Abstract:This research focused on three desert halophyte species,i.e., H. ammodendron (C.A.Mey.) Bge., S. physophora Pall.,and S. nitraria Pall. under solution culture,and the differences of their root morphology and activity in the seedling stage under varying salt concentration conditions were studied. The results show that a certain salt concentration can promote the development of these three halophytes, but rather high salt concentration will restrain their growth,especially inhibit the roots development. Under the same salt concentration condition, S. nitraria Pall. grows fast and accumulates the largest amount of biomass. Under relatively lower salt concentration,the length of axial root and the total length of roots of these three halophyte species are all increased, comparing to the control samples, S. physophora Pall. occupies the top place of roots growth,but high salt concentration will restrain the increase of total root length, among them,the restraining intensity to S. physophora Pall. is lighter than to H. ammodendron (C.A.Mey.) Bge. and S. nitraria Pall. The salinity does not bring distinct influence on the average diameter of roots of these three plant species,but trends to reduce the size. Under the solution culture conditions,the upper, middle and lower parts of the axial root of H. ammodendron (C.A.Mey.) Bge. and S. physophora Pall. are rather equally distributed,but the middle part of S. nitraria Pall. roots is significantly increased than the upper and lower parts, salt concentration does not bring marked impact on the roots spatial distribution of each species. Differences between root hair morphological characteristics at different salt concentration were tested,but no significant differences were found. Average root length and density was found to change significantly among the three species. Our research indicates that S. physophora Pall. has the highest drought-resistant and infertile-resistant among three desert halophytes. The experimental results show that the saline tolerance capacity of H. ammodendron (C.A.Mey.) Bge. is lower than the other two species,and the capacity of S. physophora Pall. is ranked at the top place.