Cacti can survive without water in the desert thanks to their ability to store water in their fleshy tissues and reduce transpiration by opening their stomata at night.
Thanks to their thick and fleshy shape, cacti limit their exposure to the sun as much as possible, which helps to reduce the surface area for evaporation. Their spines, derived from the transformation of leaves, prevent them from losing too much water by significantly reducing the exchange surface with the scorching desert air. The less contact, the less evaporation! Their compact and cylindrical body is another effective way to minimize losses by exposing a minimal surface to the blazing sun. Additionally, the thick outer skin of cacti is waterproof and tough, further limiting water loss through evaporation. Everything about them is designed to prevent even a single drop from evaporating into the dry desert air.
Cacti are true living sponges capable of accumulating large reserves of water in their internal tissues, particularly in their fleshy stems. Inside, special cells filled with liquid retain this precious reserve, forming a viscous and transparent gel: this is mucilage. This gel has two advantages: it efficiently stores water and protects it from excessive evaporation. Thanks to these reserves, a cactus can go months, or even years, without receiving a drop of rain. This survival mechanism allows the cactus to always have a reserve to survive in the driest environments.
Cacti open their stomata only at night to absorb CO₂ without losing too much water. They then engage in smart storage: they capture and retain CO₂ in the form of a special molecule, malic acid. During the day, they close their openings to prevent evaporation, and quietly use the stored CO₂ for their photosynthesis, thanks to sunlight. This shifted rhythm allows cacti to maintain their vital activity while significantly reducing water loss during intense desert heat.
Cacti have relied on a very particular root system: shallow but super extensive. This root network spreads horizontally all around the plant, sometimes for several meters, to quickly capture every drop of water as soon as it touches the ground. As soon as a shower falls, even a light one, these superficial roots quickly absorb the rare and fleeting water before it evaporates under the scorching desert sun. This allows them to maximize the short rains and the moisture from the morning dew.
The surface of cacti is covered with a kind of protective wax, thick and waterproof. This waxy coating acts as a waterproof layer, preventing excessive sweating and significantly limiting water evaporation outward. It's a bit like the cactus is wrapped in a thin plastic film but ultra-effective against drought. This waxy layer also helps to reflect sunlight, providing further protection to the plant against the scorching temperatures of the desert. A true anti-dehydration shield.
The famous Saguaro, a symbol of the American West, grows very slowly: it takes about 70 years to develop its first lateral arm!
Cactus spines serve not only as defense, but they also provide shade, thereby reducing water loss by limiting evaporation.
Did you know that some desert animals, like the Gila woodpecker, dig holes inside cacti to create their nests, thereby taking advantage of a stable temperature and protection?
Some cacti can store up to several hundred liters of water in their internal tissues, allowing them to survive without rain for years.
Contrary to a widely held misconception, cactus spines do not serve to absorb water. Their main role is to protect the plant from its predators, provide light shade, and reduce exposure to intense sunlight, thereby limiting water loss through evaporation.
When your cactus starts to wrinkle slightly, becomes soft, or seems to lose its usual shape, these are signs indicating a need for water. However, it's better to underwater than to overwater, as excess water can quickly harm the roots of cacti.
Even though many species of cactus are well adapted to the desert, not all of them can survive in extreme conditions and prolonged drought. There are certain species of cactus that are adapted to more humid or temperate climates, requiring regular care and watering.
Yes, cacti can bloom. Generally, their flowering is stimulated by factors such as temperature variations, a winter resting period, and sufficient exposure to light. It is often when they go through a dry period followed by a wet period that cacti bloom the most.
Depending on the species and environmental conditions, cacti can generally survive for several months, or even two years or more, without external water supply due to their exceptional ability to store water in their internal tissues and limit evaporation.
No one has answered this quiz yet, be the first!' :-)
Question 1/5
