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In vivo measurement of spectroscopic and photochemical properties of intact leaves using the ‘mirage effect’
Author(s) -
Havaux Michel,
Lorrain Lucie,
Leblanc Roger M.
Publication year - 1989
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(89)80763-x
Subject(s) - photothermal therapy , deflection (physics) , photoacoustic imaging in biomedicine , optics , laser , dissipation , photosynthesis , chemistry , light energy , materials science , physics , biochemistry , thermodynamics
This paper describes a new, highly sensitive, method for in vivo studies of photosynthesis based on the ‘mirage effect’ in which thermal energy dissipation from intact leaves, illuminated with intensity‐modulated light, is sensed through the periodic deflection of a laser beam propagating along the leaf surface. The photothermal deflection technique allows one to rapidly estimate the gross efficiency of photochemical energy storage by comparing the heat emission signal with and without an additional strong, photosynthetically saturating, non‐modulated light. In pea leaves, the maximal storage efficiency at low light intensities was shown to approach 55%. The general utility of this simple photothermal method is illustrated by examining the variation of the deflection signal under different conditions. The spectral resolution of this new method is shown to be much higher than that of the photoacoustic method.