© 2006 Heron Publishing—Victoria, Canada
Callose in root apices of European chestnut seedlings: a physiological indicator of aluminum stress
Yasuhiro Hirano (1, 2, 3), Lorenz Walthert (1) and Ivano Brunner (1)
1. Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), CH-8903, Birmensdorf, Switzerland / 2. Kansai Research Center, Forestry and Forest Products Research Institute (FFPRI), Kyoto 612-0855, Japan / 3. Corresponding author (yhirano@affrc.go.jp) / Received April 26, 2005; accepted July 8, 2005; published online January 15, 2006
Summary
We determined if callose formation in 1-cm-long root apices of European chestnut (Castanea sativa Mill.) seedlings is affected by naturally occurring high concentrations of aluminum (Al) under laboratory conditions and
by low base saturation (BS) of soils under forest field conditions. Under controlled conditions in the laboratory, seedlings
were treated with simulated soil solutions in the presence or absence (control) of Al. One day after exposing seedlings to
a simulated soil solution containing 168 µM Al, callose formation in the root apices had increased significantly. After 7
days, callose concentration in root apices was significantly correlated with the concentration of free Al3+ ions recovered in the simulated soil solution and with the concentration of Al in fine roots. At four field sites in southern
Switzerland, seedlings were grown for five months in either A-horizon soil with a BS above 17% or in a B-horizon soil with
a BS below 5%. Callose concentrations were significantly higher in root apices in the B horizon than in the A horizon. Callose
concentrations in root apices were negatively correlated with Ca/Al molar ratio in fine roots. We conclude that callose in
the root apices of European chestnut could be a useful physiological parameter for assessing Al toxicity under both laboratory
and field conditions.
Keywords:
base saturation, 1,3-β-glucan, Castanea sativa, free Al3+ ions, soil acidification.
