Abstract:

Lignification process was observed by the method of Phloroglucinol-HCl and content of
lignin，cellulose，polyphenol and the activity of related enzymes were measured during development with
the materials of walnut of‘Zanmei’and‘Zhenzhuxiang’. The results showed that lignification occurred
at beginning of June，already initial took shape in mid-June and completed in late July. From shell
lignification to harvest，the content of lignin，cellulose and polyphenol was increased，while polyphenol
content slightly decreased before harvest. The activities of both POD and PAL were decreased and PPO
varied little. The correlation analysis showed that lignin content was significant positive correlated with the
content of cellulose. Polyphenol content was significant positive correlated with the content of lignin.
Polyphenol content was positively correlated with cellulose. The activity of POD was significant negative
correlated with content of lignin，cellulose and polyphenol，but positively correlated with activity of
PAL.

Key words: walnut, shell, lignin, cellulose, PAL, POD, PPO