Occurrence of cytokinin-like compounds in two aquatic ferns and their exudates

Abstract

Azolla filiculoides and Salvinia molesta were grown in plastic trays containing water with or without additional nutrients. After 31 days, the ferns were harvested and the culture medium collected. Cation exchange resin, paper chromatography and High Performance Liquid Chromatography were used to purify the plant and culture medium extracts. Cytokinin-like activity was detected using the soybean callus bioassay in all the plant extracts. Activity detected co-eluted with isopentenyladenine (iP), isopentenyladenosine (iPA), zeatin (Z), zeatin riboside (ZR) and dihyrdozeatin (DHZ) for the Azolla plant extracts and with Z, ZR and DHZ for the Salvinia plant extracts. Cytokinin-like activity was also detected in the culture medium in which the ferns had been growing. This activity co-eluted with the same cytokinins found in the plant material. No cytokinin-like activity was detected in the control extract which contained water with no ferns growing in it.