Which of the following statements is not correct?

Options

A. 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.
B. Insects that consume pollen or nectar without bringing about pollination are called pollen/nectar robbers.
C. Pollen germination and pollen tube growth are regulated by chemical components of pollen interacting with those of the pistill.
D. Some reptiles have also been reported as pollinators in some plant species:

Answer

To determine which statement is not correct, we will analyze each statement one by one.

**Step 1: Analyze the first statement.**
- The first statement claims that "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."
- In reality, while pollen grains from multiple species can land on a stigma, typically only the pollen grains of the same species as the flower will germinate and grow a pollen tube into the style. However, it is misleading to say that only one pollen tube grows; in fact, multiple pollen grains of the same species can germinate, but usually only one pollen tube will successfully fertilize the ovule.
- Therefore, this statement is incorrect.

**Step 2: Analyze the second statement.**
- The second statement states that "insects that consume pollen or nectar without bringing pollination are called pollen or nectar robbers."
- This statement is correct. Insects that take nectar or pollen without aiding in the pollination process are indeed referred to as nectar robbers or pollen robbers.

**Step 3: Analyze the third statement.**
- The third statement mentions that "pollen germination and pollen tube growth are regulated by chemical components of pollen interacting with those of the pistil."
- This statement is also correct. The interaction between chemical components of pollen and the pistil is crucial for pollen germination and subsequent pollen tube growth.

**Step 4: Analyze the fourth statement.**
- The fourth statement claims that "some reptiles have also been reported as pollinators in some plant species."
- This statement is correct as well. Certain reptiles, such as some lizards, have been observed to pollinate plants.

**Conclusion:**
After analyzing all four statements, we conclude that the first statement is the incorrect one.

**Final Answer:**
The statement that is not correct is: "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."

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