A germination inhibitor in the seeds of mahoe (Melicytus ramiflorus)

Seeds of mahoe exude a brown watersoluble substance over a number of days. The properties of this exudate were examined. Mahoe seed did not germinate until all exudate was removed. Extracts of exudate inhibited germination of leached mahoe seed and five of six other species tested. Replacement of the exudate with fresh water restored germination in mahoe and in all but one test species. It is concluded that the exudate acts mainly as an autoinhibitor and has little allelopathic role. It confers an advantage on mahoe seedling establishment by allowing germination only after long periods of rain.