Question

In Nepenthes, the pitcher is formed due to modification of
A. Leaf petiole
B. Leaf lamina
C. Tendril
D. Leaflet

Answer 1

Hint: The insectivorous plants include pitcher plants. Various parts of the leaf are modified in order to trap insects. These structures are called pitchers. Tendril is modified in old genera plants. In new plants such as nepenthes, the modification occurs on the surface of the leaf.

Complete answer:
Pitcher plant is the common name of the Nepenthes. The members of Nepenthaceae and sarraceniaceae family include pitcher plants. These are the carnivorous plants. The leaves of the plants are modified as pitfall traps which a prey-trapping mechanism features a deep cavity filled with digestive liquid. These are insectivorous plants. In the old world, pitchers are developed from the tendrils of the plants. The new world includes mainly three genera given below in which pitchers develop from other parts of plants such as leaf lamina.
The Sarraceniaceae includes ground dwelling herbs.The pitcher of these plants arises from a horizontal rhizome. The marsh pitchers classified into genus Heliamphora have simple rolled-leaf pitchers. They have a spoon like structure at the top that secretes nectar.
In the nepenthaceae family, the pitcher arises from the terminal portion of the leaf. The leaf lamina is modified into a pitcher like structure to trap flying or crawling insects. The inner walls of the pitcher digest the insect which secrete a digestive fluid into the pitcher cavity.
From the above information we have found that in Nepenthes, the pitcher is formed due to modification of leaf lamina.

Hence, the correct answer is option (B).

Note: In some plants, pitcher can develop from the leaf bladder. The segments of the leaf modified into bladders. Most of these modifications are found in water. The inner wall of the leaf has digestive glands which help in digesting the trapped insects. For ex: Utricularia. Plants such as Drosera, have lamina which have numerous hairs with sticky globules. The hairs cover the insect completely and digest it.