Induced twining in ipomoea purpurea (L.) roth. Response threshold and induction by volatiles and snail damage

Twining in some Convolvulaceae can be induced by leaf damage and jasmonic acid application. This induced response is believed to reduce the likelihood of future leaf damage and it is limited by drought. This response has been detected in the Convolvulaceae family using artifi cial damage. The mechanisms and ecological implications of this response are still unknown. In this study was tested if the induced twining requires a threshold level and if it is induced by volatiles and/or by snail damage. Three separated greenhouse experiments were conducted in order to test the induced twining in Ipomoea purpurea (Convolvulaceae) by applying different levels of artifi cial damage (0, 1, 5, 10 perforations to the leaves), volatiles (ground leaves) and natural damage by snails. Plants receiving the two higher damage levels twined faster than the individuals exposed to the two lower damage levels. Plants exposed to grounded leaves (volatiles) twined faster than control plants. Finally, twining was induced by snail damage more than in undamaged plants. Most growth traits did not change in any treatment. Twining in I. pupurea can be induced by artifi cial or natural damage, and also by volatiles emitted by damaged leaves of neighbor plants, making the induced twining an ecologically relevant response.