Ultrastructural Investigations on the Two-Nucleate Pollen Grain of Tillandsia caput-medusae Morr. (Bromeliaceae)

Brighigna, Luigi; Fiordi, Ambretta Cecchi; Palandri, Mariarosa

doi:10.2307/2442712

Cited by 11 publications

(10 citation statements)

References 6 publications

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“…Generative cell and sperm cell formation in B. napus occur in a similar way to that described for other Dicotyledons (Brighina et al 1981;Schr6der 1984;Murgia et al 1986). The generative cell results from an inequal division of the microspore, and the sperm cells are formed by an equal division of the generative cell.…”

Section: Discussionsupporting

confidence: 62%

Brassica napus pollen development during generative cell and sperm cell formation

Murgia

Detchepare

Went

et al. 1991

Sexual Plant Reprod

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Brassica napus pollen development during the formation of the generative cell and sperm cells is analysed with light and electron microscopy. The generative cell is formed as a small lenticular cell attached to the intine, as a result of the unequal first mitosis. After detaching itself from the intine, the generative cell becomes spherical, and its wall morphology changes. Simultaneously, the vegetative nucleus enlarges, becomes euchromatic and forms a large nucleolus. In addition, the cytoplasm of the vegetative cell develops a complex ultrastructure that is characterized by an extensive RER organized in stacks, numerous dictyosomes and Golgi vesicles and a large quantity of lipid bodies. Microbodies, which are present at the mature stage, are not yet formed. The generative cell undergoes an equal division which results in two spindle-shaped sperm cells. This cell division occurs through the concerted action of cell constriction and cell plate formation. The two sperm cells remain enveloped within one continuous vegetative plasma membrane. One sperm cell becomes anchored onto the vegetative nucleus by a long extension enclosed within a deep invagination of the vegetative nucleus. Plastid inheritance appears to be strictly maternal since the sperm cells do not contain plastids; plastids are excluded from the generative cell even in the first mitosis.

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Section: Discussionsupporting

confidence: 62%

Brassica napus pollen development during generative cell and sperm cell formation

Murgia

Detchepare

Went

et al. 1991

Sexual Plant Reprod

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“…The generative cell, in spite of its reduced cytoplasm, like that found in Tillandsia caput‐medusae by Brighigna, Fiordi & Palandri (1981), has a relatively large amount of ERr and a very high density of mitochondria. No plastids were observed, corroborating the observations of Nakamura & Miki‐Hirosige (1985), Brighigna et al (1981) and references therein (but see Jensen, Ashton & Heckard, 1974).…”

Section: Discussionmentioning

confidence: 84%

“…Nakamura & Miki‐Hirosige (1985) believed that the simple and single layer composition of the wall indicates the lack of requirement for a firmer one since it is surrounded by the cytoplasm of the vegetative cell. Thus, transference of substances between them is possible, due to the presence of plasmodesmata (Brighigna et al , 1981; Nakamura & Miki‐Hirosige, 1985).…”

Section: Discussionmentioning

confidence: 99%

Microsporogenesis, microgametogenesis and pollen morphology of Passiflora spp. (Passifloraceae)

García

Galati

Antón

2002

Botanical Journal of the Linnean Society

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Microsporogenesis, microgametogenesis and pollen morphology of six species of genus Passiflora L. belonging to three subgenera (Passiflora, Dysosmia, Decaloba) were studied with light and scanning microscopy; P. caerulea was also examined with transmission microscopy. The tapetum is secretory, microspore tetrads are tetrahedral and pollen grains are two‐celled when shed. Small Ubisch bodies are attached to a peritapetal membrane; they are a product of tapetal activity and the rough endoplasmic reticulum (ERr) appears to be involved in their origin. The pollen grains of all the species are subspheroidal, zonocolpate, geminicolpate. Each pair of colpi anastomoses at the poles. The exine is semitectate, reticulate, heterobrochate. The muri are simplibaculate, wavy. The lumina have clavate bacula of varying height. The colpus structure is similar to that of the lumina but generally with fewer and smaller bacula. Lumina size and amount of bacula inside the lumina vary between subgenera. The grains from subgenera Passiflora and Dysosmia differ from those of Decaloba in their size and number of colpi. The pollen and microsporangium morphology of the species of subgenera Passiflora and Dysosmia are more similar than those of subgenus Decaloba. The results are discussed in relation to the current taxonomic classification. © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society of London, 2002, 139, 383–394.

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“…Besides the pollen sterility, ultrastructural changes in the pollen, before and after the anther dehiscence, have also been studied in a number of angiosperms (SANGER and JACKSON 1971;BHO-JWANI and BHATNAGAR 1999). These include the structural changes in the cytoplasm (LARSON 1965), changes in generative cell and vegetative cell (ANGOLD 1968;BRIGHIGNA et al 1981), the distribution of plastids (BRIGHIGNA and PAPINI 1997;MILOCANI et al 2006), the degree of hydration and the amount of soluble sugars (FRANCHI et al 1996(FRANCHI et al , 2002MILOCANI et al 2006). As far as Rhoeo is concerned, there is no information available on the changes in cytoplasm at ultrastructural level during pollen development.…”

Section: Discussionmentioning

confidence: 99%

Spectrum of chromosomal configurations in pollen mother cells ofRhoeo spathacea(Swartz) Stearn

Kumar

Nagpal²,

Arun

2011

Caryologia

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-Rhoeo spathacea is unusual in that its twelve chromosomes are involved in complex translocations that results in atypical meiosis with all chromosomes frequently joined end-to-end into a single ring. The detailed meiotic studies, for the fi rst time, revealed that alignment of chromosomes into a ring and / or a chain begins at very early prophase I. However, the cells at diakinesis and metaphase I do not exclusively have a ring or a chain of 12 chromosomes. Instead, they carry a range of chain confi gurations formed due to slipping of the chiasmata off the pairing segments in complex structures. While in 57.61% cells, at diakinesis, a ring or a chain was observed, in the rest 2-7 chain confi gurations existed. Similarly, at metaphase I a ring of 12 chromosomes was observed in 33.87% cells whereas in 66.13 % cells 2-9 chain confi gurations existed. The various groups of chromosomes in cells at diakinesis generally did not show any specifi c orientation pattern. However, in 17.31% cells a disjunctional arrangement of chromosomes was observed. At metaphase I also while in 82.26% cells chromosomes showed more or less non disjunctional orientations, in 17.74% cells regular arrangement of chromosomes was observed. Owing to non-disjunctional arrangement of chromosomes at metaphase I, the anaphase I distribution of chromosomes was erratic in 44.18% cells. Three to nine chromosomes were seen at two poles in 33.06% cells whereas in 11.11% cells 1-8 lagging chromosomes existed. Regular distribution of 6:6 was seen in 55.82% cells. The Pollen sterility recorded was very high i.e. 81.24% using cotton blue staining procedure. It is suggested that a wide range of chromosome confi gurations, hitherto unidentifi ed, might exist in Rhoeo spathacea which awaits to be discovered.

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Ultrastructural Investigations on the Two-Nucleate Pollen Grain of Tillandsia caput-medusae Morr. (Bromeliaceae)

Cited by 11 publications

References 6 publications

Brassica napus pollen development during generative cell and sperm cell formation

Brassica napus pollen development during generative cell and sperm cell formation

Microsporogenesis, microgametogenesis and pollen morphology of Passiflora spp. (Passifloraceae)

Spectrum of chromosomal configurations in pollen mother cells ofRhoeo spathacea(Swartz) Stearn

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