Flora's Life : in Cold Deserts
Plants in cold deserts
Just like animals, plants need to adapt to the dryness, cold temperatures, and saltiness of the soils of cold deserts.
Most of the plants in cold deserts are low shrubs (a short bushlike plant). Most cold desert shrubs are deciduous, but some are partially deciduous, meaning they lose part but not all of their leaves each year. Deciduous plants lose their leaves in dry and cold deserts due to drought, but in cold deserts the low temperatures also cause these plants to lose their leaves. Sagebrush, which only grows to a height of about 1/2 to 4 feet (15 cm to 120 cm), is one of the dominant plants in cold deserts. In some areas as much as 85 percent of the surface is covered with sagebrush, while other cold desert surfaces have only a small percentage.
The soil of cold deserts tends to be salty. Rainwater washes mineral deposits down from the surrounding land, and when the water evaporates, it leaves these minerals behind in the soil. The world's largest salt flat is located in the Iranian desert, and the Bonneville Salt Flats and Great Salt Lake are located in the Great Basin desert. There are no plants growing in regions with very high salt concentrations. But surrounding these areas is generally a region of plants, including creosote bush and salt grass, then a narrow belt of shrubs, including greasewood and finally sagebrush.
Plants growing in salty soil of cold deserts have to be xerophytes (plants that are adapted to growing in dry conditions), halophytic (plants that are tolerant of salts in the soil), and have adaptations for the cold. The desert saltbush is such a plant. This shrub has tiny evergreen leaves that appear gray due to deposits of salt that are excreted (given off) by the plant onto the surface of the leaves. This release of salt by the plant prevents the buildup of salt in the plant. The salt crystals also help to keep the plant cool by reflecting sunlight.
The climate of Antarctica does not allow extensive vegetation. A combination of freezing temperatures, poor soil quality, lack of moisture, and lack of sunlight inhibit plant growth. As a result, the diversity of plant life is very small and limited in distribution. the flora of the continent largely consists of bryophytes (there are about 100 species of mosses and 25 species of liverworts), with only two species of flowering plants, both found in the Antarctic Peninsula: Deschampsia antarctica (Antarctic hair grass) and Colobanthus quitensis (Antarctic pearlwort). Growth generally occurs in the summer, and only for a few weeks at most.