Can light-saturated photosynthesis in lowland tropical forests be estimated by one light level?

Leaf-level net photosynthesis (An) estimates and associated
photosynthetic parameters are crucial for accurately parameterizing
photosynthesis models. For tropical forests such data are poorly available
and collected at variable light conditions. To avoid over- or
underestimation of modelled photosynthesis, it is critical to know at which
photosynthetic photon flux density (PPFD) photosynthesis becomes light
saturated. We studied the dependence of An on PPFD in two tropical forests
in French Guiana. We estimated the light saturation range, including the
lowest PPFD level at which Asat (An at light saturation) is reached, as
well as the PPFD range at which Asat remained unaltered. The light
saturation range was derived from photosynthetic light-response curves, and
within-canopy and interspecific differences were studied. We observed wide
light saturation ranges of An. Light saturation ranges differed among
canopy heights, but a PPFD level of 1000 µmol/m²/s was common across all
heights,...