Designed for cutting-edge research, yet easy to learn, the LI-6800 is both a remarkable teaching tool and a powerful research instrument that provides the ability to answer new questions.
By controlling environmental conditions in the chamber for the duration of a measurement, the LI-6800 prevents multiple parameters from confounding the plant responses, ensuring more repeatability and confidence in the results.
By controlling chamber conditions, the photosynthetic response to changes in intercellular CO2 concentration is not confounded by other independent variables. The LI-6800 controls the leaf chamber environment at the setpoints with low variance (n = 3; ± standard error of the means).
As the substrate for the dark reactions, photosynthetic responses to CO2 concentration provide information about the biochemical limitations. In C3 species, these data are used to assess Amax (maximum photosynthesis rate), Vc,max (maximum rate of Rubisco carboxylation), Jmax (maximum rate of electron transport for RuBP regeneration), and triose phosphate utilization (TPU) limitations.
The 6800-02 light source consistently illuminates the leaf with intensities that mirror ambient light levels.
The ΦPSII, measured from chlorophyll fluorescence, reflects the leaf illumination across the day, driving changes in electron transport.
The chamber light sources illuminate the leaf with uniform light. Variation typically is less than ± 10% over 90% of the aperture, ensuring that photosynthesis is even across the entire chamber aperture. The average photosynthetic carbon assimilation reflects the true spot-to-spot rate across the enclosed leaf area when the leaf is uniformly illuminated (n = 3; ± standard error from the means).
At low light intensities, the carbon assimilation rate is limited by light capture to drive linear electron transport in the light harvesting complex. Assessing the gross carbon assimilation response to absorbed light (Qabs) is a measure of the quantum efficiency of photosynthesis. The quantum efficiency for Nicotiana tabacum in non-photorespiratory conditions (0.5% O2 air) is consistent with theoretical and empirically measured values (n = 2, ± standard error of the means).
The LI-6800 Portable Photosynthesis System and accessories provide unprecedented capabilities to advance research in many different applications.