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a genus of perennial tree-like plants of the family Euphorbiaceae. There is one species—the castor-oil plant, or palma Christi (Ricinus communis), which is divided into several subspecies. The most widely cultivated subspecies, which are grown for the oil that is obtained from the seeds, are Ricinus communispersicus, Ricinus c. sanguineus, Ricinus c. zanzibariensis, and Ricinus c. chinensis. It is native to northeast Africa, where it is a shrub or tree measuring up to 10 m tall. In northeast Africa, and in other tropical and subtropical countries, it is grown as an annual or a two-to-three-year crop; in temperate regions, only as an annual. The most common subspecies in the USSR are Ricinus c. persicus, Ricinus c. sanguineus, and various hybrid varieties.
Ricinus has a rodlike root and a straight, branching stem. The stem is green in Ricinus c. persicus and red or brown in Ricinus c. sanguineus. The main stem bears between five and 20 large lobed leaves and has a terminal racemose inflorescence. The flowers are cymose, resting on the axis of the inflorescence. The pistillate flowers are above and the staminate, below. In the USSR three to five racemes develop; in the tropics and subtropics, 100 to 150. The fruit is a three-celled capsule; there are 15 to 300 capsules in an inflorescence. Each cell has a hard, shiny, brightly colored seed; 1,000 seeds weigh 200–500 g. All parts of the plant contain the protein ricin and the alkaloid ricinine, which are poisonous to man and animals.
Ricinus is a photophilic, hydrophilic, and thermophile plant. Its seeds begin to sprout at 10°-13°C. The sum of the active temperatures (over 10°C) during growth and development (110–150 days) is 2500°-3200°C. The best soils are chernozems.
Castor oil is extracted from the seeds (its content is about 48–55 percent). The oil cake is a good fertilizer; after it is rendered harmless with live steam, it is suitable as cattle fodder. Cord and burlap can be manufactured from the stem fibers. The leaves can be used for feeding the silkworm (Bombyx morí). Ricinus has been cultivated in Africa since ancient times; cultivation subsequently spread to Asia, America, and Europe. The plant was introduced to Russia in the middle of the 19th century, where it was known as Turkish flax. In 1970 the worldwide planting area of Ricinus was more than 1.2 million hectares (ha); it was cultivated predominantly in Brazil, India, and China. The gross harvest of seeds was 723,000 tons; the average yield was 5.6 centners per hectare. In the USSR (in the Northern Caucasus and southern Ukraine), Ricinus plantings occupied 178,000 ha in 1970. The average harvest without irrigation was 7–12 centners per hectare, with irrigation 16–20 centners per hectare. The best varieties with indehiscent capsules are VNIIMK 165, Donskaia 34/44, Early Hybrid, Steppe 6, and Chervonnaia. In the USSR, the USA, and other countries plantings of Ricinus hybrids of the first generation have been undertaken.
For cultivation, manure (20 tons/ha) and mineral fertilizers (45 kg/ha N and 60 kg/ha PiOs) are applied. Sowing is square-nest or single-grain, with 70 cm between rows; the sowing rate for the seeds is 20–28 kg/ha. The seedlings are thinned, leaving 35,000–50,000 per ha (with irrigation, 60,000–65,000). During the growth and development stage, the spaces between rows are hoed and irrigated two or three times (watering rate is 400–500 mVha); herbicides (the sodium salt of 2, 4-dichlorophenoxyacetic acid, prometrin) are used to destroy weeds. Ricinus is harvested when the capsules on the central branches and primary branches are dry. In order to facilitate harvesting, the plant is defoliated and desiccated. Pests are wireworms, false wire-worms, and the caterpillars of the turnip and the scarce bordered straw moths. Diseases include fusarium wilt, sclerotium disease, and gray mold. Ricinus is also used as an ornamental.
REFERENCESAtlas lekarstvennykh rastenii SSSR. Moscow, 1962.
Kleshchevina. Rostov-on-Don, 1963.
Zhukovskii, P. M. Kul’turnye rasteniia i ikh sorodichi, 2nd ed. Leningrad, 1964.
Kleshchevina. Krasnodar, 1964. [Moshkin, V. A.] “Kleshchevina.” In the collection Rukovodstvo po selektsii i semenovodstvu maslichnykh kul’tur. Moscow, 1967.
See references under OIL PLANTS.
V. A. MOSHKIN