Question

Barrier to avoid self pollination between stamens and pistils is

• A. Heterostyly
• B. Herkogamy
• C. Dichogamy
• D. Dicliny

Answer 1

Answer: (B)

Herkogamy

Plants have adapted various ways to prevent self pollination, such as:

Heterostyly- It is the occurrence of 2-3 types of flowers within the same plant and such flowers have the difference in length of styles and stamens.

Herkogamy- It is the condition in which the flower structure is such that even being bisexual, the pollen grains fail to reach the stigma. In some flowers, a mechanical barrier exists between the compatible pollen and stigma so that self pollination is not possible. Sometimes, there is a hood like covering that covers the stigma.

Dichogamy- It is the condition when the anther and stigma mature at different times. Either anthers dehisce before the stigma becomes receptive (called protandry) or stigma becomes receptive before anthers dehisce (called protogyny).

Dicliny- It is the presence of only one kind of reproductive whorl in a flower. It is also called unisexuality.

Therefore, from all of the above measures, herkogamy is the one in which self pollination is prevented by floral barriers between stamens and pistils.

So, the correct answer is B.