The preparation in vitro of chrysanthemum for transplantation to soil

Paclobutrazol is a growth retardant that improves resistance of micropropagated plantlets to desiccation. It consists of two enantiomers in equal proportions, the 2R, 3R enantiomer, which blocks sterol biosynthesis, and the 2S, 3S enantiomer, which blocks gibberellin biosynthesis. Plantlets of chrysanthemum were treated with paclobutrazol, enantiomer 2R, 3R, enantiomer 2S, 3S or none of these (control). Assessments of transpiration rates, wilting under water stress and morphology indicate that the improved resistance of plantlets to desiccation can be attributed to the activity of enantiomer 2S, 3S and, hence, to inhibition of gibberellin synthesis.