Halophyte
A
halophyte is a plant that grows in waters of high salinity, coming into contact with saline water through its roots or by salt spray, such as in saline semi-deserts, mangrove swamps, marshes and sloughs, and seashores. An example of a halophyte is the salt marsh grass
Spartina alterniflora. Relatively few plant species are halophytes - perhaps only 2% of all plant species. The large majority of plant species are
glycophytes, plants which are not salt-tolerant, and are damaged fairly easily by high salinity. One quantitative measure of salt tolerance is the "total dissolved solids" in irrigation water that a plant can tolerate. Sea water typically contains 40 grams per litre of dissolved salts. Beans and rice can tolerate about 1-3 g/l, and are considered glycophytes. At the other extreme,
Salicornia bigelovii grows well at 70 g/l of dissolved solids, and is a promising halophyte for use as a crop. Plants such as barley and the date palm can tolerate about 5 g/l, and can be considered as marginal halophytes. Adaptation to saline environments by halophytes may take the form of salt tolerance or salt avoidance.