Phenol Metabolism, Phytoalexins, and Respiration in Potato Tuber Tissue Treated with Fatty Acid

Potato (solanum tuberosum L. cv Katahdin) tuber discs treated with arachidonic acid become necrotic and accumulate sesquiterpenoid phytoalexins. The arachidonic acid also causes increases in both phenylalanine ammonia lyase and lignin, but no change in total alcohol-soluble phenols. Linoleic acid does not alter any of these parameters. A high concentration of nonanoic acid promotes both necrosis and accumulation of low levels of phytoalexins, but decreased levels of phenols, phenylalanine ammonia lyase, and lignin. The respiration of the control discs and those treated with linoleic acid declines by 24 hours after treatment, but the respiration of arachidonic acid-treated discs remains constant for at least 48 hours.