NEET BIOLOGY

Detailed explanation-1: -Opuntia is a xerophytic plant. It grows in the dessert where water is very limited. In it, the leaves of areoles are modified into sharp and pointed spines.

Detailed explanation-2: -In case of cactus plants the leaves are modified into spines.

Detailed explanation-3: -The leaves of cactus are modified into spines, to prevent water loss from the surface of leaves. The green stem of the cactus plant contains chlorophyll. Thus, the stem is the centre of photosynthesis in the cactus plants instead of the leaves.

Detailed explanation-4: -In Opuntia, the spines represent the reduced leaves. To protect the plants from grazing animals and excessive transpiration, the leaf sections are modified into spines. Because of transpiration, in which sun rays extract water from the leaves, Opuntia leaves spines have tiny thorns instead of leaves.

Detailed explanation-5: -In xerophytic plants like cacti and Opuntia, the leaves are modified into spines. These spines check the loss of water from the plant body and thus help the plant to conserve water.