Abstract:

The foliar carbon isotope composition (δ¹³ C) of common woody plant species in different degrees of karst rocky desertified lands including latent (L), slight (SL), moderate (M) and severe (S) rocky desertified areas was studied. Taking the foliar δ¹³C values as the indicator of plant water use efficiency (WUE), this paper discussed the effect of the dgree of karst rocky desertification on the plant %WUE%. The average foliar δ¹³C values were compared in different degrees of karst rocky desertified plots. The results showed that the δ¹³C values of foliar in Huajiang gorge ranged from-30.280‰ to -25.546‰, averaging-28.040‰ ± 1.208‰. There were significant differences in the average foliar δ¹³C values of the different degrees of karst rocky desertification. The values in the latent rocky desertified plots were lower than those in the severe, moderate and slight rocky desertified plots. However, the foliar δ¹³C values in severe, moderate and slight desertified plots were not significantly different. These results indicated that the effects of different degrees of karst rocky desertification on %WUE% were obvious. Therefore we concluded that the environmental factors influenced by different degrees of karst rocky desertification should not be neglected. The response of the plant physiological function to the change of the environmental factors was sensitive and timely.

Key words: &delta, ¹³ C values, karst rocky desertification, plant, water use efficiency