Levels of Endogenous Abscisic Acid in Rose Achenes and Leaching with Activated Charcoal to Improve Seed Germination

Abstract

The involvement of abscisic acid (ABA) in inhibition of germination of rose achenes was studied and a method for removing ABA was established. Intact achenes of Rosa hybrida L., cv. Inspiration never germinated at 25°C under continuous irradiation with white light, whereas seeds excised from the achenes readily germinated. Seed germination was inhibited when seeds were incubated together with previously removed pericarps. The amounts of ABA released into water from these achenes, seeds, and seeds plus pericarps during the incubation were quantified by enzyme-linked immunosorbent assay (ELISA). The higher level of ABA, detected in the sample with the lower germination percentage, indicated that ABA, localized in the pericarps, inhibited the germination. Achenes of Rosa multillora Thunb. were placed on a polystyrol foam tray which had many small holes and the tray was floated in a beaker of distilled water so that the achenes were steeped in water with sufficient aeration. This procedure improved the seed germination, probably through leaching ABA from the pericarps. The germination percentage was markedly increased when activated charcoal was added to the water. The effect of the leaching was greater at 5°C than at 25°C.