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Updated: Aug 19, 2026

Measuring Rates of Herbicide Metabolism in Dicot Weeds with an Excised Leaf Assay
Published on: September 7, 2015
Carbohydrate accumulation in leaves of plants treated with the herbicide chlorsulfuron or imazethapyr is due to a
Ana Zabalza1, Luis Orcaray, Susana Gaston
1Departamento Ciencias del Medio Natural, Universidad Pública de Navarra, Campus Arrosadia, E-31006 Pamplona, Spain.
Abstract:
Herbicides that inhibit branched chain amino acid biosynthesis produce a rapid carbohydrate increase in leaves of treated plants. The relationship between these processes is not known nor is the importance of carbohydrate accumulation in the growth inhibition caused by these herbicides. This work analyzes carbohydrate concentration in sources and sinks after herbicide treatments in pea (Pisum sativum L.), as well as photosynthetic carbon assimilation, using two classes of chemicals, chlorsulfuron and imazethapyr, applied to roots or leaves. The most remarkable result was that, in addition to carbohydrate accumulation in leaves, accumulation of sucrose and/or starch in roots was detected. This pattern of carbohydrate accumulation was similar for both herbicides and independent of whether the herbicides were applied to leaves or roots. This indicates that root growth inhibition was not caused by sugar starvation in sinks. Nevertheless, the results are consistent with a decrease in sink strength, leading to the inhibition of photoassimilate translocation.
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