Sinapis arvensis L. - Charlock mustard.
Taxonomic position.Family Brassicaceae Burnett (Cruciferae Juss.), genus Sinapis L.
Biological group.Spring annual weed.
Morphology and biology.Stem is 10-100 cm tall; angulate, branched, covered with horizontally-tilted coarse simple hairs, often there are reddish-violet spots at base of branches. Lower leaves are petiolate, pinnatifid, unevenly-toothed along the edge, with roundish blunt upper lobe. Upper leaves are sessile, oblong-ovate, with pointed tip. Inflorescence is elongated raceme. Flowers are actinomorphic, consisting of four components; yellow petals are situated crosswise, twice as large as sepals. Fruit is silicle, consisting of two segments; lower segment is oblong-cylindrical, dehiscent, multi-seeded (up to 20 seeds), upper one is elongated into conical tetrahedral indehiscent, usually one-seeded beak, which is separated from the lower segment by wedge-shaped spindle. Silicle is ligneous, glabrous, stramineous, located on short and thick, slantwise-upward directed peduncles. Seeds are globular, dark-brown or almost black. It flowers in May-June, bears fruits in July-August. Maximum productivity is up to 20,000 seeds. Minimum temperature for seed germination is 2-4°C; optimum is 14-20°C. Fresh seeds germinate poorly because of their dormancy. Brown seeds have higher energy and speed of germination than black ones. Seeds germinate from depths of no more than 5-6 cm; their viability is maintained in soil for up to 10 years. Seeds partly keep their germinability while passing through the digestive system of animals.
Distribution.European part of the Former Soviet Union (except northern regions), Caucasus, Western and Eastern Siberia, the Far East, Central Asia. General distribution: Europe, North Africa, Asia Minor, Iran, Afghanistan, North America.
Ecology.Anthropochore, autochore. Mass occurrence of S.arvensis is connected with Chernozem soils of forest-steppe and steppe zones. This weed demands light and water, grows well in cultivated soil. It produces seeds earlier than spring cereals or simultaneously with them. Seedlings, emerging late in autumn, do not over-winter as a rule. This plant takes a lot of nutrients and water from soil, twice as much as oat and six times as much as barley.
Economic significance.S.arvensis is a pernicious segetal weed of spring crops, especially cereals of Chernozem regions of steppe and forest-steppe zones; sometimes it is found in vegetable gardens, in young fallows and sod fields, along roads, in abandoned places. It is an important alternative host for clubroot of crucifers, Plasmodiophora brassica, and also a source of insect pests of cultivated crucifers (aphids, cabbage flies). Young leaves and stems can be used as food. Seeds contain up to 30% fatty oil and glycoside sinigrine which dissociates into mustard-ethereal oil. This oil is used for food and industrial purposes, oilcake is used for preparation of mustard. Medicinal and bee plant. Control measures include proper crop rotation, tilled crops and fallows, proper preparation of manure, thorough checkup of crop seed purity.
Reference citations:Agaev, M.G., ed. 1988. Main agricultural weeds in crops of the Leningrad Region. In: Catalogue of VIR world collection. N 468. Leningrad: VIR. p.46-8. (in Russian).
Belykh, A.G. 1974. Weed plants of Eastern Siberia and their control measures. Irkutsk: Irkutsk Agricultural Institute. p.25-7. (in Russian).
Keller, B.A., ed. 1934. Weed plants of the USSR. V.3. Leningrad: AN SSSR. p.60-3. (in Russian).
Komarov, V.L. & Bush, N.A., eds. Flora of the USSR. V.8. 1939. Moscow-Leningrad: AN SSSR. p.467-8. (in Russian).
Nikitin, V.V. 1983. Weed plants of the USSR flora. Leningrad: Nauka. p.212. (in Russian).
Ulyanova, T.N. 1998. Weed plants in flora of Russia and other CIS countries. St.Petersburg: VIR. p.132, 135. (in Russian).