Study on Physiolog ica l Character istics and Sa lt Tolerancefor Seedlings of 11 Tree Spec ies

In greenhouse, four2month2old seedlings of eleven tree species grown in pots were subjected to salinity(NaCl) treatments in concentration of 0, 3, 5, 8 and 10 g · kg-1 of soil dry weight. The physiologicalcharacteristics of the trees were studied and their salt tolerance abilities were evaluated comp rehensively bysubordinate function value method. The results showed that: (1) W ith the increase of salinity concentration, thecontent of chlorophyll and free p raline were decreased and increased, respectively, among every kind of trees.While there were great differences in soluble sugar content and membrane permeability among the trees. (2) Aftersalt treatments, the Na+ content and K+ /Na+ value in roots, stems and leaves were significantly increased anddecreased, respectively. Whereas there was great difference in K+ content among different tree species and parts,and the Na+ content of roots was obviously higher than that of leaves. (3) Four species, S yringa japonica Dcne. ,S hepherdia a rgentea Nutt. , Ptelea trifoliate L inn. and Rhus trilobata Nutt. , had a higher salt tolerance species, andPy rus calleryana Dcne. ,V iburnum opulus L inn. , Laburnum wa tereriVossii. and Spartium junceum L inn. belonged tomedium2high salt tolerance species, and Cytisus scoparius Linn. , B etula lenta Linn. and Rhus glabra L inn. werelower than others and belonged to medium salt tolerance species. The theoretic basiswasmade for the establishmentof standard of salt resistant evaluation and popularization of the 11 tree species in this research.