Ipomoea aquatica | |
---|---|
Scientific classification | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Clade: | Angiosperms |
Clade: | Eudicots |
Clade: | Asterids |
Order: | Solanales |
Family: | Convolvulaceae |
Genus: | Ipomoea |
Species: | I. aquatica |
Binomial name | |
Ipomoea aquatica | |
Ipomoea aquatica, widely known as water spinach, is a semi-aquatic, tropical plant grown as a vegetable for its tender shoots. I. aquatica is generally believed to have been first domesticated in Southeast Asia. It is widely cultivated in Southeast Asia, East Asia, and South Asia. It grows abundantly near waterways and requires little to no care. [2]
Ipomoea aquatica grows in water or on moist soil. Its stems are 2–3 metres (7–10 ft) or longer, rooting at the nodes. The hollow cavity within the stem makes the plant buoyant. The leaves vary from typically sagittate (arrowhead-shaped) to lanceolate, 5–15 cm (2–6 in) long and 2–8 cm (0.8–3 in) broad. The flowers are trumpet-shaped, 3–5 cm (1–2 in) in diameter, and usually white in colour with a mauve centre. Propagation is either by planting cuttings of the stem shoots, which will root along nodes, or by planting the seeds from flowers that produce seed pods. [3] [4]
Ipomoea aquatica is most widely known as kangkong (also spelled kangkung), its common name in Maritime Southeast Asia, which likely originates from either Malay or one of the languages of the Philippines. [2] It is also known as water spinach, river spinach, water morning glory, water convolvulus, or by the more ambiguous names Chinese spinach, Chinese watercress, Chinese convolvulus or swamp cabbage. It is known as kōngxīncài (空心菜) in Mandarin, ong choy (蕹菜) in Cantonese and in Hawaii, and tung choi (通菜) in modern Cantonese. [5] [6] In Tamil–speaking parts of South India and Sri Lanka, this spinach is known as vallal (வள்ளல்), In Vietnamese, this spinach is called rau muống. In Bengali, it is called Burma saag (বর্মা শাক) (Burma is another term for the country of Myanmar). In Thai it is known as pak bung.
The origin of Ipomoea aquatica is not quite clear, but it is generally believed to be native to Southeast Asia and was first cultivated there. This is supported by phylogenetic studies, its ideal climatic conditions, and the number of native pathogens in the region (like Albugo spp.); as well as its predominant cultivation range, the prevalence in usage as food and traditional medicine, and the number of distinct native names in Southeast Asian languages and language families. [2] [7]
Several sources have also cited China or India as the location of the plant's domestication. [8] [9] [10] [7] [11] [12] [13] However, these claims have no supporting evidence other than the appearance of the plant's name in historical records. The first clear mention of I. aquatica in Chinese records is in the Nanfang Caomu Zhuang written by the Chinese botanist Ji Han (AD 263-307). Ji Han specifically identifies I. aquatica as being "a strange vegetable of the south" with a foreign origin brought over by "western countries". The claim for an Indian origin is based on the presence of the old name kalamba for the plant in Sanskrit, presumed to be from around 200 BC, but this is putative. [2]
Ipomoea aquatica is also found in Africa, the southwestern Pacific Islands, and northern Australia. However, in Africa and the Pacific Islands, the number of native common names isn't as varied as in Southeast Asia, and there are very few references to the local use of I. aquatica for any purpose. Similarly, in Australia, it does not have indigenous names at all and is entirely absent in the traditional diet of Indigenous Australians. These imply that I. aquatica weren't native to these regions and were likely introduced relatively late from tropical Asia. [2]
Nutritional value per 100 g (3.5 oz) | |||||||||||||||||||||||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Energy | 79 kJ (19 kcal) | ||||||||||||||||||||||||||||||||||||||||||||
3.14 g | |||||||||||||||||||||||||||||||||||||||||||||
Dietary fiber | 2.1 g | ||||||||||||||||||||||||||||||||||||||||||||
0.2 g | |||||||||||||||||||||||||||||||||||||||||||||
2.6 g | |||||||||||||||||||||||||||||||||||||||||||||
| |||||||||||||||||||||||||||||||||||||||||||||
†Percentages estimated using US recommendations for adults, [14] except for potassium, which is estimated based on expert recommendation from the National Academies. [15] |
