Aktivnost ALS enzima kod Xanthium strumarium L. i Helianthus annuus L. pod uticajem nikosulfurona

Activity of ALS enzyme extracted from leaves of Xanthium strumarium L. (XS1, XS2) and Helianthus annuus L. (HA1, HA2, HA3) populations were studied in vitro in the presence of different nicosulfuron concentrations (0; 0,01; 0,1; 1; 10, 100 μM). This activity was recorded based on acumulation of acetoin per mg of protein during time interval of 1 min (nmol acetoin/min/mg protein). Nicosulfuron was reduced ALS enzyme activity in all studied populations, wherein the level of reduction depended on population and herbicide concentracion. It was confirmed that differences in susceptibility of X. strumarium populations to nicosulfuron were not consequence of altered ALS enzyme activity, while differences in susceptibility of H. annuus populations can be in relation with its altered activity.Aktivnost ALS enzima ekstrahovanog iz listova populacija Xanthium strumarium L. (XS1, XS2) i Helianthus annuus L. (HA1, HA2, HA3) je ispitivana in vitro u prisustvu različitih koncentracija (0; 0,01; 0,1; 1; 10, 100 μM) nikosulfurona. Ova aktivnost je određena na osnovu akumulacije acetoina po mg proteina u toku vremenskog perioda od 1 min (nmol acetoin/min/mg protein). Nikosulfuron je redukovao aktivnost ALS enzima u svim ispitivanim populacijama, pri čemu je nivo redukcije zavisio od populacije i koncentracije herbicida. Potvrđeno je da razlike u osetljivosti populacija X. strumarium na nikosulfuron nisu posledica izmenjene aktivnosti ALS enzima, dok se razlike u osetljivosti populacija H. annuus mogu dovesti u vezu sa njegovom izmenjenom aktivnošću