Cactus is a desert plant. Explain how it is different from tropical plants and how to survive in extreme dry conditions
Answers
Cactus plants are able to survive in the desert because they are able to store water for long periods. You may have seen cactus plants with their green, hard and thick-walled stems with many prickly spines.
The modified and strange-looking stems of cactus store water.
The roots of a cactus are usually found near the surface and do not go deep. Whenever there is rainfall in the desert, the water is collected and stored in the wide modified greenish stem region. Water is stored in almost 90% of the cactus plant and the quantity of water stored is humongous.
The quantity of water stored depends on the size and type of cactus. In the famous Saguaro cactus which has its origins in America, approximately 750 to 1000 liters of water can be stored during a good rainfall.
In such hot and desert-like conditions, how is the cactus able to store so much water without it getting evaporated? The green wide modified stems have waxy surfaces which prevent evaporation. If the cactus plants do not have any leaves as such except for the spines, how does photosynthesis take place?
Unlike in other plants, in cactuses, it is in the greenish stem region which stores water where photosynthesis also takes place. The prickly spines of the cactus protect the plant from being eaten up by animals in search of food or water in the desert.
One of the most important aspects of a cactus plant is that it can conserve so much water. Probably, in your next science project, you can learn more about the water-conserving features of the cactus. This can inspire you to design a water harvesting or water conserving storage tank/system which can efficiently store more water.