Plant biochemistry influences tropospheric ozone formation, destruction, deposition, and response.

Tropospheric ozone (O) is among the most damaging air pollutant to plants. Plants alter the atmospheric O concentration in two distinct ways: (i) by the emission of volatile organic compounds (VOCs) that are precursors of O and (ii) by dry deposition, which includes diffusion of O into vegetation through stomata and destruction by nonstomatal pathways. Isoprene, monoterpenes, and higher terpenoids are emitted by plants in quantities that alter tropospheric O. Deposition of O into vegetation is related to stomatal conductance, leaf structural traits, and the detoxification capacity of the apoplast. The biochemical fate of O once it enters leaves and reacts with aqueous surfaces is largely unknown, but new techniques for the tracking and identification of initial products have the potential to open the black box.