New Zealand Journal of Botany abstracts
Effects of nitrogen supply on phenology and carbon assimilation in young
Nothofagus fusca
DAVID W. STEPHENS*
Department of Plant and Microbial Sciences
University of Canterbury
Private Bag 4800
Christchurch, New Zealand
Email: D.Stephens1@clear.net.nz
DAVID WHITEHEAD
Landcare Research
P.O. Box 69
Lincoln 8152, New Zealand
MATTHEW H. TURNBULL
Department of Plant and Microbial Sciences
University of Canterbury
Private Bag 4800
Christchurch, New Zealand
PETER MILLARD
Macaulay Land Use Research Institute
Craigiebuckler
Aberdeen AB9 2QJ, United Kingdom
*Present address: Department of Conservation, Private Bag 3072,
Hamilton, New Zealand.
Abstract Measurements of stem, bud, and leaf growth and leaf
loss were made on young
Nothofagus fusca, grown in sand while irrigated
with high (6 m
M), medium (3 m
M), and low (0.5 m
M)
concentrations of nitrogen, during two successive annual growth cycles. There
were differences between treatments in the nitrogen concentration per unit leaf
mass and area, and specific leaf area, in the first cycle but not during the
second cycle. During the first cycle, increasing nitrogen supply resulted in
increased leaf number, larger average leaf size, and the number and mass of
buds. During the second cycle this resulted in increased leaf number, but not
average leaf size, with increasing nitrogen supply. There were no differences
in maximum rates of photosynthesis or values for photosynthetic parameters
between the treatments. The number of leaves falling during late summer and
autumn increased with nitrogen supply. Support for this as a response to summer
water deficit was provided from measurements of the carbon isotope ratios of
the leaves.
Keywords Nothofagus fusca; nitrogen; phenology;
photosynthesis; water use efficiency
B00036
Received 24 August 2000; accepted 4 October 2001
New Zealand Journal of Botany, 2001, Vol. 39: 617-630
0028-825X/01/3904-0617 $7.00 (c) The Royal Society of New Zealand 2001
PDF file of entire paper: medium quality (981K); (scanned from paper original: notes about this process)
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