Photosynthetic rate model in response to environmental parameters for Avicennia marina (Forssk.) Veih. in an Indian mangrove forest

摘要

Photosynthetic rate models at leaf levels, viz., upper and middle canopy leaves were constructed separately in response of photosynthesis of Indian Avicennia marina to environmental variables as a major indication. The final expressions for the rates of photosynthesis were achieved by incorporating a combination of parameters involved in two separate models (already existing); namely, biochemical photosynthetic model and stomatal conductance model as inputs to two-stage least squares fitting regression method. The distinctiveness of the responses of photosynthesis in the two types of leaves to diurnally changeable factors, including solar radiation, temperature, CO₂ concentrations, water content in the atmosphere, vapour pressure deficit and relative humidity, were investigated in the respective models. Analyses of the physiological data of the leaves measured in the months of January–February indicated satisfactory performance of the models in the simulation of the respective photosynthetic rates (r 2 values, 0.97 and 0.96 for upper and middle canopy leaves, respectively).