Plant reproduction is the production of new individuals or offsprings in plants, which can be accomplished b sexual or asexual reproduction. 

Sexual reproduction produces offsprings by fusion of gametes resulting in offsprings genetically different from the parents.

Pollen grains from anther i.e. part of stamen move to stigma i.e. a part of pistil. This process called pollination. Then, the most compatible pollen grain form pollen tube and passes to a style and reaches to ovule in a ovary. 

Male nucleus fuses with female to form endosperms. Ovule converted to seed and ovary into fruit post reproduction.