Abstract: We have devloped an enzyme-linked immunosorbent assay for quantitative analysis of abscisic acid (ABA) by coupling horseradish peroxi-dase (HRP)to ABA directly as an enzyme conjugate.The sensitivity of the assay,50 f mol, is comparable to the radioimmunoassay and the established methods using alkaline phosphatase (AP) -ABA or ABA-bovineserum albumin-AP as the enzyme conjugate.The logit B/B 0 value was linear between 12.5 pg to 100 ng. For improving assay sensitivity and precicion,we have also spproachedtion scheduies, injection doses and route, enzyme conjugate concentration and the dilution of antibody against ABA.

Key words: ABA