Method for Field Measurements of CO2-Exchange. The Diurnal Changes in Net Photosynthesis and Photosynthetic Capacity of Lichens under Mediterranean Climatic Conditions
The determination and interpretation of patterns in photosynthetic primary production which are characteristic of different lichen species within their respective habitats may lead to a better understanding of habitat preferences and species distributions. However, the necessary photosynthetic CO2 exchange measurements are difficult to accomplish in the field. Thus, only a few examples of diurnal courses of photosynthetic CO2 uptake by poikilohydric organisms may be found in the ecophysiological literature. Recently mathematical models have been developed which have been used to simulate the net photosynthetic performance of lichens under natural conditions. Because such models are usually based upon physiological parameters obtained from laboratory experiments, their validity can only be established by comparing simulated rates of photosynthesis with rates actually measured in the field. Thus, the development of instrumentation and methods which allow accurate determination of CO2 exchange of lichens under natural conditions is essential.
KeywordsPhotosynthetically Active Radiation Lichen Species Light Response Curve Negev Desert Lichen Sample
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