Authors: Stephen K Herbert Karl Y Biel Thomas C Vogelmann
Publish Date: 2006/01/26
Volume: 87, Issue: 3, Pages: 287-
Abstract
The photosynthetic and photoacoustic properties of leaf samples were studied using a photoacoustic system modified for precise temperature control Data were collected over a temperature range of −10 °C to +60 °C A distinct acoustic noise transient marked the freezing temperature of the samples A positive absorption transient and a brief period of oxygen uptake marked the thermal denaturing temperature of the samples Between these extremes the effects of temperature on light absorption oxygen evolution and photochemical energy storage were quantified quickly and easily Oxygen evolution could be measured as low as −5 °C and showed a broad temperature peak that was 10 °C lower under limiting light intensity than under saturating light intensity Photochemical energy storage showed a narrower temperature peak that was only slightly lower for limiting light intensities than for saturating light intensities In a survey of diverse plants temperature response curves for oxygen evolution were determined readily for a variety of leaf types including ferns and conifer needles These results demonstrate that temperaturecontrolled photoacoustics can be useful for rapid assessment of temperature effects on photosynthesis and other leaf propertiesFinancial support for this work was from an NSF Major Research Instrumentation grant DBI9724499 to TC Vogelmann JN Nishio and SK Herbert We dedicate this paper to Professor FF Blackman on the 100th anniversary of his paper titled `Optima and Limiting Factors in which he presents an insightful discussion of the relationships between temperature and photosynthesis
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