Wound-induced phenolic accumulation and browning in lettuce (Lactuca sativa L.) leaf tissue is reduced by exposure to n-alcohols

نویسندگان

  • Young-Jun Choi
  • Francisco A. Tomás-Barberán
  • Mikal E. Saltveit
چکیده

A wound signal originates at the site of injury in lettuce (Lactuca sativa L.) leaf tissue and propagates into adjacent tissue where it induces a number of physiological responses which include increased phenolic metabolism with the de novo synthesis of phenylalanine ammonia lyase (PAL, EC 4.3.1.5), the synthesis and accumulation of soluble phenolic compounds (e.g., chlorogenic acid), and subsequent tissue browning. Exposing excised mid-rib leaf tissue to vapors (20 mol/(g FW)) or aqueous solutions (100 mM) of n-alcohols inhibited this wound-induced tissue browning by 40 and 60%, respectively. Effectiveness of the alcohol increased linearly from ethanol to the 7-carbon heptanol, and then was lost for the longer n-alcohols 1-octanol and 1-nonanol. The 2and 3-isomers of the effective alcohols did not significantly reduce wound-induced phenolic accumulation at optimal 1-alcohol concentrations, but significant reductions did occur at much higher concentrations (100 mol/(g FW)) of the 2-, a i i n s ©

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تاریخ انتشار 2005