The Effect Of Branch Magament On Growth, Water And Nitrogen Use Efficiency Of Young Apple Trees

The apple (Malus domestica Borth.) cultivar Fuji ‘Nagafu No.2’ were used as material,to study the effects of promalin on growth and15N absorption and utilization of young appletrees. The treatment was spraying promalin (1500mg/L) and the control was spraying waterin June, using conventional and15N tracer method. Measuring the growth parameters of youngapple tree, weighing or calculating related leaf quality indicators of young apple tree, andmeasuring15N absorption and utilization. The results showed that (1)The results showed thatthe plant height with promalin spraying was significantly inhibited, while the trunk diameterwas significantly increased. Leaf number and total leaf area significantly increased by97.80%and50.18%by spraying promalin, respectively. Promalin spraying treatment promoted root’sgrowth of the young apple trees, root dry weight increased by16.70%.(2) Promalin sprayingtreatment significantly raised the content of total nitrogen and15N uptake, nitrogen utilizationefficiency increased by25.07%~34.74%.(3) For the following year’s apple trees, promalinspraying treatment significantly raised the accumulation of dry matter, and the whole plantdry weight, shoot and root dry mass were significantly greater than the control. With thepassage of time, except the amount of leaves decreased, the remaining organs were increased.(4) For the following year’s apple trees,trunk, coarse roots, fine roots on Ndff%and15Ndistribution rate of spraying treatment were significantly higher than the control, while theleaves and shoots was significantly lower than the control. With the passage of time, the bothtreatment on Ndff%and15N distribution rate of newborn organs (leaves and shoots)decreased significantly, while the storage organs (trunk, thick roots) was increased. Nitrogenuse effiency of apple saplings increased24.96%~26.69%. According to experiment results,spraying promalin significantly increased the whole biomass and promoted nitrogenabsorption of young apple trees, accelerated the tree forming and structure development.We chosen4-year-old apple tree（Malus domestica Borth.）cultivar Fuji ‘Nagafu No.2’ asmaterial, to study the effect of pruning branches on the growth and water use effiency ofyoung apple trees. We investigated the plant height and trunck diameter, dry weight of eachorgan, stomatal character, gas ex-change and chlorophyll fluorescence, hydraulic conductivityand water use efficiency. The result showed that (1) under both water conditions, plant height of branch pruning trees were significantly higher than control, but their trunk diameter weresmaller. Leaf, fine root, above-ground and below ground dry weight of branch pruning treeswere significantly smaller than control.(2) Under water stress, the Pn, Ci, Gs, E, Ksh/LA ofthe branch pruning trees were significantly greater than that of the control, the leaf stomatallength in branch pruning were significantly smaller than that of the control, but stomataldensity were significantly greater than the control. For water use effiency, WUEi（Pn/Gs）ofpruning the branch was significantly greater than that of the control, but δ13C was lower thanthe control. According to the results, lower photosynthetic and transpiration rate, higher wateruse efficiency of branched trees show more drought resistance in arid regions, branch pruningcan opposite.