2. Definition
The process of formation of microspores from pollen mother cells through meiosis
is called microsporogenesis.
Microspores= pollen
Male gametophyte
3. Male reproductive organ
Consists of filament and anther
Anther is usually bilobed (lobe means locule) and dithecous (
two theca).
Anthers is the site of microsporogenesis.
The filaments nourish the anther with water and nutrients.
Stamen
Some flowers produce sterile stamens, called staminodes. E.g.,
Cannonball
filament
anther
4. Each microsporangium is surrounded by four wall layers
• Epidermis
• Endothecium
• Middle layer.
• Tapetum
Protects the inner tissues
Nourishes the developing pollen grain
Microsporangium (Pollen sac)
The center of each microsporangium contain homogenous cells called sporogenous tissues.
6. • Pollen grain represents the male gametophytes.
• Pollen grain has two layers- Exine and Intine
Pollen grain
Exine: a hard outer layer, made up of
sporopollenin. sporopollenin can
withstand high temperatures, in strong
acids and alkalis.
The exine has prominent apertures
called germ pores where sporopollenin
is absent.
Intine: The inner wall of pollen grain
is called intine.
It is a thin and continuous layer made
of cellulose and pectin.
