Changes in transfer cell distribution in the ovule of soybean after fertilization

1986 ◽  
Vol 64 (5) ◽  
pp. 965-972 ◽  
Author(s):  
M. W. Folsom ◽  
D. D. Cass
Keyword(s):  
Basal Cell ◽  
Cell Walls ◽  
Embryo Sac ◽  
Transfer Cells ◽  
Developmental Study ◽  
Cell Distribution ◽  
Metabolite Transport ◽  
Young Embryo ◽  
Nutritional Environment ◽  
Suspensor Cells

The presence of transfer cells in various regions of the postfertilization ovule of soybean is described. A developmental study shows that transfer cells, occurring in the micropylar nucellus, are formed after fertilization but destroyed by expansion of the embryo sac during transition from the zygote to the two-celled embryo. Subsequently wall ingrowths appear in five additional sites: (i) in the region where the embryonic basal cell wall is associated with the degenerated synergid, projecting into the basal cell; (ii) on the chalazal embryo sac wall projecting into the central cell; (iii) on the embryo sac wall projecting into the basal cell; (iv) on common walls of micropylar suspensor cells; and (v) on some cell walls at the micropylar end of the inner integuments. It is our opinion that these transfer cells are all involved in augmenting metabolite transport and that their orderly appearance in different areas of the ovule signifies changes in the nutritional environment of the young embryo and endosperm of soybean. Because these transfer cells are closely associated with the embryo sac wall, it is proposed that this wall is a common apoplast functioning as both a sink for metabolites from the nucellus and source for all solutes taken up by the cells of the embryo sac.

The morphology of grain abscission in Zizania aquatica

1980 ◽  
Vol 58 (21) ◽  
pp. 2269-2273 ◽  
Author(s):  
H. B. Hanten ◽  
G. E. Ahlgren ◽  
J. B. Carlson
Keyword(s):  
Wild Rice ◽  
Cell Walls ◽  
Vascular Tissue ◽  
Embryo Sac ◽  
Middle Lamella ◽  
Abscission Zone ◽  
Rice Grains ◽  
Zizania Aquatica ◽  
Parenchyma Cells ◽  
Anatomical Evidence

The anatomical development of the abscission zone in grains of Zizania aquatica L. was correlated with development of the embryo. The abscission zone is well developed when the embryo sac is mature. Soon after pollination, the first anatomical evidence of abscission appears as plasmolysis of the separation layer parenchyma cells. This is followed by separation of the layers by dissolution of the middle lamella and fragmentation of cell walls. Persistence of intact vascular tissue and presence of a surrounding cone-shaped mass of lignified cells may be involved in abscission of wild rice grains.

scholarly journals Development of Embryo Suspensors for Five Genera of Crassulaceae with Special Emphasis on Plasmodesmata Distribution and Ultrastructure

Plants ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 320 ◽  
Author(s):  
Małgorzata Kozieradzka-Kiszkurno ◽  
Daria Majcher ◽  
Emilia Brzezicka ◽  
Joanna Rojek ◽  
Justyna Wróbel-Marek ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Basal Cell ◽  
Lipid Droplets ◽  
Cell Structure ◽  
Cell Transfer ◽  
Electron Dense Material ◽  
Full Development ◽  
The One ◽  
Embryonic Structure ◽  
Suspensor Cells

The suspensor in the majority of angiosperms is an evolutionally conserved embryonic structure functioning as a conduit that connects ovule tissues with the embryo proper for nutrients and growth factors flux. This is the first study serving the purpose of investigating the correlation between suspensor types and plasmodesmata (PD), by the ultrastructure of this organ in respect of its full development. The special attention is paid to PD in representatives of Crassulaceae genera: Sedum, Aeonium, Monanthes, Aichryson and Echeveria. The contribution of the suspensor in transporting nutrients to the embryo was confirmed by the basal cell structure of the suspensor which produced, on the micropylar side of all genera investigated, a branched haustorium protruding into the surrounding ovular tissue and with wall ingrowths typically associated with cell transfer. The cytoplasm of the basal cell was rich in endoplasmic reticulum, mitochondria, dictyosomes, specialized plastids, microtubules, microbodies and lipid droplets. The basal cell sustained a symplasmic connection with endosperm and neighboring suspensor cells. Our results indicated the dependence of PD ultrastructure on the type of suspensor development: (i) simple PD are assigned to an uniseriate filamentous suspensor and (ii) PD with an electron-dense material are formed in a multiseriate suspensor. The occurrence of only one or both types of PD seems to be specific for the species but not for the genus. Indeed, in the two tested species of Sedum (with the distinct uniseriate/multiseriate suspensors), a diversity in the structure of PD depends on the developmental pattern of the suspensor. In all other genera (with the multiseriate type of development of the suspensor), the one type of electron-dense PD was observed.

