Question

Leaflet tendril and entire leaf tendril are found in respectively
A. Cucurbita, Smilax
B. Pisum, Lathyrus aphaca
C. Passiflora, Vitis
D. Luffa, Pisum

Answer 1

Hint: In botanical studies, tendril has been featured as a thread like structure. It functions to provide support to the plant via climbing on the plants. Although there is no blade or lamina present in the tendrils, they are still capable of carrying out photosynthesis.

Complete answer:
A tendril is often referred to as a specialized leaf, stem or petiole. It has a thread-like appearance. It climbs the plants thereby providing them a mechanical support. Moreover, these tendrils also help in providing attachment to plants and also in case of parasitic plants these tendrils contribute to cellular invasion usually via twinning around the proper host. These tendrils can be developed from modified leaves, auxiliary branches or modified shoots. They show sensitivity towards chemicals which helps in determination of plant growth.
The modification of terminal leaflets to form tendrils occurs in the Pisum sativum (garden pea). However, modification of the whole leaf into the tendrils occurs in Lathyrus aphaca (a yellow vetch). Also, enlargement of stipules occurs and photosynthesis is thus carried out.
On the other hand, in Passiflora, Vitis and Cucurbita axillary tendrils are found while in Luffa, reduced leaf tendrils are found and in Smilax, tendril stipulation occurs.

Hence, the correct answer is option (B).

Note: The tendrils are often found twinning around the host on the basis of their perception to touch but they have developed self-discrimination mechanism thus avoiding their twining around their own self.