Pollen germination and pollen tube growth are regulated by chemical componrnts of pollen interacting with those of the pistil.
Some reptiles have also been reported as pollinators in some plant species.
Pollen grains of many species can germinate on the stigma of a flower, but only one pollen tube of the same species grows into the style.
Insects that consume pollen or nectar without bringing about pollination are called pollen/ nectar robbers.
