What are we measuring here?

Photosynq is a platform to help you identifying plant phenotypes. Our standard measurement protocol will collect the following parameters*:

Parameter What does it mean?
PAR Photosynthetically active radiation. Fraction of the incoming light (400 nm to 700 nm) which can be utilized to drive photosynthesis
temperature Ambient temperature in degree Celsius (°C)
humidity Relative humidity in percent (%)
pressure Atmospheric pressure (mbar) - This value is not corrected to sea level as found in weather reports
contactless_temp Surface temperature in degree Celsius (°C)
SPAD A measure of leaf “greenness”. This measurement is correlated with relative chlorophyll content. Also, SPAD is often correlated with leaf nitrogen levels
Phi2 Quantum yield of Photosystem II. This measurement is essentially the percentage of incoming light (excited electrons) that go into Photosystem II. Photosystem II is where most light energy is converted into food.
LEF Linear Electron Flux. The total flow of electrons from antennae complexes (where light is captured) into Photosystem II, taking the leaf absorptivity into account. Calculated as LEF = Phi2 x PAR x 0.42
Fm Maximum variable fluorescence
F0 Minimum variable fluorescence
FmPrime Maximum variable fluorescence at steady-state conditions
Fs Variable fluorescence at steady-state conditions
F0Prime Minimum variable fluorescence during dark phase after steady-state
NPQt Estimate of non-photochemical quenching. The amount of incoming light that is regulated away from photosynthetic processes in order to reduce damage to the plant.
PhiNPQ Ratio of incoming light that goes towards non-photochemical quenching. The plant regulating excess energy in such a way as too reduce damage to the plant.
PhiNO Ratio of incoming light that is lost via non-regulated processes. PhiNO is the combination of a number of unregulated processes whose by-products can inhibit photosynthesis or be harmful to the plant.
qL Fraction of Photosystem II centers which are in the open state
PMF Proton Motive Force - We can estimate PMF by measuring the electrochromic shift (ECS). The energy (ATP) produced by the flow of protons (H+) out of the thylakoid membrane.
compass Cardinal direction in degrees from North
compass_direction Abbreviated cardinal direction (e.g. NW - North West)
angle Cardinal direction in degrees from North
angle_direction Abbreviated cardinal direction (e.g. NW - North West)
pitch Pitch is the angle the instrument is held along the short axis
roll Roll is the angle the instrument is held along the long axis

*Some of the parameters are not available for the beta version of the MultispeQ


Where can I find more information?

You can search https://pubmed.com or https://scholar.google.com if you are looking for scientific literature. Below you find a small selection of literature that will get you started:

Baker, N. R. (2008). Chlorophyll fluorescence: a probe of photosynthesis in vivo. Annu. Rev. Plant Biol. 59, 89–113. doi:10.1146/annurev.arplant.59.032607.092759.

Kramer, D. M., Cruz, J. A., and Kanazawa, A. (2003). Balancing the central roles of the thylakoid proton gradient. Trends Plant Sci. 8, 27–32. doi:10.1016/S1360-1385(02)00010-9.

Kramer, D. M., and Evans, J. R. (2011). The importance of energy balance in improving photosynthetic productivity. Plant Physiol. 155, 70–8. doi:10.1104/pp.110.166652.

Cruz, J. A., Savage, L. J., Zegarac, R., Hall, C. C., Satoh-Cruz, M., Davis, G. A., et al. (2016). Dynamic Environmental Photosynthetic Imaging Reveals Emergent Phenotypes. Cell Syst. 2, 365–377. doi:10.1016/j.cels.2016.06.001.

Kuhlgert, S., Austic, G., Zegarac, R. Osei-Bonsu, I.,Hoh, D., Chilvers, M. I., et al. (2016). MultispeQ Beta: a tool for large-scale plant phenotyping connected to the open PhotosynQ network. R. Soc. Open Sci. 3, 160592. doi:10.1098/rsos.160592.


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