Pre-fertilization in Plant: Stamen (Male Reproductive Unit)

Pre-fertilization in Plant: Stamen (Male Reproductive Unit):

Stamen: The male reproductive whorl of flower is called androecium. Individual member of androecium is called stamen. 

Anther development-

• Anther development includes the differentiation of sporogenous tissue into pollen sacs, in which microspores originate via meiosis.
• These microspores then undergo mitosis, resulting in mature pollen grains capable of fertilization.  

Structure of Anther-

• Anther is generally dithecous (having two lobes) and tetrasporongiate. Each lobe of anther contains two pollen sacs.
• In dithecous anther four pollen sacs are present. Therefore, it is tetrasporongiate.
• An immature stage of anther is represented by group of parenchymatous tissue surrounded by single layered epidermis.
• The heterogeneity (differentiation) arises when some hypodermal cells get transformed into archesporial cells. 
  

T. S. of Anther-

• The archesporial cell divides into an inner sporogenous cell and outer primary parietal cell, which form sporogenous tissue capable of producing microspore tetrads.
• The parietal cell divides to form anther wall layers, which consist of four layers: Epidermis, Endothecium, Inner to Endothecium, and Tapetum.
• The Epidermis is the outermost protective layer, Endothecium is a sub-epidermal layer, Inner to Endothecium is the middle layer, and Tapetum is the inner most nutritive layer. 

T. S. of Anther

Dehisced anther