Data From: Effects of measurement methods and growing conditions on phenotypic expression of photosynthesis in seven diverse rice genotypes

Introduction: Light response curves are widely used to quantify
phenotypic expression of photosynthesis by measuring a single
sample and sequentially altering light intensity within a chamber
(sequential method) or by measuring different samples that are
each acclimated to a different light level
(nonsequential method). Both methods are often conducted in
controlled environments to achieve steady-state results, and
neither method involves equilibrating the entire plant to the
specific light level. Methods: Here, we compare sequential and
non-sequential methods in controlled (greenhouse),
semi-controlled (plant grown in growth chamber and acclimated to
field conditions 2-3 days before measurements), and
field environments. We selected seven diverse rice genotypes
(five genotypes from the USDA rice minicore collection: 310588,
310723, 311644, 311677, 311795; and 2 additional genotypes:
Nagina 22 and Zhe 733) to understand (1) the limitations of
different methods, and (2) phenotypic plasticity of photosynthesis in
rice grown under different environments. Results: Our results
show that the non-sequential method was time-efficient and
captured more variability of field conditions than the sequential method,
but the model parameters were generally similar between the two methods
except for the maximum photosynthesis rate (Amax). Amax was significantly
lower across all genotypes under greenhouse conditions compared
to the growth chamber and field conditions consistent with prior
work, but surprisingly the apparent quantum yield (α) and the
mitochondrial respiration (Rd) were generally not different among
growing environments or measurement methods. Discussion: Our results
suggest that field conditions are best suited to quantify phenotypic
differences across different genotypes, and the nonsequential method was
better at capturing the variability in photosynthesis.