What is self-incompatibility? Why does self-pollination not lead to seed formation in self-incompatible species?

Explanation

### Step-by-Step Solution:

1. **Definition of Self-Incompatibility**:
- Self-incompatibility is a genetically controlled mechanism that prevents self-pollination in flowering plants. This means that the plant has evolved a way to avoid fertilization by its own pollen.

2. **Mechanism of Self-Incompatibility**:
- In self-incompatible species, the pollen grains produced by the plant are genetically programmed to be incompatible with the ovules of the same plant. This means that when pollen from the same flower or plant lands on its stigma, it cannot successfully fertilize the ovum.

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