Hipvs Enhance Photosynthesis While Increasing Herbivore Resistance in Brassica Rapa

Abstract Herbivore-induced plant volatiles (HIPVs) mediate plant–plant communication and can induce or prime responses in neighbouring plants. However, their effects on primary physiological processes and whether these responses are consistent across wild and cultivated varieties remain poorly understood. We investigated how exposure to HIPVs influences photosynthesis, stomatal conductance, volatile emissions, and resistance to the herbivore Plutella xylostella in two wild and two cultivated varieties of Brassica rapa . Receiver plants exposed to HIPVs increased net photosynthesis and stomatal conductance compared with plants exposed to constitutive volatiles. HIPV exposure also altered plant–herbivore interactions. In oviposition assays, P. xylostella females laid fewer eggs on HIPV-exposed plants, and larval feeding resulted in reduced leaf consumption and lower larval weight gain relative to controls. Multivariate analyses revealed qualitative shifts in volatile blend composition in cultivated varieties but not in wild populations. Together, these findings demonstrate that perception of HIPVs can enhance primary physiological activity while increasing resistance to herbivores, highlighting a link between volatile signalling and plant physiological responses.