Chlorophyll fluorescence curves for a set of trees undergoing different treatment conditions
Chlorophyll fluorescence curves for a set of trees undergoing different treatment conditions
The aim of this project is to model typical behavior of plants as opposed to their behavior under stress, via analysis of chlorophyll fluorescence curves. In this project, responses of different plant species under varying treatment conditions are being examined in the light of their photosynthetic activities. In 2001, the first set of fluorescence measurements were recorded. The procedure was roughly as follows: a leaf was exposed to a controlled light signal for two seconds and its fluorescence signal was measured and digitally recorded. Each such two-second exposure led to some 1200 observations. This process was repeated over several weeks on a number of marked leaves from various trees belonging to different species. These trees were also exposed to different treatment conditions (please refer to the Zelle-Baum open-top chamber and field designs). Typically, the fluorescence curves exhibit a fast rise to a maximum followed by a slow decline to a steady state. One of the specific aims here is to estimate the theoretical fluorescence curve (deterministic trend function) as a function of time and examine how its shape may change depending on the gradual effect of heavy metals and acid rains. The statistical methods being used here include time series analysis of repeated measures data and methods for curve estimation. The statistical modeling of the data is currently in progress. Additional fluorescence measurements are expected to be taken each year until 2004.
(* Figure prepared by Walter Dann)
Project leader:Rita
Ghosh , WSL (e-mail: rita.ghosh@wsl.ch)
Collaborators: University
of Geneva (Bioenergetics lab), WSL (Bioindications group), University of
Konstanz (Department of Mathematics & Statistics)
Acknowledgements: