© 1998 Heron Publishing—Victoria, Canada
Effects of current-year and previous-year PPFDs on shoot gross morphology and leaf properties in Fagus japonica
Kyoko Kimura (1), Atsushi Ishida (2), Akira Uemura (2), Yoosuke Matsumoto (2) and Ichiro Terashima (3, 4)
1. Graduate School of Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305 Japan / 2. Forestry and Forest Products Research Institute (FFPRI), Kukizaki, Inashiki-gun, Ibaraki, 305 Japan / 3. Institute of Biological Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305 Japan / 4. Department of Biology, Graduate School of Science, Osaka University, 1-16 Machikaneyama-cho, Toyonaka, Osaka, 560-0043 Japan (itera@chaos.bio.sci.osaka-u.ac.jp
) / Received August 15, 1997
Summary
We investigated how shoot gross morphology and leaf properties are determined in Fagus japonica Maxim., a deciduous species with flush-type shoot phenology, in which all leaves are produced in a single flush at the start
of each season. We examined relationships between current-year shoot properties and local light environment in a 14-m tall
beech tree growing in a deciduous forest. Leaf number (LN), total leaf area (TLA), and total leaf length (SL) of the current-year
shoot increased with increasing photosynthetic photon flux density (PPFD). Leaf thickness, dry mass per leaf area and nitrogen
content on a leaf area basis increased, whereas the chlorophyll/N ratio decreased with increasing PPFD. To separate the effects
of current-year PPFD from those of previous year(s), we artificially shaded a part of the uppermost leaf tier. Reciprocal
transfers of beech seedlings between controlled PPFD regimes were also made. Characteristics of shoot gross morphology such
as LN, TLA and SL were largely determined by the PPFD of the previous year. The exception was the length of the longest "long
shoots" with many leaves, in which elongation appeared to be influenced by both previous-year and current-year PPFD. In contrast,
leaf properties were determined by current-year PPFD. The ecological implications of our findings are discussed.
Keywords:
light environment within a tree, long shoots, shade leaves, shoot autonomy, short shoots, sun leaves.
