DEVELOPMENT OF MICROSPORANGIUM

 The development of microsporangium is eusporangiate type  i. e. sporangium develops from several initial cells .

In anther , some cells in the hypodermal layer being to enlarge and contain denser cytoplasm and thus becomes prominant . These prominant hypodermal cells are known as archesporial initials .

The archesporial cells divide periclinally to form outer primary parietal cells and inner primary sporogenesis cells .

The primary parietal cells divide further by periclinal wall where as the primary sporogenous cella forms the inner sporogenous tissue .

STRUCTURE 

The transverse section of a typical young anther shows that each microsporangium consist of two parts.

1 - outer wall                 2- Inner sporogenous tissue 

The wall of microsporangia has 4 layer viz 

a - Epidermis - It  is the outer most layer which protects the anther and helps indehiscance .

b - Endothecium - It is the second layer lying inner to the epidermis .It also helps in protection and dehisance .It has larger cells .

c - Middle layer - It is 1-3 layer wall present below the middle layer .It surrounds the pollensec . The cells of tapetum are large , radially elongated and tetraploid.

d - Tapetum - Tapetum provides nourishment to the developing microspore mother cells and microspore