Isoprene emissions and photosynthesis in three ferns – The influence of light and temperature

Abstract

A study was designed to determine the rates of isoprene emission and photosynthesis in three fern species [Dicksonia antarctica Labill., Thelypteris decursive‐pinnata (Van Hall) Ching and Thelypteris kunthii (Desv.) Morton] and the independent influence of light and temperature on these processes. The plants were conditioned in a growth chamber and then transferred to a controlled environment gas‐exchange chamber. Samples of the chamber atmosphere were collected; isoprene was concentrated cryo‐genically and measured by gas chromatography. Only small amounts of isoprene were detected around the ferns in the dark. Isoprene emissions increased with increasing levels of photosynthetic photon flux density (PPFD) in all three species; 50% of the maximum emission occurred at PPFD levels of 130 to 500 μmol m−2 s−1. Maximum isoprene emissions occurred between 35 and 39°C which is a lower temperature maximum than reported for angiosperms and gymnosperms. The increased emissions with temperature were primarily associated with increased biosynthetic rates for isoprene. Carbon lost through isoprene accounted for 0.02 to 2.6% of the carbon fixed during photosynthesis, depending on the PPFD level, temperature and fern species.

Monoterpene and sesquiterpene emissions from <i>Quercus coccifera</i> exhibit interacting responses to light and temperature

“…Whatever the mechanisms involved, our results showed that interactions between light and temperature responses of MT and SQT emissions can exist as it has been reported for isoprene emissions in some studies (Monson et al, 1992;Tingey et al, 1979Tingey et al, , 1987. Above all, light seems to be an important modulator of the temperature optima and high temperature decline of isoprenoid emissions from Q. coccifera shaping not only the total quantity but also the quality of the BVOC release.…”

“…Such interactive modulations of light and temperature responses may have important implications for the prediction of BVOC fluxes, because temperature and light vary throughout the day, seasons and weather conditions. Evidence for light and temperature interdependencies was first brought out by Tingey et al (1979Tingey et al ( , 1987, who determined light responses of isoprene emissions from oaks and ferns at different temperatures and temperature responses at different light levels. However, these earlier works did not evaluate the response curves on a relative scale.…”

Environmental and developmental controls over the seasonal pattern of isoprene emission from aspen leaves

“…The primary environmental controls over the instantaneous rate are light and temperature (Tingey et al 1979(Tingey et al , 1987Monson and Fall 1989;Loreto and Sharkey 1990). Control by light may explain the often-reported linkage between isoprene emission rate and the instantaneous photosynthesis rate (Sanadze 1969;Rasmussen and Jones 1973;Tingey et al 1987;Monson and Fall 1989;Sharkey 1990, 1993a;Monson et al 1991b). Temperature control is expressed through the temperature dependence of isoprene synthase, the enzyme that underlies isoprene biosynthesis (Silver and Fall 1991;.…”

“…Several past studies have provided evidence of a metabolic linkage between isoprene biosynthesis and photosynthesis (e.g., Sanadze 1969;Rasmussen and Jones 1973;Tingey et al 1987;Monson and Fall 1989;Sharkey 1990, 1993;Monson et al 1991b;Delwiche and Sharkey 1993). There appears to be no role for this linkage in determining the early-season onset of isoprene emission.…”

Fractionation of Carbon Isotopes during Biogenesis of Atmospheric Isoprene

“…The largest source of nonmethane hydrocarbons in the atmosphere is biogenic isoprene released by many trees (13), ferns (17), and tropical plants (12). Carbon lost from plants to the atmosphere as isoprene can account for up to 8% of the carbon assimilated by photosynthesis (8,10).…”