Effects of Surfactants on the Vascular Occlusion Induced by Exposure to Air in Cut Flowering Stems of Astilbe, Bouvardia, and Rose

Summary When cut flowering stems of roses ( Rosa hybrida L. ‹Sonia›), Bouvardia hybrid #x2039;Artemis Jowhite› and Astilbe hybrid #x2039;Cattleya#x203A; were held dry for 24 h at 20#x00B0;C and 60% r.h., an occlusion for water uptake developed in the lowermost segment of the stems_ When placed in water after dry storage, the flowering rose stems showed a small increase in fresh weight (FW), the stems of Bouvardia no increase in FW, and the Astilbe stems a decrease in FW. Placement of the stems in an aqueous solution containing a surfactant (Nonoxynol-8.5), prior to exposure to air, resulted in a marked increase in FW in all three investigated species when the stems were placed in watar after exposure to air. This increase in FW was not due to a reduction in the rate of transpiration during exposure to air, but to an increase in water uptake during the first day after the exposure to air. The results indicate that the occlusion is related to surface tension. Three alternative mechanisms involving surface tension are discussed.