse-to-fine approach ensures a smooth and accurate segmentation of both structures. As a rough stage, grain s...
During the early stages of microsporocyte ontogeny in Helleborus foetidus L. there is protoplasmic continuity between the cells of the tapetum and between the individual sporogenous cells, but not between the two tissues. The plasma canals and plasmodesmata are progressively sealed off by the deposition of thick callose walls, so that by the first meiotic division, each pollen mother cell is is...
Date: August 28 Place: Room 5336 (oral), Room 6302 (poster) Organizers: Stephen Blackmore, Nina Gabarayeva & Michael Hesse Contact email address: [email protected] Purpose: The science of palynology is founded entirely upon the extraordinary organisational diversity and resistance to decay of the exine. Not surprisingly therefore, there has always been great interest in understanding how ...
Ruthenium red stained a capsule external to the exine of the Azotobacter cyst. The central body is therefore surrounded by three layers, the intine, the exine, and the capsule, all containing acid mucopolysaccharide. Vesicles that appear to originate from the contracting cell membrane of the central body may account for the lipid content of the intine. The exine is composed of laminated sheets ...
Pollen exine is essential for protection from the environment of the male gametes of seed-producing plants, but its assembly and composition remain poorly understood. We previously characterized Arabidopsis (Arabidopsis thaliana) mutants with abnormal pollen exine structure and morphology that we named kaonashi (kns). Here we describe the identification of the causal gene of kns4 that was found...
In the course of a study of pollen wall development in the Gramineae two interesting relationships were noted: the locule wall and tapetal cells were bordered by spheroids which were similar chemically (resistant to acetolysis) and morphologically to the pollen exine. The pollen exine as well as the wall of the spheroids was perforated by submicroscopic channels. In the mature anther the sphero...
نمودار تعداد نتایج جستجو در هر سال
با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید