HR: 1340h
AN: B43D-1600    [Abstracts]
TI: Remote measurement of photosynthetic efficiency using laser induced fluorescence transient (LIFT) technique.
AU: * Pieruschka, R
EM: piro@stanford.edu
AF: Carnegie Institution of Washington, Department of Global Ecology, 260 Panama Street, Stanford, CA 94305, United States
AU: Rascher, U
EM: u.rascher@fz-juelich.de
AF: Forschungszentrum Jülich, Leo-Brandt-Strasse, Jülich, NRW 52425, Germany
AU: Klimov, D
EM: klimov@mbari.org
AF: Monterey Bay Aquarium Research Institute, 7700 Sandholdt Road, Moss Landing, CA 95039,
AU: Kolber, Z S
EM: zkolber@mbari.org
AF: Monterey Bay Aquarium Research Institute, 7700 Sandholdt Road, Moss Landing, CA 95039,
AU: Berry, J A
EM: jberry@globalecology.stanford.edu
AF: Carnegie Institution of Washington, Department of Global Ecology, 260 Panama Street, Stanford, CA 94305, United States
AB: An understanding of spatial and temporal diversity of photosynthetic processes, water and energy exchange of complex plant canopies is essential for carbon and climate models. Remote sensing from space or aircraft platforms provides the only practical way to characterize the vast extent of plant canopies around the globe, but the basis for relating physiological processes to remote sensing is still largely theoretical. Experiments that bridge this gap are needed. Chlorophyll fluorescence measurements have been widely applied to quantify photosynthetic efficiency and non- photochemical energy dissipation non-destructively in photosynthetically active organisms. The most commonly used Pulse Amplitude Modulated (PAM) technique provides a saturating light pulse and is not practical at the canopy scale. We report here on a recently developed technique, Laser Induced Fluorescence Transient (LIFT), capable of remote measurement of photosynthetic efficiency of selected leaves at a distance of up to 50 m and we present here continuous studies on plans growing under natural conditions during the beginning of the winter season and the onset of summer drought in this Mediterranean climate. i) Lichens showed a strong diurnal variation in photosynthetic efficiency which correlated with relative humidity; ii) Photosynthetic efficiency of annual grass decreased with progressing drought stress; iii) An oak canopy showed very little variation of quantum yield from leaf out in spring to summer; iv) The combined effect of low temperature and high light intensity during an early winter strongly reduced the photosynthetic efficiency of four different species in response to chilling stress. These measures with the LIFT correlated well with (more limited) sampling by PAM fluoromentry and gas exchange. The ability to make continuous, automatic and remote measurements of photosynthetic efficiency of leaves with the LIFT provides a new approach for studying the heterogeneity of photosynthetic efficiency within canopies and for integrating these effects from the leaf to the canopy scale.
DE: 0439 Ecosystems, structure and dynamics (4815)
DE: 0476 Plant ecology (1851)
DE: 0480 Remote sensing
SC: Biogeosciences [B]
MN: 2007 Fall Meeting