Tag: pollination and its types

Xenogamy or cross pollination is the transfer of pollen grains from the anther of one flower to the stigma of a genetically different flower. Cross pollination is performed with the help of an external agency.

Commelina bears aerial, chasmogamous (stigma and anthers exposed to pollinating agents), insect pollinated flowers and underground cleistogamous flowers. Cleistogamous flowers are bisexual flowers which never open. In such flowers, the anther and stigma lie very close to each other. When anther dehisce in the flower buds, pollen grains come in contact with the stigma of the same flower i.e, autogamy occurs. So, these flowers produce assured seed set, even in the absence of pollinators.

• There are several methods to prevent self-pollination in plants. Bisexual flowers show self-pollination. 
• Chances of self-pollination increases when pistil has increased receptivity for pollen from the same plant. Self-pollination occurs in flowers where the stamen and carpel mature at the same time. 
• Hence, to prevent self-pollination, stamen and pistil must mature at different times. 

Papaya plant is a dioecious plant. It prevents both autogamy and geitonogamy, which is a method of self pollination.

The species of birds and animals shows different types of isolation. The organisms which are located in the same habitat or geographical area but do not mate with each other. This type of isolation is known as the behavioral isolation in which different species have a different type of behavior with respect to reproduction. This prevents the interbreeding of the different species. 

The transfer of pollen from an anther of a flower of one plant to a stigma of a flower of another plant of the same species by the action of wind, insects etc is known as cross pollination.