''Soda inermis'', the opposite-leaved saltwort, oppositeleaf Russian thistle, or barilla plant, is a small (to 0.7 m tall), annual, succulent shrub that is native to the Mediterranean Basin.Plants of the World Online
''Soda inermis'' Fourr. (retrieved 5 March 2024) It is a

halophyte A halophyte is a salt-tolerant plant that grows in soil or 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. ...

(a salt-tolerant plant) that typically grows in coastal regions and can be irrigated with salt water. The plant was previously classified as ''Salsola soda'', now regarded as a

synonym A synonym is a word, morpheme, or phrase that means precisely or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are a ...

. The plant has great historical importance as a source of

soda ash Sodium carbonate (also known as washing soda, soda ash, sal soda, and soda crystals) is the inorganic compound with the formula and its various hydrates. All forms are white, odourless, water-soluble salts that yield alkaline solutions in water ...

, which was extracted from the ashes of ''Salsola soda'' and other saltwort plants. Clow, Archibald and Clow, Nan L. (1952). ''Chemical Revolution,'' (Ayer Co Pub, June 1952), pp. 65–90. . Soda ash is one of the

alkali In chemistry, an alkali (; from the Arabic word , ) is a basic salt of an alkali metal or an alkaline earth metal. An alkali can also be defined as a base that dissolves in water. A solution of a soluble base has a pH greater than 7.0. The a ...

substances that are crucial in glassmaking and soapmaking. The famed clarity of 16th-century ''cristallo'' glass from Murano and Venice depended upon the purity of "

Levant The Levant ( ) is the subregion that borders the Eastern Mediterranean, Eastern Mediterranean sea to the west, and forms the core of West Asia and the political term, Middle East, ''Middle East''. In its narrowest sense, which is in use toda ...

ine soda ash", and the nature of this ingredient was kept secret. Spain had an enormous 18th-century industry that produced soda ash from the saltworts ( ''barrilla'' in Spanish). Pérez, Joaquín Fernández (1998)
"From the barrilla to the Solvay factory in Torrelavega: The Manufacture of Saltwort in Spain,"
''Antilia: The Spanish Journal of History of Natural Sciences and Technology,'' Vol. IV, Art. 1. . Archived at WebCite fro

on 1 March 2008. Soda ash is now known to be predominantly

sodium carbonate Sodium carbonate (also known as washing soda, soda ash, sal soda, and soda crystals) is the inorganic compound with the formula and its various hydrates. All forms are white, odourless, water-soluble salts that yield alkaline solutions in water ...

. In 1807, Sir

Humphry Davy Sir Humphry Davy, 1st Baronet (17 December 177829 May 1829) was a British chemist and inventor who invented the Davy lamp and a very early form of arc lamp. He is also remembered for isolating, by using electricity, several Chemical element, e ...

isolated a metallic element from caustic soda; he named the new element "

sodium Sodium is a chemical element; it has Symbol (chemistry), symbol Na (from Neo-Latin ) and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 element, group 1 of the peri ...

" to indicate its relationship to "soda". Before "soda" was somewhat synonymous (in U.S. English) with soft drinks, the word referred to ''Salsola soda'' and other saltwort plants, and to soda ash. While the era of farming for soda ash is long past, ''S. soda'' is still cultivated as a vegetable that enjoys considerable popularity in Greece, Italy and with gourmets around the world. In Greek it is called ''almyra'', while in Italian its common names include ''barba di frate'', ''agretti'', and ''liscari sativa'' (short: lischi or lischeri). Of its culinary value, Frances Mayes has written that "Spinach is the closest taste, but while ''agretti'' has the mineral sharpness of spinach, it tastes livelier, full of the energy of spring."

Description

This annual, succulent plant can grow into small shrubs up to 0.7 m tall (sometimes called subshrubs). It has fleshy green leaves with either green or red stems. The tiny flowers develop from

inflorescence In botany, an inflorescence is a group or cluster of flowers arranged on a plant's Plant stem, stem that is composed of a main branch or a system of branches. An inflorescence is categorized on the basis of the arrangement of flowers on a mai ...

s that grow out of the base of the leaves near the stem. Robertson, Kenneth R. and Clemants, Steven E. (1997)
''Salsola Soda''
from "Amaranthaceae" chapter, in: Flora of North America Editorial Committee, eds. 1993+. ''Flora of North America North of Mexico.'' 12+ vols. New York and Oxford. Vol. 4, pp. 399–402. .

