Water balance of the foliage of cut Geraldton waxflower

Abstract

The foliage of cut Geraldton waxflower (Chamelaucium uncinatum Schau., Myrtaceae) often desiccates before flowers on the same sprig become senescent. The results of pressure-volume analysis comparing leafy and flowering sprigs suggest that leaves have relatively higher turgor and lower osmotic potentials than flowers, and that leaves are less elastic. For a similar fall in relative water content, the water potential decreases more in foliage than in flowers. Provision of exogenous ABA (10 ppm [37.8 μM]) in the vase solution effectively reduced vase solution usage and extended foliage longevity. The improved water balance achieved with ABA was apparently the result of stomatal closure. Inorganic salt (10 mM KCl) added to the vase solution also extended the longevity of Geraldton waxflower foliage.