Studies Of Ion Distribution Of Different Saline-alkali Soil And Main Tree Species In Cangzhou City

Through surveying on the tree species of the four different saline-alkali soil in Cangzhou city, this paper analyzed the distribution of tree species, and measured at the salt ion contents of salt stress on the soil and different tree species. And studied on the ion content of the soil and tree species by methods of the main factor and correlation analysis.The results were as follows:1 The tree species included 52 species,37 genera,and 24 families.The tree species of distribution in different saline-alkali soil had being inclusion relations.That is,except of Nitraria schoberi,all the tree species in the high-saline area was contained in low-saline area. As the saline-alkali degree increased and the salt stress strengthened,the amount of the tree species were gradually reduced.And the greater the saline-alkali degree increased, the more obvious downward trend.2 As the saline-alkali degree increased,the content of total salt, Na⁺,K⁺,Ca²⁺ and Mg²⁺ in the different saline-alkali soil rapidly rising,but the increased rate of ions were different,and the Na⁺ content was the largest increase.Through the main factor analyzed on the soil salt ions,only the eigenvalue of total salt and Na⁺ was greater than 1,the eigenvalues were 3.701 and 1.044,respectively,the cumulative variance contribution rate was over 94.889%.It showed that the factors which influenced the level of soil saline-alkali degree depended mainly on the content of the total salt and Na⁺.3 With the salt stress enhanced,the content of Na⁺ showed obviously increasing trend in the body of the tree species.The content of K⁺ rised in the first,and then declined in the high-saline area. The content of Ca²⁺ showed the downward trend always. The content change of Mg²⁺ showed was not clear,the overall performanced for the slow downward trend.Under salt stress, the content of Na⁺ of the roots of the tree species was significantly higher than stems and leaves,but the content of K⁺,Ca²⁺ and Mg²⁺ in the stems and leaves was significantly higher than the roots.As the salt concentration increased,the ratio of Na⁺/K⁺,Na⁺/Ca²⁺ and Na⁺/Mg²⁺ was being the upward trend,but the increased range was different in different organs or in different species.That is, the root was significantly higher than stems and leaves,and Tamarix chinensis,Ulmus pumila, Amorpha fruticosa,Fraxinus bungeana,and Mours mongolica were significantly higher than other tree species.The values of RSK,Na,RSCa,Na,RSMg,Na of various tree species increased with the salt concentration increased,but the increased range was different.In the high-saline area, the values of RSK,Na,RSCa,Na,RSMg,Na of Tamarix chinensis,Ulmus pumila,Amorpha fruticosa,Fraxinus bungeana,and Mours mongolica, were higher than Elaeagnus angustifolia,Melia azedarach and etc.4 There were very significant positive correlation between the Na⁺ content of the roots and stems,leaves of tree species in different saline-alkali soil zones(P<0.01).That shows the roots were the most critical link which controlled Na⁺ into the plant,at the same time controlled the Na⁺ concentration of plant stems and leaves.Between roots and stems,and stems with leaves,the K⁺ content was all significant positive correlation(P<0.05).It shows that the K⁺ ion of root absorption transported more up,which is played an important role in maintaining normal physiological functions of plants.And the K⁺ ion of leaf needs is transported from the stem, K⁺ is the element of mobility to the transport properties of new organizations.Between roots and stems with leaves,the Ca²⁺ content was all significant positive correlation(P<0.05).There were the significant negative correlation between the contents of Na⁺ and K⁺ in the roots of the tree species(P<0.05).And between the contents of Na⁺ and Ca²⁺ in the roots of the tree species,it was significant negative correlation(P<0.01).In the stems,the content of K⁺ and Ca²⁺ were a significant positive correlation(P<0.05),and of Ca²⁺ and Mg²⁺ were a significant positive correlation(P<0.01).In the leaves,only the content of Na⁺ and Mg²⁺ were a significant positive correlation(P<0.01).With the strengthening of salt stress,the ion of K⁺ and Ca²⁺ could inhibit the roots in the absorption of Na⁺ to ease the plants salt stress.Stems was being ion transmission organization,and it does not accumulate on the role of ion.Mg²⁺ is a plant nutrient element with chlorophyll synthesis and decomposition had important links.So the Na⁺ content of leaf increased,the plants were under salt stress.And the higher Mg²⁺ content of leaves,was in favor of the enhancement of photosynthesis,thus increased the plants salt-tolerant sexual.