Development of male gametophyte_Physic Chemistry Biology

 Process and development of male gametophyte

This topic is available on class 12 biology chapter number 2 sexual reproduction of flowering plant 

This topic is 5 mark questions of board examination

Ans. Stamen from the male reproductive unit and is made up of anther and the filament. The anther is generally bilobed with chamber  containing several pollen grains

a). Pollen grain are produced in the anther. A vary young antha comprises a mass of undifferentiated thin walled cells bounded by an epidermis.

b). The anther becomes four lobed as the anther grows,and the lobes are joined by a steril tissue called connective.

c).Each lobe contains an elongated chamber which is termed as microsporogenesis or Pollen sac.

d). A cross section of a young anther reveals that the microsporangium is surrounded on the outside by a single layered epidermis.Beneath the epidermis is a layer of cells called the endothecium.

e).The sporangial wall encloses a mass of cells characterised by their large size abundant cytoplasm and prominent nuclei this cells are called sporogenous cells.These sporogenous cells undergo a few mitotic divisions to increase their number and from the microspore mother cells or microsporocytes.

f).The microsporocytes are diploid and usually closely packed.Each diploid microsporocytes undergoes meiosis, giving rise to a group of four haploid cells, known as microspores or Pollen grains

                       

g).At maturity, the partition wall 

between two adjacent microsporangia

breaks down and the cavities of the two microsporangia merge into one pollen sac. When the pollen grains are fully formed the ripe anther splits to liberate the pollen grains.

                                                              

                      Edit by.Lutfor Rahman