POTATO TUBER-INDUCING ACTIVITIES OF SALICYLIC-ACID AND RELATED-COMPOUNDS

Salicylic acid (SA) induced potato tuberization in vitro at concentrations greater than 10(-5) M. A comparison of the tuber-inducing activities of various related CoMpounds suggested that derivatives of benzoic acid with a free carboxyl group and a substituent at the C-2 position of the benzene ring have this activity. Although SA had the strongest activity among the compounds tested, the activity was about one thousandth of that of natural jasmonic acid (1R,2S-jasmonic acid) in terms of the threshold concentration for activity. Spraying SA to leaves of plants grown under tuber-noninducing conditions (long days) induced tuberization. However, the natural occurrence of SA was not detected in the leaves of potato plants that had been grown under tuber-inducing conditions (short days) and had begun to form tubers. The results seem to exclude the possibility of the involvement of SA in the natural tuberization of potato plants.