Exploring the instability of the relationship between maximum potential electron transport rate and maximum carboxylation rate in cool-temperate deciduous forests

A clear understanding of the relationship between two photosynthetic capacity parameters, maximum carboxylation rate (Vcmax) and electron transport (Jmax), is expected to reveal plant physiology strategies critical in determining carbon water cycle terrestrial biosphere. Increasing evidence recent suggests unstable spatiotemporal contexts, casting a doubt on deriving Jmax solely from single linear function Vcmax as most gas exchange models do. In this study, we have examined instability terms seasonal interannual courses (from 2006 2014) well at different altitudes (550, 900, 1500 m a.s.l.) leaf types (sunlit shaded) only dominant species Fagus crenata Blume typical cool temperate forests Japan based long-term field dataset. Our results clearly indicated that there not remarkable variability parameters themselves but also large variations their ratios. The slope parameter best fitted for estimating varied seasons years types, sites. Further exploration with internal traits external climatic drivers revealed chlorophyll content had significant correlation (R2 = 0.72, RMSE 0.08, RPD 2.00) impacts were rather versatile. findings should hence advance dynamics Jmax–Vcmax relationship, which be considered explicitly future order substantially improve model predictions models.