AP BIOLOGY

Detailed explanation-1: -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. Q.

Detailed explanation-2: -The spines of cacti are actually modified leaves. It helps to imagine cacti as large stems with spines for leaves.

Detailed explanation-3: -Glochids or glochidia (singular “glochidium") are hair-like spines or short prickles, generally barbed, found on the areoles of cacti in the sub-family Opuntioideae. Cactus glochids easily detach from the plant and lodge in the skin, causing irritation upon contact.

Detailed explanation-4: -Cacti are plants that have succulent stems, pads or branches with scales and spines instead of leaves. Cactus pads are actually modified stems with a waxy coating. The prickly spines are modified leaves that break up the evaporative winds blowing across pad surfaces, and help shade the stem.

Detailed explanation-5: -Spines are also modified leaves. In cacti, spines are wholly transformed leaves that protect the plant from herbivores, radiate heat from the stem during the day, and collect and drip condensed water vapour during the cooler night. In the many species of the spurge family…