Abstract
We screened a compound library to identify chemicals that retarded plant growth. From a chemical library of 9,600 compounds, one compound (BSA-1) inhibited the hypocotyls length of Arabidopsis seedlings grown in the dark with an IC50 of approximately 0.35±0.05 µM. Investigation of the mechanisms underlying the action of BSA-1 suggested that this compound inhibits neither gibberellin biosynthesis nor brassinosteroid biosynthesis. Analysis of BSA-1 analogues provided clues about structurally important features for the development of new plant growth retardants.