Multiple choice The famous Avena curvature test conducted by F.W. Went proves that Plant growth regulators are auxins. Shoot apex is the site for the synthesis of growth regulating substance. . ABA is a growth inhibitor. Auxins exercise apical bud dominance. Reveal answer Fill a bubble to check yourself B Correct answer Explanation The famous Avena curvature test conducted by F.W. Went proves that shoot apex is the site for the synthesis of growth regulating substance.