1. Laser Induced Fluorescence Transient (LIFT): remote measurement of light use efficiency in ecosystems Roland Pieruschka, Uwe Rascher, Denis Klimov, Zbigniew S. Kolber, Joseph A. Berry February, 08. 2007

2. Objectives Inaccessible outer canopies - need for remote measurement of light use efficiency Evaluation of the LIFT approach by PAM fluorometry and gas exchange Measurement of cold/light stress of outer canopies in the field Implementation of the data into canopy models to reduce their uncertainty

3. LIFT – Fluorometer remote measurement: from a distance up to 50 m excitation signal: 665 nm laser diode fluorescence emission at 690 nm: collected by Cassegrian telescope and detected by avelange photodiode

4. Fast Repetition Rate Fluormetry (Kolber et al. 1998; Kolber et al. 2005. Ananyev et al. 2005)

5. What are we measuring? single vs. multiple turnover (Govindjee, 1995) FRR: sequence of single turnover fleshlets: corresponds to O-J phase (photochemical phase) kinetics of Q A - accumulation/re-oxidation with minimal effect on PQ pool PAM: multiple photochemical turnover: corresponds to O-J-I-P phase (photochemical and thermal phase) well defined final state with fully reduced PQ pool

6. Laboratory experiments: bench top FRR vs. PAM Combined measurements of: gas exchange (LI-6400) chlorophyll fluorescence using PAM and a bench top FRR measurements under non- photorespiratory conditions

7. Laboratory experiments: bench top FRR vs. PAM FRR PAM

8. Laboratory experiments: bench top FRR vs. PAM

9. Electron Transport Rates gas exchange vs. fluorescence PAMFRR (Genty et al. 1989)

10. Electron Transport Rates from FRR fluorescence and gas exchange

11. PSII quantum efficiency vs. quantum yield of CO 2 assimilation

12. Estimate of underestimation of ETR by FRR 4*(A+Rd) /PAR vs. Fv/Fm Corrected ETR

13. Summary I The LIFT/FRR is working with low excitation intensities resulting in lower maximum fluorescence then the PAM approach in particular under high light intensities However, the LIFT approach provides an advantage of remote measurement of Fv Fm -1’ as an index of stress correlated to ETR within undisturbed microenvironment of leaves

14. Field experiments Impact of cold stress on photosynthesis - Capsicum annuum - Ficus spec. - Lycopersicon esculentum - Persea americana - grass community dominated by Lolium spec.

15. Predawn measurements on Lycopersicon esculentum

16. Diurnal course: Lycopersicon esculentum

17. 1 2 4 3 Predawn measurements on Persea americana

18. target 1 target 3 Diurnal cours: Persea americana

19. Steady state fluorescence

20. Summary II The LIFT system can sensitively detect stress correlated to ETR In order to quantify photosynthetic CO 2 uptake the LIFT system has to be extended by measurements of: - light - stomatal conductance - temperature

21. Acknowledgement Marie Curie Outgoing International Fellowships (Nr: 041060 – LIFT) Joe Berry Zbigniew Kolber Uwe Rascher Denis Klimov Larry Giles Bob Haxo