AP BIOLOGY

PLANTS

THE LEAF

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
The small, slightly swollen part at the end of the petiole is called ____
A
Leaf blade
B
Leaf base
C
Vein
D
Leaf stalk
Explanation: 

Detailed explanation-1: -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-2: -The swollen part of the pedicel is known as thalamus.

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: -Such swollen leaf bases are called pulvinus leaf bases e.g., Mango, Pea, Gram, Ficus etc.

Detailed explanation-5: -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’.

There is 1 question to complete.