Phytohemagglutinin: Transitory enhancement of growth in Phaseolus and Allium

Summary Phytohemagglutinin (Difco) stimulates germination and early seedling growth in Phaseolus coccineus, but not in Ph. vulgaris, the species from which the compound is extracted. The differences to the controls reach a maximum at day 8, then they disappear. Root growth in Allium cepa is enhanced by phytohemagglutinin during the first 12 days of treatment, but only at temperatures below 20°C.