Question:

Which of the following statement is not correct?

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 consumes pollen or nectar without bringing about pollination are called pollen/nectar robbers.

Some reptiles have also been reported as pollinators in some plant species.

Pollen germination and pollen tube growth are regulated by chemical components of pollen interacting with those of the pistil.

Solution:

Pollination refers to the landing and subsequent germination of the pollen on the stigma. The arrival of a viable pollen grain on a receptive stigma does not guarantee fertilization. Interspecific incompatibility refers to the failure of pollen from one species to germinate and/or grow on the stigma of another species. Intraspecific incompatibility is incompatibility that occurs within a species. Self-incompatibility—incompatibility between the pollen and the stigmas of the same individual. If the pollen and the stigma are compatible, the pollen takes up water (hydrates) and the pollen tube emerges. The pollen tube grows down the style of the carpel toward the micropyle.