''Arthrocaulon macrostachyum'',

synonym A synonym is a word, morpheme, or phrase that means exactly 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 all ...

''Arthrocnemum macrostachyum'', is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

of flowering plant in the amaranth family. It is native to coastal areas of the

Mediterranean Sea The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the ea ...

and the

Red Sea The Red Sea ( ar, البحر الأحمر - بحر القلزم, translit=Modern: al-Baḥr al-ʾAḥmar, Medieval: Baḥr al-Qulzum; or ; Coptic: ⲫⲓⲟⲙ ⲛ̀ϩⲁϩ ''Phiom Enhah'' or ⲫⲓⲟⲙ ⲛ̀ϣⲁⲣⲓ ''Phiom ǹšari''; T ...

and parts of the

Middle East The Middle East ( ar, الشرق الأوسط, ISO 233: ) is a geopolitical region commonly encompassing Arabian Peninsula, Arabia (including the Arabian Peninsula and Bahrain), Anatolia, Asia Minor (Asian part of Turkey except Hatay Pro ...

, where it grows in coastal and inland

salt marsh A salt marsh or saltmarsh, also known as a coastal salt marsh or a tidal marsh, is a coastal ecosystem in the upper coastal intertidal zone between land and open saltwater or brackish water that is regularly flooded by the tides. It is dominated ...

es,

alkali flats A dry lake bed, also known as a playa, is a basin or depression that formerly contained a standing surface water body, which disappears when evaporation processes exceeds recharge. If the floor of a dry lake is covered by deposits of alkaline c ...

, and other habitats with

saline soils Soil salinity is the salt content in the soil; the process of increasing the salt content is known as salinization. Salts occur naturally within soils and water. Salination can be caused by natural processes such as mineral weathering or by the ...

Description

''Arthrocaulon macrostachyum'' is a much-branched

subshrub A subshrub (Latin ''suffrutex'') or dwarf shrub is a short shrub, and is a woody plant. Prostrate shrub is a related term. "Subshrub" is often used interchangeably with "bush".Jackson, Benjamin, Daydon; A Glossary of Botanic Terms with their Der ...

growing in clumps up to a metre high (3 ft). The plants have horizontal woody stems that may root at the nodes, branching into erect, jointed, succulent green stems. The

leaves A leaf (plural, : leaves) is any of the principal appendages of a vascular plant plant stem, stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", wh ...

are small and scale-like, clasping the stem but with the tips free. The flowers are minute, produced in threes in terminal, cylindrical spikes. The

perianth The perianth (perigonium, perigon or perigone in monocots) is the non-reproductive part of the flower, and structure that forms an envelope surrounding the sexual organs, consisting of the calyx (sepals) and the corolla (petals) or tepals when ...

is conical and has three teeth. The

hermaphrodite In reproductive biology, a hermaphrodite () is an organism that has both kinds of reproductive organs and can produce both gametes associated with male and female sexes. Many Taxonomy (biology), taxonomic groups of animals (mostly invertebrate ...

flower A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechani ...

s are wind-pollinated, and the

fruit In botany, a fruit is the seed-bearing structure in flowering plants that is formed from the ovary after flowering. Fruits are the means by which flowering plants (also known as angiosperms) disseminate their seeds. Edible fruits in particu ...

is small, has a membranous

pericarp Fruit anatomy is the plant anatomy of the internal structure of fruit. Fruits are the mature ovary or ovaries of one or more flowers. They are found in three main anatomical categories: aggregate fruits, multiple fruits, and simple fruits. Aggre ...

, and contains a single seed.

Distribution and habitat

''A. macrostachyum'' is found around the coasts bordering on the Mediterranean Sea and the Red Sea, and ranges northwards into the

Jordan Valley The Jordan Valley ( ar, غور الأردن, ''Ghor al-Urdun''; he, עֵמֶק הַיַרְדֵּן, ''Emek HaYarden'') forms part of the larger Jordan Rift Valley. Unlike most other river valleys, the term "Jordan Valley" often applies just to ...

