What is pollination ? Describe its types.

$\rightarrow$ Male and female gemates in flowering plants are produced in the pollen grain and embryo sac respectively.

As both types of gametes are non motile they have to be brought together for fertilisation to occur.

Pollination is the mechanism to achieve this objective. Transfer of pollen grains (shed from the anther) to the stigma of a pistil is termed as pollination.

Flowering plants have evolved an amazing array of adaptations to achieve pollination.

Kinds of pollination : Depending on the source of pollen, pollination can be divided into three types: $(a)$ Autogamy $(b)$ Geitonogamy $(c)$ Xenogamy.

$(a)$ Autogamy : In this type, pollination is achieved within the same flower. Here there is tranfer of pollen grains from the anther to the stigma of the same flower. In a normal flower which opens and exposes the anthers and the stigma, complete autogamy is rather rare. Autogamy in such flowers requires synchrony in pollen release and stigma receptivity and also, the anthers and the stigma should lie close to each other so that self-pollination can occur. Autogamy normally becomes possible in bisexual flowers.

In flowers possessing autogamy anther and stigma, both mature at the same time. So pollination becomes possible. eg. In Apeaceac, Lameacea and cacateceac family self pollination takes place. Due to movement of style, stigma comes near to anther.