The Endosperm

Vijayaraghavan, M. R.; Prabhakar, Kumkum

doi:10.1007/978-3-642-69302-1_7

Cited by 71 publications

(56 citation statements)

References 93 publications

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“…However, we observed polar nuclei more frequently than we observed a secondary nucleus in these cells. In vivo, fusion of polar nuclei is accompanied by fusion of the two nucleoli (Vijayaraghavan and Prabhakar, 1984). This is in agreement with our results that indicate the existence of only one large nucleolus in the secondary nuclei.…”

Section: Discussionsupporting

confidence: 93%

“…Most of the cell organelles, including large starch grains, are clustered around the nuclei of unfertilized central cells as well as the nuclei of in vitro-produced primary endosperm cells. Similar observations were made with in vivo material of many other species (Vijayaraghavan and Prabhakar, 1984).…”

Section: Discussionsupporting

confidence: 84%

“…In vivo, maize endosperm development is described as a nuclear type of endosperm formation (Lopes and Larkins, 1993). We did not observe that karyogenesis and cytokinesis were coupled in the first division of the in vitro-produced primary endosperm cell, as is typical for the helobial type of endosperm development in some monocotyledonous species (Bhatnagar and Sawhney, 1981;Vijayaraghavan and Prabhakar, 1984). However, we observed a narrowing in the in vitro-fertilized, four nuclei-containing endosperm cell, which incompletely divided the cell into two chambers.…”

Section: Discussioncontrasting

confidence: 54%

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Endosperm Development after Fusion of Isolated, Single Maize Sperm and Central Cells in Vitro

et al. 1998

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We demonstrate here the possibility of endosperm development in vitro after the fusion of pairs of an isolated sperm and an isolated central cell of maize. The occurrence of karyogamy and the time course of the fusion of sperm and central cell nuclei are presented. The fusion of the sperm nucleus occurred either with one of the two polar nuclei or with the secondary nucleus and was completed within 2 hr after in vitro cell fusion. The in vitro study of early events after cell and nuclear fusion indicates that the resulting primary endosperm cell develops into a characteristic tissue capable of self-organization apart from the mother tissue. The technology presented here opens the way for new cellular and molecular studies, especially of early events after sperm and central cell fusion. These studies should lead to a better understanding of the processes of double fertilization and endosperm development.

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Section: Discussionsupporting

confidence: 93%

Section: Discussionsupporting

confidence: 84%

Section: Discussioncontrasting

confidence: 54%

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Endosperm Development after Fusion of Isolated, Single Maize Sperm and Central Cells in Vitro

et al. 1998

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“…Three general types of endosperm development are recognized (Brink and Cooper, 1947;Vijayraghavan and Prabhakart, 1984;Friedman, 1994): ab initio cellular, in which all mitoses are followed by wall development; nuclear, in which free nuclear divisions result in a syncytium that later becomes cellularized; and helobial, where the first division divides the central cell into separate micropylar and chalazal chambers that develop independently. Cereal grains undergo the nuclear type of development with cell walls forming in the immediate vicinity of the developing embryo region (micropylar) earlier than those in the large chalazal region (Engell, 1989).…”

Section: Introductionmentioning

confidence: 99%

“…From this perspective, the endosperm emerges as a model system for the study of plant development. It is abundant, fast growing, and consists of only two cell types that can be mechanically separated (Jakobsen et al, 1989), and importantly, genetic mutants affecting the development of the endosperm are known (Sheridan and Neuffer, 1980;Felker et al, 1985;Bosnes et al, 1987Bosnes et al, , 1992Kowles et al, 1992).Three general types of endosperm development are recognized (Brink and Cooper, 1947;Vijayraghavan and Prabhakart, 1984;Friedman, 1994): ab initio cellular, in which all mitoses are followed by wall development; nuclear, in which free nuclear divisions result in a syncytium that later becomes cellularized; and helobial, where the first division divides the central cell into separate micropylar and chalazal chambers that develop independently. Cereal grains undergo the nuclear type of development with cell walls forming in the immediate vicinity of the developing embryo region (micropylar) earlier than those in the large chalazal region (Engell, 1989).…”

mentioning

confidence: 99%

Endosperm Development in Barley: Microtubule Involvement in the Morphogenetic Pathway.

1994

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An immunofluorescence study of sectioned barley endosperm imaged by confocal laser scanning microscopy provided three-dimensional data on the relationship of microtubules to the cytoplasm, nuclei, and cell walls during development from 4 to 21 days after pollination (DAP). Microtubules play an important role throughout endosperm ontogeny. The syncytium is organized into units of nuclear-cytoplasmic domains by nuclear-based radial microtubule systems that appear to control the pattern of the first anticlinal walls at 5 to 6 DAP. After 7 DAP, phragmoplasts of two origins (interzonal and cytoplasmic) guide wall formation. Large compartments formed by the "free growing" walls in association with cytoplasmic phragmoplasts formed adventitiously at interfaces of opposing microtubule systems are subsequently subdivided by interzonal phragmoplastlcell plates to give rise to the starchy endosperm. During development of the aleurone layer from 8 to 21 DAP, the microtubule cycle is typical of plant histogenesis; cortical microtubules are hooplike, and preprophase bands of microtubules predict the division plane. INTRODUCTIONIn spite of the enormous economic importance of cereal endosperm in agriculture and industry, surprisingly little is known about its development and evolution. The endosperm is an enigma in that (1) it is a product of double fertilization &e., the union of one sperm cell with the egg results in the diploid zygote and the other sperm with one or more nuclei results in the primary endosperm nucleus); (2) unlike the embryo, which follows generally recognized patterns of plant histogenesis, the endosperm is so unlike any other plant tissue that it has been called a monstrosity; and (3) the endosperm has proven extremely difficult to study because in its early stage, it is a delicate liquid coenocyte contained within the innermost chamber of the developing seed.The evolutionary introduction of the endosperm into the life cycle of angiosperms is unknown. Double fertilization occurs in gymnosperms (Friedman, 1992), but the second fertilization results in an additional embryo that competes for resources during development. In angiosperms, the second fertilization results in the primary endosperm nucleus from which develops the nutritive tissue. The endosperm could either be a delayed continuation of female gametophyte development triggered by the second fertilization event and therefore homologous to the nutritive gametophyte in gymnosperms (Thomas, 1907), or the endosperm may be a highly modified supernumerary embryo (Sargant, 1900). Support for the second hypothesis is amassed by Friedman (1994), who argues that the endosperm is a homolog of the embryo, or in other words, an organism in its ownTo whom correspondence should be addressed.right. Recent molecular data demonstrating the expression of the same or homologous genes in the embryo and endosperm (Aalen et al., 1994) lend support to this view. From this perspective, the endosperm emerges as a model system for the study of plant development. It is abundant...

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