Periplasmodium

0.01 sec.

Periplasmodium

a mass of protoplasm that usually forms by fusion of cell protoplasts of the amoeboid tapetum (as in the sporangia of numerous ferns and the microsporangia of certain angiosperms and gymnosperms). In selaginellas and horsetails certain sporogenous cells also participate in periplas-modium formation, whereas in the Psilotophyta and the Iso-ëtales the periplasmodium forms by fusion of the protoplasts of some of the sporogenous cells.

The periplasmodium penetrates the cavity of the sporangium and is used in feeding the developing sporogenous cells and spores. In seed plants it also nourishes the male gametophytes (pollen grains) in the early stages of development. In a number of Pteridophyta, periplasmodium substances are deposited on the surface of the spore’s exine, forming an outer covering—the perisporium. In the sporangia of Salviniaceae, the periplasmodium hardens to form massulae.

Want to thank TFD for its existence? Tell a friend about us, add a link to this page, add the site to iGoogle, or visit the webmaster's page for free fun content.

?Page tools

Printer friendly
Cite / link

Feedback

Mentioned in	?		References in periodicals archive	?		Encyclopedia browser	?		Full browser	?
No references found			Formation and development of the tapetal periplasmodium in Tradescantia bracteata. The tapetum and systematics in monocotyledons by Furness, Carol A.; Rudall, Paula J. / The Botanical Review In secretory tapeta the cells remain in situ until their degeneration, while in amoeboid tapeta the tapetal protoplasts move into the loculus, forming a periplasmodium that is in direct contact with the developing microspores. Orbicules in angiosperms: morphology, function, distribution, and ... by Huysmans, Suzy; El-Ghazaly, Gamal; Smets, Erik / The Botanical Review			peripheral faults peripheral hemodynamics peripheral initiation peripheral interconnect peripheral interface channel peripheral membrane protein peripheral milling peripheral nervous system peripheral operation peripheral processing peripheral processor peripheral sink peripheral speed peripheral stream Peripheral Technology Group peripheral transfer peripheral units peripheral vision peripheral-limited periphery periphery wall periphlebitis Periphrasis Periphyton periplasm Periplasmodium periplast Periploca Periplus periproct peripteral Peripteros periptery Periptychidae Peripylina perisarc perisaturnium Periscelidae Perischoechinoidea Periscope Periscope Antenna periscopic sextant periscopic sight Perisperm Perisporiaceae Perissodactyla peristalith Peristalsis peristaltic charge-coupled device peristaltic pump peristasis			periphrastic periphrastic Periphrastic conjugation periphrastical periphrastically periphrastically periphytic periphytic periphyton periphyton Periphyton Stormwater Treatment Area Periphyton-Based Stormwater Treatment Area Periplaneta Periplaneta Periplaneta americana Periplaneta australasiae periplantar shoe periplasm periplasm periplasm periplasmic periplasmic periplasmic Periplasmic Escherichia Coli Protein Periplasmic Ligand-Binding Protein Periplasmic space Periplasmic space Periplasmic space Periplasmic space Periplasmic Zinc-Binding Protein Periplasmodium periplast periplast Periploca Periploca Periploca graeca Periploi Periplous Periplus Peripneumonia Peripneumonic periporitis periportal periportal necrosis Periposeidion Periposeidion periproct periproct periproctitis periproctitis periprostatic periprostatitis peripteral peripteral Peripteros Peripteros Peripterous Periptery Periptery Periptychidae peripylephlebitis

Encyclopedia

Free Tools:	For surfers: Free toolbar & extensions \| Word of the Day \| Help For webmasters: Free content \| Linking \| Lookup box \| Double-click lookup

Disclaimer
All content on this website, including dictionary, thesaurus, literature, geography, and other reference data is for informational purposes only. This information should not be considered complete, up to date, and is not intended to be used in place of a visit, consultation, or advice of a legal, medical, or any other professional.