Modification of the Vegetative Development of Phaseolus Vulgaris With N,n‐dimethylaminomaleamic Acid

Bean plants treated with N, N‐dimethylaminomaleamic acid (DMAM) were characterized by a reduction in plant height, dark‐green foliage, short, thick internodes, restricted petiole extension, and, at high concentrations, a slight reduction in leaflet expansion and dry matter accumulation. DMAM specifically affects internodal and petiolar tissues. The inhibitory stimulus of DMAM is readily translocated following application to a single leaf and the subsequent suppression of stem elongation increased with increasing dose. The failure of the rachises of the trifoliate leaves to fully extend resulted in an overlapping of the bases of the lamellae of the individual leaflets. The inhibitory effects of DMAM on stem elongation can be completely reversed with gibberellin A 3 (10 or 100 ppm). This might suggest, that DMAM may be interfering with the natural synthesis of gibberellin in the plant.