AP BIOLOGY

Detailed explanation-1: -The point of attachment of the leaf petiole to the stem is called pulvinus. In some leguminous plants, leaf base is swollen which is called pulvinus. Pulvinus regulates the movement of leaflets in plants like Mimosa.

Detailed explanation-2: -There may be swollen regions at either end of the petiole known as pulvina (singular = pulvinus) that are composed of a flexible tissue that allows leaf movement. Pulvina are common in the bean family Fabaceae and the prayer plant family Marantaceae. A pulvinus on a petiolule is called a pulvinulus.

Detailed explanation-3: -The swollen leaf base is called pulvinus. (A) Sheathing leaf base is found in monocotyledons. (B) In some leguminous plants the leaf base may become swollen, which is called the pulvinus.

Detailed explanation-4: -Stipule is a pair of small leaflike appendage present at the base of petiole in many plants. Stipules may appear as glands, scales, hairs, spines or leaf-like structures. They protect the emerging leaf or bud. Thus the correct answer is ‘stipule’.