Many of the waters where water spinach grows are fed by domestic or other waste. Pigs in southeast Asia are a natural reservoir for the parasite Fasciolopsis buski . Infections in the Mekong regions resulted from feeding on water spinach. Infections of F. buski in humans through water spinach can be anticipated. The infection can be prevented by proper preparation such as frying or boiling. [16] Contamination with thermotolerant coliforms (ThC) or protozoan parasites with fecal origin, are very likely when the water spinach is planted in wastewater fed urban systems. [17] Water spinach has great potential as a purifier of aquatic habitats. It is an efficient accumulator of cadmium, lead, and mercury. This characteristic can be dangerous if water spinach is planted for human or animal feed in polluted aquatic systems. Mercury in water spinach is composed mostly as methylmercury and has the highest potential of becoming a threat to human health. The edible parts of the plant have a lower heavy metal concentration. The stems and bottom of the edible portion of the plant are higher in concentration and should be removed to minimize the heavy metal intake. [18] [19]
The vegetable is a common ingredient in East, South and Southeast Asian dishes, such as in stir-fried water spinach. [20] In Singapore, Indonesia, and Malaysia, the tender shoots along with the leaves are usually stir-fried with chili pepper, garlic, ginger, dried shrimp paste ( belacan / terasi ) and other spices. In Penang and Ipoh, it is cooked with cuttlefish and a sweet and spicy sauce. Also known as eng chhai in the Hokkien dialect, it can also be boiled with preserved cuttlefish, then rinsed and mixed with spicy rojak paste to become jiu hu eng chhai. Boiled eng chhai also can be served with fermented krill noodles – belacan bihun – and prawn mi. [21]
In Burmese cuisine, water spinach is the primary ingredient in a Burmese salad called gazun ywet thoke (ကန်စွန်းရွက်သုပ်), made with blanched water spinach, lime juice, fried garlic and garlic oil, roasted rice flour and dried shrimp. [22]
In Indonesian cuisine it is called kangkung; boiled or blanched together with other vegetables it forms the ingredient of gado-gado or pecel salads in peanut sauce. Some recipes that use kangkung include plecing kangkung from Lombok, mie kangkung (kangkong noodles) from Jakarta, and petis kangkung from Semarang. [23]
In Thailand, where it is called phak bung (Thai: ผักบุ้ง), it is eaten raw, often along with green papaya salad or nam phrik , in stir-fries and in curries such as kaeng som . [24]
In the Philippines, where it is called kangkóng, the tender shoots are cut into segments and cooked, together with the leaves, in fish and meat stews, such as sinigang . The vegetable is also commonly eaten alone. In adobong kangkóng (also called apan-apan), it is sautéed in cooking oil, onions, garlic, vinegar, and soy sauce. [25] In ensaladang kangkóng (or kinilaw na kangkóng), it is blanched and served in vinegar or calamansi juice and fresh tomatoes and onions with salt and pepper to taste. [26] [27] In binagoongang kangkóng (or ginisang kangkóng), it is sautéed with garlic and topped with bagoong alamang (shrimp paste) or bagoong isda (fermented fish) and sliced fresh tomatoes and onions, commonly also with cubed crispy liempo (pork belly) or pork adobo. It can also be spiced with siling haba or siling labuyo peppers, soy sauce, black pepper, and sugar. It differs from adobong kangkóng in that it does not use vinegar. [28] [29] [30] [31] A local appetiser called crispy kangkóng has the leaves coated in a flour-based batter and fried until crisp, similar to Japanese vegetable tempura. [32] [33]
Using aquatic macrophytes to remove nutrients from wastewater and to control freshwater eutrophication has been reported to be a feasible way of phytoremediation. Various plants, including I. aquatica, have been tested for this use. Owing to its being edible and thus marketable, it could be an attractive option for this use. [35]
Water spinach is fed to livestock as green fodder with high nutritive value—especially the leaves, for they are a good source of carotene. It is fed to cattle, pigs, fish, ducks, and chicken. [36] In limited quantities, I. aquatica can have a somewhat laxative effect. [2]
I. aquatica is used in the traditional medicine of southeast Asia and in the traditional medicine of some countries in Africa. In southeast Asian medicine it is used against piles, and nosebleeds, as an anthelmintic, and to treat high blood pressure. In Ayurveda, leaf extracts are used against jaundice and nervous debility. [37] In indigenous medicine in Sri Lanka, water spinach is supposed to have insulin-like properties.
