Since many organic compounds which were used on cucumber root test had stimulated root growth and had indicated their anti-auxin properties. It was, therefore, thought desirable to find out their relative response on abscission. Hence a series of experiments were initiated to determine their effect on Coleus blumei petiole abscission.
(2) Concentrations of 10, 100 and 1000 ppm of 2, 3, 5-triiodobenzoic, 4,4’-methylenebis-3-hydroxy-2-naphthoic, l-hydroxy-2-naphthoic, and 3-hydroxy-2-naphthoic acids applied in lanolin to the cut surface stimulated the abscission of debladed coleus petioles. The rate of abscission was directly proportional to the dosage applied.
(3) When 2, 3, 5-triiodobenzoic acid 1000 ppm was applied simultaneously on the debladed petioles with either 4, 4’-mcthylenebis,-3-hydroxy-2-naphthoic acid 10 ppm, 3-hydroxy.2-naphthoic acid 100 ppm, 1-hydroxy-2-naphthoic acid 1000 ppm, increased stimulation of abscission was noted.
(4) When 2, 3, 5-triiodobenzoic acid 1000 ppm, or 4, 4’-methylenebis-3-hydroxy-2-naphthoic acid 10 ppm, or 3-hydroxy-2-naphthoic acid 100 ppm, or l-hydroxy-2-naphthoic acid 1000 ppm was applied midway between the abscission zone and the cut surface with naphthaleneacetic acid 100 ppm applied on the tips of debladed petioles, the response of naphthaleneacetic acid was reduced. A similar action was recorded when these materials were" applied in a spiral fashion, thus indicating that these materials have anti-auxin properties.
(5) The compound 1 -naphthoic acid at a 10 ppm concentration applied on the out surface of debladed petioles delayed the abscission of coleus petioles. However, 1000 ppm concentration was found to accelerate the abscission.
