Poster: Late and Moved Abstracts

Abs # 974: Simultaneous measurements of chlorophyll fluorescence emission and of gas exchange of higher plant leaves in static and dynamic environments.

Presenter:	Soukupova, Julie , soukupova@greentech.cz
Authors	Soukupova, Julie  (A)   Nedbal, Ladislav  (A) (B)  Trtilek, Martin  (C)   Santrucek, Jiri  (D)
Affiliations:	(A): Institute of Landscape Ecology ASCR (B): Institute of Physical Biology JCU (C): PSI (Photon Systems Instruments), Ltd. (D): Faculty of Biology JCU
Web Site:	http://www.greentech.cz

Imaging kinetic fluorimeter FluorCam (www.psi.cz) was used to map fluorescence transients over an attached sunflower leaf in a variety of well-defined external conditions. Simultaneously, portable photosynthesis system Cirras-1 (www.ppsystems.com) was employed to monitor integral leaf parameters: CO2 uptake and transpiration. The parallel monitoring of leaf heterogeneity by fluorescence and of integral leaf performance by gas exchange was aimed at dissecting the role of spatial and temporal heterogeneity in static and dynamic environments. First, we measured light saturation curves for a variety of temperatures and air composition ratios. The photosynthetic heterogeneity over the leaf area in the steady-state was evaluated by comparing 2-D resolved and integral data measured in constant light. Second, the dynamic environment was modeled by harmonically modulated irradiance that was earlier shown to lead to far-from-equilibrium photosynthesis that vastly differs from the activity attained in the steady-state conditions (Nedbal et al. (2003) Biochim.Biophys.Acta: Bioenergetics 1607: 5-17). Here, we show that the different plant behavior is reflected in significantly different heterogeneity of the photosynthetic activity over the leaf area in static and dynamic environments.