Studies On Absorption And Resistance Of Soil Cadmium And Lead Stress To Three Ornamental Fruit Trees

Pyrus ussuriensis,Prunus salicina Lindl. and Armeniace sibiriea Lam was used as materials in this experiment.The reaction of the physiological and biochemical and growth were studied under the stress of heavy metal(cadmium,lead)in the soil by two year s seedlings in pots in greenhouse. The distribution and accumulation of heavy metals were analyzed in the three species and resistance of the three species was evaluated. Every species was designed under different concentration gradient, Cd⁺:0,50,100,200,250mg/kg(pure Cd²⁺), Pb²⁺:0,200,800,1500,2500(pure Pb²⁺),(showed CK, Cd50, Cd100,Cd200, Cd250; Pb200,Pb800,Pb1500,Pb2500).The results were as follows:1.The translocation and enrichment of Cd²⁺ and Pb²⁺is different among three seedlings. Cd²⁺and Pb²⁺ accumulation ability of Pyrus ussuriensis was the strongest, the accumulation coefficient of each organs of Pyrus ussuriensis were higher than others; Cd²⁺ and Pb²⁺ accumulation content in organs of three tree species was root>stem>leaf. The accumulation coefficient of each tree species stem to Cd²⁺ was Pyrus ussuriensis>Prunus salicina Lindl.>Armeniace vulgaris Lam2. From the appearances of plant, leaves appeared chlorosis and necrosis's spots symptom under the stress of heavy metals,and leaves became more small. In general the lower concentration of Cd²⁺ and Pb²⁺ can stimulate the growth of base diameters, seedling heights, new branches and leaves.however, with the enhancing of Cd²⁺and Pb²⁺ concentration, each indexes decreased.3. It is different that evaluation of the resistance of the different tree species.The resistance of three tree species to heavy metals was appraised using subordinate function. The results showed that the resistance of three tree species to Cd²⁺ was Pyrus ussuriensis>Prunus salicina Lindl>Armeniace vulgaris Lam; the resistance of three tree species to Pb²⁺ was Prunus salicina Lindl>Pyrus ussuriensis>Armeniace vulgaris Lam. Pyrus ussuriensis is higher ability of resistance and enrichment than others. So we think that Pyrus ussuriensis was used as ornamental tree in downtown.4.The reaction of the physiological and biochemical is different with enhancing of the concentration of the Cd²⁺ and Pb²⁺. chlorophyll content in leaves of three tree species declined, It was achieved significant level in contrast with the highest concentration treatment(Cd250. Pb2500) and CK. Armeniace vulgaris Lam was the most distinct, Prunus salicina Lindl.was at second place, Pyrus ussuriensis was the least. Relative conductivity rate of three tree species leaves enhanced with increase of heavy metals and the difference among tree species was significant. The content of MDA of three tree species seedlings first enhanced then decreased with the enhancing of the concentration of Cd²⁺ and Pb²⁺,the content of critical of each tree species was Pyrus ussuriensis>Prunus salicina Lindl.>Armeniace vulgaris Lam; the activity of POD of the seedlings first enhanced then decreased with the enhancing of the concentration of Cd²⁺ and Pb²⁺;The content of critical of each tree species was Armeniace vulgaris Lam>Prunus salicina Lindl.>Pyrus ussuriensis;The content of Pro enhanced with enhancing of the concentration of the Cd²⁺ and Pb²⁺, Variation of soluble carbohydrate content under Cd²⁺ and Pb²⁺ in leaves of three seedlings enhanced with the enhancing of the concentration of Cd²⁺ and Pb²⁺;The content of protein increase with enhanced of heavy metals; The activity of root of three seedlings first enhanced then decreased with the enhancing of the concentration of Cd²⁺ and Pb²⁺.The activity of root of each tree species was Prunus salicina Lindl.>Pyrus ussuriensis>Armeniace vulgaris Lam.