The relationship of tissue chlorogenic acid concentrations and leaching of phenolics from sunflowers grown under varying phosphate nutrient conditions

A large increase in the concentration of the isomers of chlorogenic acid was observed in extracts of sunflowers grown under phosphate-deficient conditions when compared with phosphate-sufficient plants. More phenolic compounds were leached from living intact roots, dried roots, and tops of phosphate-deficient plants than from phosphate-sufficient ones. These leachates did not contain any of the isomers of chlorogenic acid or caffeic acid but did contain scopolin. The influence of phosphate deficiency on polyphenol concentrations in plants and their possible role in allelopathic interactions between plants are discussed.