Multiple choice Who were the first scientists to isolate gibberellin in crystal form? Kurosawa Yabuta and Sumiki Cross et. al. Macmillan and others Reveal answer Fill a bubble to check yourself B Correct answer Explanation Gibberellin was first isolated in 1935 in crystal form by Teijiro Yabuta and Sumuki, from fungal strains (Gibberella fujikuroi) provided by Kurosawa.