Question

In Opuntia the spines are modification of
a. Leaf
b. Branch
c. Epidermis
d. Flower

Answer 1

Hint: Opuntia, also called prickly pear. It belongs to the cactus family, Cactaceae. These are xerophytic plants which are mostly found in deserts. Their water requirement is very low. These plants adapt to survive in hot temperatures. These plants are best suited for semiarid conditions.

Complete answer:
Opuntia are classified as succulents because they exhibit pronounced water storage. They have a shallow root system which allows rapid water uptake. They have thick waxy coating which reduces the excessive loss of water and the photosynthetic pathway is replaced by crassulacean acid metabolism (CAM). It allows these plants to uptake carbon dioxide at night when water loss is minimum.
Opuntia is one of the most diverse species and is widely distributed around the world. Most of the wild species of opuntia are found in Mexico.

Morphology of Opuntia
Opuntia are slow growing plants which aren’t very deep rooted. The roots of opuntia spread horizontally. It has very thick stems called cladode which are oblate in structure and succulent. The epidermis is thick with a waxy coating to reduce the water loss and also reflects the sun rays. Leaves of opuntia are generally reduced to spines but may exist in young clades. These spines protect the plant from excessive transpiration and predators. Some varieties of opuntia do not have spines. Some opuntia species have flowers which occur on 1-2 years of cladodes. The flowers are usually of pink color. The fruit of opuntia is reddish, ellipsoid, succulent, and edible.

Hence, the correct answer is option (a).

Note: Opuntia are used as decorative plants in homes, offices, etc. They are also known for treating diabetes, high cholesterol, obesity as it has many antiviral and anti-inflammatory properties. The leaves, fruits, and flowers are the edible parts of the opuntia and are used in medicines. Some people may face side effects of consuming it, which include, diarrhea, headache, nausea.