ABSTRACT
Most immunoanalysis methods can detect picogram quantities of cytokinins and, combined with high-performance liquid chromatography, provide a high level of selectivity. This chapter discusses the preparation and use of specific antibodies in immunoaffinity and immunoassay techniques used for cytokinin analysis. Quantification of cytokinins by immunoassay is based upon the competition of cytokinins present in a sample with a known quantity of labeled or immobilized cytokinin for binding to an anticyto-kinin antibody. Anticytokinin antibodies have been prepared in the form of antisera, mainly in rabbits, or monoclonal antibodies derived from mice or rats. The specificity and sensitivity of a cytokinin immunoassay is dependent upon the cross-reactivity and relative affinity of the antibody or antiserum with structurally similar cytokinins. Cross-reactivity characterization provides information regarding the relative affinities of the anticytokinin antibody for structurally-related cytokinins, and the determination of assay detection limits. The development of immunoassay procedures for use in cytokinin research has enhanced the ease and sensitivity with which cytokinins are quantified.
