(2 CHLOROETHYL) TRIMETHYLAMMONIUM CHLORIDE AND RELATED COMPOUNDS AS PLANT GROWTH SUBSTANCES. III. EFFECT ON GROWTH AND FLOWERING OF THE TOMATO

W ittwer, S. H., and N. E. T olbert. (Michigan State Univ., E. Lansing.) (2‐Chloroethyl) trimethylammonium chloride and related compounds as plant growth substances. III. Effect on growth and flowering of the tomato. Amer. Jour. Bot. 47(7) : 560–565. Illus. 1960.—Application of 10 –3 to 10 –7 M solutions of (2‐chloroethyl) trimethylammonium chloride, (2 bromoethyl)‐trimethylammonium bromide, or (2,3‐n‐propylene) trimethylammonium bromide to the roots of the tomato plant markedly altered growth and promoted earlier flowering. Treated plants developed thicker stems, and dark‐green, savoyed leaves. The growth changes were similar to those produced by exposure to high light intensities and low temperatures, and were opposite to, and more persistent than, those induced by gibberellin. A stepwise regulation in the magnitude of growth and dry matter accumulation in tomato plants followed application of chemicals of increasing concentration to cultural solutions. This growth response varied from a stimulation at 10 –7 M to a marked suppression at 10 –4 M without delay of flowering or visible injury. The control of growth and flowering by the use of these chemicals offers several practical possibilities for their utilization in tomato culture.