Weeds
Alisma plantago-aquatica L. - Great Water Plantain
Systematic position.
Family Alismataceae, genus Alisma L.Biological group.
Perennial rhizome plant.Morphology and biology.
Rhizome thick (to 2 cm thick, usually wider than long), tuberose-form. Stem 10-70 cm in length, straight, branched in upper half only. Leaves green; lower ones only sessile, widely linear, swimming; the other ones aerial, long-petiolate; their plates big, ovoid or widely ovoid, with cordate base usually, with pointed apex. Inflorescence large, paniculate, piramidal, gradually narrowing upward, contains 5-6(upto 10) somewhat connivent whorls. Sepals about 3 mm in length, 2 mm in width, ovoid or widely ovoid, often pointed, green. Petals twice as long as sepals, usually abscising, white or (from outside) pale-pink. Fruits 2-3 mm in length, obliquely obovoid, mainly shallowly one-striated. Reproduction by seeds and vegetatively (by underground organs). Flowering in June - August.Distribution.
Europe (except Arctic), the Caucasus, Siberia (except Arctic), the Far East, Middle Asia.Ecology.
Grows in shallow water along banks of reservoirs, in ditches, swamps; in zone of irrigate agriculture grows on rice fields, near banks of reservoirs, canals, and irrigation canals. Prefers abundant moist soils (mature plants endure practically any depth of water at rice cultivation). Germinating capacity increases to 40-60% in 3-5 years after keeping seeds in soil (in the first 2 years the germinating capacity is weak). The seed viability keeps 5-7 years. The seeds sprout from soil depth to 1 cm at water depth to 10 cm. The young rhizome sprouts endure water depth 25-30 cm and more.Economic significance.
Abundant weed on thinned crops of rice. Malignant specialized weed on rice fields in Krasnodar Territory of Russia, in Ukraine, Middle Asia, Kazakhstan. One plant can produce to 21 thousand seeds, which mature earlier than rice, easily dropping and contaminating soil. Rice-shoots develop slowly at their first stages. A. plantago-aquatica is resistant to flood, but being very susceptible to shade; therefore the thickened rice crops (200 plants per sq.m) shade the weeds and detain their growth. Therefore, the weeds do not form inflorescences and do not produce seeds. Control measures on fallow fields of the crop rotation system. The main measures are autumn and spring plowing, and pre-sowing drying of soil (dry rhizomes completely lose their viability; they do not also sprout from the soil depth of more than 10 cm, quickly perishing). Periodical cutting of the weed is necessary on meadows.Related references:
Bazdyrev, G.I., Zotov L.I. & Polin, V.D. 2004. Weed plants and measures of their control in modern agriculture. Moscow: MSKHA. 288 p. (in Russian).Komarov, V.L. & Il.in, M.M., eds. 1934. Flora of the USSR. V. 1. Leningrad: AN SSSR. 302 p. (in Russian).
Shatalov, T.A., ed. 1987. Weed plants and their control in Rostov Region. Rostov-na-Donu: Persianovka. 102 p. (in Russian).
Vasilchenko, I.T. & Pidotti, O.A. 1975. Manual of the weed plants of irrigated agriculture. Leningrad: Kolos. 376 p. (in Russian).