Tuberous wood sorrel
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Tuberous wood sorrel ( Oxalis tuberosa ) |
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| Oxalis tuberosa | ||||||||||||
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The tuberous wood sorrel ( Oxalis tuberosa ), also known as Oka , Yam or Peruvian wood sorrel , is a species of wood sorrel ( Oxalis ) from the family of wood sorrel plants (Oxalidaceae).
description
The tuberous wood sorrel is a perennial , succulent , herbaceous plant . The roots form highly branched rhizomes , the tips of which swell into fleshy tubers . The tubers are about 4 × 3 cm, white, green, orange, pink, or red, and covered with small triangular scales. The upright or prostrate, fleshy twigs reach up to 30 cm in length and 1 cm in diameter. They are dark green to purple in color and densely covered with downy hairs. The somewhat translucent petioles are spread out and 7 to 10 cm long. The leaves are divided into three fleshy leaves. These are inverted heart-shaped, about 25 × 22 mm in size, green to purple and have downy hair at least on the underside.
The inflorescences appear terminally as five to eight-fold umbels . The yellow flowers on 15 to 17 cm long stems are up to 2 cm in diameter.
The number of chromosomes is 2n = 64.
distribution
The exact origin of the species is no longer verifiable. Presumably it comes from Colombia , but is widespread as a cultivated and useful plant from Venezuela to Bolivia and especially in the high Andes of Peru .
Systematics
As a result of the intensive cultivation of the species , probably over a thousand years , many varieties have emerged. With the aim of producing larger, more nutritious and tastier tubers, little emphasis was placed on the flowers of the plants during breeding , so that varieties were created that are no longer blooming today and can only be propagated via the tubers. In particular, the varieties with yellow and red tubers are sterile . In many varieties, the set of chromosomes also deviates significantly from normal. So are diploid , triploid , tetraploid , hexaploid and aneuploid varieties known.
Cultivation and Use
| fresh | dried | |
| Energy (J) | 255 | 1360 |
| Water (g) | 84.1 | 15.3 |
| Proteins (g) | 1.0 | 4.3 |
| Carbohydrates (g) | 13.3 | 75.4 |
| Ash (g) | 1.0 | 3.9 |
| Calcium (mg) | 2 | 52 |
| Phosphorus (mg) | 36 | 171 |
| Iron (mg) | 1.6 | 9.9 |
| Retinol (µg) | 1 | 0 |
| Riboflavin (mg) | 0.13 | 0.08 |
| Niacin (mg) | 0.43 | 0.85 |
| Vitamin C (mg) | 38.4 | 2.4 |
As a food , the species is of regional importance in the Andes. As Apilla or Ibia , it is grown there by highland Indians . The main cultivation areas are at an altitude of 3,500 to 3,800 m above sea level. According to estimates, the cultivation area in Peru is around 20,000 hectares. 3 to 12 tons are produced per hectare per year. However, cultivars should produce a yield of up to 97 t per hectare and year.
Young leaves and sprouts contain oxalic acid , which gives them their sour taste, usually only in small quantities, so that they can be used as a salad or vegetable . The tubers contain significantly less oxalic acid, but instead contain starch and larger amounts of vitamin C , see table.
In New Zealand , where the species was planted as early as 1860, it has gained importance as a starch supplier and is relatively widespread. It is called yam there , although it is not to be confused with yams, also called yams.
The tuberous wood sorrel was introduced to Europe as early as the 19th century, but has only been able to establish itself in agriculture to a limited extent. Nowadays it is only by lovers used horticulturally. The cultivation is basically the same as for potatoes : The tubers are planted around March to April, depending on the climate. An ideal location is sunny but rather cool and moist. During the growth phase, like with potatoes, you can pour some soil towards the plant; this supports the formation of tubers and prevents the tubers from becoming "green" by sunlight. The harvest takes place (other than potatoes) after the first frost. Since the tuberous wood sorrel is a short-day plant , it forms the tubers in autumn. Because of the short time to grow, the tubers stay quite small here. If they are kept cool and dry, they can be stored until the next spring. Left to their own devices, the above-ground parts of the plants die in winter and sprout again from the tubers in spring.
literature
- W. Franke: Nutzpflanzenkunde , Stuttgart 1985
- H. Marzell: Morphology of Useful Plants , Heidelberg 1970
- Simon Hickmott: Growing Unusual Vegetables , Ecological Books 1999 ISBN 1-899233-11-3
- Ben-Erik van Wyk: Food Plants of the World , Timber Press 2005 ISBN 978-0-88192-743-6
- BR Trognitz & M. Hermann: Inheritance of tristyly in Oxalis tuberosa (Oxalidaceae) , Heredity 86 (5): 564-573, 2001
- Eve Emshwiller & Jeff J. Doyle: Origins of domestication and polyploidy in oca (Oxalis Tuberosa: Oxalidaceae). 2. Chloroplast-expressed glutamine synthetase data , American Journal of Botany 89: 1042-1056, 2002
- Eve Emshwiller: Biogeography of the Oxalis tuberosa Alliance , The Botanical Review 68 (1): 128–152, 2002
- Daniel de Azkue & Arturo Martínez: Chromosome number of the Oxalis tuberosa alliance (Oxalidaceae) , Plant Systematics and Evolution 169 (1-2): 25-29, 1990
Individual evidence
- ↑ Oxalis tuberosa at Tropicos.org. In: IPCN Chromosome Reports . Missouri Botanical Garden, St. Louis