Dr. Christophe Wiart cites several promising studies showing improvements in blood glucose levels in humans and rats and concludes that clinical trials are warranted. [38]
Antioxidant bioactive compounds and anti-microbial substances can be detected in water spinach. [39] Furthermore, plant extracts of water spinach inhibit cancer cell growth of Vero, Hep-2 and A-549 cells, though they have moderate anti-cancer properties. [37]
Ipomoea aquatica is most commonly grown in east, south, and southeast Asia. It flourishes naturally in waterways, and requires little if any care. It is used extensively in Indonesian, Burmese, Thai, Lao, Cambodian, Malay, Vietnamese, Filipino, and Chinese cuisine, especially in rural or kampung (village) areas. The vegetable is also extremely popular in Taiwan, where it grows well. During the Japanese occupation of Singapore in World War II, the vegetable grew remarkably easily in many areas, and became a popular wartime crop.
Water spinach has been found to be cultivated in the following countries: [2] [40]
In the United States it is cultivated in California, Florida, Hawaii, Texas, Arizona, and the U.S. Virgin Islands. [41] It is also found in Africa and in its wild form, is collected and used by the Sambaa people in Tanzania. [2] [42]
Water spinach is also potentially suitable for cultivation in greenhouses in more temperate regions. [40]
In non-tropical areas, it is easily grown in containers given enough water in a bright sunny location. It readily roots from cuttings.[ citation needed ]
Water spinach is ideal for sub-tropical and tropical climate, as it does not grow well below 23.9 °C (75.0 °F) and is sensitive to frost. High soil moisture is beneficial for growth. Clay soils and marshy soils rich in organic matter are suitable for water spinach. The ideal pH range for the growth is from 5 to 7. The provision of shade has been shown to have a positive influence on the yield of water spinach. [36]
Water spinach is cultivated in a variety of systems. In Hong Kong, two methods are traditionally used: the dryland method and the wetland method.
In the dryland method, water spinach is grown on raised beds which are separated by irrigation ditches. The seeds can be sown directly onto the beds. Alternatively, a nursery may be used and the seedlings are transplanted when they reach a sufficient size. In either case, the distance between the plants should be about 12 centimetres (4.7 in) by the time they are 15 centimetres (5.9 in) tall. Regular irrigation is crucial in the dryland system and so is sufficient fertilization. Water spinach cultivated with the dryland method is ready for harvest 50 to 60 days after sowing. Harvesting is done by pulling up the whole plant. [43]
The wetland method is the traditionally more common and important method for cultivation in Hong Kong: In the wetland method, water spinach is cultivated on flat fields surrounded by raised banks, which have oftentimes been used as rice paddies in the past. These former rice paddies have a heavy clay soil with an iron-pan. This helps to retain water for the water spinach. The seedlings to be used in this method are usually grown in a nursery on a dry field, as germination under water is quite poor. Six weeks after sowing, cuttings can be taken from the seedlings for transplantation. One cutting is an approximately 30 centimetres (12 in) long cut from the stem containing seven or eight nodes. This is then planted in the field with a spacing of about 40 centimetres (16 in). The field is prepared beforehand by flooding it to a depth of 3 to 5 centimetres (1.2 to 2.0 in). The soil itself is tramped into a liquid mud so that the cuttings can root easily. Once the plants are established, the depth of the flooding is increased to 15 to 20 centimetres (5.9 to 7.9 in). The first harvest in the wetland method can usually be done at around 30 days after transplantation. Also, the harvesting differs from the dryland system: In the wetland, the upper part of the main shoot is cut at about water level. This stimulates lateral growth and produces horizontal shoots carrying vertical branches. After the first harvests, every seven to ten days throughout the summer, these vertical branches can be harvested. After the planting period, the fields are drained and once the fruit of the water spinach is ripe, it is harvested, dried, then trodden to release the seeds which are to be used for the following season. [43]
How much fertilizer is used for the cultivation strongly depends on the region. Most research is from the 1980s and 1990s. Generally, it has been shown that a dose of 60 kilograms (130 lb) N/ha is sufficient and that the application of K can be beneficial on the yield. Also, the application of plant growth regulators, for example Adenine and Zetanine,[ clarification needed ] has been found to be an effective means to promote water spinach growth. One study has determined, that the highest yields are produced with the application of 60 kg/ha of N, 90 kg/ha of P2O5 and 50 kg/ha of K2O for the first harvest. For the second harvest the optimal fertilization was determined as 120 kg/ha of N, 45 kg/ha of P2O5 and 100 kg/ha of K2O. [36]
