Assertion (A): Cleistogamous flowers produce assured seed sets in the absence of pollinators.
Reason (R): Cleistogamous flowers have exposed anthers and stigma.
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → Assertion is true but reason is false.
Assertion (A): Cleistogamous flowers produce assured seed sets in the absence of pollinators. — True. Cleistogamous flowers do not open at all. Their pollen reaches the stigma of the same flower, so they set seed even when there are no pollinators.
Reason (R): Cleistogamous flowers have exposed anthers and stigma. — False. Exposed anthers and stigma are the feature of chasmogamous flowers. In a cleistogamous flower the anthers and stigma lie close to each other inside the closed flower. When the anthers dehisce in the bud, the pollen grains touch the stigma.
So A is true but R is false.
NCERT Extract:
Pollination – “… Some plants such as Viola (common pansy), Oxalis, and Commelina produce two types of flowers – chasmogamous flowers which are similar to flowers of other species with exposed anthers and stigma, and cleistogamous flowers which do not open at all …. In such flowers, the anthers and stigma lie close to each other. When anthers dehisce in the flower buds, pollen grains come in contact with the stigma to effect pollination. Thus, cleistogamous flowers are invariably autogamous as there is no chance of cross-pollen landing on the stigma. Cleistogamous flowers produce assured seed-set even in the absence of pollinators.”