نتایج جستجو برای: micropyle
تعداد نتایج: 189 فیلتر نتایج به سال:
The mechanisms of compatible pollination are less studied than those of incompatible pollination and yet most of the angiosperms show self-compatibility. From the release of pollen from anthers to the penetration of the micropyle by the pollen tube tip, there are numerous steps where the interaction between pollen and the pistil can be regulated. Recent studies have documented some diverse ways...
Intestinal contents from 12 scaled quail (Callipepla squamata), 10 bobwhite quail (Colinus virginianus), 20 harlequin quail (Cyrtonyx montezumae), 35 California quail (Lophortyx californicus), 15 Gambel's quail (Lophortyx gambelii), and 29 mountain quail (Oreortyx pictus) were examined for coccidian oocysts. Only 18 (14.9%) of 121 birds had coccidian oocysts in their feces at the time of collec...
Eimeria carmelinoi n.sp., is described in the teiid lizard Kentropyx calcarata Spix, 1825 from north Brazil. Oocysts subspherical to spherical, averaging 21.25 x 20.15 micro m. Oocyst wall smooth, colourless and devoid of striae or micropyle. No polar body or conspicuous oocystic residuum, but frequently a small number of fine granules in Brownian movement. Sporocysts, averaging 10.1 x 9 microm...
Eichhornia azurea and E. crassipes are morphologically easy to distinguish, however, their seeds similar differentiated only by size, which makes identification difficult, especially when collected directly from the seedbank. We identified characters for distinguish of these species through macrosculpture analyzes seed coat (size, shape, epidermal pattern, structure primary secondary microsculp...
The micropylar region of the Rosy barb, Barbus conchonius, egg consists of 7-10 grooves and ridges, which drain directly into a funnel-shaped vestibule, the only point on the chorion through which sperm-egg contact is achieved during fertilization. Results of time-lapse video microscope study and computer-aided analysis of sperm motility pattern in the micropylar region showed that the fertiliz...
Double fertilization in flowering plants requires the delivery of two immotile sperm cells to the female gametes by a pollen tube, which perceives guidance cues, modifies its tip growth direction, and eventually enters the micropyle of the ovule. In spite of the recent progress, so far, little is known about the signaling events in pollen tubes in response to the guidance cues. Here, we show th...
The orientation and morphology of the female cone are important for wind pollination in gymnosperms. To examine the role of female reproductive structures associated with wind pollination in Ginkgo biloba, we used scanning electron microscopy and semithin section techniques to observe the development of female short shoots and ovules in G. biloba before and during the pollination period. The ov...
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