These pictures are closeups of pollen on the stigma of a tomato flower. One can see the individual pollen grains sitting on the stigma. There is one single grain that looks like the moon rising on the left of the bottom picture. The long white strand adjoining the pollen grain to the stigma is the pollen tube. This will eventually grow down into the style and fertilize the ovules in the ovary producing seed.
Conditions must be right for the adherence of pollen to the stigma, for the pollen to be active and for pollen tube germination to occur. Factors such as temperature, humidity and light all play a role in the process of pollination.
The process of pollination is the transfer of the pollen to the stigma. The process of fertilization occurs when the pollen tube reaches the ovules in the ovary (not shown).