Treatment with the herbicide TOPIK induces oxidative stress in cereal leaves

Leaf disks as well as intact 7-day-old plants of winter wheat (Triticum aestivum L., cv. Mironovskaya 808), winter rye (Secale cereale L., cv. Estafeta Tatarstana), and maize (Zea mays L., cv. Kollektivnyi 172MV), were treated with the aryloxyphenoxypropionate class herbicide TOPIK, concentrate-emulsion (active ingredient is clodinafop-propargyl (CP), 8–800 μg/L), and the effects of short-term action (up to 3 h) and long-term aftereffect (up to 3 days) on physiological and biochemical indices related to oxidative stress development were studied. The herbicide induced changes, predominantly increases in lipid peroxidation (LPO) intensity, superoxide anion O2- generation, total antioxidant activity (AOA), and catalase (CAT) and ascorbate peroxidase (APOX) activity, although the response by plants was nonlinear and depended on the herbicide concentration and duration of treatment. The highest level of generation of O2- was observed in the leaves of maize and winter wheat treated by 800 μg/L CP, both in the short- and long-term. As TOPIK concentration increased, so too did LPO and AOA in leaves, confirming the presence of oxidative stress in the cells of all three cereals. Antioxidant enzymes were most active in winter rye and wheat, and least active in maize indicating a protective antioxidant mechanism in the first two cereals.

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► Leaf disks or intact 7-day-old wheat, rye and maize plants were treated with the herbicide TOPIK (8–800 μg/l).
► Short-term action (⩽3 h) and long-term (⩽3 days) aftereffects induced oxidative stress.
► It was noted increases in O2- generation and LPO intensity after TOPIK treatment.
► AOA, and CAT and APOX activity increase in leaves too.
► Responses depended on the herbicide concentration and duration of treatment.