Abstract:

【Objective】 In order to explain the dynamic changes of absorption and transportation of zinc in apple tree with different zinc content level of apple orchard, the annual regularity of distribution and transportation of zinc nutrition was studied. 【Method】 Zinc concentration in soil and organs from apple cultivar ‘Fuji’ with rootstock M . hupehensis Rehd in the diseased apple tree (lack zinc) and the normal apple tree were determined at different stages. 【Result】 The concentration and the annual regularity of soil zinc nutrition in both diseased apple tree (lack zinc) and normal apple tree was consistent, but the content of zinc in 20-40 cm layer of diseased tree was lower than that of normal tree. The difference of root zinc concentration between diseased and normal tree was significant, the root of diseased trees showed a rise-and-fall motif, but in normal tree it kept higher level. The content of zinc in perennial shoots of normal tree kept high level, and increased in later period of development, but the diseased tree showed an inverse tendency. The tendency of the changes of zinc concentration in new organs under different zinc levels were similar in general, but the concentration of zinc in normal trees exhibited more than that of diseased trees. 【Conclusion】 The lower content of available zinc in the layer where the apple tree roots concentrated was the main reason for the diseased trees (lack zinc), besides, the diseased trees resulted in the lower transportation index of upward/roots of zinc induced by zinc restoration in the lower position in later period of development and the inhibition of zinc uptake of apple trees. Meanwhile, Zn-deficiency disturbed the rhythm of zinc absorption of trees and resulted in that the diseased trees formed specific zinc translocation regularity, i.e. the zinc supplying ability of roots was low in spring and summer and had difficulty to uptake zinc while large amount of zinc was restored in roots in the later period of development.

Key words: apple trees, zinc, organs, annual dynamics