Data analysis
Zeitgeiber Time 0 (ZT0) was calculated based on meteorological sunrise
(07:30 for Populus deltoides and Populus trichocarpa ;
07:00 for Malus domestica ; 06:00 for Asclepias speciosa ,Quercus muehlenbergii , and Rosa grandiflora ; 06:30 forGinkgo biloba and Cedrus deodar ), observed sunrise forPinus ponderosa (08:30) or the time that growth lights turned on
(08:30 for Capsicum annuum ). Diurnal variation was tested within
each species using a repeated measures linear regression using the
{lme} function of the {nlme} package in R (Pinheiro et al .,
2018). Relative Vc,max andJmax were calculated for each species by
standardizing to the highest average value (i.e. dividingVc,max and Jmax at each
time point by the peak Vc,max andJmax ) within a species.