LI-6800 Advanced Photosynthesis Fluorescence Measurement System

The maximum rate of plant photosynthetic carbon assimilation depends on the ability of phosphorylated Calvin Benson cycle intermediates to produce the final product. When the carbon assimilation rate of plants reaches its maximum value, it enters the TPU (utilization efficiency of phosphate glucose) restriction stage, where the concentration of inorganic phosphate decreases, limiting the production of ATP and the increase in photosynthetic rate.

This photosynthetic paradigm involves several regulatory processes (usually taking a few minutes), particularly the decrease in Rubisco enzyme activity and the establishment of proton driven electron transfer quenching. Therefore, when plants are suddenly introduced into the TPU restriction stage, photosynthesis cannot be regulated and the photosynthetic rate will fluctuate.

Researchers use Dynamic Assimilation ™ Technique (DAT), chlorophyll fluorescence, and spectral measurement techniques were used to study the regulation of photosynthesis at three time scales: immediate (before slow regulation begins); Within a few minutes (Rubisco enzyme inactivation); After 30 hours (protein level regulation occurs).

Activate the Dynamic Assimilation of LI-6800 ™ Technique (dynamic absorption measurement technology)

Upgrading the system to 1.5.02 will enable this feature

Researchers have found that electron transfer occurring in the light system triggers non photochemical quenching. In the first 5 minutes, energy dependent quenching was established, and Rubisco enzyme was inactivated by 40%, relieving the pressure on the electron transfer chain.

After several hours of adaptation, the accumulation of photoinhibition weakened the importance of the energy dependent quenching pathway.

After a day of adaptation, the plant no longer exhibits symptoms of phosphate limitation. Research has found that plants regulate their photosynthesis to achieve a state that is not limited by phosphate, which is consistent with the phenomenon commonly observed in outdoor environments. This makes the phosphate limitation in the photosynthetic environment model more complex.

题目： A Timeline of Photosynthetic Regulation during Phosphate-Limited Photosynthesis Created Using Dynamic Assimilation Techniques

Speaker: Alan McClain, Graduate Research Assistant, Michigan State University

Host: Michigan State University and LI-COR Biosciences

Date and Time: Lovember 17, 2021; Time: 10:00 AM CST (corresponding to 00:00 AM Beijing time on November 18, 2021)

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