Which one of the following statements is not true ?

Options

A. Tapetum helps in the dehiscence of anther
B. Exine of pollen grains is made up of sporopollenin
C. Pollen grains of many species cause severe allergies
D. Stored pollen in liquid nitrogen can be used in the crop breeding programmes

Answer

To determine which statement is not true among the provided options, we will analyze each statement step by step.

### Step-by-Step Solution:

1. **Analyze Option A**: "Tapetum helps in the nascence of anther."
- The tapetum is a layer of cells in the anther that provides nourishment to the developing pollen grains. However, it does not play a role in the formation (nascence) of the anther itself. Therefore, this statement is incorrect.

2. **Analyze Option B**: "Exine of pollen grain is made up of sporopollenins."
- The exine is indeed the outer layer of the pollen grain, and it is primarily composed of sporopollenin, which is a robust and resistant biopolymer. This statement is true.

3. **Analyze Option C**: "Pollen Grain of Many Species Causes Several Allergies."
- Pollen grains are known to be allergens for many individuals, causing allergic reactions such as hay fever. This statement is also true.

4. **Analyze Option D**: "Stored pollens in liquid nitrogen can be used in the crops."
- Pollen can be preserved in liquid nitrogen at extremely low temperatures (-196 degrees Celsius) for future use in breeding programs and crop improvement. This statement is true as well.

### Conclusion:
After evaluating all the options, we find that **Option A** is the statement that is not true.

### Final Answer:
**Option A** is not true.

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