Carbohydrate Accumulation in Leaves of Plants Treated with the Herbicide Chlorsulfuron or Imazethapyr Is Due to a Decrease in Sink Strength

• Published in: Journal of agricultural and food chemistry 2004-12, Vol.52 (25), p.7601-7606
• Main Authors: Zabalza, Ana, Orcaray, Luis, Gaston, Susana, Royuela, Mercedes
• Format: Article
• Language: English
• Subjects: Agrochemicals products; Biological and medical sciences; carbohydrate content; Carbohydrate Metabolism; Chemical control; chlorsulfuron; Fundamental and applied biological sciences. Psychology; Herbicides - administration & dosage; imazethapyr; leaves; Nicotinic Acids - administration & dosage; Other agrochemicals used in plant protection (herbicides, fungicides, etc.); Parasitic plants. Weeds; peas; pesticide application; Photosynthesis; Phytopathology. Animal pests. Plant and forest protection; phytotoxicity; Pisum sativum; Pisum sativum - drug effects; Pisum sativum - metabolism; Plant Leaves - drug effects; Plant Leaves - metabolism; Plant Roots - metabolism; Pollution effects and side effects of agrochemicals on crop plants and forest trees. Other anthropogenic factors; Pollution effects. Side effects of agrochemicals; source-sink relationships; starch; sucrose; Sulfonamides - administration & dosage; Triazines - administration & dosage; Weeds
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf0486996

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. Keywords: Imazethapyr; chlorsulfuron; carbohydrates; Pisum sativum