The Preparation Invitro Of Chrysanthemum For Transplantation To Soil .4. The Effects Of 11 Growth-Retardants On Wilting

Plantlets of Dendranthema grandiflora 'Pennine Reel' were grown from nodal sections on Sorbarods saturated with liquid medium containing 0-3 mg l-1 of various growth retardants. After 4 weeks they were transferred to compost and maintained at a relative humidity of 42% at 27.5-degrees-C. Wilting was assessed over a period of 3 h. Plantlets treated with paclobutrazol, flurprimidol, triapenthenol, chlorphonium chloride, uniconazol and ancymidol showed dose-related reductions in wilting up to a concentration of 3 mg l-1. Responses to tetcyclacis and mepiquat chloride were weaker, and no responses to chlormequat chloride, BTS 44584 or diaminozide could be detected. These observations are compatible with an hypothesis that resistance to wilting derives from inhibited synthesis of gibberellins.