Question

In Primula, cross pollination is favoured by

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

Answer 1

Answer: (C)

Heterostyly

Primula has two types of flowers:

1. Pin eyed or the long styled flowers: These flowers have long stigmatic papilli and short stamens with small pollen.

2. Thrum eyed or the short styled flowers: These flowers have short style, short stigmatic papilli and long stamens with large pollen grains

The stigma of Pin eyed flowers is at the level of anthers in Thrum eyed flowers and the stigma of Thrum eyed flowers is at the level of anthers of Pin eyed flowers.

Thus, pollen from Thrum eyed flowers can pollinate only the pin eyed flowers and the pollen from Pin eyed flowers can pollinate only the Thrum eyed flowers, but not in their own type and only cross pollination can occur.

This phenomenon of having more than one type of flowers in the same plant is Heterostyly which promote cross pollination.

Hence, in Primula, cross pollination is favoured by Heterostyly.

So, the correct answer is C.