UC Irvine

The light, temperature and stomatal conductance dependencies of volatile organic compound (VOC) emissions from ten plant species commonly found in the Mediterranean region were studied using a fully controlled leaf cuvette in the laboratory. At standard conditions of temperature and light (30°C and 1000μmolm-2s-1 PAR), low emitting species (Arbutus unedo, Pinus halepensis, Cistus incanus, Cistus salvifolius, Rosmarinus officinalis and Thymus vulgaris) emitted between 0.1 and 5.0μg (C) (total VOCs) g-1 dwh-1, a medium emitter (Pinus pinea) emitted between 5 and 10μg (C)g-1 dwh-1 and high emitters (Cistus monspeliensis, Lavendula stoechas and Quercus sp.) emitted more than 10μg (C)g-1 dwh-1. VOC emissions from all of the plant species investigated showed some degree of light dependency, which was distinguishable from temperature dependency. Emissions of all compounds from Quercus sp. were light dependent. Ocimene was one of several monoterpene compounds emitted by P. pinea and was strongly correlated to light. Only a fraction of monoterpene emissions from C. incanus exhibited apparent weak light dependency but emissions from this plant species were strongly correlated to temperature. Data presented here are consistent with past studies, which show that emissions are independent of stomatal conductance. These results may allow more accurate predictions of monoterpene emission fluxes from the Mediterranean region to be made. © 2002 Elsevier Science Ltd. All rights reserved.