Indirect Evidence for Hormone Translocation

Well before the discovery of auxins and gibberellins during the 1920 s hormone movement had been suggested as occurring in plants. As early as in 1879 Julius Sachs, considering observations on correlations between main axes and side shoots, proposed substances other than nutrients as involved in these phenom- 

Abbreviations ABA = abscisic acid 2,4-D = 2,4-dichlorophenoxyacetic acid DNP = 2,4-dinitrophenol GA3 = gibberellic acid IAA = indole-3-acetic acid IB A = indole-3-butyric acid NAA = naphthalene-1-acetic acid NPA = naphthylphthalamic acid PEP = phos-phoenolpyruvate 2,3,5-T = 2,3,5-trichlorophenoxyacetic acid TIBA = 2,3,5-triiodoben-zoic acid. 

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