Abstract: Systems and methods for measuring plant leaf gas exchange based on instantaneous mass balance in the sample chamber. The response of leaf net assimilation rate (Anet) to computed leaf internal CO2 concentration (C1) is measured by continuously varying the input CO2 concentration and measuring the continuous difference between chamber input (reference) and output (sample) concentrations to compute a continuous series of Anet values, which can then be plotted against computed Ci. When combined with a similar response test using an empty chamber test to allow for sample chamber mixing and/or gas analyzer match dynamics and/or small flow-related residual time delays, such method provides accurate and rapid A Ci response (RACiR) curves in a much shorter time than conventional methods.

Abstract: Systems and methods for measuring plant leaf gas exchange based on instantaneous mass balance in the sample chamber. The response of leaf net assimilation rate (Anet) to computed leaf internal CO2 concentration (Ci) is measured by continuously varying the input CO2 concentration and measuring the continuous difference between chamber input (reference) and output (sample) concentrations to compute a continuous series of Anet values, which can then be plotted against computed Ci. When combined with a similar response test using an empty chamber test to allow for sample chamber mixing and/or gas analyzer match dynamics and/or small flow-related residual time delays, such method provides accurate and rapid A Ci response (RACiR) curves in a much shorter time than conventional methods.

Abstract: Methods, devices, and systems for measuring carbon assimilation based on simultaneous or near-simultaneous measurements of chlorophyll fluorescence and stomatal conductance of plant. A sample containing chlorophyll, such as a plant leaf, is illuminated with light, e.g., in the form of a single saturating pulse or multiple pulses, and chlorophyll fluorescence and stomatal conductance of the chlorophyll sample are measured. A porometer or infra-red gas analyzer is used to measure stomatal conductance and a photodetector is used to measure fluorescence. A carbon assimilation value for the chlorophyll sample is determined using the measured chlorophyll fluorescence and the measured stomatal conductance.