Adaptations of Plants - Adaptation in Desert Plants (Xerophytes)

Desert plants, like cacti, often have no leaves, or their leaves are small and needle-like to reduce water loss through evaporation. In many desert plants, leaves have transformed into thorns, which help minimise water loss and protect the plant from animals.

• The stems of desert plants store water and food, making them thick and fleshy. This helps the plant survive during dry periods.
• Since leaves are absent or small, the green stems perform photosynthesis, allowing the plant to make its own food.
• Desert plants have long roots that go deep into the soil to find water, and some roots spread wide to absorb water over a large area.
• A thick, waxy coating on the stems helps reduce water loss by sealing in moisture.

Cactus

1. Aim: To observe and compare the water loss (transpiration) in a cactus and a leafy plant.

2. Requirements

• Two potted plants: one cactus and one leafy plant
• Two plastic bags
• String or rubber bands

3. Procedure

• Take a potted cactus and a potted leafy plant.
• Loosely tie a plastic bag around the leaves of each plant, making sure the bags cover the leaves.
• Place both plants in sunlight from early morning.
• In the afternoon, bring the plants into the classroom.
• Observe the inside of the plastic bags for any signs of water condensation.

4. Conclusion: There will likely be more water droplets inside the bag covering the leafy plant than the cactus. This indicates that leafy plants lose more water through evaporation (transpiration) compared to cactus plants, which are adapted to conserve water.