摘要
13C of 367 C3 herbaceous plants was measured in loess area in northern China. Their δ13C values vary between ?21.7%. and ?30.0%., with a mean of ?26.7%.. In the center of Loess Plateau (semimoist area) with annual precipitation of 400–600 mm, the δ13 C values of C3 herbaceous plants range from ?24.4%. to ?28.5%., with a mean of ?27.5%.. In the west of Loess Plateau (semiarid and arid area) with annual precipitation less than 400 mm, they range between ?21.7%. and ?30.0%., with a mean of ?26.2%.. Annual precipitation is the main factor that makes δ13C values of C3 herbaceous plants in the west greater than those in the central Loess Plateau. The composition of δ13C in C3 plants increases with deceasing annual precipitation, and the mean change is ?49%./100 mm.
d 13C of 367 C3 herbaceous plants was measured in loess area in northern China. Their d 13C values vary between -21.7 and -30.0, with a mean of -26.7. In the center of Loess Plateau (semimoist area) with annual precipitation of 400─600 mm, the d 13C values of C3 herba-ceous plants range from -24.4 to -28.5, with a mean of -27.5. In the west of Loess Plateau (semiarid and arid area) with annual precipitation less than 400 mm, they range between -21.7 and -30.0, with a mean of -26.2. Annual precipitation is the main factor that makes d 13C val-ues of C3 herbaceous plants in the west greater than those in the central Loess Plateau. The composition of d 13C in C3 plants increases with deceasing annual precipitation, and the mean change is -0.49/100 mm.
基金
the National Natural Science Foundation of China(Grant Nos.40072059,40273006 , 49894174).