A DEVELOPMENTAL STUDY OF WILD RICE, ZIZANIA AQUATICA L.

1960 ◽  
Vol 38 (5) ◽  
pp. 719-741 ◽  
Author(s):  
Cynthia E. Weir ◽  
Hugh M. Dale
Keyword(s):  
Wild Rice ◽  
Embryo Sac ◽  
Developmental Study ◽  
Abscission Layer ◽  
Potential Yield ◽  
Zizania Aquatica ◽  
History Of ◽  
Nuclear Changes ◽  
Well Differentiated ◽  
The Many

The life history of wild rice is traced from the appearance of the first submersed leaves in the spring until the seed of this annual plant is buried at the bottom of a lake in the fall. The characteristics of the three types of leaves are discussed. The change from the simple vegetative apex to the many-tipped, young inflorescence occurs early. Thus the potential yield in rice grains is determined as the tips of the upright leaves reach the surface of the water and before the stem elongates. The inflorescence develops acropetally as does each spikelet. Only at the later stages can the pistillate and staminate spikelets be distinguished. The development of the microspores and the nuclear changes in the embryo sac have been elucidated. In Zizania the embryo development has been found to be a variant of that found in Poa while the endosperm develops chiefly from the outside. A well-differentiated abscission layer develops at the base of each spikelet.

THE ORIGIN AND DEVELOPMENT OF THE EMBRYO SAC AND YOUNG EMBRYO OFLORANTHUS RUBROMARGINATUSENGLER

1951 ◽  
Vol 33 (2) ◽  
pp. 223-237 ◽  
Author(s):  
R. De V. Pienaar
Keyword(s):  
Embryo Sac ◽  
Young Embryo

scholarly journals The Placenta of Physcomitrium patens: Transfer Cell Wall Polymers Compared across the Three Bryophyte Groups

Diversity ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 378
Author(s):  
Jason S. Henry ◽  
Karen S. Renzaglia
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Cell Wall Composition ◽  
Transfer Cells ◽  
Primary Cell ◽  
Transfer Cell ◽  
Primary Cell Wall ◽  
Slight Variation ◽  
Wall Ingrowths ◽  
Cell Wall Polymers

Following similar studies of cell wall constituents in the placenta of Phaeoceros and Marchantia, we conducted immunogold labeling TEM studies of Physcomitrium patens to determine the composition of cell wall polymers in transfer cells on both sides of the placenta. Sixteen monoclonal antibodies were used to localize cell wall epitopes in the basal walls and wall ingrowths in this moss. In general, placental transfer cell walls of P. patens contained fewer pectins and far fewer arabinogalactan proteins AGPs than those of the hornwort and liverwort. P. patens also lacked the differential labeling that is pronounced between generations in the other bryophytes. In contrast, transfer cell walls on either side of the placenta of P. patens were relatively similar in composition, with slight variation in homogalacturonan HG pectins. Compositional similarities between wall ingrowths and primary cell walls in P. patens suggest that wall ingrowths may simply be extensions of the primary cell wall. Considerable variability in occurrence, abundance, and types of polymers among the three bryophytes and between the two generations suggested that similarity in function and morphology of cell walls does not require a common cell wall composition. We propose that the specific developmental and life history traits of these plants may provide even more important clues in understanding the basis for these differences. This study significantly builds on our knowledge of cell wall composition in bryophytes in general and in transfer cells across plants.

Ultrastructure of the developing embryo sac of sunflower (Helianthus annuus) before and after fertilization

1991 ◽  
Vol 69 (1) ◽  
pp. 191-202 ◽  
Author(s):  
Hua Yan ◽  
Hong-Yuan Yang ◽  
William A. Jensen
Keyword(s):  
Plasma Membrane ◽  
Helianthus Annuus ◽  
Embryo Sac ◽  
Active Role ◽  
Central Cell ◽  
Wall Material ◽  
Young Embryo ◽  
Before And After ◽  
Membrane Contact ◽  
Female Germ Unit

