Question

In a sweet pea, tendrils are modified
A. Stipule
B. Stem
C. Leaf
D. Leaflet

Answer 1

Hint: A tendril is defined as a plant organ that is specialized to provide anchor and support the stems. Leaves, leaflets, leaf tips, or leaf stipules may be modified as tendrils. Stem branches also can be modified as tendril. Other special plant structures fulfil a similar function, but the tendril is specialised to support the plant to climb upwards.

Complete answer:
Tendril is a specialized lateral organ that strongly has the ability of coiling and this is the reason that causes tendrils can encircle any object. In a few plants, the leaf axis gets modified in a tendril. This tendril is formed to help in climbing. A tendril is a thin threadlike or coil like strand which is produced usually from the node of a stem modified shoots, modified leaves, or auxiliary branches. Tendrils are prehensile and sensitive to touch stimuli. Generally, the tendril is used for climbing by plants to get a support and attachment.
Now let us gather some information about given options:
Stipule: it is a leaf-like appendage that are small in size. These are born on the base of the leaf stalk. The stipule sometimes gets modified into tendril and performs the function similar to tendril. It is present in smilax
Stem: In some plants the axillary buds present on the stem modify to form tendrils. They provide support to the weak and tender stem e.g.. tendrils are present in grape vine, gourds (pumpkins, watermelon, cucumber).
Leaf : leaf is a flat and photosynthetic organ. Tendril performs the function of photosynthesis just as the leaf does. Sometimes the whole leaf can be modified into tendril. It is usually seen in lathyrus sativus
Leaflet :- a leaflet is not born on the main stem but it is born on the petiole . It is a leaf like structure. Sometimes the entire leaf does not get converted into tendril. It is usually seen in Pisum that is sweet pea.

Our correct option is (D) that is leaflet.

Note: Tendrils are long and thin structures. They are thread-like structures that are spirally coiled. They are used to climb the plants. They coil around the nearby support. Auxin helps to grow the tendrils. Sometimes petiole may also be terminating into tendril. It is seen in Nepenthes.