Effects Of Root Restriction On Apple Nursery Trees Qulity And Ralated Physiological Mechanisems Research

One-year-old apple nursery‘T337’/ Malus prunifolia(Willd.) Borkh and two-year-old apple(Malus domestica Borth.)cultivar ‘Fuji Nagafu No. 2’/‘T337’/ Malus prunifolia(Willd.) Borkh were used as experimental material.Which were subjected to root restriction in four methods:root pruning, transplanting,transplanting with root pruning and transplanting with nonwoven fabric root restriction cultivation,and the controls are the normal growth of apple nursery trees.Measuring apple nursery growth and physiological indices, then comparing the effcts of different root restriction methods on apple nursery quality and relative physiological indices. Experimental results showed:1.Root restriction had significant inhibitory effect on the growth of apple nursery,which became more and more obvious with the extension of growth period and the methods or degree of root restriction effectedgrowth velocity of apple nursery,root restriction reduced leaf weight,leaf area,and the amount coarse roots,and increasedtotal root length,total root surfarea,total root volume,total tips and the amount fine root.Root pruning could increaseunderground biomass,and the impact of root restriction on abovegroundbiomass is more significant than underground.This study refer to Apple nursery plants standard, and comparatied with the quality of root restriction apple trees shows, according to therequirements on the quality of apple nursery such as, plant height, diameter, branch number,thenumber of lateral root and so on, moderate rootrestriction(pruning and transplanting) could improve the quality of apple nursery,but excessiverootrestrictioncouldnot achieve role to improve the quality of the apple nursery although it increased the number of lateral rootsbecause the inhibition effect on aboveground growth is too big,.2. Root restriction reduced the net photosynthetic rate(Pn), stomatal conductance(Gs), intercellular CO2 concentration(Ci), transpiration rate(Tr),and increased water use efficiency(WUE) of apple nursery.The content of ZR was higher than control in leaf but the content of ZR in root was on the contrary. The content of ABA was higher than control both in leaf and root after transplanting. In addition,the content of IAA was significant rised in leaf but reduced in root.The total soluble sugar gradually increased in leaf of apple nursery, The sucrose content showed a trend of increase after the first reduce.Moderate rootrestriction inceased the content of sucrose in earlier pierod but excessiverootrestriction reduced it. The total soluble sugar content showed a trend of increase after the first reduce and,the soluble sugar was higher than control in the earlier pierod.