| Because of the better adaptability, fast growth and the diversity of use ,Black Locust is the most successfully intrduced tree of three including poplar and euclypt.In order to enrich the tree resourse and select the best Black Loust with many better characteristics Prof. Yang introduced a few clone from Germany. In this paper the reproduction and salt resistance had been studied and the result shows that:(1) After the observation of experimental field and the data analysis, the result shows that all the clones can live in the experimental field and adapt the enviroment. Of all the clones, Rcr is the best because of its fast growth and the perfect stem shape.(2)Through the analysis of the data of the cuttage experiment with complete randomized block design of clone 4N and the data of 4N, Rcr, local species with the orthogonal test, the result shows that the NAA and IBA+NAA are better than IBA,which can improve the rooting rate.And the major factor that influenced the rooting rate was the kind of hormone. The best combination is 4N, 500 mg/L-1 and IBA+NAA.(3)In 28 days salt stess a few physiological and biochemical indexes of 4N, Rcr, 2488 which were plant in pot were determined. The result shows that the hight, leaf growth, and biomass of all the clones were restrained by the salt stress and and the high salt cocentration will enhance the effect. The salt stress also influences the chlorophyll content and the photosynthesis, the variation of among the component of chlorophyll and chl a/b is different. The indexes of photosynthesis of all the four clones' pn Tr Rs Ci had significant diurnal change law, and pn and Tr diurnal change basically presented double peak curve, the change law of Rs and Ci presented negative interrelation. With the salt consistence increasing, pn and Tr declined and Rs increased, but change extent of clones was defferent. The effct of salt stress on Ci is little; the variation of pn Tr Rs Ci of the leaf of same part is same, but the difference appears under high salt concentration. As the salt concentration increased the conductance of all the clones also increased the conductance of root is higher than the stem and leaf. The variation of MDA content is very similar to the cnonductance. The enzyme activity, membrane permeability and the content of free proline were studied under salt stress. The results indicated that SOD and POD activiy increased under low salt stress, but decreased under high salt stress. With the salt consistence increasing, membrane permeability of root, stem and leaf were increased, but the change extent was defferent,among organs, root's was the largest and leafs was the less.With the salt concentration increasing, contents of free proline of root ,stem and leaf were increased. The result showed that the Na+ content in the plant increased as the solution concentration increased, but the increasing range was different in different tissues, the Na+ content in root was the highest and the content in stem was higher than that in leaf .As the salt stress increased, the K+ content decreased in the root and stem. The change of the K+ content in leaf was small. The change of the Ca2+ content in leaf of all clones under the salt stress wasidentical. The decreasing range of the Ca2+ content in the root was smaller than that of in stem and leaf. Cl" content in the plant increased as the solution concentration increased, but the increasing range was different in different tissues. The CL" content in leaf was the highest, the stem 's was higher than roots. Mg2+ content in the plant decreased as the solution concentration increased, but the decreasing range was notable in different treatment.As the salt solution concentration increased, the ratios of Na+ to K+, Na+ to Ca2+ and Na+ to Mg2+were increasing, but the extent in root was bigger than that in stem and leaf. The RSk, Na, RSca. Na, RSca, Na declined as the salt concentration increased. All the analysis shows that the sequence of the salt resistance is Rcr>B>2488>4N.
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