Photosynthetic pathways, life forms, and reproductive types for forage species along the desertification gradient on Hunshandake desert, North China

摘要

Floristic compositions, life forms, reproductive types for forage species, and their responses to desertification in Hunshandake desert were studied. 164 species, in 30 families and 94 genera, were identified with C-3 (137 species), C-4 (25 species), and CAM (2 species) photosynthesis. Of the 25 C-4 species, 76 % were grasses and Chenopodiaceae species (hereafter chenopods). This suggests that the C-4 species mainly occurred in a few families in the desert region. The reduction of C-3 species and the increase of C-4 species with desertification indicated that C4 species might have higher tolerance to environmental stresses (e.g. dry and poor soil). Relatively more hemicrytophyte and therophyte forms in the desert are related to the local temperate climate and vegetation dynamics. Relatively greater proportions of C-4/C-3 and clonal species/sexual species at mobile dune showed that the C-4 species and clonal species could make greater contribution to sand land restoration in the Hunshandake desert.