Distribution

''Salsola soda'' is native in Eurasia and North Africa. Historically, it was well known in Italy, Sicily, and Spain. In modern Europe, it is also found on the Atlantic coasts of France and Portugal and on the Black Sea coast. It has become naturalized along the Pacific coast of North America, and there is concern about its invasiveness in California's salt marshes. It is also reported to be naturalized in South America.

Soda ash and the biology of sodium accumulation

The ashes obtained by the burning of ''S. soda'' can be refined to make a product called soda ash, which is one of the

materials essential to making soda-lime glass,

soap Soap is a salt (chemistry), salt of a fatty acid (sometimes other carboxylic acids) used for cleaning and lubricating products as well as other applications. In a domestic setting, soaps, specifically "toilet soaps", are surfactants usually u ...

, and many other products. The principal active ingredient is

, with which the term "soda ash" is now nearly synonymous. The processed ashes of ''S. soda'' contain as much as 30% sodium carbonate. A high concentration of sodium carbonate in the ashes of ''S. soda'' occurs if the plant is grown in highly saline soils (i.e. in soils with a high concentration of sodium chloride), so that the plant's tissues contain a fairly high concentration of sodium ions. ''S. soda'' can be irrigated with sea water, which contains about 40 g/L of dissolved sodium chloride and other salts. When these sodium-rich plants are burned, the carbon dioxide that is produced presumably reacts with this sodium to form sodium carbonate. It is surprising to find a higher concentration of sodium than of potassium in plant tissues; the former element is usually toxic, and the latter element is essential, to the metabolic processes of plants. Thus, most plants, and especially most crop plants, are "

glycophyte A halophyte is a salt-tolerant plant that grows in soil or 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, Marsh, marshes and Slough (hydrology) ...

s", and suffer damage when planted in saline soils. ''S. soda'', and the other plants that were cultivated for soda ash, are "

halophytes A halophyte is a salt-tolerant plant that grows in soil or 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. ...

" that tolerate much more saline soils than do glycophytes, and that can thrive with much larger densities of sodium in their tissues than can glycophytes. The biochemical processes within the cells of halophytes are typically as sensitive to sodium as are the processes in glycophytes. Sodium ions from a plant's soil or irrigation water are toxic primarily because they interfere with biochemical processes within a plant's cells that require

potassium Potassium is a chemical element; it has Symbol (chemistry), symbol K (from Neo-Latin ) and atomic number19. It is a silvery white metal that is soft enough to easily cut with a knife. Potassium metal reacts rapidly with atmospheric oxygen to ...

, which is a chemically similar

alkali metal The alkali metals consist of the chemical elements lithium (Li), sodium (Na), potassium (K),The symbols Na and K for sodium and potassium are derived from their Latin names, ''natrium'' and ''kalium''; these are still the origins of the names ...

element. Tester, Mark and Davenport, Romola (2003). "Na⁺ Tolerance and Na⁺ Transport in Higher Plants,
''Annals of Botany''
91: 503-527. . The cell of a

such as ''S. soda'' has a molecular transport mechanism that sequesters sodium ions into a compartment within the

plant cell Plant cells are the cells present in Viridiplantae, green plants, photosynthetic eukaryotes of the kingdom Plantae. Their distinctive features include primary cell walls containing cellulose, hemicelluloses and pectin, the presence of plastids ...

called a "

vacuole A vacuole () is a membrane-bound organelle which is present in Plant cell, plant and Fungus, fungal Cell (biology), cells and some protist, animal, and bacterial cells. Vacuoles are essentially enclosed compartments which are filled with water ...

". The vacuole of a plant cell can occupy 80% of the cell's volume; most of a halophyte plant cell's sodium can be sequestered in the vacuole, leaving the rest of the cell with a tolerable ratio of sodium to potassium ions. In addition to ''S. soda'', soda ash has also been produced from the ashes of '' S. kali'' (another saltwort plant), of glasswort plants, and of

kelp Kelps are large brown algae or seaweeds that make up the order (biology), order Laminariales. There are about 30 different genus, genera. Despite its appearance and use of photosynthesis in chloroplasts, kelp is technically not a plant but a str ...

, a type of seaweed. The sodium carbonate, which is water-soluble, is " lixiviated" from the ashes (extracted with water), and the resulting solution is boiled dry to obtain the finished soda ash product. A very similar process is used to obtain

potash Potash ( ) includes various mined and manufactured salts that contain potassium in water- soluble form.

(mainly

potassium carbonate Potassium carbonate is the inorganic compound with the formula . It is a white salt, which is soluble in water and forms a strongly alkaline solution. It is deliquescent, often appearing as a damp or wet solid. Potassium carbonate is mainly used ...

