Ideally methods and parameters to assess photosynthesis in the microalga Chlorella
vulgaris must be rapid, non-invasive, accurate, and simple to implement. Methods such
as the Quantum Yield of photosynthesis (phi(Po) or F-v/F-m) yield rapid results but
do not reflect the actual electron turnover of PSII (ETRII). Alternatively, methods
that calculate ETRII take several minutes to execute, require expensive instrumentation,
and manual input. In this work, we describe a method to estimate ETRII in real-time
via predictive statistic modelling. This method utilises the Kautsky induction curve
and a low-cost chlorophyll a fluorometer. Our model optimises the fit of linear regressions
between the normalized fluorescence intensity after F-m (named S-ETR) and ETRII measurements
using traditional methods. This allows for an estimation of ETRII in real-time through
Kautsky induction curves alone. S-ETR can then be used as a faster alternative to
quenching analysis to determine bioenergetics performance during steady state and
can be assessed with any chlorophyll fluorometer capable of measuring the Kautsky
induction curve. The S-ETR parameter allows for a high-throughput and high-resolution
assessment of photosynthesis while being non-invasive, having lower production costs,
and with lower technical requirements. Furthermore, the biophysical bases of the method
are discussed.
