ICSE Class 9 Answered

Self pollination may be:

• Autogamy - Here pollen moves to the female part of the same flower
• Geitonogamy -Here pollen is transferred to another flower on the same plant.

Mechanisms promoting self-pollination:

1. Bisexuality-  The presence of bisexual flowers (male and female organs in the same flower ) is a must for self pollination. 

2. Homogamy. Maturation of anthers and stigma of a flower at the same time i.e. homogamy is essential for self-pollination.

3. Cleistogamy - When pollination and fertilization occur in unopened flower bud, it is known as cleistogamy.  It ensures self pollination and prevents cross pollination.  Cleistogamy has been reported in some varieties of wheat, barley, oats and several other grass species.

4. Position of Anthers -  In some species, stigmas are surrounded by anthers in such a way that self pollination is ensured.  Such situation is found in tomato and brinjal.  In some legumes, the stamens and stigma are enclosed by the petals in such a way that self pollination is ensured.  Examples are green gram, black gram, soybean, chickpea and pea.