A Study on Foliar Carbon Isotope Composition(δ~(13)C) and Water Use Efficiency of Different Populus deltoides Clones under Water Stress

Foliar carbon isotope composition(δ 13C), total biomass and long_term water use efficiency(WUE L) of 12 Populus deltoides clones were studied under water stress in the greenhouse. Total biomass of clones decreased greatly while δ 13C increased. The single element (clones) variance analysis and multiple comparison of WUE L under same water treatment indicated that the difference between clones was significant, J 2, J 6, J 7, J 8, J 9 were excellent clones with high WUE L. The significant differences between water treatments and clones were showed by two elements variance analysis of δ 13C, and water was proved to be the primary factor which affected δ 13C under water stress by the comparison of MS(Mean Square) and F value. Under same water treatment, our results also indicated that there was a good positive correlation between δ 13C and WUE L, high WUE L always went with high δ 13C, and δ 13C may be a credible indirect index on estimating WUE L between P. deltoides clones.