Definitions for tapetumtəˈpi təm
This page provides all possible meanings and translations of the word tapetum
Random House Webster's College Dictionary
Bot. a layer of nutritive tissue in a developing sporangium or anther that is absorbed as the spore matures.
Anat. any of certain membranous layers or layered coverings, as in the choroid coat in certain animals.
Category: Anatomy, Zoology
Origin of tapetum:
1705–15; < NL; ML tapētum coverlet (L, only pl.) < Gk tapēt-, s. of tápēs carpet
A membranous layer of tissue
an area in the pigmented layer of the choroid coat of the eye in many animals, which has an iridescent or metallic luster and helps to make the eye visible in the dark. Sometimes applied to the whole layer of pigmented epithelium of the choroid
The tapetum is a layer of nutritive cells found within the sporangium, particularly within the anther, of flowering plants. Tapetum is important for the development of pollen grains. The cells are usually bigger and normally have more than one nucleus per cell. As the sporogenous cells undergo mitosis, the nuclei of tapetal cells also divide. Sometimes, this mitosis is not normal due to which many cells of mature tapetum become multinucleate. Sometimes polyploidy and polyteny can also be seen. The unusually large nuclear constitution of the tapetum helps it in providing nutrients and regulatory molecules to the forming pollen grains. The following processes are responsible for this: ⁕Endomitosis ⁕Normal mitosis not followed by cytokinesis ⁕Formation of restitution nuclei ⁕Endoreduplication Tapetum helps in pollenwall formation, transportation of nutrients to inner side of anther, synthesis of callase enzyme for separation of microspore tetrads.
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