POLLINATION

Pollination is defined as the transfer of mature pollen grains from the anther to the stigma of the same flower or in different flower  of the same plant or in different flower of different plant by the help of agents .

Pollen grains are immobile so that can not be reach the stigma by themselves and requires external agency like wind  , water , animal , insect , etc 

Theophrstus has written as pollination in cate pollen .

TYPE OF POLLINATION 

Pollination is of 2 types 1- self pollination 

             It is the transfer of pollen grains from the anther of a flower to the stigma of either the same or genetically similar flower 

Self pollination involves only one parent plant . It is of 2 types 

a- Autogamy - When the pollen are transferred from the anther to the stigma of the same flower is called autogamy .

It is possoble when anther and stigma are closed to each other .

b- Geitonogamy - In this type of pollination the pollen grains of one flower are transferred to the stigma of another flower are transferred to the stigma of another flower belonging to either the same plant or genetically   similar plant.

Geitonogamy is morphologically cross pollination but genetically self pollination .

2- Cross pollination 

Cross pollination is the transfer of pollen grainsfrom the anther of the one flower to the stigma of another genetically different flower .

It is also known as allogamy .

It may be two types 

a- Xenogamy -When the pollen grains of a flower is transferred to the stigma o a different flower on a different plant of the same species .

b- Hybridization - When pollen grain of a flower are transferred to stigma of a different flower of a different of the different species.