Abstract: A field experiment was conducted in Inner Mongolian dune to investigate the contribution of clonal integration to genet expansion and ramet establishment in clonal plants in semi-arid inland dune. In the experiment, the developing parts (plant observing unit) of two rhizomatous grass species Psammochloa villosa (Trin.) Bor and Leymus secalinus (Georgi.) Tzvel. were subjected to the treatment of severing rhizomes. The 7 characters relevant to the elonal growth of the plant observing units were investigated such as total length of shoots, number of shoots, number of rhizomes, length of main rhizome, total length of rhizomes, number of main rhizome nodes and total number of rhizome nodes. The results showed that the increments in those plant characters were reduced by the treatment in P. villosa, while no effect of the treatment was observed in L. secalinus. The results suggest an interspecific difference in clonal integration and in its contribution to clonal growth. In P. villosa, clonal integration and clonal growth offer great contributions to the survival of the plants in the sandy grassland characterized where water shortage, strong transevaporation, infertility, habitat patchiness and frequent disturbance were most characteristic.

Key words: Psammochloa villosa, Leymus secalinus, Inland dune, Rhizome, Clonal growth, Clonal integration