Caper bush (Capparis spinosa): Introduction, Classification, Description, Propagation, Harvest and Processing, Economic Importance
Introduction
About 250 species of the genus Capparis can be found throughout the Old and New World’s tropical and subtropical climates. The polymorphic C. spinosa L. complex exhibits a broad palaeotropical and subtropical range. This plant, sometimes known as the Caper bush, is a perennial winter deciduous species that produces enormous white to pinkish blooms and rounded, fleshy leaves (Ramezani and Aghel, 2008). The two primary cultivars of capers are Capparis spinosa L. and Capparis ovata Desf (Kan and Arslan, 2004). Three subspecies of C. spinosa exist C. spinosa var. aegytia, C. spinosa var. spinosa, and C. spinosa var. inermis. C. spinosa was separated into two subspecies by Lam. Higton and Akeroyd: subspecies spinosa and subspecies rupestris (Sm) Nyman (Saadaoui et al. 2013). A caper plant typically grows 30 to 50 cm tall. C. spinosa, can grow to a height of 2.5 m and is found between 200 and 300 a.s.l (Kan and Arslan, 2004). The plant has a robust system of perennial roots. It can pierce the ground up to 40 metres deep (Olmez et al., 2004). The plant may grow in arid places as well. Spines can develop on leaf stipules. First-year branches bear flowers (Rivera et al., 2002; Yilmaz et al., 2002).
Classification
Kingdom: Plantae
Order: Brassicales
Family: Capparaceae
Genus: Capparis
Species: C. spinosa
Scientific Name: Capparis spinosa
Common Name(s): Caper bush, Flinders rose
Description
1. The perennial plant known as the Caper bush, or Capparis spinosa, is also known as the Flinders rose and has broad, fleshy leaves and white to pinkish-white blooms.
2. The plant is best known for its fruit, or caper berries, which are typically eaten salted or pickled, and its edible flower buds (capers), which are used as a flavouring or garnish.
3. The shrubby plant has numerous branches and thick, glossy leaves that range in shape from oblong to circular. The flowers include four sepals, four white to pinkish-white petals, many long stamens that are violet in colour, and a solitary stigma that typically rises well above the stamens. They are complete, pleasantly scented, and showy.
4. Capers flowers have four sepals, four petals, and a single stamen. They have a moderate perfume and range in colour from white to pink.
5. Violet-coloured anthers are present. The flowers contain nectar. Bees or wasps can pollinate it (ozzi, 2001; Rivera et al., 2002).
6. Pedicel 2–6 (–9) cm. Calyx zygomorphic; sepals 1.5-2 0.6-1.1 cm, outside with trichomes, interior glabrous; sepals of outer whorl navicular lanceolate, outside with numerous glands, basally shallowly saccate; sepals of inner whorl 1-2 cm, not saccate or galeate, not broadest near the base, 3-4.5 mm deep in distal half. Petals dimorphic, as long as or just a little longer than anterior sepals; anterior 2 petals white, distinct, claw 4-7 mm, blade oblong obovate, 1-2 cm, outside with trichomes, apex subemarginate; posterior 2 petals yellowish green to green, enclosed by sepals, thickened, margin connate from the base almost to the middle.
7. Around 80 stamens; uneven, 2-4 cm filaments; and 2-3 mm anthers. Gynophore approximately 1 cm, occasionally sparsely villous at the base; ovary elliptical, 3–4 mm, glabrous, with a vertical thin furrow and ridge at the apex; placentas 6–8; many ovules; style and stigma indistinct, mound-like. Flat, 4-5 mm long stipular spines with a recurved apex.
8. Leaf blades are oblong, obovate, broadly elliptic, or suborbicular, 1.3-3 1.2-2 cm, 1-1.7 as long as wide, juicy when young but later leathery, and have a petiole of 1-4 mm. Secondary veins 4 (or 5) on either side of the midvein, base rounded, apex acute, obtuse, or retuse but spine-tipped. Midvein is abaxially elevated but progressively becomes obscure from base to apex. Flowers grow singly in the higher axils; symmetrical buds.
9. The ellipsoid or ovate-shaped caperberry is the name of the caper fruit. Unexpectedly, mature fruits opened, releasing their seeds (Sozzi, 2001).
10. The C. spinosa fruit is an oblong to somewhat pyriform berry with lengthy gynophores (35-70 mm). Fruit is dehiscent, ellipsoid to oblong ovoid, 1.5-4 0.8-1.8 cm, with 6-8 lengthwise thin ridges; fruiting pedicel and gynophore are right angles to one another, measuring 3-7 cm, 1.5-2 mm in diameter, and 1.5-2 mm in diameter, respectively. Reniform seeds are small (2-4 mm) (Tutin et al, 1993).
Cultivated forms
Caper cultivation takes place currently under certain climatic circumstances, including a protracted xerothermic phase and strong wind exposure. In the warmer months, the creation of flower buds, which lasts from April through September, is at its highest.
Climate
Capers can be grown in semi-arid conditions. The ideal climate for caper plants consists of bright sunlight and dry heat. Plants thrive in regions with 200–600 mm of precipitation per year and can readily withstand summertime temperatures of 35–40°C. However, the caper is a cold-sensitive plant with a temperature hardiness range comparable to other subtropical fruits, such as pomegranate, fig, and especially olive trees (-9 °C) (Kan and Arslan, 2004). However, caper plants can be found in Northeast Anatolia’s colder regions where olive trees cannot be grown (Muharrem et al., 2009).
