SIGNIFICANCE OF BETAINES IN THE INCREASED CHLOROPHYLL CONTENT OF PLANTS TREATED WITH SEAWEED EXTRACT

Seaweed extract, prepared by alkaline extraction of Ascophyllum nodosu m (L.) Le Jol., applied either to the soil or to the foliage of tomato plants, produced leaves with higher chlorophyll levels than those of control plants. The effects on leaf chlorophyll content were investiga ted using a cucumber bioassay procedure devised for cytokinins. The se aweed extract was shown to increase the chlorophyll levels of the cucu mber cotyledons, but 'peaks' of activity were obtained when widely dif ferent concentrations were used. The possibility that these effects we re the result of betaines present in the extract was considered. Glyci nebetaine, gamma-aminobutyric acid betaine and delta-aminovaleric acid betaine all produced significantly enhanced chlorophyll concentration s in the cotyledons. 'Peaks' of activity were observed for each be-tai ne: for glycinebetaine at 10(-6) and between 10(-4) and 10(1) mg l-1, for gamma-aminobutyric acid betaine at 10(-6), between 10(-4) and 10(- 1), and 10(1) mg l-1, and for delta-aminovaleric acid betaine between 10(-5) and 10(1) mg l-1. It was concluded that the effects of enhancin g chlorophyll levels produced by the seaweed extract were due, at leas t in part, to betaines.