An entirely new design, the LI‑6800 Portable Photosynthesis System is a technological innovation that can reveal the mechanisms of photosynthesis.


Featuring the latest advancements in non-dispersive infrared gas analysis technology

At LI-COR, we know gas analysis. That is why our gas analyzers are trusted to make the most important measurements around the world, from the Mauna Loa Observatory to regional networks that monitor greenhouse gas emissions using the eddy covariance method. This expertise sets the LI-6800 apart from other photosynthesis systems.

differential CO2/H2O gas analyzer

The LI-6800 features one of the best differential CO2/H2O gas analyzers we have ever developed. The differential gas analyzer consists of two analyzers—sample and reference—that are machined from a single aluminum block, and that share a number of critical components. The sample analyzer measures air that has been exposed to the leaf, whereas the reference analyzer measures conditioned reference air. Photosynthetic assimilation is computed from flow rate, leaf area, and the difference between the readings from the sample and reference gas analyzers.

The gas analyzers in the LI-6800 are highly durable and stable, ensuring that the LI-6800 will be a valuable investment for many years.

Innovations to air flow controller for fewer leaks and better results

Creating a new instrument from scratch, we began with this directive: Make the system less prone to leaks.

Leaks are a problem when making differential measurements because leaks lead to direct errors. We designed a new flow control mechanism that eliminates a common cause of leaks. A single tube carries conditioned air from the console to the head and a patented system of valves controls the flow to leaf chamber and sample gas analyzer, while the remaining flow goes to the reference gas analyzer. This configuration significantly reduces the total length of tubing for the system, while eliminating the possible effect of leaks as air moves from the console to the sensor head.

We designed a novel, dual articulated chamber closure that clamps over each leaf with uniform pressure. And, we selected gasket material that readily conforms to the leaf surface and resists diffusion. These features help prevent leaks around the chamber-leaf interface, leading to improved measurements.

In addition, the system monitors flow and notifies you if it detects a leak, so you can address it right away.

Dual articulated chamber closure
6800-01 Multiphase Flash Fluorometer

Advanced fluorometer to reveal the photochemical mechanisms of photosynthesis

Adding immensely to the descriptive nature of a photosynthesis measurement, measurements of chlorophyll a fluorescence provide information about the light-driven electron transfer rate and non-photochemical quenching, an assortment of reactions that collectively protect a leaf when it absorbs excessive light energy.

We equipped the LI-6800 with one of the most sophisticated fluorometers available. Designed specifically for combined gas exchange and chlorophyll fluorescence measurements over the same leaf area, the fluorometer features a user-configurable modulation rate and integrated intensity. It automatically controls irradiance during all phases of a saturating flash, and is capable of traditional saturating flashes at intensities of 16,000 mol m-2 s-1 over a 6 cm2 leaf area.

With high modulating frequencies (up to 250 kHz), the LI-6800 fluorometer can fully characterize the fluorescence induction transient of a leaf at high resolution. Combined gas exchange and fluorescence measurements provide a more complete picture of photosynthesis than either technique alone. The LI-6800 is the only combined gas exchange and fluorescence system to offer this feature.

“Being able to enter the leaf width into the program has been really helpful to get real‑time readings.”

– Randy Long, last year's winner

Read More

How it's Different

caretContinue Reading

Scroll to Top