Changes of phenols and adjustability of the walnut shoot

The study on the changes of phenols and adjustability of the walnut shoot shows that the content of phenols in phloem is higher than that in the xylem,that in the late fruiting variety is higher than that in the early fruiting variety and that in the rest period is higher than that in the growth period annually;the change of activity of polyphenol oxidase （PPO）shows an opposite pattern of change with higher activity at the growth period and lower activity at the rest period. There are different abilities of anti-cold in different cultivars shoots.