Spatial distribution and time-course of polyphenol accumulation as a defense response induced by wounding in the phloem of Chamaecyparis obtusa


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  • • The spatial distribution and time-course of accumulation of polyphenols induced by wounding were examined in the phloem of Chamaecyparis obtusa.
  • • The bark of C. obtusa was wounded and segments around the wound were obtained 2, 4 and 8 wk later. Polyphenol accumulation was analyzed by histochemical light-microscopic examination and by the quantification of extracted polyphenols.
  • • By histochemical observation, the accumulation of polyphenols was observed in callus tissue, parenchymatic zone, periderm, phloem parenchyma cells and epithelial cells. Polyphenols were significantly accumulated in the callus tissue and parenchymatic zone. The amount of soluble polyphenols in the callus tissue had increased 2.5 times after 8 wk compared with the phloem before wounding. In the necrotic tissue, soluble polyphenols were reduced by 65% after 2 wk and then gradually increased.
  • • The time-course of polyphenol accumulation and chemical change in response to wounding were different among individual tissues in the phloem of C. obtusa. We suggest that the interaction of these responses is related to induced resistance in the phloem.