Extended Data Table 1 Within species effects of [CO2]a and watering level on leaf water relations, instantaneous gas exchange, indicators of leaf photosynthetic capacity, and starch content

From: Physiological responses to low CO2 over prolonged drought as primers for forest–grassland transitions

  1. Leaf water relations parameters: Eplant (canopy evapotranspiration), RWC (leaf relative water content), Ψleaf (midday leaf water potential), and Ψpd (predawn leaf water potential). Instantaneous gas exchange parameters: gs (operational stomata conductance), and Aop (operational photopsynthetic rate). Indicators of leaf photosynthetic capacity: RLIGHT (respiration rate in the light), initial quantum yield for CO2 fixation (Y(CO2)LL), light saturated gross assimilation rate (GASAT), light compensation point (LCP), carboxylation efficiency (CE), maximal rubisco carboxylation rate (VCMAX), maximal PEP carboxylation rate (VPMAX), CO2 compensation point (Γ), and CO2-saturated assimilation rate (ASAT). Starch content: leaf starch concentration, and root starch concentration. Output from repeated-measures ANOVA in SAS (v.9.4; SAS Institute, Cary, NC, USA). Modelled main effects were [CO2]a, (200 ppm, 400 ppm or 800 ppm), watering level (WL: 80%, 60%, 50%, 40%, 30%, recovery), and their interaction; individual plant was the random effect. Analyses were: PROC MIXED (linear model) for normal data with homogenous variance; PROC GLIMMIX (generalized linear mixed model, dist = gaussian, logit identity) for normal data with heteroscedasticity; and PROC GLIMMIX (dist = gamma, logit link) for non nomal data (absolute values were used in the case of variables with negative values). In all analysis individual comparisons for significant model effects were performed with Fisher’s PLSD differences (LSMEANS or ILINK option of the LSMEANS statement in GLIMMIX). The table shows the F-statistic with numerator and denominator degrees of freedom and P-values. Numbers in cells represent: first number is Fndf,ddf: F value, numerator degrees of freedom, denominator degrees of freedom. Second number is P-value.
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