3Malamy J E. Intrinsic and environmental response pathways that regulate root system architecture [J]. Plant Cell Environ, 2005,28: 67-77.
4Xiao C W,Sang W G,Wang R Z. Fine root dynamics and turnover rate in an Asia white birch forest of Donglingshan Mountain, China [J]. Forest Ecol Manag,2008,255:765-773.
5Jackson .J E. World- wide development of high density planting in research and practice[J]. ISHS Acta Horticulture, 1989 : 17-27.
6Sarwar M,Skirvin R M,Kushad M, et al. Selecting dwarf apple (Malus dornestica Borkh) trees in vitro:multiple cytokinin tolerance expressed among three strains of 'McIntosh' that differ in their growth habit under field condi- tions [J]. Plant Cell Tiss 0rg,1998,54:71-76.
7De Silva H N, Hall A J, Tustin D S, et al. Analysis of distribution of root length density of apple trees on different dwarfing rootstocks [J]. Ann Bot-London, 1999,83:335-345.
8Stone E L,Kalisz P J. On the maximum extent of tree roots [J]. Forest Ecol Manag, 1991:46:59-102.
9Fernandez R T,Perry R L,Ferree D C. Root distribution patterns of 9 apple rootstocks in 2 contrasting soil types [J]. J Am Soc Hortic Sei, 1995, 120:6-13.
10Neilsen G H,Parchomchuk P,Berard R,et al. Irrigation frequency and quantity affect root and top growth of fertigated 'MeIntosh: apple on Mg, M26 and M7 rootstock [J]. Can J Plant Sci,1997,77:133-139.