Question

Write the difference between chasmogamous and cleistogamous flowers.

Answer 1

Hint: Chasmogamous and cleistogamous are two terms that explain the position of reproductive structures in flowers. Flowers carry out self-fertilization when cross fertilisation is not possible. Two major flower types are the Chasmogamous and Cleistogamous flowers.

Complete Answer:
A flower is the reproductive structure of a plant that contains the male and female gametophytes. The male reproductive structure is the androecium, represented by a whorl of stamens and the female reproductive structure is the gynoecium. Fertilization takes place after pollination occurs. Some flowers display self-fertilization, while cross fertilisation is seen in certain flowers.

Chasmogamous flower	Cleistogamous flower
1. Chasmogamous flowers have exposed anthers and stigma.	1. Cleistogamous flowers remain closed and the anthers and stigma lie close to each other.
2. Chasmogamous flowers are usually cross-pollinated. Since cross pollination occurs, chasmogamous flowers require pollinators.	2. Cleistogamous flowers can only carry out self-pollination.
3. To promote cross-pollination, chasmogamous flowers often have strikingly colored petals and nectar guides to attract and reward pollinators.	3. Cleistogamous flowers do not need pollinators or attractive floral parts or nectaries to reward pollinators.
4. In chasmogamous flowers, the seeds produced are genetically distinct.	4. In the absence of pollinators, cleistogamous flowers develop assured seed-set.

Note: Total autogamy is very unusual in a normal open flower with exposed anthers and stigma. Autogamy requires synchrony in the release of pollen and receptivity of stigma in such flowers and both the anthers and the stigma should lie close to each other to facilitate self-pollination.