In the wild, cacti plants have braced the desert conditions for many years. How does a cactus survive in the desert? I’m sure you know that. But if not, you will today!
Extreme temperatures. Little rainfall. Odd climate patterns.
Cacti plants know best how to maneuver around them. They relish in them. If any plant can adapt to harsh conditions, it’s the cactus plant.
So, how are they able to do this? How have they been able to put in places known to be a death sentence for most plants? What makes cacti different?
Obviously, they’ve been able to develop specialized features, but what are they?
They’re not like the average plant growing in places where water is an everyday thing. They’ve adapted to especially take advantage of the little rainfall in their natural habitat.
Continue reading about these adaptations below, and let us know what you think. Some of them you might already know, but others are pretty cool!
Spines Not Leaves
Spines are one of the most notable features in cactuses.
Instead of having leaves, the stems are covered in a number of these prickly structures. You know, the spiky little fellas that they have, ouch! They guard against desert herbivores, but that’s not important for now. (Maybe a future article, let us know!)
Here’s how cacti plants are adapted to saving water by having spines. It’s pretty interesting …
- The white spines are made up of dead cells at a mature age. This means they don’t take up water as it would have been if they were alive. Just one less part for the plant to worry about, right?
- They trap air around the plant. This air provides a thin cover over the plant, preventing water loss by evaporation and transpiration.
- The spines, with their number, add up to provide a considerable amount of shade for the plant. Such an adaptation lowers the cactus surface’s temperature, reducing water loss.
- In instances of fog/mist, the spines condense it into water droplets that fall off to the base of the plant, where they are absorbed immediately – courtesy of the nature of the roots, as you’ll see below.
To ensure you know how to handle the thorns on a cactus properly, check out this article!
A Highly-specialized Root System
Cacti roots differ from other plants in several ways, which are adaptations to survive the desert terrain better.
- They’re shallow and widespread to take advantage of any light rains in the desert. That means they can absorb much water within the shortest time.
- They can grow new tiny roots very fast when it rains. These contribute to the more rapid absorption of water. The roots also dry up quickly so they don’t become another burden for the plant.
- The root cells have a very high concentration of salts. An essential adaptation that translates to a higher water absorption rate.
In some specific cacti species, the roots are also used as water storage organs. In this case, the species will have a taproot larger than itself for this sole purpose.
The Well-Equipped Stem to Store Water
Where does cactus store water? For most cacti species, the stems are the main water storage organs. And the species have particular adaptations, not just to store but also to retain the water. Have a look at a few significant characteristics:
#1. Stem Shapes
Cacti species have varied shapes that contribute immensely to water storage and retention capabilities. Cylindrical and spherical shapes are adapted to bring about a low surface area to volume ratio, reducing atmospheric water loss. These shapes also reduce the heating effects of the sun.
In other words, cactus plants have lower-than-average evaporation rates.
#2. The Shrinking Ability
Particular cacti have specific features on their stems. For instance, the ribs and flutes on a species, like the rounded ball cactus stem, enable it to shrink quickly during prolonged desert droughts and expand when it rains.
Shrinking is an adaptation that ensures a small surface area, reducing water loss.
Expanding gives the stem enough room to take up as much water as possible.
Wax on Cacti
The stems and spines of any cactus plant have a layer of thick wax. The functionality behind this is so that cacti can stop water loss as much as possible.
With the thick layer of wax mixed with the ability to shrink and expand, the wax serves a multifunctional purpose. It helps the cacti retain as much water as possible without allowing the sun, or the idea of evaporation, to affect cacti as much as it would with your average plant.
Short Growing Seasons and Long Periods of Dormancy
Cacti grow only during the short rainy seasons and stay dormant for the long dry months of the desert.
This adaptation ensures water efficiency as the stored water is only used in vital processes such as photosynthesis. The development of new cells and tissues (water-intensive) is confined to periods of rain when water is aplenty.
Photosynthesis occurs in the leaves during the day for most plant species. But not for a good deal for cacti.
At night, this vital process occurs in the stems (as the cacti are devoid of leaves). Such an adaptation ensures the plant loses very little water as its stomata are only open at this time when temperatures are at the minimum.
Water is a valuable commodity to many organisms, but its value probably increases hundreds of times in a desert setting. Every drop counts. Cacti get this all very well. So, they try to keep as much of it as possible through various adaptations.
And that’s how they’ve thrived in the deserts for years.
Cacti are amazing at dealing with really tough places to live. They’ve changed over time to store water, grow spines instead of leaves, and handle lots of heat and little rain. This helps them live where many other plants can’t. As our world’s climate changes, we can learn much from how cacti handle tough conditions.
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Richard | Editor-in-chief at Succulent City
Hey everyone! I’m Richard. Welcome to my blog, which is all about succulents, cacti, and a bit about air plants. Ten years back, in 2013, I began my journey with succulents. It started as a simple hobby, crafting and selling charming succulent-themed pins and decorations. But as time passed, my fascination with these remarkable plants grew, and I gained extensive knowledge about them. Therefore, Succulent City is the blog as you see it is now. Enjoy your visit and happly planting!