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 alergies
D. Stored pollen inliquid nitrogen can be used in the crop breeding programmes

Answer

To determine which statement is not true, we will analyze each of the four statements provided in the question.

### Step-by-Step Solution:

1. **Examine the First Statement:**
- **Statement:** Tapetum helps in the dehiscence of anther.
- **Analysis:** The tapetum is indeed the innermost layer of the anther, but its primary function is to nourish the developing pollen grains. The dehiscence of the anther, which is the process of the anther opening to release pollen, is actually facilitated by the endothecium layer. Therefore, this statement is **not true**.

2. **Examine the Second Statement:**
- **Statement:** Exine of pollen grain is made up of sporopollenin.
- **Analysis:** The exine is the outermost layer of the pollen grain and is indeed composed of sporopollenin, which is known for its durability and resistance to degradation. This statement is **true**.

3. **Examine the Third Statement:**
- **Statement:** Pollen grain of many species causes severe allergies such as Parthenium, which is commonly known as carrot grass.
- **Analysis:** It is well-documented that pollen from certain species, including Parthenium, can cause severe allergic reactions in humans. This statement is **true**.

4. **Examine the Fourth Statement:**
- **Statement:** Stored pollen in liquid nitrogen can be used in crop breeding programs.
- **Analysis:** This statement is also true. Cryopreservation of pollen in liquid nitrogen is a technique used in crop breeding to preserve genetic material for future use.

### Conclusion:
After analyzing all four statements, we conclude that the first statement is the only one that is **not true**.

### Final Answer:
The statement that is not true is: **Tapetum helps in the dehiscence of anther.**

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