© 2007 Heron Publishing—Victoria, Canada
Optimal conditions for visualizing water-conducting pathways in a living tree by the dye injection method
Toshihiro Umebayashi (1), Yasuhiro Utsumi (2, 3), Shinya Koga (2), Susumu Inoue (2), Yasuki Shiiba (2), Keita Arakawa (4), Junji Matsumura (5) and Kazuyuki Oda (5)
1. Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, Hakozaki 812 -8581, Japan / 2. Shiiba Research Forest, Graduate School of Agriculture, Kyushu University, Shiiba 883-0402, Japan / 3. Corresponding author (utsumi@forest.kyushu-u.ac.jp) / 4. Laboratory of Wood Biology, Graduate School of Agriculture, Hokkaido University, Sapporo 060-8589, Japan / 5. Laboratory of Wood Science, Graduate School of Agriculture, Kyushu University, Hakozaki 812-8581, Japan / Received May 18, 2006; accepted September 5, 2006; published online April 2, 2007
Summary
To elucidate the water-conducting pathways in living trees by the dye injection method, suitable sample preparation procedures
are needed. We evaluated quantitatively the properties and concentrations of three dyes (acid fuchsin, basic fuchsin and safranin)
widely used for this purpose, and determined the optimal conditions required to avoid artifacts after dye injection into the
sap stream of Pieris japonica D. Don. Among the dyes tested, an aqueous solution of acid fuchsin at a concentration of 0.1% or more was the most useful
for delineating water movement. In non-transpiring stem segments, the vertical movement of acid fuchsin by capillarity and
diffusion from the dye injection site was limited. However, acid fuchsin moved rapidly in the horizontal direction by capillarity
and diffusion, and most xylem cells were stained within 2 h. A delay of more than 2 h between dye injection and examination
of the tissues greatly reduces the precision of the method. Use of the dye injection method without appropriate, well-defined
experimental procedures may give rise to misleading information about the functional water-conducting pathway in living trees.
Keywords:
acid fuchsin, basic fuchsin, Pieris japonica, safranin, xylem elements.
