The Development of ELISA and IRA for Cytokinin Estimation and their Application to a Study of Lunar Periodicity in Ecklonia maxima (Osbeck)Papenf.

Changes in the cytokinin-like activity in the seaweed Ecklonia maxima during a lunar cycle was determined. Bioassays were performed on lamina, stipe and holdfast material individually. For a more detailed investigation on the cytokinins in the stipe, which is the commercially important component, several immunoassays were developed. An enzyme-linked immunosorbent assay was developed for isopentenyladenosine (IPA), but because of low precision this assay system was not suitable for isopentenyladenine analysis. Sensitive radioimmunoassays were developed for zeatin (Z)and ribosylzeatin (ZR). Bioassay results indicated that cytokinin-like activity in the stipe, lamina and holdfast material followed similar trends, which suggested a close link to lunar periodicity. The levels of activity reached a maximum at approximately full moon and last quarter. Immunoassay of the stipe indicated the presence of Z, ZR and IPA. Their fluctuations in concentration during the lunar cycle were similar to that obtained by bioassay, with IPA being detected in the highest concentrations.