| The effects of iso-osmotic conditions (-0.79 MPa and -1.83 MPa) of salt stress (NaCl) and water stress (PEG) on seedling growth, and ionic absorption and distribution in different organs of Nitraria sibirica were studied, and the relationship between drought resistance and salt tolerance was analyzed. The results showed that, compared to the control, the plant height, stem diameter, taproot length and dry weight of seedlings decreased significantly (P＜0.05), while the contents of soluble sugar, proline and MDA increased significantly (P＜0.05) under the treatments of -1.83 MPa salt and PEG., in which the growth inhibition effect of salt treatment exceeded significantly (P＜0.05) that of PEG treatment. Under NaCl stress, the Na+ content in different organs of Nitraria sibirica seedlings showed an upward trend, the K+ content rose firstly and then went down, and the contents of Ca2+ and Mg2+ as well as the ratios of K+/Na+, Ca2+/Na+ and Mg2+/Na+ showed a downward trend. Under PEG stress, the Na+ content in different organs of Nitraria sibirica seedlings went down firstly and then rose, the contents of K+, Ca2+ and Mg2+ decreased, and the ratios of K+/Na+, Ca2+/Na+ and Mg2+/Na+ rose firstly and then went down. Among different organs, the change magnitude of ions was the largest in roots, followed by stems, and the smallest in leaves. Nitraria sibirica seedlings could resist salt stress by changing the distribution of salt ions and regulating their balance in the plants, and could resist drought stress by accumulating a large amount of small organic molecules. |