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Variations in Composition and Water Use Efficiency of Plant Functional Groups Based on Their Water Ecological Groups in the Xilin River Basin

2003; Wiley; Volume: 45; Issue: 10 Linguagem: Inglês

0577-7496

Shiping Chen, Bai Yongfei, Xingguo Han,

Plant Ecology and Soil Science

Major plant species in the Xilin River Basin were grouped into six plant functional groups(PFGs) based on their water ecological groups: xerophytes, mesoxerophytes, xeromesophytes, mesophytes,hygromesophytes and hygrophytes. We surveyed the composition, δ13C values and proline concentrationof PFGs in eight different plant communities along a soil moisture gradient. Results show that: (1) PFGsoccurred variously in eight steppe communities with different soil moisture status. In wetter habitats,hygromesophytes and hygrophytes were more abundant and accounted for the majority of abovegroundbiomass, whereas xerophytes and mesoxerophytes became more conspicuous in dryer habitats; (2) thenumerical order of the mean δ13C values of PFGs is as follows: xerophytes (-26.38‰) = mesoxerophytes(-26.51‰) ＞ xeromesophytes (-27.02‰) ＞ mesophytes (-27.56‰) = hygromesophytes and hygro-phytes (-27.80‰); (3) xerophytes maintained relative higher δ13C values and water use efficiency (WUE) inhabitats of different water availability, whereas δ13C values of xeromesophytes were more sensitive tochange in soil water availability; (4) From xerophytes to hygrophytes, their proline content markedly in-creased. Significantly positive correlations existed between proline and biomass or δ13C values of differentwater ecological groups.