ALLELOPATHIC ACTIVITY OF CENTAUREA DIFFUSA AND CENTAUREA TWEEDIEI: EFFECTS OF CNICIN AND ONOPOEDONPICRIN ON SEED GERMINATION, PHYTOPATHOGENIC BACTERIA AND SOIL

M. EUGENIA SESTO CABRAL, A. MARIO FORTUNA, ELMIRA C. DE RISCALA, CÉSAR A. N. CATALÁN AND E. ELIZABETH SIGSTAD

ALLELOPATHY JOURNAL

International Allelopathy Foundation

Año: 2008 vol. 21 p. 183 - 190

0971-4693

ABSTRACT The effect of soils amended with cnicin and onopordopicrin (major metabolites isolated from Centaurea diffusa and C. tweediei, respectively) on seed germination of tomato (Lycopersicum esculetum L.), lettuce (Lactuca sativa L.), wheat (Triticum aestivum L.) and honey weed (Leonurus sibiricus L.) was investigated. Both substances drastically reduced the germination of lettuce and honey weed. Since cnicin was active against some Gram (-) phytopathogenic bacteria, its effect on soil was investigated by calorimetric techniques. Cnicin at 0.1 mg g-1 concentration selectively inhibited some soil  microorganisms. Key words: Allelopathy, calorimetry, cnicin, Leonorus sibiricus, lettuce, onopordopicrin, seed germination, soil microbial activity, tomato, wheat.