Effects Of Branch Bending On Endogenous Hormones ,carbon And Nitrogen Nutrition For Red Fuji/malus Hupehensis

The study used the apple trees(Malus domestica Borkh. cv Red Fuji)/Malus hupehensis as the materials, was carried out in the apple orchard of Shezhuang,Yiyuan County, Zibo City, and in Shandong Agricultural University fruit research station from 2007 to 2009. Enzyme-linked immunosorbent assays (ELISA) technology was used to investigate the dynamic changes of the new shoot growth and the endogenous hormone contents of pot apple trees after branch bending. Trees labelled with stable isotope ¹³C,¹⁵N in pot condition were studied to explore the effects of branch bending angle on characteristics of ¹³C,¹⁵N distribution ratio, while trees in field condition were used to explore the effects of branch drooping on characteristics of absorption, distribution and utilization of ¹⁵N-urea through soil application in spring. The main results were as follows:Bend branch angle obviously inhibit the growth of new shoots. At autumn shoot growing stage,The growth lengths of control,horizontal branch and drooping branch were 50.7cm,21.4cm and 18.1cm respectively, this indicated that the branch length of control was obviously higher than that of branch bending. The levels of endogenous ABA in shoot tip of horizontal branch and drooping branch were 17.5% and 29.2% more than that of control, while the levels of GA,IAA decreased significantly. meanwhile the level of ZR decreased unconspicuously. The level of endogenous ABA in fine roots of branch bending was significantly higher than that of control, whereas the levels of GA and IAA decreased in different grade angle, and the content of ZR showed little different. The ratio of (IAA+GA+ZR)/ABA in new shoot tip and fine roots decreased along with the bending angle, the length in shoot tip of control,horizontal branch and drooping branch were 2.11,1.61,1.36 respectively at autumn shoot growing stage.The ¹³C distribution ratio to roots decreased significantly along with the bending angle. The maximum value of ¹³C distribution ratio to roots was found at autumn shoot growing stage, and the ratio of control,horizontal branch and drooping branch were 46.39%,36.39%,26.73% respectively. The ¹³C distribution ratio to leaves was positive conrrelation with branch bending angle, and the ratio of control,horizontal branch and drooping branch were 30.15%,42.40%,54.97% respectively at autumn shoot growing stage. However, the ¹³C distribution to fine roots and new shoots decreased along with bend angle. The distribution to above-ground organs showed as the following: branch drooping > branch horizontal >control, whereas distribution to perennial organs had no obvious difference.The ¹⁵N utilization ratio of treated plant was lower than that of control, and the significant difference was found at autumn shoot growing stage, that of control,branch horizontal and branch drooping were 5.29%,3.87%,4.05%. The ¹⁵N distribution ratio to new shoots of treated plant was significantly lower than that of control, while the distribution ratio of leaves was significantly higher than that of control. The ¹⁵N distribution ratio to new shoots and perennial organs of treated plant was significantly lower than that of control.Experiments in field condition indicated that the Ndff value of roots in treated plant was obviously lower than that of control. Ndff value of fine roots was obviously different during multiple phenophases, while significant variance in Ndff value of coarse roots was found after fruit rapid-swelling stage. There was no regular pattern between Ndff value of leaves in short and middle shoots between the treatment and the control. Meanwhile, Ndff value of fruits, long shoot and leaves in long shoot with treatment was obviously lower than that of control before fruits were harvested, while Ndff value of perennial organs in treated plant was obviously higher than that of control after fruits were harvested. The ¹⁵N distribution ratio to short and middle shoots of treated plant was significantly higher than that of control, while difference of distribution to fruit between the treatment and the control was significant only after fruit rapid-swelling stage. Moreover, the distribution ratio to long shoot of treated plant was obviously lower than that of control before fruits were harvested. The ¹⁵N utilization ratio of treated plant was lower than that of control, and the significant difference was found after fruit rapid-swelling stage, the ¹⁵N utilization ratio of treated plant and control were 21.083% and 26.495% respectively.