The ultrastructure of the embryo sac of the sunflower (Helianthus annuus) was investigated before and after fertilization. In the young embryo sac, walls were observed that completely surrounded the egg, synergids, and the central cell. However, as maturation continued, the extent of the wall changed. By the time the embryo was mature, the chalazal portion of the walls of the egg and synergids had disappeared so these cells have a plasma membrane to plasma membrane contact. This is also true for the central cell, which has plasma membrane contact with the egg and synergids. However, the chalazal and lateral walls of the central cell become considerably thicker at this time. Before the entry of the pollen tube, the synergid that is located toward the placenta degenerates. After fertilization, a wall forms over the chalazal portion of the zygote and the persistent synergid. The endosperm appears to play an active role in this process, contributing substantial amounts of wall material. However, the wall covering the chalazal portion of the zygote is not complete by the time the zygote divides. In the proembryo, ribosome density increases and lipid bodies decrease in number. The suspensory cell has autophagic vacuoles that encircle some of the organelles. Our results support the concept that the egg, synergids, and central cell form a single functional unit, the female germ unit. Key words: sunflower, ultrastructure, embryo sac, female germ unit.

scholarly journals Anatomy of the pericarp and seed-coat of Lithraea molleoides (Vell.) Engl. (Anacardiaceae) with taxonomic notes

2005 ◽  
Vol 48 (4) ◽  
pp. 599-610 ◽  
Author(s):  
Sandra Maria Carmello-Guerreiro ◽  
Adelita Aparecida Sartori Paoli
Keyword(s):  
Calcium Oxalate ◽  
Seed Coat ◽  
Outer Layer ◽  
Cell Walls ◽  
Embryo Sac ◽  
Vascular Bundles ◽  
Developing Seed ◽  
Secretory Canals ◽  
Polyhedral Cells ◽  
Parenchymal Cells

The aim of the present work was to record anatomical data for the fruit and seed of Lithraea molleoides (Vell.) Engl, and compare the results with those for L. brasiliensis and the genera Schinus and Rhus. The L. molleoides fruit was a drupe with a friable and lignified exocarp. The mesocarp was parenchymatous with large secretory canals associated with vascular bundles. The endocarp consisted of four layers: an outer layer of polyhedral cells with prismatic crystals of calcium oxalate, and three inner layers of sclereids in a palisade arrangement. The ovule was anatropous, unitegmic, and crassinucelate. In the chalazal region, a cup-like zone of tanniniferous parenchymal cells formed the hypostase. The developing seed had a circinotropous-like shape, that originated through curvature of the long, coarse funicle that surrounded the tegument and embryo sac. The ripe seed was endotestal with bar-like thickenings or pittings in the cell walls.

Ultrastructural Aspects of the Embryo Sac ofJasione MontanaL.: Cell Walls

Caryologia ◽  
1973 ◽  
Vol 25 (sup1) ◽  
pp. 109-120 ◽  
Author(s):  
Christel Berger ◽  
Olga Erdelská
Keyword(s):  
Cell Walls ◽  
Embryo Sac

scholarly journals Structure of the extrafloral nectaries of Vicia (L.) Fabaceae

2013 ◽  
Vol 53 (2) ◽  
pp. 5-13
Author(s):  
Małgorzata Stpiczyńska
Keyword(s):  
Basal Cell ◽  
Transfer Cells ◽  
Extrafloral Nectaries ◽  
Stalk Cell ◽  
Vicia Sativa ◽  
Abaxial Surface ◽  
Dense Cytoplasm

Extrafloral nectaries on the abaxial surface of stipules were investigated in the <i>Vicia angustifolia, Vicia sativa, Vicia sepium</i> and <i>Vicia grandiflora</i>. In V. <i>angustifolia</i> nectaries were also located on the calyx surface. Nectaries were consisted of secretory hairs and 2-31ayers of subepidermal cells. Secretory hair was built of four cells of head, one stalk cell and basal cell. Head cells showed character of transfer cells because of walls ingrowths and dense cytoplasm with numerous mitochondria.

Cotton embryogenesis: pollen tube development in the nucellus

1969 ◽  
Vol 47 (3) ◽  
pp. 383-385 ◽  
Author(s):  
William A. Jensen
Keyword(s):  
Pollen Tube ◽  
Gossypium Hirsutum ◽  
Cell Walls ◽  
Embryo Sac ◽  
Dense Material ◽  
Nucellar Cell ◽  
Electron Dense Material

The nucellus of cotton (Gossypium hirsutum) contains a column of specialized cells which degenerate before the pollen tube reaches the nucellus. The pollen tube grows between the walls of these degenerate cells. The growth of the pollen tube crushes most of these cells but does not cause the degeneration of additional nucellar cells. An electron-dense material is found in the nucellar cell walls associated with the growth of the pollen tube for about one-half the thickness of the nucellus. This material appears to spread in a wave-like fashion from the tube through the walls of the nucellar cells. Both the walls and cytoplasm of the cells do not appear changed after the passage of the material. The dense material never reaches the embryo sac itself.

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