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(365) The impact of herbicide deposition on plant phytochemistry and its ecological implications. Elmegaard, Niels1, Kjær, Christian1, Kvist Nielsen, Jens2, Bruus Pedersen, Marianne1, 1 2 ABSTRACT- The content of six phenolic compounds was recorded in leaves from the annual herb Fallopia convolvulus exposed separately to eight different herbicides. The herbicides represented six different modes of action. All the herbicides affected the composition of phenolic compounds in the leaves for a short period of time. One group of herbicides, the sulfonylurea-compounds, induced an elevation of the concentration of coumaroyl glucose and caffeoyl glucose in the leaves for more than 16 days. They also induced an alteration of host plant quality to an associated specialist herbivore Gastrophysa polygoni. Such impact on host plant quality could not be demonstrated for two other plant-herbivore systems, ie. Pieris brassica:Brassica napus and Sitobion avenae:Triticum aestiva. Thus the response is, as far as we know, specific for sulfonylurea-compounds and F. convolvulus , but we find it likely that a similar response can be found in other plant-herbivore systems. It is concluded that herbicides may change phytochemistry and host plant quality to herbivores. It is possible that this may have ecological implications for the performance of sensitive species followed by changes in species composition etc. in ecosystems where sensitive species are subjected to herbicide deposition. Key words: phenolics, sulfonylurea, plant-herbivore effects, lab-field extrapolation |
