| With the development of the society, the interference on the environment was more and more serious and copper from industry and agriculture often resulted in soil pollution. Both copper smelting and copper products producing, especially copper mill-tailings mishandling in industry and the application of cupric fungicides (Bordeaux mixture), sewage water irrigation, sewage sludge and farmyard manure containing copper can result in soil pollution and degeneration. This paper was done on the base of the investigation of copper content in orchard soils in order to study the toxic mechanism of copper to pot-planting young apple trees and four apple parent stock seedings planted in brown earth (Hap udic luvisol CSC system). At the same time, the chemical remediation on copper toxcity to pot-planting apple trees of application Fe, Ca, K and organic manure under the condition of high copper level was discussed.1. The effects of high copper stress on apple trees growthWith high copper stress, apple trees grew slowly, presented netlike chlorosis in leaves, and the toxic symptoms changed with the change of season and time: No obvious negative effect in growth at the very bigenning-growing slowly in the spring tips quick growth period-symptoms relieved after rainy season-grewing slowly and chlorosis in leaves the next spring until rainy season-brown spots appeared in leaves in autumn.Under high copper stress, Apple trees only had a small root with less root hair. The proportion of yough roots was lower and the ability of insistence diseases descented. The study showed that all apple trees' roots of copper treatments had been infected by Rosellinia necatrix. Prill except that of the treatment CK.2. The effects of high copper stress on the growth of apple trees and parent stocks seedingsHigh copper stress caused apple trees to grow slowly. The correlation between the relative date (y) of beginning spring-tips fast growing and the copper level (x) was highlysignificant (y=0.1225x~2.000, r=0.9924**). Trees of high copper treatment began spring-tips fast growing was 37 days later than that of the treatment CK.Under high copper stress, the apple trees' biomass yield declined. The total biomass yield of high copper treatment Cu320 was 58.09% of CK treatment. The significant negative correlation appeared between the total biomass yield (y) and the copper level (x) (y=-0.5625x+550.28, r=-0.9283*). By this equation, the application of copper to soil which can decline 10% of the biomass yield of Tengmuyihao apple tree planted on brown earth was 77.56mg kg'1.Different parent stocks had different resistance to copper stress. The height, chest diameter and biomass yield of Tiechehaitang, Pingyitiancha, and Balenghaitang obviously declined with the increasing of copper stress, while those of Shengjinghaitang increased first and then declined. Conclusion was made that Shengjinghaitang had stronger resistance to copper stress than the others.3. The effects of high copper stress on medium and trace elements of apple parent stocksHigh copper stress obviously increased the copper contents in parent stocks, and most of copper accumulated in roots. The copper contents in roots of the four parent stocks (Shengjinghaitang, Tiechehaitang, Pingyitiancha and Balenghaitang) were 17.08, 27.03, 29.97 and 5.27 times more than that of their stems, and 26.18, 51.55, 56.91 and 14.13 times more than that of leaves.Under high copper stress, the roots of parent stocks were inhibited from absorbing Fe, Ca, Zn and Mg, from transporting them to stems and leaves, and from these elements' accumulating in organs. But difference still appeared between elements and breeds.4. The effects of high copper stress on POD isozyme in leaves of apple treesBy biochemical technique, the reason of copper toxicity in apple trees on the point of POD isozyme was studied. Ten POD isozymes were discovered in leaves of apple trees. Under high copper stress, toxic substances was induced in apple trees and three POD isozymes' (e, f and g) activ... |
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