The effects of caffeic, vanillic, p-coumaric, chlorogenic, and ferulic acids, ragweed parthenium (Parthenium hysterophorus L. # PTNHY) residue and extracts on the growth, ion uptake, and chlorophyll content of 3-week-old tomatoes (Lycopersicon esculentum Mill. ‘Walter’) grown in the greenhouse were determined Vanillic, p-coumaric, chlorogenic, and ferulic acid at 10−3 M and parthenium extract at 0.5% (w/v) significantly reduced tomato root and shoot dry weight. Ragweed parthenium residue at 0.5% (w/w) and extract at 0.5% (w/v) significantly reduced tomato shoot and root dry weight. Leaf nitrogen content was reduced by phenolic acids (10−3 M) and ragweed parthenium extract (0.5%). Phosphorus content was reduced by all phenolic acids at 10−3 M and ragweed parthenium extract at 0.5% (w/v). In addition, p-coumaric and ferulic acids at 10−4 M reduced phosphorus content. No consistent relationship between chlorophyll content and tomato growth reduction was observed.
