How Do Desert Plants Retain Water?

Sharp thorns and spikes on many desert plants deter thirsty animals.

The desert may seem an unlikely place for life to exist, but a variety of plants have adapted to the hot, dry conditions. Many of their adaptations help them retain water, which allows them to thrive for long periods of time without rainfall.

Succulent Features

Succulent desert plants have shallow roots that rapidly absorb water after rare rainfalls. Their thick stems or leaves store the water for long periods, while waxy coatings prevent water from escaping through their skins. Some, such as agaves, develop only a few leaves, which minimizes the surface area through which water can escape, according to the Center for Sonoran Desert Studies at the Arizona-Sonora Desert Museum.

Thorns

Instead of traditional leaves, many desert plants develop thorns or spikes. These help minimize surface area to prevent evaporation and sometimes -- when pointing downwards -- guide water droplets to the roots.

Photosynthesis

Unlike other plants that photosynthesize by opening their stomates (or pores) during the day to collect carbon dioxide, desert plants close their stomates by day. This keeps the sun from zapping their water reserves. Instead, they open at night to gather carbon dioxide, according to professor Arthur Stern's article "Photosynthesis" on the University of Massachusetts Amherst website.

Fun Fact

In another method of water retention, the thorns and spikes on many desert plants scare off thirsty animals who otherwise would drink the plants' water.

References

• Arizona-Sonora Desert Museum Center for Sonoran Desert Studies: How Plants Cope With the Desert Climate
• University of Massachusetts Amherst: Photosynthesis
• Dalhousie University: Biology of Cacti