Moreover, we also found the special physiological effect of ABA treatment alone on other leaf photosynthetic parameters, such as an increase in the maximum RUBP carboxylation rate, leaf respiration rate, maximum electron transport, and maximum triose-phosphate utilization rate of L. chinensis leaves and a reduction in the light compensation point and light saturation estimates.
Lower incident PFDs within the shaded canopy induced leaves with characteristic shade attributes: low light-saturated photosynthesis; low light saturation but large leaf areas.
The dark respiration (Rdark), the light compensation point (Ic), the light saturation point (Ik), and Φi and Amax were estimated from individual light-response curves using Photosyn Assistant software, version 1.1.2 (Dundee Scientific, Dundee, UK).
Leaves were darkened with a leaf clamp for 15 min prior to measurements, and rapid light curves were measured using pre-installed software to estimate the relative efficiency of photon conversion (quantum yield) at low irradiances (ΦPAM), the light saturation point (Ik,PAM, µmol m−2 s−1) and the maximum electron transport rate (ETRmax, µmol m−2 s−1).
Elevated CO2 and temperature both increased light sensitivity and the light saturation level of photosynthesis.
One of the key parameters in these algorithms is the chlorophyll-normalised production rate under light saturation (referred to as the light saturation parameter or the assimilation number).
The suitable light saturation point for algal growth was approximately 100 150 μmol m−2 s−1.
S. superba exhibited a much higher light saturation point for photosynthesis than S. katochaete.
The temporal evolution of microalgae concentration was predicted by accounting for light saturation, photoinhibition, and respiration.
The light saturation index was calculated from rETR divided by α [65], [66].
