Abstract
Abscisic acid-β-D-glucosyl ester (ABA-GE) was recently found in Citrus junos peel as a main allelopathic substance. Aqueous methanol extracts of fruit peel of C. junos, C. unshiu and C. hassaku inhibited the growth of the roots and hypocotyls of lettuce, cress and alfalfa seedlings, and there was a good correlation between ABA-GE concentrations in fruit peel of C. junos, C. unshiu and C. hassaku and the inhibitory activities of their aqueous methanol extracts. Annual changes in concentrations of ABA-GE were determined in C. junos, C. unshiu, C. sudachi fruits and leaves. The concentrations in fruits of C. junos increased rapidly from the end of October, but the concentrations in the others did not increase so. The inhibitory activities of aqueous methanol extracts obtain from fruits and leaves of C. junos, C. unshiu, C. sudachi also correlated well with their ABA-GE concentrations.
