engleski

Effect of norflurazon on duckweed (Lemna minor L.)

Norflurazon is a herbicide that inhibits the biosynthesis of carotenoid pigments and therefore causes photooxidative damage. The effect of 1´10-6 mol dm-3 and 2´10-7 mol dm-3 concentrations of norflurazon was studied by Lemna-test. The plant growth, recorded during 14 days of cultivation (photoperiod 16/8 light to darkness, light intensity 80 mE m-2 s-1), was stimulated by 2´10-7 mol dm-3 concentration while higher concentration did not affect the growth. Both concentrations of norflurazon inhibited chlorophyll and carotenoid accumulation. Concentration 1´10-6 mol dm-3 decreased the chlorophyll a, chlorophyll b, b-carotene and lutein content up to 25-30% of control level. The prominent reduction (up to 50%) of other carotenoids (violaxantin and neoxantin) was also noticed. The accumulation of pigments after treatment with lower concentration was near to those of control plants. Norflurazon in both tested concentrations lowered guaiacol peroxidase activity in crude plant extracts. More prominent decrease was caused by higher concentration (approximately 60% of control level) while after treatment with lower concentration activity was approximately 90% of control level.

norflurazon; pigments; Lemna minor

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