engleski

Bioassay for detecting the susceptibility of sugar beet on mesotrione residues in different soils

Mesotrione is a 4-hydroxyphenylpyruvate dioxygenase (HPPD)-inhibiting herbicide that indirectly inhibits carotenoid production in susceptible plants. It is non-persistent herbicide and is therefore presumably not phytotoxic for use in crop rotation. Although defined as non-persistent, it is known that mesotrione’s persistance can vary depending on the soil’s physicochemical properties. The aim of this study was to determine the phytotoxicity of mesotrione residues in sugar beet grown on two different soil types: (1) hipogley and (2) humofluvisol. Mesotrione was applied on both soils at doses of 0 ; 0.25 ; 0.5 ; 1 ; 2 ; 4 ; 6 and 8 μg a.i. per 200 g of soil. The application was done using a thin layer chromatography sprayer. The growing of sugar beet was conducted in a growth chamber under constant climatic conditions for 3 weeks. Symptoms of phytotoxicity (bleaching) were assessed at 7, 14 and 21 days after application (DAA) by using a 0 to 100 % scale (where 0 = no effect and 100 = plant death). The fresh weight of sugar beet was determined on the 21st day, after which the total carotenoid content was determined by spectrophotometry. The highest visually evaluated phytotoxicity on both soils was determined on the 21 DAA. On humofluvisol, damages were noticed already at the lowest dose (0.25 μg a.i. per 200 g soil). The sugar beet plants were completely damaged at 4 μg a.i. on humofluvisol and at 6 μg a.i. on hipogley soil. A correlation in the reduction of fresh weight with the reduction of total carotenoid content was established on both soils. A significantly higher reduction of both parameters already at the lowest dose was established on the humofluvisol.

bioassay ; mesotrione ; residues ; sugar beet

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