title: Ecophysiological investigations on lichens of the Negev desert : V. A model to simulate net photosynthesis and respiration ofRamalina maciformis.
abstract: Previous publications have reported on investigations of CO2exchange in the desert lichenRamalina maciformis both in its natural habitat in the Negev and in the laboratory. Utilizing laboratory data, net photosynthesis and dark respiration were expressed as mathematical functions of the most important environmental factors. Based on these relationships, a model is developed that allows one to predict CO2exchange of the plant. Input data are light intensity, temperature, and water content of the thallus, together with a measure of the rate of the seasonal change of photosynthetic and respiratory activity. The validity of the model is tested by comparing simulated daily courses of CO2uptake and release of the lichen with independent results of CO2exchange measurements conducted in the field during and after the condensation of dew. The sensitivity of the model is shown by simulating changes in the input data of temperature and water content of the lichen.
authors.affiliation: Lehrstuhl für Botanik II, Botanisches Institut der Universität, Mittlerer Dallenbergweg 64, D-8700, Würzburg, Federal Republic of Germany.
authors.forename: O L
authors.initials: OL
authors.lastname: Lange
authors.affiliation: Lehrstuhl für Botanik II, Botanisches Institut der Universität, Mittlerer Dallenbergweg 64, D-8700, Würzburg, Federal Republic of Germany.
authors.forename: I L
authors.initials: IL
authors.lastname: Geiger
authors.affiliation: Lehrstuhl für Botanik II, Botanisches Institut der Universität, Mittlerer Dallenbergweg 64, D-8700, Würzburg, Federal Republic of Germany.
authors.forename: E -D
authors.initials: E-
authors.lastname: Schulze