''Eleocharis dulcis'', the Chinese water chestnut or water chestnut, is a grass-like

sedge The Cyperaceae are a family of graminoid (grass-like), monocotyledonous flowering plants known as sedges. The family is large, with some 5,500 known species described in about 90 genera, the largest being the "true sedges" genus '' Carex'' ...

native to

Asia Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an are ...

, tropical

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

, and

Oceania Oceania (, , ) is a geographical region that includes Australasia, Melanesia, Micronesia, and Polynesia. Spanning the Eastern and Western hemispheres, Oceania is estimated to have a land area of and a population of around 44.5 million ...

. It is grown in many countries for its edible

corm A corm, bulbo-tuber, or bulbotuber is a short, vertical, swollen underground plant stem that serves as a storage organ that some plants use to survive winter or other adverse conditions such as summer drought and heat (perennation). The word ' ...

s. The water chestnut is not a nut, but an aquatic vegetable that grows in marshes, under water, in the mud. It has stem-like, tubular green leaves that grow to about . The water caltrop, which also is referred to by the same name, is unrelated and often confused with the water chestnut. The small, rounded corms have a crisp, white flesh and may be eaten raw, slightly boiled, or grilled, and often are pickled or tinned. They are a popular ingredient in Chinese dishes. In China, they are most often eaten raw, sometimes sweetened. They also may be ground into a

flour Flour is a powder made by grinding raw grains, roots, beans, nuts, or seeds. Flours are used to make many different foods. Cereal flour, particularly wheat flour, is the main ingredient of bread, which is a staple food for many cul ...

form used for making water chestnut cake, which is common as part of '' dim sum'' cuisine. They are unusual among vegetables for remaining crisp even after being cooked or canned, because their

cell wall A cell wall is a structural layer surrounding some types of cells, just outside the cell membrane. It can be tough, flexible, and sometimes rigid. It provides the cell with both structural support and protection, and also acts as a filtering mec ...

s are cross-linked and strengthened by certain phenolic compounds, such as oligomers of ferulic acid. This property is shared by other vegetables that remain crisp in this manner, including the tiger nut, lotus root and spurge nettle root. The corms contain the antibiotic agent puchiin, which is stable to high temperature. Apart from the edible corms, the leaves can be used for cattlefeed, mulch or

compost Compost is a mixture of ingredients used as plant fertilizer and to improve soil's physical, chemical and biological properties. It is commonly prepared by decomposing plant, food waste, recycling organic materials and manure. The resulting ...

. If eaten uncooked, the surface of the plants may transmit fasciolopsiasis.

Ecology

In the dry season of the

Northern Territory The Northern Territory (commonly abbreviated as NT; formally the Northern Territory of Australia) is an Australian territory in the central and central northern regions of Australia. The Northern Territory shares its borders with Western Aust ...

Australia Australia, officially the Commonwealth of Australia, is a sovereign country comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands. With an area of , Australia is the largest country by ...

magpie geese The magpie goose (''Anseranas semipalmata'') is the sole living representative species of the family Anseranatidae. This common waterbird is found in northern Australia and southern New Guinea. As the species is prone to wandering, especially ...

eat the bulbs of water chestnuts, allowing them to put on fat for the wet season and ensuring they are ready for breeding. In the wet season, water chestnut leaves are used to build their floating nests.ECOS: Indigenous icon at risk from sea level rise.
Blogs,

CSIRO The Commonwealth Scientific and Industrial Research Organisation (CSIRO) is an Australian Government agency responsible for scientific research. CSIRO works with leading organisations around the world. From its headquarters in Canberra, CSIRO ...

. Retrieved 30 November 2011.

Nutrition

Raw water chestnuts are 74% water, 24%

carbohydrate In organic chemistry, a carbohydrate () is a biomolecule consisting of carbon (C), hydrogen (H) and oxygen (O) atoms, usually with a hydrogen–oxygen atom ratio of 2:1 (as in water) and thus with the empirical formula (where ''m'' may o ...

s, 1%

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, res ...

, and contain very little fat. In a 100-gram reference amount, raw water chestnuts supply of food energy, are rich (20% or more of the Daily Value, DV) in vitamin B₆ (25% DV), and contain moderate amounts of other B vitamins,

manganese Manganese is a chemical element with the Symbol (chemistry), symbol Mn and atomic number 25. It is a hard, brittle, silvery metal, often found in minerals in combination with iron. Manganese is a transition metal with a multifaceted array of ...

, and

potassium Potassium is the chemical element with the symbol K (from Neo-Latin '' kalium'') and atomic number19. Potassium is a silvery-white metal that is soft enough to be cut with a knife with little force. Potassium metal reacts rapidly with atmos ...

(10% to 17% DV, table).

Taste

Raw water chestnuts are slightly sweet and crunchy. Boiled water chestnuts have a firm and slightly crunchy texture, with a mild and slightly nutty flavor that may easily be overpowered by seasonings or sauces with which the water chestnut is served or cooked. They may be combined with bamboo shoots,

coriander Coriander (;

ginger Ginger (''Zingiber officinale'') is a flowering plant whose rhizome, ginger root or ginger, is widely used as a spice and a folk medicine. It is a herbaceous perennial which grows annual pseudostems (false stems made of the rolled bases of ...

, sesame oil, and snow peas. Steamed or sauteed vegetable dishes may contain water chestnuts, such as noodle or rice recipes. They may also be added to minced-meat fillings and dishes, such as Cantonese dim sum-style steamed meatballs, to add a crunchy texture. The Thai dessert '' thapthim krop'', with water chestnuts as its main ingredient, was named one of the world's best 50 desserts in 2019 by ''CNN Travel''.

Agronomic properties

Cultivation

The crop can be cultivated in paddies, wide by up to long to allow for mechanization, or in a hydroponic culture. As it is an aquatic plant, it should always be submerged in approximately of water. The crop needs continuously high soil temperatures, ideally . At , the corms begin to sprout. Soil is ideally a sandy loam with pH 6.5 to 7.2. The plant produces two types of subterranean rhizomes. Under long-daylength conditions, rhizomes grow horizontally and then turn upwards forming daughter plants. Under short-daylength conditions, the rhizomes grow downward and produce a

at the tip. The

photoperiod Photoperiodism is the physiological reaction of organisms to the length of night or a dark period. It occurs in plants and animals. Plant photoperiodism can also be defined as the developmental responses of plants to the relative lengths of light a ...

also significantly influences how fast the corms grow. Corms begin to develop much more slowly if the photoperiod exceeds 12 hours. The corms are also the propagating material. Alternatively, transplants can be used. Machinery such as tractor-mounted vegetable planters can be used for plantation.

Plant nutrition

Nitrogen addition is beneficial for corm production, applying a dose before planting and another dose when corms begin to enlarge. To further improve nutrient levels, potassium and phosphorus mineral

fertilizer A fertilizer (American English) or fertiliser (British English; see spelling differences) is any material of natural or synthetic origin that is applied to soil or to plant tissues to supply plant nutrients. Fertilizers may be distinct from ...

s can be used before planting, where the uptake ratio is . Also organic mulch, especially mushroom compost, shows good results.

Harvest

Once the corms turn dark brown, they should be harvested. If left in the soil after this point in time, corms will get sweeter, however shelf life will decline. The corms can be harvested using a modified gladiolus corm harvester once the paddy is drained. Alternatively, a "water-suction harvester" can be used without the need to drain the paddy. The corms have to be washed after harvest and brushed once they are dry.

Yield

The per plant yield was described at per season (fresh matter). In China, yields are reported between , while in the United States a range between has been mentioned.

Storage

The harvested corms are best stored at . At this temperature, transpiration and thus weight loss are minimized. This will also delay

sprouting Sprouting is the natural process by which seeds or spores germinate and put out shoots, and already established plants produce new leaves or buds, or other structures experience further growth. In the field of nutrition, the term signifies ...

and minimize deterioration resulting from small injuries. Corms should not be stored at temperatures above as otherwise the corms will begin to sprout. If the corms need to be stored longer term, they can also be kept in a

bleach Bleach is the generic name for any chemical product that is used industrially or domestically to remove color (whitening) from a fabric or fiber or to clean or to remove stains in a process called bleaching. It often refers specifically, to ...

solution of 1000ppm.

Pests

Chinese water chestnut is usually not very prone to pests; nevertheless, some animals and fungi may attack the plant: Water fowl may damage the stems and corms, especially when plants are young. Similarly,

rodent Rodents (from Latin , 'to gnaw') are mammals of the order Rodentia (), which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are rodents. They are n ...

s and grazing animals pose a threat to the Chinese water chestnut, which may be discouraged by keeping the paddy inundated. Caddisfly larvae (Trichoptera) and other leaf-eating

caterpillar Caterpillars ( ) are the larval stage of members of the order Lepidoptera (the insect order comprising butterflies and moths). As with most common names, the application of the word is arbitrary, since the larvae of sawflies (suborder Sy ...

s also feed on the stems. However, unless complete defoliation below the waterline occurs, the plants can normally tolerate this damage. Plant hoppers ( Fulgoridae) and

scale insect Scale insects are small insects of the order Hemiptera, suborder Sternorrhyncha. Of dramatically variable appearance and extreme sexual dimorphism, they comprise the infraorder Coccomorpha which is considered a more convenient grouping than th ...

s feed on plant sap and may cause subsequent death. Other pests include the

nematode The nematodes ( or grc-gre, Νηματώδη; la, Nematoda) or roundworms constitute the phylum Nematoda (also called Nemathelminthes), with plant- parasitic nematodes also known as eelworms. They are a diverse animal phylum inhabiting a bro ...

s '' Ditylenchus'' and '' Dolichodorus heterocephalus''. Fungal species can also attack the Chinese water chestnut. In warmer climates, a

rust Rust is an iron oxide, a usually reddish-brown oxide formed by the reaction of iron and oxygen in the catalytic presence of water or air moisture. Rust consists of hydrous iron(III) oxides (Fe2O3·nH2O) and iron(III) oxide-hydroxide (FeO( ...

is caused by '' Uromyces'', and '' Cylindrosporium eleocharidis'' causes stem

blight Blight refers to a specific symptom affecting plants in response to infection by a pathogenic organism. Description Blight is a rapid and complete chlorosis, browning, then death of plant tissues such as leaves, branches, twigs, or floral orga ...

References

External links

Porcher Michel H. et al. 1995 - 2020, Sorting Eleocharis Names. Multilingual Multiscript Plant Name Database - A Work in Progress. Institute for Land & Food Resources. The University of Melbourne (2004)
* {{Authority control dulcis Root vegetables Plants described in 1833 Taxa named by August Wilhelm Henschel Flora of Asia Flora of Africa Flora of Australia Freshwater plants Cormous plants Taxa named by Nicolaas Laurens Burman