Microsporogenesis

Estimated time: 9 minutes

CBSE: Class 12
CISCE: Class 12

Definition: Microsporogenesis

The process of formation of microspores from the sporogenous tissue is said to be microsporogenesis.

CBSE: Class 12
CISCE: Class 12

When microspores of a tetrad do not separate and remain attached together in groups, they are called compound pollen grains.

CBSE: Class 12
CISCE: Class 12

A compact mass formed when all microspores within a pollen sac remain united as a single structure is called a pollinium.

CBSE: Class 12
CISCE: Class 12

Type of Pollen Tetrad	Arrangement of Microspores	Distinct Feature	Example
Tetrahedral	Four microspores at the corners of a tetrahedron	Only three microspores visible from one side	Rhododendron, Nicotiana
Isobilateral	All four microspores arranged in one plane	Microspores lie opposite each other	Cucurbita
Decussate	Microspores arranged in two crossed pairs	Cross-like arrangement	Magnolia
T-shaped	Three microspores in a row and one at right angle	Forms a T-shape	Aristolochia
Linear	Four microspores arranged in a straight line	All microspores in one row	Halophila

Maharashtra State Board: Class 12

Microsporogenesis is the process in which pollen mother cells (PMC) undergo meiosis to form haploid microspores (pollen grains).
Each PMC divides meiotically to produce a tetrad of four haploid microspores.
Microspores separate at maturity and develop into pollen grains.
A pollen grain has a two-layered wall called sporoderm: outer exine and inner intine.
Exine is made of sporopollenin, a tough and resistant substance, and contains germ pores for pollen tube growth.
Intine is the inner layer made of cellulose and pectin.
Pollen viability (ability to germinate) depends on temperature and humidity; it is short (about 30 minutes) in crops like rice and wheat but can last for months in some plant families.