Photosynthetic pathways and life form types for native plant species from Hulunbeier rangelands, Inner Mongolia, North China

Abstract

Photosynthetic pathway types (C 3, C 4, and CAM) and life forms of native species from Hulunbeier rangelands, north China were studied. Of the total 258 species, 216 species in 132 genera and 42 families had C 3 photosynthetic pathway, including dominant herbs, e.g. Stipa baicalensis Roshev. and Leymus chinensis (Trin.) Tzvel., Filifolium sibiricum Kitam. and Arudinella hirta (Thunb.) Koidz. 38 species in 28 genera and 10 families were found with C 4 photosynthesis, and 4 species in 2 genera and 1 family had CAM photosynthetic pathway. The occurrence of C 4 species was common in Gramineae and Chenopodiaceae, and the two families were leading ones within C 4 plants. More than 52 % of the total 258 species were in H form, 21 % in Th form, 19 % in G form; the other life form types, e.g. Ch, M, N, and HH, formed less than 3 %. 68 % of C 4 species were in Th form and 24 % in H form, indicating that these types were the dominant life forms for C 4 species in the rangeland region. The occurrence of C 4 species was closely related with plant habitats, disturbed lands had the highest C 4 abundance (55 % of the total C 4 species), followed by grasslands and sandy soil, and forests had the lowest C 4 abundance (8 %). Hence the occurrence of C 4 species could be efficient indicator for rangeland dynamics in Hulunbeier rangelands.