Soil
In nutrient-poor, well-drained gravelly soils, plants can grow. It typically flourishes in rocky, anhydrous habitats that are fully exposed to the sun, and it can endure temperatures beyond 40 °C (Levizou et al., 2004). Large, widespread roots that delve far into the soil are developed in mature plants. As a result, it may even grow in extremely poor soils. Capers tolerate salt and thrive in areas where there is a lot of sea spray. The caper’s vegetative canopy covers the earth’s surface, which helps preserve the water reserves in the soil (Olmez et al., 2004).
Propagation
Caper plants can be propagated from either seeds or cuttings. Caper seeds are small and sluggish to develop into transplantable seedlings, making them poor candidates for seed propagation. Fresh caper seeds rapidly germinate, but only in little amounts. Caper seed should be stratified to get high germination percentage. This allowed seeds to be stored in a wet medium for 2-3 months at or below 0°C (Tansu and Kocabaa, 1997; Sozzi, 2001; Yilmaz et al., 2002). Caper seed coatings are particularly resistant to absorbing water (Cesari, 2003). The seed coverings contain lignins as well. According to reports, the use of plant growth regulators, especially gibberellins, raised the germination rate of caper seeds from 22% to 64%. (Macchia and Casano, 1993; Soyler and Khawar, 2007; Suleiman et al., 2009). Some animals can spread the seeds (Tansu and Kocabaa, 1 997; Sozzi, 2001). Cuttings of capers are challenging to root (Soyler and Arslan, 2000; Kan et al., 2002). In Mediterranean regions, February, March, or April are the optimum times to collect cuttings. Basal parts that are more than 1 cm in diameter, 8 cm long, and have six to ten buds can be used to make stem cuttings. With bottom heat, the rooting medium must be thoroughly emptied. Increased rooting may benefit from the application of IBA (Muharrem et al., 2009).
Planting, Irrigation, Pruning and Fertilization
Planting for commercial production might begin in January, February, or March. The planting spacing can be used in dry areas (2×2 or 3×3) and wet areas (4×4 or 5×5). It is possible to plant roughly 2,000 plants per acre, depending on how rough the topography is. Plants in their first year do not prefer excessive irrigation. Better drip irrigation if it is possible (Muharrem et al., 2009). For the strongest seedling, 250 ppm GA3 plus 8000 ppm KNO3 could be advised, as well as 100 ppm GA3 plus 1000 ppm KNO3 for the best germination rate of caper seeds (Saeed Khaninejad et al., 2012). After three to four years, the yield should reach its maximum. To get rid of water sprouts and dead wood, plants are cut back in the winter. For high productivity, pruning is essential. As flower buds appear on branches that are a year old, severe branch pruning is required. 1 to 3 kilogrammes of caper flower buds can be harvested from plants that are three years old. Caper plantations can survive for 20 to 30 years. In the production of capers, fertilisation is not a major concern (Muharrem et al., 2009).
Harvest and Processing
Capers are mostly produced for closed flower buds. After harvest, these unopened flowers are exported (Soyler and Aslan, 1999). It is crucial for the harvest that only unopened flower buds are harvested on dry days. The entire growing season is spent frequently harvesting. Unopened flowers are kept after harvesting by being placed in a 20% vinegar solution or by being covered with salt. The gathered caper buds were categorised based on their diameter.
Culinary Uses
Unopened caper flower buds have a significant commercial value in countries that produce capers, as was previously indicated. These flower buds were either preserved in granular salt or vinegar pickles. Additionally, young shoots and semi-mature fruits (like caperberries) can be pickled for use as a condiment. Capers provide pungency, a strange scent, and saltiness to foods like pasta sauces, pizza, seafood, meats, and salads. They also have a strong, spicy flavour. It was intriguing that methyl isothiocyanate, which is produced from glucocapparin molecules derived from crunched plant tissues, gives capers a flavour akin to that of mustard and black pepper, which is derived from mustard oil. The pantheon of traditional Mediterranean flavours, which also includes olives, rucola (also known as garden rocket), anchovies, and artichokes, is significantly enriched by capers. Tender young branches of caper plants can be eaten as a vegetable or preserved in the majority of the world. Mature and semi-mature fruits are occasionally consumed like cooked vegetables (Muharrem et al., 2009).
Phytochemistry
Saccharides and glycosides, flavonoids, alkaloids, terpenoids and volatile oils, fatty acids, and steroids are among the components of C. spinosa (Yang et al., 2008). Flavonoids, indoles, and phenolic acids make up the majority of the substances present in C. spinosa (Zhou et al., 2010).
Economic Importance
The largest markets for capers are the nations that make up the European Union. They need caper flower buds of the highest calibre. According to what we know, the EU has denied imports from various North African nations due to harmful residue identified in the items. However, the global market is open for any items that have received the proper certification. Additionally, the production of capers organically will create a new market opportunity. Because caper growing conditions are excellent in Turkey, a sound marketing strategy will help this local plant become a hit in the export market. On the other hand, there must be advertising in the factory. Consequently, a successful commercial can also raise its usage in Turkey (Muharrem et al., 2009).