Ion distribution, absorption and translocation characteristics of Alhagi sparsifolia in adaptation to saline habitat.

Abstract

In order to explore the adaptive capacity of Alhagi sparsifolia to soil salinity (mild, mo-derate, severe saline soil), the distribution, adsorption and translocation characteristics of Na+, K+, Ca2+, Mg2+ in different organs of A. sparsifolia, which is a dominant native vegetation in southern edge of Tarim basin, were investigated. The results showed that when grown on a mild and moderate saline soil, Na+ distribution in different organs of A. sparsifolia followed the order of stem≈thorn>leaf>root; when grown on a severe saline soil, Na+ distribution followed leaf>stem≈thorn>root. The distribution of Ca2+ and Mg2+ followed leaf >thorn>stem>root. With the increase of soil salt level, Na+ content in different organs of A. sparsifolia increased, while K+ content in leave decreased; meanwhile the increasing soil salt level significantly decreased the K+/Na+ ratio in both root and leave, as well as the Ca2+/Na+ and Mg2+/Na+ ratios in all organs. The selective transportation coefficients for Ca2+-Na+ and Mg2+-Na+ followed order of stem-leaf>stem-thorn>root-stem under saline habitats. Based on the integrated analysis, in order to adapt to salinity habitat, A. sparsifolia could use multiple organs to accumulate Na+, depending on soil salt level. Na+ could accumulate in stem and thorn at a relative low level, but in leaves at high levels. Besides, Ca2+ and Mg2+ could be the inorganic osmotic adjustment substances for A. sparsifolia to adapt the saline environment.