Plants have features as different as fingerprints for different reasons. Flowers are meant to be pollinated, leaves absorb sunlight on a tree, and the dandelion weed’s seeds scatter in the wind. However, one of nature’s strangest features is a cactus’s thorns. What purposes could thorns possibly have?
Self-Protection and Growth
Many desert animals will try to eat cacti so thorns discourage potential predators. They are like a suit of armor. Some animals such as bighorn sheep and tortoises have adapted to eating these plants anyway, but this does not make the needles useless. Another major use for them aside from protection is reproduction.
Most species of cacti grow from seeds, but there are exceptions. For instance, cholla cactus thorns are very sensitive to movement and will rapidly detach and stick to any animals passing nearby. However, they will eventually fall off, take root, and grow a new cholla.
Water Retention
Cacti thrive in dry and arid environments like deserts and its thorns help to “reduce water evaporation”. Because they have a “small surface area” instead, they limit water loss and water is stored in the plant’s stem. Cacti would bake under the harsh sun if they had ordinary leaves instead.
Temperature Control
A cactus would be at the sun’s mercy without its spines. They provide shade during the day and reflect harmful rays. Desert temperatures can also drop from forty to sixty degrees Fahrenheit at night, but thorns keep heat inside. In short, they are a cactus’s air conditioning unit and coat in one.
These practical prickles are just one small part of one of the planet’s hardiest plants; they are simple but useful. Cacti don’t need leaves or much water thanks to them.
Read more “Why? – Series” articles on our Zealousness blog Why? – Series – iN Education Inc. (ineducationonline.org).
Sources
- Johnson, Noelle. “Why Is a Cactus Covered in Spines?” Birds and Blooms, Birds and Blooms, 25 Aug. 2022, www.birdsandblooms.com/gardening/gardening-basics/why-are-cacti-covered-in-spines/.
- “Nature’s Fortress: How Cacti Keep Water in and Predators out – Lucas C. Majure.” YouTube, YouTube, 18 Nov. 2021, www.youtube.com/watch?v=g9Szzb2YBXY.
