Cacti are stem succulents that are found in arid and semi-arid regions. Apart from their unique structure and shape of growing, many other factors make them unique among other succulents.
Most succulents have the ability to store water. Cacti are no different in this case. Cacti hold more water compared to other succulents to bear with the harsh environments they grow in. Some important and unique features that make cactus different from others are the wax coating on their stem and pads that helps their loss of water drastically to a minimum.
Many plant lovers have a doubt—how do cacti manage to store water? Let us look into answering the same and some other questions in the coming lines.
How Do Cacti Manage To Store Water?
Cacti are unique because of their capacity to store large amounts of water compared to other plants and succulents. Cacti follow a specialized way to sustain in harsh climates; one of them is storing a large amount of water.
Here are those unique traits of cacti that make them store water:
They Breath and Photosynthesise at night
All the plants create their food in the form of glucose by a process called photosynthesis. Almost all the plants do this process in the day by directly absorbing sunlight for the same. However, this is not the case with cacti. Cacti perform photosynthesis; however, they do this at night, which is better than harsh days.
Cacti open their stomata and areolas at night, thus producing oxygen and glucose via photosynthesis at night. Thus they start protecting themselves from the harsh sunlight in the daytime. Cacti and a few more succulents are the only plants that produce oxygen at night.
Cacti don’t have leaves. The leaves of the cacti have evolved into spines. Spines take responsibility to protect the plant from thirsty animals around. Spines are one of the preliminary reasons why cacti manage to survive and store water in them.
Specialized Root Propagation
Cacti are also different by their root propagation. In general, the roots of plants/trees grow deep downward to get to groundwaters. However, the roots of the cacti are shallow —just below the surface—and the extent to long distances away from the plant. This way, they could absorb as much water as possible from surrounding areas.
As stated in the previous lines, cacti have some additional traits that add up to their advantage. These prickly plants have a wax coating on them to ensure evaporation of water from them. Their fleshy stems are flexible that can bulge or shrink depending upon the amount of water in them.
Where Does Cactus Store Water?
Cacti have evolved over the years to get ready to survive in harsh conditions without water for several days altogether. Thus, they have developed a rare ability to store water.
Stem as the water reservoir
Their unique shapes and growth pattern characterize cacti. The stem of these prickly plants accounts for this unique shape. Cacti have bulged and fleshy stems because of the water content in them. Some cacti have barrel-shaped stems, while others have padded stems—however, the tendency to store water in them is persistent across all the species.
Does Cactus Store water in Roots?
It is said that stems are the reservoirs of water for the cactus plant. Is the stem the only storage of water? Not really. Roots and shoots of cacti are also evolved to store water when needed. During rains, the roots hold water till their capacity adding to the water holding capacity. The specialized root system that spreads over a longer range helps them access larger areas, thus more water during rains.
Not only roots but other parts also account for the storage of water. Shoots, spines, and fruits also act as storage of water when needed. Spines are not only protectors of the stem; they also absorb water during fogs.
Collapsible-Water storage cells
Cacti need water to survive, just like other plants. However, they need to store water to sustain themselves in harsh environments. What is the mechanism by which cacti store water?
The stem and other parts that store water is made up of special cells known as—Collapsible-water storage cells.
Collapsible water storage cells are evolved forms of cortex cells that are evident in all plants. These specialized cortex cells have two layers in cacti.
The outer layer is green and accounts for photosynthesis. This layer functions towards producing glucose and oxygen at night. It is important to understand that the storage of water occurs at the cell level itself. · The inner layer of these collapsible water storage cells stores water. This helps the plant to stay healthy for longer periods.
Mucilage cells in the stem also account for better storage of water in the cacti stem. Mucilage cells in cacti form a carbohydrate tissue capable of binding water.
Insights and Bottom Line
Cacti could sustain in harsh conditions due to their unique traits. The preliminary trait is the storage of water in them. Storage is made possible by having unique features like succulent tissue, wax-coated skin, spines for protection from thirsty animals, etc. The fleshy stem can expand and contract depending upon the water content. All these factors have their importance in making storage of water possible in cacti.