What adaptations does a cactus have to help it survive in the desert?

Question

What adaptations does a cactus have to help it survive in the desert?

Answer 1

Lots of information at the reference:

Answer 2

Cacti have many adaptations that allow them to live in dry areas; these adaptations let the plant collect water efficiently, store it for long periods of time, and conserve it (minimizing water loss from evaporation).

Cacti have a thick, hard-walled, succulent stem - when it rains, water is stored in the stem. The stems are photosynthetic, green, and fleshy. The inside of the stem is either spongy or hollow (depending on the cactus). A thick, waxy coating keeps the water inside the cactus from evaporating.

Many cacti have very long, fibrous roots, which absorb moisture from the soil. Some, like ball cacti, have shorter, more compact roots that absorb dew water that falls off the cactus.

Instead of leaves, most cacti have spines or scales (which are modified leaves). These spines and scales do not lose water through evaporation (unlike regular leaves, which lose a lot of water). The spines protect the cactus from predators (animals that would like to eat the cactus to obtain food and/or water). Areoles are circular clusters of spines on a cactus. Flowers bud at an areole and new stems branch from an areole.

Answer 3

To add to what has already been stated about adaptations of cacti, the stomata are sunken in pits on the stems.  The pits is filled with hairs which tends to keep the humidity high in the pit allowing the guard cells of the stomata to remain open for gas exchange!  

The spines that densely covers some cacti also are reflective of solar radiation.

Cacti can also be found as epiphytes high up in tropical rain forest trees.  The habitat is actually quite dry because of high rate of evaporation.  By attaching to branches, the cacti can get enough sunlight to survive whereas on the forest floor they would not get enough light!

Answer 4

☼ Waxy leaves (or needles) to reduce water loss by evapouration

☼ Needles with little surface area for little water loss

☼ Huge roots to anchor into the sand

☼ Huge stem for water storage

All I can think of right now. I have a feeling i'm doing your biology h/w for you, but oh well, I knwo the answer! xx.

Answer 5

THE SPIKES

prevent animals from eating the leaves

provides shade keeping the internal heat of the plant low

it channels the rain drops to the base of the plant



its waxy cuticle prevents transpiration

have less stomata than other plants

have the ability to accommodate any amount of water at different times