The Fuji / M. hupehensis. Biennial plants were selected

and the different doses of vitamin B6 (VB6) and compound vitamin B (COB) were added under pot experiments to study the effects on biological characteristics and physicochemical properties of apple trees. The pot experiments were carried out in 2006. VB6 and COB were added into the soil of Fuji on 26th May. And the doses were 0 (control)

0.02

0.03

0.04 g/plant respectively.The plant height

diameter

leaf area

leaf antioxidant activity

chlorophyll content

photosynthetic fluorescence parameters and the growth and distribution of roots were determined. The results showed that different doses of VB6 and COB had different effects on plant height

stem diameter

plant biomass

leaf area and antioxidant activity

photosynthetic fluorescence parameters and root distribution of apple trees.The plant growth was significantly improved by the addition of VB6 and COB. COB of 0.04 g/plant treatment had the most significant effects on aboveground growth

and VB6 with 0.03 g/plant increased leaf area most significantly

i.e. 22%. The plant height

stem diameter and tip length were increased by 24%

34%and 45% significantly

compared with the control in October

and no significant difference were observed between VB6 of 0.03 g/plant and COB of 0.04 g/plant. The total length

weight

volume and surface area of the underground were significant improved under VB6 of 0.03 g/plant and COB of 0.04 g/plant

and the number of root tip and bifurcation also increased significantly. There was no significant difference in antioxidant enzyme activities of apple leaves under VB6 of 0.02 g/plant and COB of 0.02 g/plant

compared with control. The resistance of plants was significantly enhanced under VB6 of 0.03 g/plant and COB of 0.04 g/plant

with the increased activities of antioxidant enzymes. The chlorophyll contents in apple leaves were significantly improved

and the photosynthetic fluorescence characteristics were also improved remarkably

and there was no significant difference between VB6 of 0.03 g/plant and COB of 0.04 g/plant. The results showed that VB6 of 0.03 g/plant and COB of 0.04 g/plant had the most significant effect on the biological traits and physicochemical properties of apple trees. In view of the higher effective dose and cost of COB

it was recommended to use VB6 to improve soil nutritional conditions.