How Does a Cactus Survive in the Desert?

Whenever someone visualizes a desert-like landscape, they almost always imagine vast sand dunes, a hot sun, a couple of camels, and wild cacti.

Unlike most green plants that require ample shade, water, and humidity, a wild cactus is naturally adapted to thriving in deprivation and can survive a shockingly long lifespan in the harsh desert conditions in the USA.

If you are wondering what makes the humble cactus so much more resistant and tolerant than most other plants, take a look at its incredibly unique physical differences.

While other plants have thin stems and a leafy structure, a cactus has a thick trunk and a thorny exterior. These are the exact features that allow this desert plant to grow under immense heat and without much water.

Keep reading to learn about how the cactus is different from most other succulents and green plants and how its unique physical appearance helps the plant retain its high level of tolerance.

How Do a Cactus’ Physical Features Help It Survive in the Desert?

Lack of Leaves

One of the most unique features that help make an instant distinction between a cactus and other plants is its lack of leaves.

In general, most green plants, flowering species, succulents, etc., all have leaves or similar leaf-like structures that help create a doorway between the plant and its external surroundings.

Since a leaf’s upper and bottom surfaces have multiple tiny holes, the plant can transpire and diffuse water whenever required.

For instance, if the heat from the direct sun increases the plant’s internal temperature, the leaves will react by transpiring water.

When the water evaporates off of the leaf’s surface, it creates a cooling effect, which helps bring down the plant’s internal temperature and saves it from overheating.

While this natural mechanism is excellent, it can lead to immense water loss, which will dehydrate the plant and kill it.

On the contrary, cacti have absolutely no leaves on their bodies. This limits their exposure to the outside environment and helps control water loss, which is crucial for a plant that grows in dry and arid desert conditions.

Thorny and Spikey Exterior

Another unique physical feature of a cactus is its thorny and spikey exterior. Since the desert plant has no leaves, it is covered with thin needle-like thorns that fall out and regrow throughout the year.

Although the thorns add to the wild cactus’ unique appearance and raw appeal, they also enhance the plant’s tolerance and make it a perfect fit for the hot desert climate.

Since thorns are completely different from leaves, they do not have any tiny holes on their surface to facilitate the transpiration or diffusion of water droplets.

As a result, no matter how dry the external air is, no water will diffuse out of the desert plant, and it will be able to retain its hydration for a long period.

Moreover, since the thorns point outwards and are generally long, they can cast shadows on the cactus’ green and exposed body.

Although a single thorn’s shadow is quite significant, the collective shadows from the thousands of thorns on its body can offer the plant incredible shade.

As a result, the plant is well-shielded from the sun’s direct exposure and is protected from overheating. This cancels out the need for transpiration or leaves.

Furthermore, the thorny exterior of a cactus also helps protect it from getting eaten by wild desert animals. Since the animals do not want to get stung by all the thorns, they choose to stay away.

As a result, most breeds of wild cacti can survive for more than a hundred years without any additional care or effort.

Thick Trunk-like Stem

There is a reason why both the cactus and the camel are known for their desert-like origins. Like a camel that stores water inside its hump, a cactus uses its large and wide trunk-like stem to do the same.

Unlike other plants with vessels running through their thin stems, a cactus’ trunk contains a large water reservoir. This helps conserve considerable amounts of water for dry seasons when rainfall is scarce.

In general, a fully grown Saguaro desert cactus is able to store a whopping 200 gallons (about 757.08 L) of water at a time. This helps it retain its hydration throughout the year, which helps keep up its immunity and growth rate.

Unique Roots

Like any other plant species, a cactus’ survival and hydration also directly depend on its roots. If the cactus’ roots are to die, the entire plant will be deprived of any more water absorption.

However, while cactus roots also help absorb water and nutrients like any other plant roots, they do have certain functional differences that help them be a better fit for desert soil.

In general, most plant roots have a limited capacity to absorb water. For instance, if you plant a succulent inside a pot and overwater it, its roots will only absorb the amount of water their cells have the capacity for.

Once their capacity to absorb water is met, they will no longer allow any more water to pass through the cell walls.

On the contrary, cactus roots are adapted to absorbing any moisture they can find. Since the desert soil is generally dry and has very little water, the roots try their best to soak in any water drops that they can find.

Hence, even when the weather is too hot, and there is very little rain, the cactus will either work on absorbing any available moisture from the soil or will live off of its stored water reserves.

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Final Thoughts – Bring Home a Desert Plant Now!

The incredible drought tolerance of a wild cactus allows it to thrive in harsh desert conditions and endure strong periods of heat, especially in countries like the USA. By having a thorny exterior, a thick trunk-like body, and highly absorbent roots, this desert plant can withstand dryness, lack of rain, and direct sunlight throughout its long lifespan.

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