In the research described here, stems of 'Mahoroba Pink Flash' with three to four fully open flowers and three to five flower buds were cut and stood in tap water for one-and-a-half hours. The stems were then standardised by reducing their length to 60cm, stripping the leaves from the bottom 15cm of each stem and removing flowers and flower buds to leave just three flowers and three buds per stem.
The prepared stems were next stood for 24 hours in solutions either of four per cent sucrose or of four per cent sucrose plus 10 micromolar abscisic acid (ABA). Some of the sucrose in each solution was labelled with carbon-13.
All stems treated with sucrose alone had at least one damaged leaf, while none were damaged when ABA was added to the sucrose. The distribution of carbon-13 showed that transport of the added sugar to the leaves was blocked by ABA while transport to the flowers was encouraged, as was the transport of sugars already present in the stems.
Effect of Abscisic Acid on the Distribution of Exogenous Carbon Derived from Sucrose Applied to cut Eustoma Flowers by Shimizu-Yumoto, Kondo, Sanoh, Ohsumi and Ichimura (2010). Journal of Horticultural Science & Biotechnology 85 (1): 83-87. The authors' abstract of their manuscript can be seen in full at www.jhortscib.com
Dr Ken Cockshull is Emeritus Fellow at Warwick HRI