Modelling the response of wheat canopy assimilation to atmospheric CO₂ concentrations

Abstract

Summary• The predictive capacity of two simulation models with different degrees of complexity for the calculation of assimilate production, was tested at different time scales, using a data set of wheat grown in an open-top-chamber experiment at two CO 2 concentrations.• Observed values of net canopy assimilation (Pn) were obtained from wheat plants grown at ambient (410 µ mol mol − 1 ) and elevated (680 µ mol mol − 1 ) CO 2 mole fractions. Pn was simulated by using either simple multiple regression equations (AFRCWHEAT2) or by highly detailed calculations of leaf energy balances and the coupling of photosynthesis with stomatal conductance ( LINTULCC2).• Irrespective of the developmental stage of the crop or variation in weather, the models accurately simulated canopy assimilation and growth. We conclude that the response of aboveground-biomass production to elevated CO 2 concentrations was explained primarily by the effects of CO 2 on radiation-use efficiency and assimilate production.• The models explained satisfactorily the daily course of Pn, its integrated daily totals, and the seasonally produced aboveground biomass, both at ambient and elevated CO 2 concentrations. Specific problems in the simulations were identified and discussed.

Intrinsic changes in photosynthetic parameters of carrot leaves under increasing CO₂ concentrations and soil moisture regimes

“…At -70 kPa, g s remained at 0 mol m -2 s -1 despite C a increased. These results are in acceptance with observations made by Rodriguez et al (2001). They have reported a decrease in g s in wheat plants under EC growth conditions.…”

Testing different CO2 response algorithms against a FACE crop rotation experiment

“…Others employ a [CO 2 ]-dependency of the photosynthesis-light response curve [24][25][26]. Only a few approaches use leaf-level biochemical algorithms, which require extensive parameterization and are therefore more applicable to biochemical process research [e.g., 27].…”

Root growth, water uptake, and sap flow of winter wheat in response to different soil water conditions

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