Some Characteristics of Water Flow through Isolated Rose Stem Segments1

Abstract

Abstract Water flow through isolated 5 cm stem segments of rose ( Rosa hybrida L. cv. Cara Mia) increased for 4-7 hours and then decreased linearly for several hours thereafter. Decreased rate of flow has been termed blockage rate. Flow rates varied inversely with segment length and directly with head pressure but blockage rates were unaffected by either variable. Maximum flow increased and blockage rates decreased as solution pH was decreased over a range from pH 6 to pH 3. Flow rates at 3°C were about half of flow rates at 24° and the addition of sucrose to the solution further reduced flow. Viscosity differences account for the flow rate decrease at lower temperature but did not account for the sucrose effect. Millipore filtration of water from a variety of sources resulted in substantial increase in flow rates.