To install click the Add extension button. That's it.

The source code for the WIKI 2 extension is being checked by specialists of the Mozilla Foundation, Google, and Apple. You could also do it yourself at any point in time.

Kelly Slayton
Congratulations on this excellent venture… what a great idea!
Alexander Grigorievskiy
I use WIKI 2 every day and almost forgot how the original Wikipedia looks like.
Live Statistics
English Articles
Improved in 24 Hours
Added in 24 Hours
What we do. Every page goes through several hundred of perfecting techniques; in live mode. Quite the same Wikipedia. Just better.


From Wikipedia, the free encyclopedia

A microsporangium (plural microsporangia) is a sporangium that produces spores that give rise to male gametophytes. Microsporangia are notable in spikemosses, and a minority of ferns. In gymnosperms and angiosperms (flowering plants), the microsporangia produce the microsporocyte, also known as the microspore mother cell, which then creates four microspores through meiosis. The microspores divide through mitosis to create pollen grains. The term is only applicable to plants that exhibit heterospory and is not used for bryophytes.

YouTube Encyclopedic

  • 1/3
    6 013
    34 664
  • 🌷Microsporangium || Microsporogenesis || Anther wall development
  • Biology Sexual Reproduction in Plants part 4 (Microsporogenesis) class 12 XII


Development of pollen sacs

A very young anther consists of actively dividing meristematic cells surrounded by a layer of epidermis. It then becomes two-lobed. Each anther lobe develops two pollen sacs. Thus, a two-lobed anther develops four pollen sacs situated at four corners of the anther. Development of pollen sacs begins with the differentiation of archesporial cells in the hypodermal region below epidermis at four corners of the young anther. The archesporial cells divide by periclinal division to give a subepidermal primary parietal layer and a primary sporogenous layer. The cells of the primary parietal layer divide by successive periclinal and anticlinal divisions to form concentric layers of pollen sac wall. The wall layers from periphery to centre consist of:

  1. A single layer of epidermis between, which becomes stretched and shrivels off at maturity
  2. A single layer of endothecium. The cells of endothecium possess fibrous thickenings. They remain thin-walled and constitute stomium (line of dehiscence) in the shallow groove in between the two microsporangia of the anther lobe
  3. One to three middle layers. Cells of these layers generally disintegrate in the mature anther
  4. A single layer of tapetum. The tapetal cells may be uni-, bi- or multinucleate and possess dense cytoplasm. The cells of the primary sporogenous layer divide further and give rise to diploid sporogenous tissue.

See also

  • Antheridia, haploid structures that gives rise to male gametes; present on the gametophytes of bryophytes, ferns, and many algae, as well as water moulds and some fungi


This page was last edited on 9 June 2017, at 16:48.
Basis of this page is in Wikipedia. Text is available under the CC BY-SA 3.0 Unported License. Non-text media are available under their specified licenses. Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc. WIKI 2 is an independent company and has no affiliation with Wikimedia Foundation.