Deserts are very dry land areas. While people mostly associate deserts with hot temperatures, some desserts are actually very cold. Rainforests, on the other hand, receive an enormous amount of rain. Despite the extreme differences in these climates, both desserts and rain forests are homes to many types of plants. However, many of the characteristics of these plants are very different. Through evolution, these plants have adapted specialized structures that aid them in surviving in their environments.
Desert plants fall into one of two categories: xerophytes and phreatophytes. Xerophytes are dessert plants that experienced changes in their structures which allow them to survive in the dessert. Phreatophytes are plants that merely adapted by stretching their roots further beneath the soil in search of water. Rainforest plants are defined more by the area of the rainforest they inhabit. Plants in the upper canopy have dark green leaves which reflect light, preventing water from being lost when the sun dries the leaves. Lower plants have to be more concerned with not getting enough sunlight and having too much water.
Some dessert plants rely on dormancy in order to survive. The seeds of these plants remain in the soil until moisture arrives, encouraging them to germinate. Rainforest plants do not have to worry about not having enough moisture to grow. However, due to the canopy, many rainforest plants have to worry about not having enough sunlight, something that is abundant for desert plants. Some plants seek out sunlight by climbing, such as vines. Other plants, like rainforest shrubs, have the ability to grow quickly when openings appear in the rainforest canopy.
The structure of many desert and rainforest plants allow them to survive better in their environments. Cactus, a desert plant, has no leaves but has shallow roots, spines that provide shade, a waxy outer edge and the ability to store water. The roots of the cacti are designed to rapidly collect water whenever it does rain. Leaves are small or nonexistent on desert plants because plants lose water through leaves via a process called transpiration. For rainforest plants, transpiration is a good thing and plants often have extra-large leaves with extra pores in order to give off excess water. The leaves and stems have adapted to give off water quickly in order to prevent stems from snapping under the weight of the water.
Despite the dryness of the desert, there is water deep underground on a layer of the earth called the water table. Some plants, like the mesquite tree, stretch their roots deep underground in order to tap into these water reserves. Rainforest plants have specialized roots also, but their roots are more concerned with supporting trees that are often unstable as a result of wet, loose soil. Stilt roots or buttress roots are used to keep rainforest trees stabilized.
Rainforests have far more diversity than deserts. Very few plants have been able to adapt to dry environments. However, in rainforests, resources are plentiful. The diversity of life in rainforests benefits all of the species by providing a variety of sources of food for animals and also by minimizing the chance that one particular species of plant dies from insect infestation.