A halophyte is a plant which is capable of surviving in a highly salty environment. An estimated two percent of plant species are halophytic, with the vast majority of plants being glycophytes which will not survive on a salty substrate. Although halophytes make up a very small percentage of the overall plant population, they play a number of important roles in the environment, and they have some potentially useful industrial applications.
These plants can survive in a number of environments. Many are designed to grow in salt marshes and estuaries, where there is a high concentration of salty water. Others can live on cliffs and dunes near the ocean, and some are adapted for near-desert environments where water supplies may be limited and highly saline. A halophyte which lives in the desert is typically a succulent, so that it can store water to ensure that it has an ample supply.
Researchers distinguish between facultative halophytes and obligate halophytes. A facultative halophyte is a plant which can live in salty conditions, but would prefer to avoid salt, if possible. For example, plants which thrive during the rainy season, when salt concentrations are diluted, are usually facultative halophytes which tolerate the salt, but do not particularly enjoy it. An obligate halophyte, on the other hand, actually needs salt to survive.
Many people who have been to the beach have seen examples of halophytes, and they have also seen an example of one of the important roles that these plants play. Halophytes help to prevent erosion, which means that they keep beaches in shape, and allow beaches to build up over time. These plants can also turn a salt marsh into an area of solid ground, by slowly allowing decaying organic matter and soil to build up around their roots, stems and leaves. Halophytes shape the environments they live in, changing the surface of the Earth in the process. Certain halophyte species can also be used as animal fodder, an advantage in some communities.
Gardeners sometimes take advantage of these plants when they want to establish landscaping in a harsh, salty environment. By using native halophytes, gardeners can conserve water and energy, and preserve rare and interesting native species. These plants can also potentially be used in the manufacture of biofuels. One big advantage of using halophytes for biofuels is that it isn't necessary to dedicate arable land to the production of halophytes for fuel production, since these plants grow in areas which are unarable for conventional crops.