Carbon isotope ratios of C-4 plants in loess areas of North China

Carbon isotope ratios (delta C-13) of 89 C-4 plant samples were determined from the loess area in North China. delta C-13 values vary between -10.5%o and -14.6 parts per thousand with a mean of -12.6 parts per thousand. Along a precipitation gradient from the semi-moist area to the semiarid area, then to the arid area, the delta C-13 values of C-4 plants show a slight decreasing trend. The delta C-13 values of C-4 plants in the dry season are found lower than those in the wet season. These trends are opposite to those observed for C-3 species.Geosciences, MultidisciplinarySCI(E)EI14ARTICLE197-1024