Question

Flowering plants with hermaphrodite flowers have developed many reproductive strategies to ensure cross-pollination. Study the given outbreeding devices adopted by certain flowering plants and answer the questions that follow.

Note : All plants belong to the same species. No pollen tube growth/inhibition of pollen germination on stigma. Pollen germination on stigma.

• [(a)] Name and define the outbreeding device described in the above table.
• [(b)] Explain what would have been the disadvantage to the plant in the absence of the given strategy.

Hint:

Self-incompatibility ensures genetic diversity by preventing self-fertilization, even within the same species. It helps in maintaining vigour and adaptability in plant populations.

Answer 1

Step 1: The outbreeding device shown in the table is self-incompatibility. Definition: Self-incompatibility is a genetic mechanism that prevents self-pollen (or pollen from genetically similar individuals) from fertilizing the ovule by inhibiting pollen germination or pollen tube growth on the stigma of the same plant.
Step 2: Disadvantage of absence: In the absence of self-incompatibility, the plant would undergo self-pollination, which would lead to:

• Reduced genetic variability.
• Increased chances of inbreeding depression (accumulation of harmful alleles).
• Reduced adaptability of the species in changing environments.