Effects of Trunk Girdling Once and Twice on Tree's Nutrition Status and Its Allocation Regularity of Grape

To explore the effects of trunk girdling once and twice on tree's nutrition status and its allocation regularity of grape,Trees of Rose Honey grape were used to examine the effects of on the contents of carbon and nitrogen nutrition,mineral nutrition of leaves,branches above slash-cut and roots below slash-cut and its allocation regularity by trunk girdling once and twice.The results showed that girdling could significantly improve the content of non-structural carbon such as soluble sugar and starch of leaves,branches above slash-cut,and decrease the contents of soluble protein and total nitrogen,increase significantly carbon-nitrogen ratio,one of which peak of leaf carbon-nitrogen ratio was 9.04after girdling once,5.35girdling twice,while control during the same period was only 4.89.On the other hand, girdling could not only significantly decrease the content of non-structural carbon such as soluble sugar and starch of roots,but also significantly decrease the contents of soluble protein and total nitrogen,so that carbon-nitrogen ratio suffered some degree of lowered.Thereinto,after girdling once the lowest value of its carbon-nitrogen ratio was only 1.16,3.06girdling twice,while control was 3.15in the same period. Trunk girdling once on the influence of carbon nutrition was significantly greater than trunk girdling twice.Moreover,girdling could also significantly decrease the contents of phosphorus,potassium,ferrum and copper of leaves,branches and roots,thereinto,girdling twice on the influence of the contents of ferrum and copper were significantly greater.And the contents of the first sampling had significant difference,the iron content of the leaves 75.05μg/g DW,and control was 85.29μg/g DW;the iron content of branches was 76.45μg/g DW,copper 7.82μg/g DW,while the control was 95.96and 10.74 μg/g DW,respectively.