Foliar δ13C Values and Water Use Efficiency of Semi-arid Plants in Horqin Sandy Land,China

Water was a key factor restricting the plantation in sandy areas. Foliar δ13C value regarded as an indicator of longterm water use efficiency(WUE) of plants was generally used to evaluate the adaptability of plants to arid and semi-arid environment. In Horqin sandy land of China, the foliar δ13C values of 114 species in 35 families naturally growing in the area, and 15 species of sand-fixing trees and shrubs were measured and analyzed in 2012. The results showed that 97 species in all 114 species were C3plants and only 17 species were C4plants. Most C4plants belonged to Gramineae family. The foliar δ13C value of C3plants was between -25.000 and -31.075‰ with an average of-28.226‰, while those of C4plants between -12.578 and -16.334‰, with an average of -13.678‰. The δ13C values of mature leaves collected in August were averagely 0.85‰ less than that of juvenile leaves collected in June. The foliar δ13C values and WUE of 15 sand-fixing tree species in Horqin sandy land ranked in the order as: S.vulgaris >H.rhamnoides >C.ovata >P.mongolica >T.chinensis >R.typhina >S.matsudana >E.angustifolia >U.pumila >S.gordejevii >X.sorbifolia >C.microphylla >H.fruticosum >C.korshinskii >E.bungeanus.