Bushiness and cytokinin profile in dormant and sprouting tubers of Zantedeschia

摘要

The commercial Zantedeschia industry faces a potentially serious problem with the cultivar Florex Gold periodically producing weak, poor performing "bushy" plants in their second growing season. As these plants are derived from tissue culture, it had been suggested that the use of cytokinin during the tissue culture process might be a causative factor. Endogenous cytokinin concentration and profile in dormant and sprouting Zantedeschia tuber eyes (buds) of the cultivars Florex Gold (prone to bushiness) and Best Gold (not prone to bushiness) were determined by high-performance liquid chromatography and radioimmunoassay. During sprouting the total cytokinin concentration in Florex Gold tuber eyes rose tenfold, with a 40-fold increase in the nucleotides. No role for endogenous cytokinin concentration or profile in the expression of the bushy syndrome was established, as there were no measurable differences between bushy and control Florex Gold samples, whether dormant or sprouting. However, sprouting tuber eyes from the cultivar Florex Gold had nearly twofold more cytokinin than sprouting eyes from the cultivar Best Gold, which may in some way predispose Florex Gold to bushiness.