Pollens are microscopic seed mass of varied physiological appearances that contains the microgametophyte that gives rise to male gametes.
These are carried out by external factors like wind, water, animals, etc known as pollination.
The pollen houses the reproductive cell that forms the gamete and the vegetative nuclei form the pollen tube.
Gynoecium
It is the female reproductive part also called a pistil.
It has three main parts stigma, style and ovary.
The top part of the pistil is called the stigma on which the pollen lands, style is the long narrow stalk that connects to the stigma and the ovary is the swollen sac-like structure below housing the ovules.
Pollen tube of the same species grows into the style to reach the ovary.
When the pollen of the same species falls onto the stigma, the vegetative cell differentiates and forms a pollen tube.
This pollen tube secretes enzymes that dissolve the tissues of style as it moves towards the ovary.
On reaching the ovary the reproductive cell matures into a male gamete and fertilizes with the egg cell while the pollen tube degenerates.