What crop grows best irrigated with sea water?
By Chelsie Vandaveer
June 13, 2002
killerPlants Tendrils: ~~1~~2~~3~~4~~5~~
Suggested Reading: Click here.
Annual glasswort (Salicornia bigelovii Torrey) is a succulent growing in the salt marshes and estuaries of North America. It is a halophyte, a plant that grows in the presence of salt. Annual glasswort is thought to tolerate as much as 200 parts per thousand salts or five times the concentration of sea water.
Sodium and chloride ions are disruptive to enzymes and cellular processes of most plants, but glasswort makes the most of its habitat. This salt tolerance allows the plants to colonize large tracts of mud flats too saline for other species. When heavy rains lower salt concentrations on the mud flats, glassworts often appear wilted.
Plant biologists (Dietrich, Parks, et al, 2001) at the University of Arizona found that annual glasswort takes up the sodium then pumps the ions into the vacuoles of the cells. This sequestering keeps the ions away from the metabolic processes taking place in the cytoplasm. Glassworts showed enhanced growth when raised in high concentrations of salt--the plants grew bigger with larger cells and they were more succulent.
Strangely, in another study at the University of Arizona, biologists (Lu, Bush, et al, 2001) found that glasswort seeds germinate best in distilled water and poorest in water with 70 ppt salts. But seed germination could be increased in sea water if temperatures were cool (16 degrees C).
Why all the science going into a salt-tolerant weed? Salt build-up on irrigated land has forced farmers to abandon fields. Lack of freshwater keeps many coastal areas from being farmed. Annual glasswort seed is approximately 30 percent oil and 70 percent meal. It can replace freshwater seed crops like sunflowers and soybeans in those areas.
The Institute for Systematic Botany with the University of South Florida has photographs of the annual glasswort. To view the photographs, click on the link:
http://www.plantatlas.usf.edu/main.asp?plantID=3805
Click on the Images tab, then the individual images to enlarge.
killerPlants Tendrils: ~~1~~2~~3~~4~~5~~
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