Cupreous preparation and zincous preparation played a role in regulating root growth and development of Ginkgo biloba.The chemical root control preparations of Cu 100 g·L-1,ZnCO3120,160 g·L-1,Zn（AC）2 120,160 g·L-1 and DK 1 g·L-1 were able to inhibit the length of first classical latteral root,thereby they controled root growth.The first classical lateral roots treated with cupreous preparation and diquat preparation were shorter than that treated with zincious preparation,however the later produced seedlings with better quality.The length of first classical lateral root,the number of out-side roots with the diameter under 1 mm,and the number of root tips as diameter under 1 mm had linear correlations between them,thus the number of out-side roots could be a better index than the length of first classical lateral root for determining the effective of the root control.
