A comparison of tapetal structure and function in pteridophytes and angiosperms

Parkinson, Barbara M.; Pacini, Ettore

doi:10.1007/bf00985107

Cited by 28 publications

(18 citation statements)

References 133 publications

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“…Dickinson and Lewis (1973) described tryphine formation preceded by the breakdown of the plasma membrane of the parietal tapetum causing organelles to be released into the loculus. The typical apoptotic bodies are membrane-bound, while the tryphine seems to be released into the loculus during tapetum degeneration (Dickinson andLewis 1973, Parkinson andPacini 1995). In T. a l b i d a and L. r a u s c h i i these heterogeneous aggregates are not contained in a membrane envelope.…”

Section: Discussionmentioning

confidence: 97%

Programmed-cell-death events during tapetum development of angiosperms

1999

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Summary. Programmed-cell-death events in the tapetum of two angiosperms (Lobivia rauschii Zecher and Tillandsia albida Mez et Purpus) are described by ultrastructural methods. Tapetum degradation appears to be a type of programmed cell death, with the cellular remnants necessary for pollen development, acting as products of holocrine secretion. Diagnostic features of apoptosis during tapetum development are: general shrinkage of the whole cell and the nuclei; condensation of the chromatin at the periphery of the internal nuclear membrane; the enlargement of the endoplasmicreticulum cisternae to circumscribe portions of the cytoplasm; the persistence of mitochondria together with microfilament bundles until the last stages of tapetal degeneration.

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Section: Discussionmentioning

confidence: 97%

Programmed-cell-death events during tapetum development of angiosperms

1999

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“…Pollenkitt is a hydrophobic mixture of materials, composed mainly of saturated and unsaturated lipids (Dobson, 1988), carotenoids (Hesse, 1993;Lunau, 1995), flavonoids (Wiermann and Gubatz, 1992), proteins and carbohydrates (Parkinson and Pacini, 1995;Santos et al, 2003;Weber, 1996, also for review). Differences in pollenkitt composition have been reported in the heterantherous species Lagerstroemia indica which has two pollen forms produced by pollinating and feeding anthers (Nepi et al, 2003).…”

Section: Chemical Compositionmentioning

confidence: 99%

Pollenkitt – its composition, forms and functions

Pacini

Hesse

2005

Flora - Morphology, Distribution, Functional Ecology of Plants

294

229

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“…Se relaciona con los procesos de esporogénesis en briófitos y pteridófitos, así como con la microsporogénesis de gimnospermas y angiospermas; contribuye con los procesos de dispersión (Pacini & Franchi 1993), con la generación de sustancias de reserva y con la formación de precursores biosintéticos del esporodermo y de la pared de los granos de polen (Lugardon 1990, Polowick & Sawhney 1993, Parkinson & Pacini 1995, Pacini 1997, Furness & Rudall 2001, Furness 2008. Los dos tipos, el secretor (celular) y el plasmodial se encuentran ampliamente distribuidos en las plantas terrestres (Parkinson & Pacini 1995, Furness 2008. El tapete de H. brevifolia es de tipo secretor, se origina a partir de la capa celular interna de la pared del esporangio y se mantiene hasta que finalmente degenera cuando las esporas alcanzan la madurez.…”

Section: Discussionunclassified

Ontogenia del esporangio y esporogénesis del licopodio Huperzia brevifolia (Lycopodiaceae) de las altas montañas de Colombia

Barón

Landazábal

Ballesteros

et al. 2009

RBT

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Sporangia ontogeny and sporogenesis of the lycopodium Huperzia brevifolia (Lycopodiaceae) from the high mountains of Colombia. Huperzia brevifolia is one of the dominant species of the genus Huperzia living in paramos and superparamos from the Colombian Andes. A detailed study of the sporangium's ontogeny and sporogenesis was carried out using specimens collected at 4200m above sea level, in Parque Natural Nacional El Cocuy, Colombia. Small pieces of caulinar axis bearing sporangia were fixed, dehydrated, paraffin embedded, sectioned in a rotatory microtome, and stained using the common Safranin O-Fast Green technique; handmade cross sections were also made, stained with aqueous Toluidine Blue (TBO). The sporangia develops basipetally, a condition that allows observation of all the developmental stages taking place throughout the caulinar axis of adult plants. Each sporangium originates from a group of epidermal cells, axilar to the microphylls. These cells undergo active mitosis, and produce new external and internal cellular groups. The sporangium wall and the tapetum originate from the external group of cells, while the internal cellular group leads to the sporogenous tissue. Meiosis occur in the sporocytes and produce simultaneous types tetrads, each one giving rise four trilete spores, with foveolate ornamentation. During the sporangium ripening, the outermost layer of the wall develops anticlinally, and inner periclinal thickenings and the innermost one perform as a secretory tapetum, which persists until the spores are completely mature. All other cellular layers colapse. Rev. Biol. Trop. 57 (4): 1141-1152. Epub 2009 December 01.

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A comparison of tapetal structure and function in pteridophytes and angiosperms

Cited by 28 publications

References 133 publications

Programmed-cell-death events during tapetum development of angiosperms

Programmed-cell-death events during tapetum development of angiosperms

Pollenkitt – its composition, forms and functions

Ontogenia del esporangio y esporogénesis del licopodio Huperzia brevifolia (Lycopodiaceae) de las altas montañas de Colombia

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