Airborne cues accelerate flowering and promote photosynthesis in Brassica rapa

Abstract

1. Volatile cues can induce and/or prime plant defences, but it is less well known if plants also respond by altering growth and reproduction-related parameters. 2. Here we evaluated whether plant volatile cues can elicit changes in growth, flower production, net photosynthesis rate and defences in receiver plants and whether those responses are similar to those elicited in response to direct herbivore-feeding. 3. Our results demonstrate that exposure to volatiles emitted from damaged neighbours accelerated the time to first flowering, increased the number of flowers produced and the net photosynthesis rate, but did not alter the fresh harvested plant biomass and volatile defences, compared to non-exposed plants. Earlier flowering was also observed for plants exposed to volatiles from undamaged plants. 4. These responses differed from those of plants exposed to actual herbivore-feeding for which feeding enhanced net photosynthesis rate but reduced growth and had no effect on reproduction and defence in response to subsequent herbivory. 5. Synthesis. These findings document that plant airborne cues can influence floral traits of receiver plants. In particular, the flower phenology is modulated, and photosynthesis is enhanced, suggesting that carbon allocation could be directed toward reproduction.