New Zealand Journal of Botany abstract
Response in chlorophyll a fluorescence of six New Zealand tree species
to a step-wise increase in ultraviolet-B irradiance
J. E. HUNT*
F. M. KELLIHER
Manaaki Whenua - Landcare Research
P.O. Box 69
Lincoln, New Zealand
*Also at Department of Plant Science
Lincoln University
D. L. McNEIL
Department of Plant Science
P.O. Box 84
Lincoln University
New Zealand
Abstract A laboratory protocol to quantify damage from a
sudden increase in ultraviolet-B irradiance (UV-B, waveband 280-320 nm) to
cucumber (cv. Poinsett) seedlings, including saturating photosynthetically
active irradiance (400-700 nm, 1200 umol/m2/s), was determined
using leaf chlorophyll a fluorescence measurements to estimate
photoinhibition. Seedlings of six native New Zealand tree species, grown in a
common garden, were irradiated for 4 h, receiving a total
biologically-effective UV-B dose of 17 kJ/m2 or about twice that on
a clear summer day in New Zealand.
There was a wide range of responses to an increase in UV-B irradiance
including a 20% increase in photoinhibition for two shade tolerant species and
10% increase for the shade intolerant red beech (Nothofagus fusca). The
other species were not affected. Mountain beech (N. solandri var.
cliffortioides ) was particularly tolerant of high UV-B doses. Leaf and
epidermal thickness, and flavonoid concentration did not correspond well with
species response.
Keywords ultraviolet-B irradiance; chlorophyll a
fluorescence; native trees; cucumber
B95045
Received 11 October 1995; accepted 8 May 1996
PDF file of entire paper: medium quality (594K); (scanned from paper original: notes about this process)
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