Question

The phenomenon of floral parts acting as a barrier to self pollination is
A. Heterostyly
B. Dichogamy
C. Dicliny
D. Herkogamy

Answer 1

Every living organism as well as plants are produced offspring for the next generation. This is one of the ways used by the plants for producing offspring. In plants, the fertilization between the male and female gametes takes place through pollination.

Complete answer:
Pollination is the process of fertilization used by the plants. Where the pollen grains from male anthers transferred to the female stigma for producing new offspring. These pollen grains are transferred by various insects, wind, water, etc.
When the process of transferring pollen grains from the anthers to the stigma occurs in the same flower or another flower produced by the same plant, this type of pollination is known as self-pollination. There are two types of self-pollination which are autogamy and the other is geitonogamy.
The plants generally used various methods to prevent the process of self-pollination.
Heterostyly is a type of prevention which plants use. Due to this, there is the occurrence of 2-3 types of flowers within the same plant. The flowers used this way, they have a difference in length of styles and stamens.
When the anther and stigma got mature but the time of maturity is different this condition is called dichogamy. In that case, Either the anther got fused before the stigma and becomes receptive which is called protandry or the stigma got fused before anther and becomes receptive which is called protogyny.
When only one kind of reproductive whorl is found in a flower then this condition is called dicliny. This is also known as unisexuality.
Herkogamy is such a condition when the flower structure is bisexual but the pollen grains are not able to reach the stigma. There are some flowers where a mechanical barrier is found between the compatible pollen and stigma. Due to this barrier self-pollination does not take place.
Herkogamy is the phenomenon where self-pollination is prevented by floral barriers.

Hence, the correct answer is option (D).

Note: The pollen grains transferred from the male anther to the female stigma by the various insects, air, water, etc. This is known as pollination, which takes place for the fertilization. If this transfer of pollen occurs in the same flower, that means both the stigma and anthers are present in the same flower then the pollination will be called self-pollination. But sometimes this self-pollination does not occur as a mechanical barrier is present between the compatible pollen and stigma. This condition is called herkogamy.