Instantaneous and historical temperature effects on alpha-pinene emissions in Pinus halepensis and Quercus ilex.

We compared the role of instantaneous temperature and temperature history in the determination of alpha-pinene emissions in Mediterranean conifer Pinus halepensis that stores monoterpenes in resin ducts, and in Mediterranean broad-leaved evergreen Quercus ilex that lacks such specialized storage structures. In both species, alpha-pinene emission rates (E) exhibited a significant exponential correlation with leaf temperature and the rates of photosynthetic electron transport (Jco2+o2) started to decrease after an optimum at approximately 35 degrees C. However, there was a higher dependence of E on mean temperature of previous days than on mean temperature of current day for P.

Sensitivity of terpene emissions to drought and fertilization in terpene-storing Pinus halepensis and non-storing Quercus ilex.

We studied the effects of water stress, fertilization and time course on foliar volatile terpene emission rates by Quercus ilex and Pinus halepensis in a garden experiment. The terpenes mostly emitted by both species were alpha-pinene, beta-pinene, beta-myrcene and Delta(3)-carene. P.