Halophyte

Halophyte

A halophyte is a plant that naturally grows where it is affected by salinity in the root area 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" (smooth cordgrass). Relatively few plant species are halophytes - perhaps only 2% of all plant species. The large majority of plant species are "glycophytes," and are damaged fairly easily by salinity. Glenn, E. P., Brown, J. J., and Blumwald, E. (1999). "Salt Tolerance and Crop Potential of Halophytes," "Critical Review in Plant Sciences," Vol. 18, No. 2, pp. 227-255. DOI: [http://dx.doi.org/10.1080/07352689991309207 10.1080/07352689991309207] ]

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 liter (g/l) of dissolved salts (mostly sodium chloride). Beans and rice can tolerate about 1-3 g/l, and are considered glycophytes (as are most crop plants). At the other extreme, "Salicornia bigalovii" (dwarf glasswort) grows well at 70 g/l of dissolved solids, and is a promising halophyte for use as a crop. [Glenn, E. P.; Brown, J. J.; O'Leary, J. W. (1998). [http://www.miracosta.edu/home/kmeldahl/writing/..%5Carticles/crops.pdf "Irrigating Crops with Seawater,"] " [http://www.sciam.com Scientific American] ", Vol. 279, no. 8, Aug. 1998, pp. 56-61.] Plants such as barley ("Hordeum vulgare") and the date palm ("Phoenix dactylifera") 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 (see halotolerance) or salt avoidance. Plants that avoid the effects of high salt even though they live in a saline environment may be referred to as facultative halophytes rather than 'true', or obligatory, halophytes.

For example, a short-lived plant species that completes its reproductive life cycle during periods (such as a rainy season) when the salt concentration is low would be avoiding salt rather than tolerating it. Or a plant species may maintain a 'normal' internal salt concentration by excreting excess salts through its leaves or by concentrating salts in leaves that later die and drop off.

Halophytes as Biofuel

Some halophytes are being studied for use as biofuel precursors. Halophytes can be grown in harsh environments and typically do not compete with food crops for resources, making them a promising source of ethanol [ [http://www.iata.org/pressroom/facts_figures/fact_sheets/alt_fuels.htm Alternative Fuels ] ] .

ee also

*Atriplex (saltbush) (orache) (orach)
*Babassu
*Switchgrass
*Yerba mansa
*Tetragonia tetragonoides (Warrigal greens, a leaf vegetable used somewhat like spinach or silver beet)

References


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  • halophyte — [ alɔfit ] n. f. • 1878; gr. hals, halos « sel » et phyte ♦ Sc. Végétal qui croît en milieu salé. ● halophyte nom féminin Végétal (plante supérieure, algue ou champignon) vivant dans une eau sursalée ou sur un sol salé. halophyte n. f. BOT Plante …   Encyclopédie Universelle

  • Halophyte — Hal o*phyte (h[a^]l [ o]*f[imac]t), n. [Gr. a ls, alo s, salt + fyto n a plant.] (Bot.) A plant found growing in salt marshes, or in the sea. [1913 Webster] …   The Collaborative International Dictionary of English

  • halophyte — [hal′ə fīt΄] n. [ HALO + PHYTE] a plant that can grow in salty or alkaline soil …   English World dictionary

  • Halophyte — Cakile maritima et Ammophila arenaria Une halophyte, ou plante halophyte ou plante halophile est une plante adaptée aux milieux salés ou par extension aux milieux à pression osmotique importante. L une des halophytes les plus connues est la… …   Wikipédia en Français

  • halophyte — noun Etymology: International Scientific Vocabulary Date: circa 1886 a plant (as saltbush or sea lavender) that grows in salty soil and usually has a physiological resemblance to a true xerophyte • halophytic adjective …   New Collegiate Dictionary

  • halophyte — Plant that grows in or tolerates salt rich environments …   Dictionary of molecular biology

  • halophyte — halophytic /hal euh fit ik/, adj. /hal euh fuyt /, n. a plant that thrives in saline soil. [1885 90; HALO + PHYTE] * * * …   Universalium

  • halophyte — noun Any plant that tolerates an environment having a high salt content …   Wiktionary

  • halophyte —   a plant that is able to tolerate environments with a high level of salt. Found usually in coastal areas or arid areas where potential evapotranspiration exceeds precipitation for large parts of the year …   Geography glossary

  • halophyte — [ haləfʌɪt, heɪlə ] noun Botany a plant adapted to growing in saline conditions …   English new terms dictionary

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