The photosynthesis of steppe plant based on the Energy Plant Functional Groups

Energy Plant Functional Groups (Energy PFGs) is a kind of functional classification method based on plant energy properties. The sun energy was transformed into chemical energy and stored in plants by plant photosynthesis. A field survey was conducted to determine the relationships between Energy PFGs and plant photosynthetic characteristics by measuring the leaf photosynthetic parameters of Leymus chinensis、Cleistogenes squarrosa、Potentilla acaulis using a LI6400 Portable Photosynthesis System in Typical Steppe of Xilingol from the end of July to mid August. The photosynthetic included the diurnal variations of net photosynthetic rate (Pn), stomatal conductance (Sc), transpiration rate (Tr). This study showed that the diurnal variation of Pn of all the plants took on doublepeak curve with remarkable midday depression, peaking at 12 and 16 oclock and depressing at 12 to 14 oclock, respectively. The Pn, Sc and Tr of highenergy PFGs was lower than that of lowenergy PFGs, and this phenomenon was related to vigorous life activities and reproduction strategy of lowenergy PFGs.