Capparis spinosa (PROSEA)
Capparis spinosa L. var. mariana (Jacq.) K. Schumann
- Protologue: Bot. Jahrb. 9: 201 (1888).
- Family: Capparidaceae
- Chromosome number: 2n = 24, 38
- Capparis cordifolia Lamk (1785),
- C. mariana Jacq. (1797),
- C. sandwichiana DC. (1824).
- Mariana caper-bush, Mariana caper, caper (En).
- Câprier (Fr)
- Malaysia: melada
- Philippines: alcaparras.
Origin and geographic distribution
The well-known caper-bush (C. spinosa L.) is distributed from the Mediterranean through the Near East to India. It was introduced early in post-Columbian times as a cultigen into the Mariana Islands, from where it spread and naturalized in Polynesia and eastern Malesia, i.e. Indonesia (Lesser Sunda Islands), Papua New Guinea (New Ireland, New Britain) and the Philippines (Luzon, Bohol). Historical notes indicate that Mariana caper-bush was cultivated in Guam in the second half of the 18th Century. The flower buds were harvested, pickled and exported as capers in the same way as the well-known Mediterranean delicacy. The Indo-Pacific population is very uniform and has developed into a form (var. mariana) that is, taxonomically and geographically, distinct from other forms of C. spinosa not found between India and Timor (Indonesia). C. spinosa was also introduced into Australia, where it naturalized and developed into a distinct form too.
Commercial capers are the pickled flower buds of C. spinosa; they are used as a condiment. Capers derived from the south-European forms of the species have considerable economic importance in Mediterranean countries like France, Spain, Italy and northern Africa. The flower buds of the Indo-Pacific Mariana caper-bush (var. mariana) are used similarly, but Mariana caper-bush has lost importance in the Pacific and South-East Asia. Capers are characteristic of Mediterranean cuisine. They are used in salads, mayonnaise and other cold sauces. They keep their spicy taste during cooking, and combine well with grilled or stewed meat, and even better with fish. The pickled fruits are popular in southern France ("cornichons de câprier”) and in Italy ("caperone” or "taperone”). Capers have been approved for food use by the Food and Drug Administration (FDA) of the United States.
The caper-bush is also used in traditional medicine, but not in South-East Asia. The flower buds have a beneficial effect on lesions of the vascular system. Infusions or decoctions obtained from root bark are used for ailments like dropsy, anaemia, general atony and arthritis. In India, root bark is considered a purgative, tonic, diuretic, anthelmintic, emmenagogue and analgesic, and plant extracts are a common ingredient of hepatoprotective herbal drugs and traditional medicines such as Liv-52.
Production and international trade
Mariana caper-bush is still reportedly cultivated in some localities in Luzon (Philippines), but for some unknown reason its cultivation did not spread further into South-East Asia. At present, capers are mainly produced in southern Europe (France, Spain, Italy), where it has long been a specialty crop. The caper-bush has been introduced into other subtropical regions for adaptation trials, e.g. in California (United States) and Argentina. World production is estimated at a few thousand t.
The sharp taste of capers is similar to that of the mustards and horseradish (Capparidaceae and Cruciferae are closely allied). They have a similar effect as digestive stimulant. In capers the attractive flavour is caused by capric acid. Per 100 g edible portion, capers contain: water 79 g, protein 5.8 g, fat 1.6 g, carbohydrates 6.5 g, fibre 5.4 g, ash 1.6 g. Caper-bush contains rutin and a number of kaempferol- and quercetin-derived flavonoids. Yellow rutin crystals are present in small groups on the flower buds.
Adulterations and substitutes
Capers are expensive. Substitution by flower buds of other Capparis spp. may happen to a certain extent. In Europe true capers are sometimes adulterated with young flower buds of Caltha palustris L. (Ranunculaceae), Ficaria verna Huds. (Ranunculaceae), Sarothamnus scoparius (L.) Wimm. ex Koch (Leguminosae), Tropaeolum majus L. (Tropaeolaceae), with young fruits of Euphorbia lathyrus L. (Euphorbiaceae) and with young fruits of the caper plant itself.
- Shrub, up to 2 m tall, branches usually prostrate. Twigs terete, unarmed, with short, floccose, greyish indumentum which soon disappears.
