Self/non-self discrimination in tendrils of the vine Cayratia japonica with electrical signals

Recent studies have shown that the vine Cayratia japonica (C. japonica) has a self/non-self discrimination ability via its tendrils. However, the mechanism of self/non-self discrimination in tendrils of C. japonica remains unclear. Here, we show that tendrils of C. japonica discriminated between self and non-self plants with electrical signals generated by the contact of tendrils. We conducted touch experiments with C. japonica and detected electrical signals generated by the contact of tendrils. We found that when the tendril contacted the stem and did not coil around it, the electrical signal was transmitted from the stem to the tendril. On the other hand, when the tendril coiled around the stem, no electrical signal was transmitted. These results suggest that the electrical signals inhibited the coiling of tendrils, and the following experiment was conducted to verify this hypothesis: (1) when the tendrils did not coil around the stems after contacting the stems, the tendrils were removed from the stems and contacted a stick to coil around it. (2) Contact stimuli were applied to the part of the stems where the tendrils did not coil around, and the tendril uncoiled. We found that self/non-self discrimination was realised by electrical signals that inhibited coiling generated by contact stimuli.