METHOD: ELISA, Western CONDITIONS: Green House - 14-16h light METHOD NARR: Trichome exudate was collected and used in ELISA and Western Blotting tests. The ELISA was developed to detect and quantify PPO in type A trichomes and pnm. Hybrids between ber and tbr were generated and subjected to the same tests. RESULTS NARR: An individual trichome yields a detectable, linear ELISA signal, with saturation occuring at 40-50 trichomes. One ber type A t possess ~1ng of PPO. Genetic background appears to influence PPO expression. AUTHOR EXPLANATION: Trichome density vs. PPO quantity varies with leaf age and implications are discussed.