- Leaves alternate, simple, glaucous; petiole 0.7-1.3 cm long; blade subfleshy when fresh, herbaceous when dried, ovate-elliptical to suborbicular, 1.5-7.5 cm × 2.5-5.5 cm, base truncate to rounded, apex rounded to obtuse, veins in 5-7 pairs.
- Flowers solitary, axillary, showy and fragrant; pedicel 4.5-7.5 cm long, glabrescent; buds conical when young, later bulging, ultimately 2-2.5 cm in diameter; calyx strongly zygomorphic, glabrescent, with sepals in 2 pairs, the posterior sepal deeply saccate, 2.5-4 cm × 1.7-2.5 cm, the other sepals subovate, 2-2.5 cm × 0.7-2.5 cm; petals 4, in 2 pairs, white, turning red-purplish, upper pair rhombic, 3-5.5 cm × 2-4 cm, with a thick fleshy base, lower pair 3-3.5 cm × 1.5-3.3 cm; stamens 100-190, 4.5-6 cm long, white to reddish; pistil on a 6-7 cm long gynophore which is hairy near the base.
- Fruit a berry with a thin, leathery to corky pericarp, ellipsoidal, 2.5-5 cm × 1.3-1.5 cm, olive-green with distinct ribs.
- Seeds numerous, subglobose, 4 mm in diameter, embedded in yellow fruit pulp.
Growth and development
Fresh seeds germinate readily, but germination of dried seeds is very erratic due to seed-coat-induced dormancy. The root system is very extensive and capable of penetrating deep in the soil. The xerophytic character of the caper-bush is a complex response to drought, involving osmotic adjustment, regulated stomatal opening, cell wall plasticity and increased root density. C3-physiology has been recorded for Capparis. Flowering starts about one year after sowing, is continuous but takes place only on one-year-old branches. Caper-bush is noctiflorous. Pollination is by insects. It begins producing after about one year, and reaches full production after 3-4 years. In southern Europe the commercial life-span is about 15 years, before it has to be replanted because of declining yields.
Other botanical information
C. spinosa is a widespread, polymorphic, complex species in which several distinct forms have developed that have been distinguished in the botanical literature as formas, varieties, subspecies or also often as species. There has been no comprehensive study of the whole complex. The typical, spiny variety (var. spinosa) occurs in the Mediterranean. Only var. mariana occurs in South-East Asia; it is characterized by the slightly tomentose, glabrescent, unarmed twigs, the relatively large and orbicular leaves without apical spine and very large flowers with one saccate sepal. In India and the western Himalayas var. himalayensis (Jafri) Jacobs occurs (twigs late glabrescent, petiole 2-7 mm long, gynophore 4.5-7 cm long). In Australia var. nummularia (DC.) F.M. Bailey developed from an introduction different from the one in South-East Asia (twigs sometimes with short spines, leaves suborbicular with petiole 6-9 mm long, gynophore up to 5 cm long and glabrous).
Capparis L. is a large pantropical genus of about 250 species, predominantly distributed in sunny, warm and dry habitats that have seasonal climates. There are about 40 species on mainland South-East Asia and about 20 species in Malesia. Some species are used as ornamentals (showy flowers), often in hedges (spines). Some species in South-East Asia have edible fruit pulp (C. buwaldae Jacobs, C. pyrifolia Lamk, and C. zeylanica L.) and some are used medicinally (C. micracantha DC., C. pyrifolia Lamk, C. sepiaria L. and C. zeylanica L.).
Mariana caper-bush is xerophytic and thrives under semi-arid or seasonal conditions. It occurs in the drier parts of South-East Asia in the lowlands, often along seashores, up to 350 m altitude. It grows well at temperatures over 40 °C and at an annual rainfall of 350 mm only. It is found on dry, well-drained sandy soils derived from lava or limestone. It is salt-tolerant. Other forms of C. spinosa grow and are cultivated under comparable conditions.
Propagation and planting
No specific information is available on the agronomy of var. mariana, but methods applied to the caper-bush in general probably apply. The caper-bush can be propagated by seed or by cuttings. In vitro propagation is also possible. Germination is promoted by chemical scarification of seeds in sulphuric acid. Seeds are sown a few cm deep in a seed-bed. Vegetative propagation by cuttings seems better suited to intensive cultivation, for reasons of homogeneity. Cuttings should be taken from vigorous branches with a diameter of over 1.5 cm. When sufficiently developed and rooted, seedlings or cuttings are transplanted to the field at spacings of 2-2.5 m × 2-2.5 m, resulting in densities of 1600-2500 plants/ha.
