LAUSR

ABSTRACT Many plants exhibit systemic induced resistance (SIR) coordinated among numerous branches after damage to a single localized tissue. Recently, it has been revealed that damaged leaves release a variety of volatile organic compounds (VOCs) into their surroundings that induce SIR. The phenomenon has been described for only four species in field experiments. We investigated induced resistance to herbivory in beech, a dominant tree in Japan. We examined whether volatile cues were required for SIR by determining natural levels of leaf damage for assay branches that were on the same plant as treatment branches. We found when a local branch was mechanically clipped, the proportion of leaf segments that were damaged by herbivores was reduced. However, when a clipped branch was covered with a plastic bag, the proportion of leaf segments that were damaged was the same as that of the control. These results suggested that SIR in beech trees required air contact.