Taiwan: In Taiwan, the usual fertilization includes the basic application of about 10 t/ha of cow manure followed by 50 kg/ha of ammonium sulfate after each harvest. [36]
Bangkok: In Bangkok, it is common to apply about 300 kg/ha of NPK fertilizer twice a month. [36]
Indonesia: In Indonesia, usually 150 kg to 300 kg of NPK are applied per hectare. [36]
There are several pathogens and pests reported, affecting I. aquatica. Pathogens include Pythium , causing problems like damping-off, Cercospora leaf spot and root nematodes. [11] Also, aphids may be problems in fields. Additionally, there are several polyphagous insects feeding on I. aquatica. Lepidoptera species include Diacrisia strigatula Walker and Spodoptera litura. The "woolly-bear" caterpillars (D. virginica [Fabricius]) of the eastern United States and D. strigatula (Chinese tiger moth) are other species with wide food preferences. [44] A specialist pathogen on I. aquatica is the oomycete Albugo ipomoeae-aquaticae, though its range is restricted to southern and southeast Asia. [2]
Ipomoea aquatica is listed by the USDA as a noxious weed, [45] especially in the states of Florida, California, and Hawaii, where it can be observed growing in the wild. [46] In the US, water spinach has mainly become a problem in Florida; why is unclear although the fast growth rate has been cited as a threat to native plants in certain areas of Florida. [47] It could be owing to the time since introduction, or owing to climatic factors. [43] I. aquatica has been extensively cultivated in Texas for over 30 years, having been originally brought there by Asian immigrants. Because no evidence indicates the plant has escaped into the wild, Texas lifted its ban on cultivation for personal use with no restrictions or requirements, noting its importance as a vegetable in many cultures, and also began permitting cultivation for commercial sales with the requirement of an exotic species permit. [48] Possession of I. aquatica has been prohibited in Florida since 1973, but it is still being grown and sold illegally. Some of the infestations in Florida public lakes have been eradicated, or at least attempts have been made. [49] In Sri Lanka it invades wetlands, where its long, floating stems form dense mats which can block the flow of water and prevent the passage of boats. [50]
The sweet potato or sweetpotato is a dicotyledonous plant that belongs to the bindweed or morning glory family, Convolvulaceae. Its large, starchy, sweet-tasting tuberous roots are used as a root vegetable. The young shoots and leaves are sometimes eaten as greens. Cultivars of the sweet potato have been bred to bear tubers with flesh and skin of various colors. Sweet potato is only distantly related to the common potato, both being in the order Solanales. Although darker sweet potatoes are often referred to as "yams" in parts of North America, the species is even more distant from the true yams, which are monocots in the order Dioscoreales.
Morning glory is the common name for over 1,000 species of flowering plants in the family Convolvulaceae, whose current taxonomy and systematics are in flux. Morning glory species belong to many genera, some of which are:
Momordica charantia is a tropical and subtropical vine of the family Cucurbitaceae, widely grown in Asia, Africa, and the Caribbean for its edible fruit. Its many varieties differ substantially in the shape and bitterness of the fruit.
Saag also spelled sag or saga, is a Indian Cuisine leafy vegetable dish eaten with bread, such as roti or naan, or in some regions with rice. Saag can be made from mustard greens, collard greens, basella or finely chopped broccoli along with added spices and sometimes other ingredients, such as chhena.
Chayote or Sicyos edulis, also known as christophine, mirliton and choko, is an edible plant belonging to the gourd family, Cucurbitaceae. This fruit was first cultivated in Mesoamerica between southern Mexico and Honduras, with the most genetic diversity available in both Mexico and Guatemala. It is one of several foods introduced to the Old World during the Columbian Exchange. At that time, the plant spread to other parts of the Americas, ultimately causing it to be integrated into the cuisine of many Latin American nations.
Basella alba is an edible perennial vine in the family Basellaceae. It is found in tropical Asia and Africa where it is widely used as a leaf vegetable. It is native to the Indian subcontinent, Southeast Asia and New Guinea. It is naturalized in China, tropical Africa, Brazil, Belize, Colombia, the West Indies, Fiji and French Polynesia.
Taro is a root vegetable. It is the most widely cultivated species of several plants in the family Araceae that are used as vegetables for their corms, leaves, stems and petioles. Taro corms are a food staple in African, Oceanic, East Asian, Southeast Asian and South Asian cultures. Taro is believed to be one of the earliest cultivated plants.
