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 with out 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 pistil
D. Some reptiles have also been reported as pollinators in some plant species

Answer

To determine which statement is not correct regarding pollination and pollen behavior in flowering plants, we will analyze each option provided in the question.

### Step-by-Step Solution:

1. **Analyze the First Statement:**
- **Statement:** "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."
- **Evaluation:** This statement is incorrect. Pollen grains from different species are generally not compatible and do not germinate on the stigma of flowers from other species. Only pollen from the same species can germinate and grow into the style.

2. **Analyze the Second Statement:**
- **Statement:** "Insects that consume pollen or nectar without bringing about pollination are called pollen nectar robbers."
- **Evaluation:** This statement is correct. Insects that take pollen or nectar without facilitating pollination are indeed referred to as nectar robbers.

3. **Analyze the Third Statement:**
- **Statement:** "Pollen germination and pollen tube growth are regulated by chemical components of pollen interacting with those of the pistil."
- **Evaluation:** This statement is also correct. The interaction between the chemical components of pollen and the pistil is crucial for pollen germination and tube growth.

4. **Analyze the Fourth Statement:**
- **Statement:** "Some reptiles have also been reported as pollinators in some plant species."
- **Evaluation:** This statement is correct. Certain reptiles are known to act as pollinators, and this type of pollination is referred to as zoophily.

### Conclusion:
After evaluating all the statements, the first statement is identified as the incorrect one. Therefore, the answer to the question is:

**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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