Foliar δ~(13)C 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 δ~(13)C 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 δ~(13)C 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 C_3 plants and only 17 species were C_4 plants. Most C_4 plants belonged to Gramineae family. The foliar δ~(13)C value of C_3 plants was between -25.000 and -31.075‰ with an average of-28.226‰, while those of C_4 plants between -12.578 and -16.334‰, with an average of -13.678‰. The δ~(13)C values of mature leaves collected in August were averagely 0.85‰ less than that of juvenile leaves collected in June. The foliar δ~(13)C 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.