Where do you think cacti keep all that water they need to thrive in the desert? a place with sporadic and unpredictable downpours?
The trick, it turns out, is that this plant has evolved mechanisms for efficiently absorbing, storing, and using water over time.
Where do cacti then keep their water? Cactus water is mostly stored in the stem’s compressible water storage cells. However, the roots of some cacti have been adapted specifically for the purpose of storing water. The water-storing cells, which can collapse, can be seen as voids or holes in the stem and can hold onto water for a considerable amount of time.
In addition, there are ribs or flutes present, which allow water to accumulate. When the cactus is at its greatest size, the ribs/flutes are hidden within the swelling stem, but they become exposed during a period of stem contraction.
Cacti require water much like any other plant. However, water is typically scarce because of the locations where it grows. This plant has evolved a broad variety of adaptations to the scorching climate that allow it to store the little water it receives for a reasonably long time.
Cactus spines, which seem like needles, are really highly modified leaves that assist the plant avoid being eaten by predators and conserve water by cutting down on wind circulation.
The Cactus Cortex Stores Water In What Way?
Cactuses are able to store more water due to evolutionary changes that increased the thickness of the plant’s cortex. An inner water-storing zone and an outer photosynthetic zone are found on cactus cortices.
Although it looks very different from a normal leaf, the top layer is green and absorbs carbon dioxide for photosynthesis. Due to rapid changes in volume and form caused by the uptake and excretion of water, the walls of these cells are extremely flexible, lignified, and elastic and contain fewer chloroplasts than those of typical cells.
Collapsible water-storage cells of a cactus plant are kept alive not merely because water can be stored there but also because it can be rapidly made accessible to the plant’s photosynthetic cells. Additionally, the plant’s growing flower buds, axillary buds, fruits, and other structures may easily access the water.
Cactus cells, on the other hand, are thicker and more resistant to shrinking since they are responsible for absorbing water. With less water available, the inner cortex cells of the cactus shoot release more water, redistributing it to other plant cells to minimize water stress and keep photosynthesis going.
Cortex water-storage tissues have evolved to become more flexible over time, and this has the potential to cause epidermal concerns.
Succulent plants only develop epidermal cells at the terminals of their shoots and roots, therefore a swollen stem after a rainstorm may reduce the quantity of water the plant can take in.
Most cacti, however, are exceptions to this rule due to the fact that their ribbed or tuberculated stems have a pleated surface that allows them to absorb as much water as possible.
What is the process of modifying the cactus root system so that it can absorb water better?
Growing up in desert environments would lead you to believe that cacti have more extensive root systems in order to provide a reliable connection to underground water. But unfortunately, this is not the case.
The cactus sends out new root systems after it rains. In extreme cases of dryness, however, some roots can dry out and fall off the plant altogether in an effort to save its water supply.
Some cacti, shortly after germination, send down a long, sturdy taproot. The plant’s taproot has two purposes: it acts as a sturdy anchor so the plant doesn’t get swept away in heavy rains, and it reaches into the subsurface soil where there is more water.
How Do Mucilage Cells Store Water in Cactus?
The mucilage cells of a cactus plant play a surprising function in the plant’s ability to store water. These cells are ubiquitous in cacti and are thought to be extremely adaptive in the plant, allowing the cactus to store more water.
Even while mucilage cells are most commonly associated with mosses, they can be found in other plants. Some plants have a slimy sensation when sliced because they contain cells like this. Mucilage cells combine to generate the main carbohydrate tissue that can bind and retain water rather tenaciously.
But if the mucilage cells of a cactus plant are so good at retaining water, how does it benefit any of the other cells? Like the cactus cortex mentioned above, the collapsible water-storage cells must never hoard water for themselves at the expense of the rest of the plant.
Can Cactus Survive In Deserts With Any Other Traits?
Cacti have developed a number of mechanisms to reduce water loss, including cells that may expand and contract to store water, cells that produce mucilage, and a unique root system.
Actually, the thorny spines of certain cacti actually work as rain gutters, carrying precipitation down to the plant’s roots. Every plant has pores called stomata that may open and close to let in or let out carbon dioxide for photosynthesis.
The term “stomata” is used to describe the many tiny holes present on the surface of plants. Plants capture carbon dioxide in the process of photosynthesis and use it to create carbohydrates.
Normally, stomata open during the day and close at night. However, because so much water is lost each time these pores open, this process can be problematic for arid plants like the cactus.
It’s a gamble for a plant to open its stomata and risk losing water if it’s attempting to conserve its supply. Cacti and other desert plants are unusual in that they open their stomata at night rather than during the day.
Cacti are able to retain a lot of water because of the colder night temperatures, the absence of daylight, and the quiet breeze. However, cacti can’t produce food at night since they can’t photosynthesize.
For this reason, it stores carbon dioxide overnight and begins photosynthesis first thing in the morning when sunlight is at its peak. To survive in the harsh desert environment, even leafy cacti like the Pereskia have adapted in a similar fashion.