) from the ashes of hardwood trees. Because halophytes must also have potassium ions in their tissues, even the best soda ash derived from them also contains some potash (potassium carbonate), as was known by the 19th century. Plants were a very important source of soda ash until the early 19th century. In the 18th century, Spain had an enormous industry producing ''

barilla ''Barilla'' refers to several species of salt-tolerant (halophyte) plants that, until the 19th century, were the primary source of soda ash and hence of sodium carbonate. The word "barilla" was also used directly to refer to the soda ash obtain ...

'' (one type of plant-derived soda ash) from saltwort plants. Similarly,

Scotland Scotland is a Countries of the United Kingdom, country that is part of the United Kingdom. It contains nearly one-third of the United Kingdom's land area, consisting of the northern part of the island of Great Britain and more than 790 adjac ...

had a large 18th-century industry producing soda ash from kelp; this industry was so lucrative that it led to overpopulation in the

Western Isles The Outer Hebrides ( ) or Western Isles ( , or ), sometimes known as the Long Isle or Long Island (), is an island chain off the west coast of mainland Scotland. It is the longest archipelago in the British Isles. The islands form part ...

of Scotland, and one estimate is that 100,000 people were occupied with "kelping" during the summer months. The commercialization of the

Leblanc process The Leblanc process was an early industrial process for making ''soda ash'' ( sodium carbonate) used throughout the 19th century, named after its inventor, Nicolas Leblanc. It involved two stages: making sodium sulfate from sodium chloride, fol ...

for synthesizing sodium carbonate (from salt,

limestone Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science) ...

, and

sulfuric acid Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid (English in the Commonwealth of Nations, Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen, ...

) brought an end to the era of farming for soda ash in the first half of the 19th century.

Cultivation and culinary uses

The Italian name ''agretti'' is commonly used in English to refer to the edible leaves of ''S. soda''; ''barba di frate'' (or friar's beard) is the most common of the Italian names. This plant is not a summer green and should be started early indoors or in autumn. The seed is notorious for poor

germination Germination is the process by which an organism grows from a seed or spore. The term is applied to the sprouting of a seedling from a seed of an angiosperm or gymnosperm, the growth of a sporeling from a spore, such as the spores of fungi, ...

at about 30 to 40% standard, much like

rosemary ''Salvia rosmarinus'' (), commonly known as rosemary, is a shrub with fragrant, evergreen, needle-like leaves and white, pink, purple, or blue flowers. It is a member of the sage family, Lamiaceae. The species is native to the Mediterranean r ...

. Though the plant is often grown in saltwater-irrigated land in the Mediterranean Basin, it will grow without salt water. ''S. soda'' is harvested in bunches when small, or cropped regularly to encourage new growth when mature. It is most commonly boiled and eaten as a leafy vegetable; the recommendation is to cook it in boiling water until the leaves soften, and to serve while some bite (crunch) remains (much like samphire). It can also be eaten raw; it is said to taste "grassy and slightly salty with a pleasant, crunchy texture". ''Salsola soda'' is sometimes confused with a plant known in Japan as ''okahijiki'' (land seaweed), which is actually the species '' S. komarovii''. The harvested leaves of the two species have a similar appearance.

Phytoremediation

''Salsola soda'' has also been studied as a

bioremediation Bioremediation broadly refers to any process wherein a biological system (typically bacteria, microalgae, fungi in mycoremediation, and plants in phytoremediation), living or dead, is employed for removing environmental pollutants from air, wate ...

"biodesalinating companion plant" for crops such as tomatoes and peppers when they are grown in saline soils. The ''Salsola soda'' extracts enough sodium from the soil to improve the growth of the crop plant, and better crop yields result despite the competition of the two plants for the remaining minerals from the soil.

References

External links

* *
PLANTS Profile for ''Salsola soda''.
Natural Resources Conservation Service, United States Department of Agriculture. Retrieved 3 November 2006. *Excellen
gallery of photographs
of ''Salsola soda'' (''soude commune'') from Bouches du Rhône region of France. From ''Banque de données Botaniques et Ecologiques'', Universite Aix-Marseille, France. Retrieved 30 November 2006.
''Salsola soda''
listing at website ''Plants for a Future'' (http://www.pfaf.org). Retrieved 7 December 2006. {{Taxonbar, from=Q54932224, from2=Q2713171 Leaf vegetables Amaranthaceae Halophytes Industrial history Phytoremediation plants Plants described in 1753 Taxa named by Carl Linnaeus Barilla plants Flora of Malta