Apparent photosynthetic capacity exhibits substantial diurnal variation
There is substantial diurnal variation in apparent photosynthetic capacity (apparent Vcmax ­ andJmax ) (ranging from 0% change to over 50% decline). This variation has been ignored by TBMs, which typically use fixed estimates of apparent Vcmax and by leaf level physiologists who previously lacked an approach to collect high temporal resolution data in vivo . While we found interspecific differences in the diurnal response, the decline in apparentVcmax and apparent Jmaxhas important implications for modelling photosynthetic carbon uptake and should not be ignored.