The C4 photosynthetic pathway and life forms in grassland species from North China

C-4 photosynthetic pathway and life form were determined for 159 species in 71 genera and 13 families in the grassland of North China. 45 % of the C-4 species were found in Graminae, 19 % in each of Cyperaceae and Chenopodiaceae. More than 51 % of these C-4 species were in therophyta and 36 % hemicryptophyta, while fewer species were in nanophanerophyta (9 %) or geophyta (5 %). The numbers Of C-4 species and their life forms were closely related with grassland deterioration and succession in North China. This indicated that the C-4 species had greater capacity to tolerate environmental stress (e.g. drought and salinity) caused by animal grazing and cultivation.