Question

Plants in which pollination and fertilisation occurs in the unopened flower bud is

• A. Xenogamy
• B. Geitonogamy
• C. Pliestogamy
• D. Cleistogamy

Hint:

The word Cleistogamy comes from the Greek "kleistos," meaning closed, and "gamos," meaning marriage.
This translates literally to a "closed marriage," describing self-pollination that occurs within a closed floral bud.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Pollination mechanisms in plants can be broadly categorized into self-pollination (autogamy) and cross-pollination (allogamy).
Some plants have evolved specialized floral adaptations that guarantee self-fertilization by preventing exposure to foreign pollen.

Step 2: Detailed Explanation:
Cleistogamy is a specialized form of self-pollination that occurs within permanently closed (cleistogamous) flowers.
In cleistogamous plants, the flower buds never open, and pollination occurs entirely within the closed petal dome.
As the anthers mature, they dehisce inside the bud, shedding pollen grains directly onto the receptive stigma of the same flower.
This ensures high reproductive success and seed set, even in the complete absence of insect or wind pollinators.
However, this mechanism limits genetic diversity because it results in obligate self-fertilization.
Let us review the other terms to clarify the differences:
- Xenogamy refers to cross-pollination where pollen from one plant is transferred to the flower of a genetically different plant.
- Geitonogamy refers to a type of self-pollination where pollen from one flower is transferred to another flower on the same plant.
- Pliestogamy is a non-standard or misspelled botanical term.
Since cleistogamy is the term for pollination and fertilization occurring within permanently closed flowers, it is the correct answer.

Step 3: Final Answer:
The process of pollination and fertilization inside permanently closed flower buds is called cleistogamy.