In Angioperms all the four microspores of tetrad are covered by a layer which is made up of :

Options

A. Pectocellulose
B. Callose
C. Cellulose
D. Sporopollenin

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about the layer that covers the four microspores of a tetrad in angiosperms.

2. **Identifying the Structure**: In angiosperms, during the process of microsporogenesis, microspores are formed from the microspore mother cell. These microspores initially exist as a tetrad, which is a group of four microspores.

3. **Composition of the Layer**: The layer that surrounds these microspores is made up of a substance called callose.

4. **Role of Callose**: Callose is a polysaccharide that plays several important roles in plants, including:
- Providing structural support.
- Protecting plant cells from biotic (living) and abiotic (non-living) stresses.
- Contributing to the differentiation of pores in phloem and functioning of stomatal closure cells.

5. **Formation and Breakdown**: During microsporogenesis, callose deposits form on the walls of the microspore mother cell at the beginning of prophase. This thick callose layer remains intact even when the microspores are arranged in tetrads. When the microspores are released from the tetrad, the callose layer undergoes lysis (breakage).

6. **Conclusion**: Based on the information gathered, the answer to the question is that the layer covering the microspores in angiosperms is made up of callose.

**Final Answer**: The layer is made up of callose.

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