Analyses and modeling of regional and global ecosystems necessitates quantification of ecophysiological behavior of various plant functional types. In this study, we inverted a model of stomatal conductance and a simple leaf photosynthesis model based on gas exchange data of plant leaves from 167 multi-diurnal observations on 124 plant species involved in 41 independent studies all over china.
Results/Conclusions
Statistical analysis of the inversed model parameters showed that the means of the model parameters are significantly different among six functional groups of evergreen broadleaved arbores, deciduous broadleaved arbores, coniferous arbores, shrubs, herbaceous, and crops. The comparison of responses of stomatal conductance to moisture stress indicates that the three arbores functional groups had smaller maximum stomatal conductance than the shrubs, the herbaceous, and the crop groups. The stomata conductance of the herbaceous and the crops had the lowest tolerance but the highest sensitivity to soil water stress. However, the herbaceous and the crops groups are the most tolerant to vapor deficit on leaves. Among the woody functional groups, the shrubs group is the most tolerant and resistant to moisture stress in soil and air. In contrast, the two broadleaved arbores (deciduous and evergreen) groups are the least tolerant to vapor deficit, and the evergreen broadleaved arbores also has the lowest tolerance to soil water stress. Inverting the photosynthesis model showed that the deciduous functional types showed higher light saturation and compensation than the evergreen groups, and the herbaceous and crops have much high maximum assimilation rates than the woody functional types. The results were discussed in the context of regional ecosystem response to past and future climate changes. In particular, we offered hypothetical explanations to the important results of a regional study(Fang, 2003) which concluded that the NPP of deciduous forests in northern China was found to have the second smallest increase over the period from 1982 to 1999 among 11 vegetation types in an important inventory study. The lower increase in NPP of the deciduous forests may be largely because of their high stomatal sensitivity to the increased air moisture stress and moderate tolerance to the increased soil water stress because of the increased temperature and decreased precipitation in northern China in the period.