. It is also present in the Middle East, including Iran and Pakistan, where it grows in the muddy coastal swamps immediately inland from the

mangroves A mangrove is a shrub or tree that grows in coastal saline or brackish water. The term is also used for tropical coastal vegetation consisting of such species. Mangroves are taxonomically diverse, as a result of convergent evolution in several ...

(''

Avicennia marina ''Avicennia marina'', commonly known as grey mangrove or white mangrove, is a species of mangrove tree classified in the plant family Acanthaceae (formerly in the Verbenaceae or Avicenniaceae). As with other mangroves, it occurs in the intertid ...

'') that border the coast. In the delta region of the Mediterranean coast of Egypt, it dominates some plant communities in the

habitats.

Research

In a study, plants of ''A. macrostachyum'' were germinated at six

sodium chloride Sodium chloride , commonly known as salt (although sea salt also contains other chemical salts), is an ionic compound with the chemical formula NaCl, representing a 1:1 ratio of sodium and chloride ions. With molar masses of 22.99 and 35.45 g ...

(NaCl) concentrations, and grew best at 200 to 400 mM NaCl. It was found that the plants were salt-tolerant and grew well at a range of salt concentrations. About 60% of their dry mass was ash, and the plants were capable of accumulating a substantial quantity of sodium and chlorine ions. The seeds of many

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. T ...

s germinate after rains which reduce the salinity levels of the soil surface layer. ''A. macrostachyum'' can germinate at salinity levels of at least 800 mM NaCl, and at even higher concentrations in the presence of added calcium ions. Research was undertaken into the remediation of oil-contaminated soil in the Persian Gulf. The marshland concerned was covered by an algal mat but was otherwise vegetation-free. The creation of drainage channels was followed by the return of

crab Crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" (abdomen) ( el, βραχύς , translit=brachys = short, / = tail), usually hidden entirely under the thorax. They live in all the ...

s to the affected areas close to the channels. They churned up the mud and increased the oxygen content, which was quickly followed by the germination of ''A. macrostachyum'', ''

Halocnemum strobilaceum ''Halocnemum strobilaceum'' is a species of flowering plant in the subfamily Salicornioideae of the family Amaranthaceae. It is native to coastal areas of the Mediterranean Sea and the Red Sea and parts of the Middle East and central Asia, where ...

'' and ''

Salicornia europaea ''Salicornia europaea'', known as common glasswort or just glasswort, is a halophyte, halophytic annual dicot flowering plant in the family Amaranthaceae. Glasswort is a succulent herb also known as ‘Pickle weed’ or ‘Samphire, Marsh samph ...

''. The crabs advanced into the polluted area at the rate of about one metre per year (3 ft), resulting in a gradual increase in the vegetated area. ''A. macrostachyum'' tolerates levels of

cadmium Cadmium is a chemical element with the symbol Cd and atomic number 48. This soft, silvery-white metal is chemically similar to the two other stable metals in group 12, zinc and mercury. Like zinc, it demonstrates oxidation state +2 in most of ...

in the soil that other plants find toxic. It can

bioaccumulate Bioaccumulation is the gradual accumulation of substances, such as pesticides or other chemicals, in an organism. Bioaccumulation occurs when an organism absorbs a substance at a rate faster than that at which the substance is lost or eliminated ...

the metal and play a role in the

phytoremediation Phytoremediation technologies use living plants to clean up soil, air and water contaminated with hazardous contaminants. It is defined as "the use of green plants and the associated microorganisms, along with proper soil amendments and agronomi ...

of sites contaminated by cadmium. The seeds of ''A. macrostachyum'' contain between 22% and 25% oil, with an unsaturated

fatty acid In chemistry, particularly in biochemistry, a fatty acid is a carboxylic acid with an aliphatic chain, which is either saturated or unsaturated. Most naturally occurring fatty acids have an unbranched chain of an even number of carbon atoms, fr ...

content of 65% to 74%, and are being investigated as a possible source of edible oil.

References

{{Taxonbar, from1=Q42682007, from2=Q3624240, from3=Q95936594 Amaranthaceae Plants described in 1853 Barilla plants Flora of Malta