DENDROLOGY

Detailed explanation-1: -Cactus survive in deserts due to following adaptations: It has a flat green stem to store water and prepare food by photosynthesis. The stem is also covered with a thick waxy layer, which helps to retain water. Its roots go deep into the soil for absorbing water.

Detailed explanation-2: -Cacti grown in arid areas have developed intrinsic water management systems, such as water collection through spines, water absorption through trichome, and water storage using mucilage.

Detailed explanation-3: -The outer skin of the saguaro is waxy to prevent water loss through evaporation. It also contains chlorophyll and is the site of photosynthesis – by eliminating leaves, cacti are able to reduce water loss even further.

Detailed explanation-4: -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. Root systems are usually broad and shallow, and rainwater is soaked up quickly.