Response of juvenile Pseudopanax crassifolius to gibberellic acid and paclobutrazol

Abstract Gibberellic acid and paclobutrazol (an inhibitor of endogenous gibberellin synthesis) were applied separately and in combination to young seedlings of Pseudopanax crassifolius (A. Cunn.) C. Koch in an attempt to induce the mature phase by the reduction of endogenous gibberellins. Exogenous gibberellins caused increased shoot extension and node formation and induced hyponasty in the juvenile leaves. Plants treated with paclobutrazol showed a severe inhibition of growth which was totally relieved by exogenous gibberellic acid. Treatment with paclobutrazol did not, however, induce any mature characteristics in the plants.