Bruns-Strenge, S/ Lange, OL 1992: Photosynthetische Primärproduktion der Flechte Cladonia portentosa an einem Dünenstandort auf der Nordseeinsel Baltrum. III. Anwendung des Photosynthesemodells zur Simulation von Tagesläufen des CO2-Gaswechsels und zur Abschätzung der Jahresproduktion [Photosynthetic primary production of the lichen Cladonia portentosa in a dune habitat at the Island Baltrum in the North Sea. III. Use of the photosynthesis model to simulate daily courses of CO2 exchange and to calculate the annual production]. - Flora186: 127-140. [RLL List # 148 / Rec.# 2575] Keywords: ANNUAL PRODUCTION/ CO2 EXCHANGE/ PHOTOSYNTHESIS/ PRIMARY PRODUCTION
Abstract: 5 fig. 3 tab. ["In the spring, summer and fall, days with rain resulted in the greatest CO2 fixation, followed by days with fog and by days with nocturnal hydration which took place mainly by dew fall. In contrast during winter, the average CO2 uptake on rainy days was much less due to low light intensities, and days with dew fall were associated with the highest CO2 gain. The fall was the season during which estimates of CO2 fixation by the lichen were greatest, however, photosynthetic productivity during spring and in the summer was similar in magnitude. In contrast, carbon gain in the winter was less than half of that predicted for the other seasons. In the annual total, 66% of the net production of the lichen resulted due to moistening by rain, 22% by fog, and 10.4% to nocturnal moistening by dew condensation. The integrated balance of the photosynthetic production of the lichen for a typical year was 27.9 mmol CO2 per g dry weight. This annual carbon gain equals ca. 79% of the carbon content of the thallus. Apparently only a small proportion of this primary production is incorporated into new biomass of the slowly growing lichen. We suggest that excess carbon fixation may be necessary due to substantial leaching of assimilates, especially during moistening by rain. This assimilated carbon may be lost due to the open structure of the lichen thallus."]