2004 Volume 53 Issue 12 Pages 1495-1500
Much physiological information on trees has been provided to be basically available for understanding their rolls in forested ecosystems, such as being stressed by probable continuous acidification. With xylem sap, though its flow characteristics have been well examined diurnally and seasonally by measuring the flow rate, its chemistry has been left unprovided with sufficient information on a continuous change in the composition and/or amounts of dissolved species, as understood to be probably due to a lack of in vivo observations. Here, with a Konara stand, a method for the examination of xylem sap chemistry comprising continuous collection of ionic species with use of ion-exchange fibers and determination of species adsorbed is proposed. Application of the method gave the tollowing results: (1) Ionic species collected by the ion exchange fibers were effectively desorbed to be determined. (2) Major ions in the xylem sap were potassium and calcium to change from 70 to 93% and from 13 to 4%, respectively, reflecting an air temperature rise and a radiation change from early spring to summer. Thus, though some difficulties are left to be solved, the present method is potentially applicable for monitoring the chemistry of xylem and/or phloem saps in trees.
