Biogenic Emissions and CO sub(2) Gas Exchange Investigated on Four Mediterranean Shrubs

At Castelporziano, Italy, monoterpene emission rates were determined for pistachio and rosemary growing in a dune area, and isoprene emission rates were measured for erica and myrtle growing in the understory of a pine oak forest. For rosemary and pistachio, the most observed compounds were 1,8-cineol, limonene, alpha -pinene, and beta -pinene; and alpha -pinene, linolool, beta -pinene, and sabinene, respectively. For both species, peak emissions occurred at noon, with low emission rates at night. The overall carbon loss due to monoterpene emissions was about 0.01 0.10% of the C gain. For myrtle and erica, isoprene emission rates were similar to those of the incident light intensity and the net assimilation rates. For these species, the C loss due to isoprene emission ranged 0.2 0.5% of the C gain.