Comparative Growth Retarding Activity in Relation to Endogenous Tissue Concentration of Daminozide and a Pyrrolidino Analog (Uni-629) in Phaseolus vulgaris L. and Chrysanthemum morifolium Ramat
N-pyrrolidino succinamic acid (Uni-F529) was considerably superior to succinic acid 2,2 dimethyl hydrazide (daiminozide. SADH) in inhihiting stem elongation in Phaseolus vulgaris L. `Black Valentine' and Chrysanthemum morifolium Ramat, `Bright Golden Anne'. This was true in winter or summer greenhouses. Under controlled temperature and light conditions tissue concentrations of daminozide were higher than those for Uni-F529. Neither daminozide nor Uni-F529 was metabolized significantly in beans during the 3 to 7 day test periods. The greater activity of the pyrrolidino analog relative to daminozide must reflect increased activity at the site of action and/or reduced storage of Uni-F529 at inactive sites in plants.