In the main production areas in southern Europe, mulching is recommended in the first year to ensure optimal rooting. Pruning is performed each winter to remove dead wood and water sprouts. The branches should be pruned severely as flowering takes place on one-year-old branches.
Diseases and pests
Little is known about diseases and pests of Mariana caper-bush. In intensive cultivation in the Mediterranean area, some diseases and pests have been observed but biocides are hardly applied.
Young flower buds are harvested at regular intervals of 8-12 days. Harvesting is very labour-intensive.
Annual yields of 1-3 kg of dried flower buds per plant, or 3-4 t/ha are reported from southern Europe.
Handling after harvest
Fresh buds are very bitter, dried ones are pleasantly spicy but quickly lose their aroma. Harvested buds are usually first kept in the dark for 3-4 hours and subsequently put into vinegar or salted vinegar. After 8 days they are removed from the vinegar, pressed and transferred to fresh vinegar, which process is repeated after another 8 days. Subsequently they are graded according to size by means of sieves, the smallest ones being the best quality (called "nonpareil” capers).
Genetic resources and breeding
The variability in var. mariana is rather small, which may be the result of a one-off introduction into the Indo-Pacific region. Institutional germplasm collections of C. spinosa are maintained in Italy and Spain. Caper-bush is predominantly outbreeding. The wide variability of the species as a whole offers good prospects for breeding programmes.
Although capers do not have a sizable clientele in South-East Asia at present, the food market in this region is expanding and absorbing many culinary specialties from around the world. Most communities in this region have a liking for pungent spices and also for pickles, so capers may find a footing. Due to the presence of Mariana caper-bush in the region, increased demand can be met by local production instead of relying on imports.
- Barbera, G. & Di Lorenzo, R., 1984. The caper culture in Italy (Capparis spinosa and Capparis ovata). Acta Horticulturae 144: 167-171.
- Higton, R.N. & Akeroyd, J.R., 1991. Variation in Capparis spinosa L. in Europe. Botanical Journal of the Linnean Society 106: 104-112.
- Jacobs, M., 1965. The genus Capparis (Capparaceae) from the Indus to the Pacific. Blumea 12: 385-541.
- Prashar, R. & Kumar, A., 1994. Chemopreventive action of Liv. 52 on DMBA-induced papillimagenesis in skin of mice. Indian Journal of Experimental Biology 32(9): 643-646.
- Rhizopoulou, S., 1990. Physiological responses of Capparis spinosa L. to drought. Journal of Plant Physiology 136(3): 341-348.
- Rodrigo, M., Lazaro, M.J., Alvarruiz, A. & Giner, V., 1992. Composition of capers (Capparis spinosa): influence of cultivar, size and harvest date. Journal of Food Science 57(5): 1152-1154.
- Sharaf, M., El-Ansari, M.E. & Saleh, N.A.M., 1997. Flavonoids of four Cleome and three Capparis species. Biochemical Systematics and Ecology 25(2): 161-166.
- Sozzi, G.O. & Chiesa, A., 1995. Improvement of caper (Capparis spinosa L.) seed germination by breaking seed coat-induced dormancy. Scientia Horticulturae 62(4): 255-261.
Sources of illustrations
Mansfeld, R., 1986. Verzeichnis landwirtschaftlicher und gärtnerischer Kulturpflanzen (ohne Zierpflanzen) [Register of agricultural and horticultural plants in cultivation (without ornamentals)]. Schultze-Motel, J. et al., editors 2nd edition. Vol. 1. Springer Verlag, Berlin, Germany. Fig. 48, p. 269 (habit flowering twig, fruit on gynophore); van Steenis, C.G.G.J. (Editor), 1960. Flora Malesiana. Series 1. Vol. 6. Wolters-Noordhoff Publishing, Groningen, the Netherlands. Fig. 23, p. 90 (flower bud). Redrawn and adapted by P. Verheij-Hayes.
- H.C. Ong & J.S. Siemonsma