Question

Petiole is modified into tendril in
A. Gloriosa
B. Passiflora
C. Nepenthes
D. Luffa

Answer 1

Tendrils are modified stem, leaf or petiole. Tendrils are thread-like special structures of climbing plants which attach themselves to some other body or object to provide support for the developing plant. Leaves may be present in some plants. Tendril can also perform photosynthesis.

Complete answer:
Petiole is modified into tendril in Nepenthes.
A leaf is a lateral and flattened structure borne on the stem. Leaf develops at the node and bears a bud in its axil. It develops from the shoot apical meristem. Leaves are the most important vegetative organ for photosynthesis.
A typical leaf comprises of three parts:

Leaf base: It is the lowermost (basal) part of the leaf and it is attached to the node of the stem known as leaf base. Stipules are the lateral small leaf-like structures. In some leguminous plants, the leaf base swells which is known as pulvinus.
Petiole: It is the cylindrical stalk that joins the leaf base with the leaf blade or lamina. Petiole holds the leaf blade above the level of the stem to provide sufficient light to the leaf. It produces a cooling effect in the leaves by providing fresh air to the surface of the leaf.
Lamina or leaf blade: It is the green and expanded part of the leaf. It is supported by the veins and veinlets. The prominent vein present in the middle of the leaf blade is known as midrib. It also acts as a channel for transport of water, minerals and food material.

So the correct answer is option C.

Note: Tendrils are also modifications of the entire leaf (Lathyrus sativus), leaflet (Pisum), stipule (Smilax), leaf apex (Gloriosa) and inflorescence (Antigonon). Phyllotaxy is the arrangement of the leaves on the stem or its branches.