New leaf area options for the LI-6800 Portable Photosynthesis System are available. Measurable leaf areas ranging from 2 cm2 all the way to 36 cm2 mean you can take measurements on leaves of nearly any shape and size.
An accurate measure of leaf area is an important parameter for calculating assimilation rate. If the area of the chamber occupied by the leaf completely covers the aperture, the leaf area calculation is simple — for example, with the 3×3 cm aperture, the measurable leaf area becomes 9 cm2. If the leaf does not completely cover the aperture, however, you must determine the leaf area through other means. For large leaves, the new Large Leaf and Needle Chamber is available. For smaller or irregularly shaped leaves, the Clear-top Chamber and Multiphase Flash™ Fluorometer feature interchangeable inserts with different sizes of apertures. This makes it easier to completely fill the chamber area with the leaf, which simplifies the leaf area calculation. Additionally, an on-board leaf area calculator works well for plants that have consistently shaped leaves or blades of grass.
New Large Leaf and Needle Chamber
For very big leaves, a 6×6 cm chamber area is available with the new Large Leaf and Needle Chamber (6800-13). The large leaf chamber aperture minimizes edge effects and maximizes signal-to-noise ratios, improving the accuracy of all measurements. The higher signal-to-noise ratios are especially helpful for seeing differences in low-flux measurements, such as measurements of dark respiration. The high flow rates of the LI-6800 — not found in any other photosynthesis system — make measurements over such a large leaf area possible.
The Large Leaf and Needle Chamber has a durable, transparent top for ambient-lighted CO2 and H2O flux measurements. The optional Large Light Source attaches directly to this chamber for controlled lighting with any combination of red, green, blue, and white light. The large 6×6-cm leaf area features two high-precision thermocouples for more accurate temperature data.
For smaller leaves, change the leaf area size of the Clear-top Chamber (6800-12A). The Clear-top chamber includes three interchangeable leaf area aperture inserts, so you can easily restrict measurable leaf area of the chamber: 3×3 cm, 2×3 cm, and 1×3 cm. The Clear-top Leaf Chamber has a durable, transparent top for ambient-lighted CO2 and H2O flux measurements. The optional Small Light Source attaches directly to this chamber for individually controlled red and blue light.
The Multiphase Flash Fluorometer (6800-01A) is a combined light source and chamber for simultaneous measurements of gas exchange and chlorophyll a fluorescence from the same leaf area. Choose a 6-cm2 or 2-cm2 leaf area by swapping interchangeable apertures. The fluorometer provides uniform illumination intensities up to 2500 mmol m-2s-1. Variation in light intensities is less than 10% of the mean over 90% of the leaf area. This high uniformity means the leaf experiences more consistent assimilation, minimizing artifacts that can cause errors.
Leaf Area Calculator
Leaves don’t completely fill the chamber area? If you know leaf width, you can use the leaf area calculator on the instrument console. In this short video, Jason shows how.