Preplanting treatment of freshly harvested potato tubers with 2% thiourea [62-56-6] or 0.0004% gibberellin stimulated the conversion of starch into sugar and increased the respiration intensity.Stimulating cuts strengthened the effects of the chem. growth stimulants, and the combination treatment markedly shortened the time between planting and sprouting.Tubers, treated with cuts and chems., had an increased vitality, accelerated germination rate and growth, and a powerfully developing root system.