The prediction and measurement of photosynthetic rate of Spartina townsendii (sensu lato) in the field.
Abstract
A simple model was constructed which predicted the rates of leaf photosynthesis (Fc) of the temperate C4 species S. townsendii, in the field, from the prevailing light and temp. The parameters of the model were derived from laboratory studies. The model was tested by measuring Fc with 14CO2 at regular intervals through 1 growing season at a field site on the Humber estuary. Measured and predicted values of Fc were similar, except during the early part of the growing season when the model significantly overestimated Fc. The results showed that high values of Fc, previously reported in laboratory studies, were also a feature of S. townsendii growing on an intertidal marsh in the UK. In contrast to most other C4 species, exposure of S. townsendii to air temp. below 10 deg C, and even to ground frosts, had little effect on subsequent Fc.