Which of the following statements is not correct?
| 1. | Insects that consume pollen or nectar without bringing about pollination are called pollen-nectar robbers. |
| 2. | Pollen germination and pollen tube growth are regulated by chemical compounds of pollen interacting with those of the pistil. |
| 3. | Some reptiles have also been reported as pollinators in some plant species. |
| 4. | 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. |