Tapetum (botany)
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The tapetum is a specialised layer of nutritive cells found within the anther, of flowering plants, where it is located between the sporangenous tissue and the anther wall. Tapetum is important for the nutrition and development of pollen grains, as well as a source of precursors for the pollen coat.[1] 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
Types of tapetum
Two main tapetum types are recognised, secretory (glandular) and plasmodial (amoeboid). In the secretory type a layer of tapetal cells remains around the anther
Amongst the
References
- ^ P.L. Polowick, V.K. Sawhney 1993. Differentiation of the Tapetum During Microsporogenesis in Tomato (Lycopersicon esculentum Mill.), with Special Reference to the Tapetal Cell Wall.Furness & Rudall 2001 Annals of Botany, Volume 72, Issue 6, December 1993, Pages 595–605
- ^ a b Furness & Rudall 2001.
Bibliography
- Furness, Carol A.;