Chinese spinach can mean any of several plants grown as leaf vegetables in China :
Shrimp paste or prawn sauce is a fermented condiment commonly used in Southeast Asian and Coastal Chinese cuisines. It is primarily made from finely crushed shrimp or krill mixed with salt, and then fermented for several weeks. It is sold either in its wet form or sun-dried and either cut into blocks or sold in bulk. It is an essential ingredient in many curries, sauces and sambal. Shrimp paste can be found in many meals in Cambodia, Indonesia, Laos, Malaysia, Myanmar, the Philippines, Singapore, Thailand, and Vietnam. It is often an ingredient in dip for fish or vegetables.
The generic term for condiments in the Filipino cuisine is sawsawan. Unlike sauces in other Southeast Asian regions, most sawsawan are not prepared beforehand, but are assembled on the table according to the preferences of the diner.
Moringa oleifera is a fast-growing, drought-resistant tree of the family Moringaceae, native to the Indian subcontinent and used extensively in South and Southeast Asia. Common names include moringa, drumstick tree, horseradish tree, or malunggay.
Sayur asem or sayur asam is an Indonesian vegetable soup. It is a popular Southeast Asian dish originating from Sundanese cuisine, consisting of vegetables in tamarind soup.
Nasi pecel also known as Sega pecel in Javanese is an Indonesian rice dish from Java served with pecel. The vegetables are usually kangkung or water spinach, long beans, cassava leaves, papaya leaves, and in East Java often used kembang turi. It is often eaten with fried tempeh and traditional crackers called peyek. It is popular in East and Central Java.
Bamboo shoots or bamboo sprouts are the edible shoots of many bamboo species including Bambusa vulgaris and Phyllostachys edulis. They are used as vegetables in numerous Asian dishes and broths. They are sold in various processed shapes and are available in fresh, dried, and canned versions.
Tauco, Taucu, Taotjo, Tao Jiew or Tauchu is a paste made from preserved fermented yellow soybeans in Chinese Indonesian, Malaysian and Thai cuisines. Tauco is made by boiling yellow soybeans, grinding them, mixing them with flour, and fermenting them to make a soy paste. The soy paste is soaked in salt water and sun-dried for several weeks, furthering the fermentation process, until the color of the paste has turned yellow-reddish. Good tauco has a distinct aroma. The sauce is also commonly used in other Indonesian cuisine traditions, such as Sundanese cuisine and Javanese cuisine. Taucu is generally used in cooking by Chinese Malaysians, Singaporeans, Bruneians, and Thais.
Limnocharis flava is a species of aquatic flowering plant which is native to Mexico, Central America, South America, Cuba, Haiti and the Dominican Republic but widely naturalized in southern and southeastern Asia: India, Sri Lanka, Cambodia, Burma, Thailand, Vietnam, Indonesia, Malaysia, Brunei and southern China.
Plecing kangkung is an Indonesian spicy water spinach dish from the island of Bali and Lombok. Plecing kangkung is made from blanched water spinach leaves and served cold with plecing sambal made from ground red chili pepper, shallot, garlic, bird's eye chili, candlenut, kaffir lime, shrimp paste, salt, and sugar. As a side for the Lomboknese dish ayam taliwang and Balinese dish ayam betutu, plecing kangkung is also usually served with additional ingredients such as bean sprouts, string beans, fried peanuts, and urap's grated spicy coconut dressing.
Stir-fried water spinach is a common Asian vegetable dish, known by various names in Asian languages. Water spinach is stir-fried with a variety of vegetables, spices, and sometimes meats. It is commonly found throughout East, South and Southeast Asia; from Sichuan and Cantonese cuisine in China, to Indonesian, Burmese, Cambodian, Filipino, Malaysian, Singaporean, Taiwanese, and Vietnamese cuisine; to Sri Lankan cuisine and Bengali cuisine in South Asia.
Binagoongan is a Filipino cooking process consisting of vegetables or meat sautéed or braised in bagoong alamang, garlic, black peppercorns, and bay leaves. Some recipes also add pineapples, chilis, or coconut cream to balance the flavors. The dish is characteristically quite salty with a strong umami flavor, which is why it is always paired with white rice and never eaten on its own. It is very similar to pinatisan which is cooked with patis, one of the by-products of fermenting bagoong.
{{cite web}}
: CS1 maint: archived copy as title (link){{cite web}}
: CS1 maint: bot: original URL status unknown (link)