Cactuses always seemed to be one of the fascinating gifts of nature to me while growing up. I always wondered how can a plant survive for months without any supply of water in the midst of hollow deserts…So,
How does cactus store water? Cactuses are well adapted with the drought based desert conditions & have evolved a system of storing water in their stem with the help of water storage cells. These cells help in enhancing the water storage space within the stem by increasing the surface area which leads to more storage of water. Some extreme drought-prone cactuses have the ability of water storage even in their root system. They can absorb and retain water for a long time using these abilities.
How do cactuses collect water?
Cactuses are normally found in regions that face a steady water crisis all year round.
When it rains, it pours. So incidentally they have developed a stunning water management system that firstly helps in the absorption and collection of water through
- Trichomes (Small hairs)
Where do Cacti store their water?
Cactuses store this water in the mucilage cells located in the stems and sometimes even in the roots (Source).
Plants in the water sufficient areas generally use only a small portion of the water absorbed for growth, the rest of it gets lost by the process of leaf transpiration. However, cactuses do not have that luxury and manage every drop of water available carefully to survive.
The basic adaptations that have helped cactuses to store water for a long time, put up with drought in the desert areas, and to prevent water loss are as follows:
- They have modified their leaves to spines which help in better retention of water by minimizing transpiration
- Intense system of collection of water from underground and atmosphere via the vast root system and spines respectively.
- The spines help in protecting the cactus from other animals which otherwise can consume the water off the plant.
- The spines can even obtain water from a deep fog which normally develops during the dawn due to the sudden temperature differences in the day and night. The collected water is then stored in the mucilage cells of the stem.
Along with the modification of spines, they also have the following modifications
- A thick waxy skin that prevents water loss and also helps in reflecting heat during the daytime.
- Deep well-developed roots to properly reach underground water.
- Large fleshy stems that ensure large storage space for water. An elaborate system of storing the unused water in the mucilage cells of the stem is something that allows them to put up with drought.
Why do Cacti Store Water in their stems?
- They store water in their stem as it is the most fleshy and thick part of the whole body.
The stem has in due course of time evolved to be thick and fleshy in the inside that ensures proper spacious storage space for water and is covered with thorns and wax from outside that protects and prevents water loss respectively.
- The stem is flexible and as it acts as a water reservoir it can expand or shrink depending upon its water content inside.
How do cactus survive without water in hot deserts?
- Cactuses are succulents that have evolved in a way that makes them highly suitable to survive in desert conditions.
Even if you want to grow cactus in your home, ideally it will thrive only when you provide it with the suitable soil and environment it will normally get in its habitat.
Why is this?
Well because they have adapted themselves to survive in that drought-prone conditions for so long that they can’t survive well in waterlogged conditions.
Their adaptation had 4 major objectives:
- To obtain and absorb water from the environment minutely
- Properly store water by saving every last drop available and use it efficiently for the longest time possible
- Prevent the loss of water
- To protect themselves from extreme heat to a certain degree and from other animals
Cactuses have a well-developed root system that facilitates water absorption to minute level from the below soil. It can go extremely deep penetrating the deep soil levels in search of water and it is also highly branched.
They also have spines that not only protect them from animals but also help in absorbing moisture and preventing water loss.
- Along with all these, they have a waxy coating on their stem which favors the prevention of loss of water and keeps it cool by reflecting the Sun.
- They have specialized mucilage cells that help in water storage and their stem is especially fleshy for this purpose alone. So when it rains once in a while, they end up storing that water to maximum potential and as they have superior water storage and usage system coupled with prevention of transpiration and water loss, they end up leaving without water for a long time.
Do cactus have roots that help in collecting water?
Yes, they sure do. In fact, most of their roots are well developed extensively.
They are deep and branched so that they can read the underground water reservoir and can soak every bit of water from the soil that is available. There are various types of roots:
- Aerial roots are not extremely common among all cactuses. It arises above the soil in situations where the soil does not hold much water however the air moisture is high.
- So these roots can collect that extra bit of water from the environment.
- The Lateral roots are extremely common among cactuses. They grow in clusters and are hairy.
- Lateral roots grow covering a lot of surface area underground and this ensures that they can absorb as much moisture from the soil as possible.
- These roots are important for the proper survival of cactuses as water is scarce in desert conditions and these help them to exploit every last bit of water available.
- Taproots are the anchors of the plant. They help the cactus to remain properly rooted in the soil and goes extremely deep in search of obtaining water from the underground reserve.
- They are the very first kind of roots to develop in the life of cactuses and them last throughout their life.
How long can a Cactus Store Water?
Well, this varies as per the cactus type, its size, the kind of environment it is in.
Some cactuses can store water for as long as four months especially in the winter and there is almost no need of watering them frequently during that time. Bigger cactuses like the barrel cactus can also put up for months without water. Some particular species of cactus can store water for as long as two years.
Cactuses are one of the best plants you can consider to grow as it is extremely low maintenance. Provide them with suitable cactus mix soil, water them when the soil feels truly dry, provide them with suitable sunlight and they will be good to go.
To sum the question up, “How do Cactus store Water?”
- They have a wide range of adaptations that helps them to firstly collect every drop of water available around them underground or in the atmosphere.
- Cactuses then store away the water in the mucilage cells of the stem for future use.
- Some varieties of cactus can even store water in their roots.
If you have any further queries feel free to comment below!