Storage Lipids in Developing and Germinating Pollen Grain of Flowering Plants

TETRASPORE is required for male meiotic cytokinesis in Arabidopsis thaliana

Development ◽

10.1242/dev.124.13.2645 ◽

1997 ◽

Vol 124 (13) ◽

pp. 2645-2657 ◽

Cited By ~ 5

Author(s):

M. Spielman ◽

D. Preuss ◽

F.L. Li ◽

W.E. Browne ◽

R.J. Scott ◽

...

Keyword(s):

Arabidopsis Thaliana ◽

Pollen Development ◽

Male Meiosis ◽

Pollen Grain ◽

Flowering Plants ◽

External Wall ◽

Normal Pollen ◽

Wide Range ◽

Asymmetric Divisions ◽

And Function

In flowering plants, male meiosis occurs in the microsporocyte to produce four microspores, each of which develops into a pollen grain. Here we describe four mutant alleles of TETRASPORE (TES), a gene essential for microsporocyte cytokinesis in Arabidopsis thaliana. Following failure of male meiotic cytokinesis in tes mutants, all four microspore nuclei remain within the same cytoplasm, with some completing their developmental programmes to form functional pollen nuclei. Both of the mitotic divisions seen in normal pollen development take place in tes mutants, including the asymmetric division required for the differentiation of gametes; some tes grains perform multiple asymmetric divisions in the same cytoplasm. tes pollen shows a variety of abnormalities subsequent to the cytokinetic defect, including fusion of nuclei, formation of ectopic internal walls, and disruptions to external wall patterning. In addition, ovules fertilized by tes pollen often abort, possibly because of excess paternal genomes in the endosperm. Thus tes mutants not only reveal a gene specific to male meiosis, but aid investigation of a wide range of processes in pollen development and function.

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Elektronenmikroskopische Beobachtungen an der vegetativen Zelle im auskeimenden Pollenkorn von Oenothera hookeri Torr. et Grey

Zeitschrift für Naturforschung B ◽

10.1515/znb-1963-1219 ◽

1963 ◽

Vol 18 (12) ◽

pp. 1092-1097 ◽

Cited By ~ 8

Author(s):

Lothar Diers

Keyword(s):

Endoplasmic Reticulum ◽

Golgi Apparatus ◽

Nuclear Envelope ◽

Vegetative Cell ◽

Generative Cell ◽

Pollen Grain ◽

Serial Sections ◽

Lipid Inclusions ◽

Intense Activity ◽

Germinating Pollen

According to the intense activity of the vegetative cell in the germinating pollen grain, the cytoplasm shows a highly organized structure. Concerning the structure the vegetative cell differs strongly from the generative cell. In the vegetative cell the big nucleus shows a very lobed shape. Large invaginations of the cytoplasm into the nucleus can be frequently observed. Series of adjacent sections show that deep and flat vesicles which may often broaden to unusual large cisternae, extend through the vegetative plasm and form by interconnections a highly developed endoplasmic reticulum which is continuous with the nuclear envelope. The leucoplasts contain large starch grains and very few lamellae, in many sections only one lamella is visible. Sometimes, a process of a leucoplast deeply reaches into another leucoplast. In some leucoplasts and mitochondria there are concentric stripes which, according to serial sections, are the margins of invaginations of the cytoplasm or of another organell. In the numerous mitochondria the inner folds have the form of cristae, tubules are not so frequently seen. The edges of the flattened sacs of the Golgi - apparatus expand to vacuoles which seem to separate from the flattened cisternae. Typical for the vegetative plasm are numerous small vacuoles. Relatively large, ringshaped or uniform dark bodies are assumed to be lipid inclusions.

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Elektronenmikroskopische Beobachtungen an der generativen Zelle von Oenothera hookeri Torr. et Gray

Zeitschrift für Naturforschung B ◽

10.1515/znb-1963-0712 ◽

1963 ◽

Vol 18 (7) ◽

pp. 562-566 ◽

Cited By ~ 30

Author(s):

Lothar Diers

Keyword(s):

Endoplasmic Reticulum ◽

Inclusion Bodies ◽

Generative Cell ◽

Cytoplasmic Inclusion ◽

Pollen Grain ◽

Lipid Bodies ◽

Lamellar System ◽

Varying Thickness ◽

Cytoplasmic Inclusion Bodies ◽

Germinating Pollen

In the germinating pollen grain the generative cell shows the structure of a meristematic cell. It is separated from the cytoplasm of the vegetative cell by a clearly visible wall, on the average about 30 — 60 mµ thick. This wall appears to be formed by two darkly stained membranes including a lighter region of varying thickness. In the generative cell there are a big nucleus, plastids which show a scarcely developed lamellar system but no starch grains, mitochondria, dictyosomes. very probably lipid bodies and unidentified cytoplasmic inclusion bodies. The endoplasmic reticulum is continuous with the membranes of the nuclear encelope and extends through the cytoplasmic substance in which no vacuoles are recognizable.

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