Desert Plant Adaptations
Crucifixion thorn has green stems where photosynthesis takes place.
We have four dominant plants of the Chihuahuan
Desert in the Nature Park - creosote
bush (Larrea tridentata), honey
mesquite (Prosopis glandulosa), tarbush
(Flourensia cernua), and crucifixion thorn (Koeberlinia
spinosa). These plants, along with other plants of the Chihuahuan
Desert, have developed numerous adaptations that allow them to cope
with the extreme temperatures, low water availability, and high
solar radiation found in this environment
and leaves of the plants are often specialized for desert conditions.
For example, perennial grass roots that are shallow and dense collect
water quickly when it rains. Other plants, like honey mesquite, have deep
root systems that can tap into longer-term water sources. Since leaves
are a primary source of water loss, it is not uncommon to find desert
plants with small leaves (e.g., creosote bush) or with leaves so small
they look like they have no leaves at all (e.g., crucifixion thorn).
The fishhook barrel
cactus (Ferocactus wislizenii) has accordion pleating
that allows it to expand and store large quantities of water when it is
available. Finally, cacti and some succulents use a special type of photosynthesis
that functions only at night when temperatures are lower and humidity
is higher, so plants lose less water to evaporation.