Cytokinin and gibberellin delay regreening of spathe tissue of Zantedeschia ‘Best Gold’

• Several synthetic plant hormones were evaluated for their influence on regreening of discs excised from the spathe of Zantedeschia ‘Best Gold’.
• Application of BAP or GA3 alone at 0.1 mM resulted in 1–5 d delay on regreening of the spathe tissue.
• The most effective treatment in delaying regreening was from the simultaneous application of GA3 and BAP in a ratio of 1:1 (v:v) at 0.1 mM, wherein regreening was delayed for more than 10 d.
• This treatment was then tested on the entire inflorescence, resulting in a delay in regreening for between 7 and 8 d.

Spathe regreening is a primary determinant limiting the postharvest quality for most hybrids of Zantedeschia, e.g. ‘Best Gold’, wherein the spathe commences regreening approximately two days after it is fully open. To identify an effective method to postpone the regreening, several synthetic plant hormones were evaluated for their influence on changes in color during regreening of discs excised from the spathe of ‘Best Gold’. The tested synthetic plant hormones included 6-benzylaminopurine (BAP), zeatin, N1-(2-chloro-4-pyridyl)-N3-phenylurea (CPPU) and GA3 at concentrations up to 0.1 mM. A concentration of BAP at 0.5 mM resulted in phytotoxicity symptoms on discs. Subsequently, the effect of a combination of BAP and GA3 on the regreening was examined. Application of the cytokinins (in particular BAP at 0.1 mM) or GA3 alone resulted in a one to five day delay in regreening on the spathe tissue. The most effective treatment in delaying regreening was from the simultaneous application of GA3 and BAP in a ratio of 1:1 (v:v) at 0.1 mM, wherein regreening was delayed for more than ten days. This treatment was then tested on the entire inflorescence, resulting in a delay in regreening for between seven and eight days.