Can the capacity for isoprene emission acclimate to environmental modifications during autumn senescence in temperate deciduous tree species Populus tremula?

Abstract

Changes in isoprene emission (Φ(isoprene)), and foliage photosynthetic (A) rates, isoprene precursor dimethylallyldiphosphate (DMADP), and nitrogen and carbon contents were studied from late summer to intensive leaf fall in Populus tremula to gain insight into the emission controls by temperature and endogenous, senescence-induced, modifications. Methanol emissions, characterizing degradation of cell wall pectins, were also measured. A rapid reduction in Φ(isoprene) and A of 60-70% of the initial value was observed in response to a rapid reduction of ambient temperature by ca. 15°C (cold stress). Later phases of senescence were associated with further reductions in Φ(isoprene) and A, with simultaneous major decrease in nitrogen content. However, during episodes of temperature increase, A and in particular, Φ(isoprene) partly recovered. Variation in Φ(isoprene) during senescence was correlated with average temperature of preceding days, with the highest degree of explained variance observed with average temperature of 6 days. Throughout the study, methanol emissions were small, but a large burst of methanol emission was associated with leaf yellowing and abscission. Overall, these data demonstrate that the capacity for isoprene emission can adjust to environmental conditions in senescing leaves as well, but the responsiveness is low compared with mid-season and is also affected by stress.

Emissions of green leaf volatiles and terpenoids from Solanum lycopersicum are quantitatively related to the severity of cold and heat shock treatments

“…The air used for the experiments was drawn from outside and passed through a custom-made ozone trap based on HCl-activated copper tubing (residual ozone level < 1 nmol mol −1 ) as applied previously (Sun et al, 2012).…”

Atmospheric mixing ratios of methyl ethyl ketone (2-butanone) in tropical, boreal, temperate and marine environments

“…The air samples were drawn into multi-bed stainless steel cartridges (10.5 cm length, 3 mm inner diameter, Supelco, Bellefonte, PA, USA) filled with Carbotrap C 20/40 mesh (0.2 g), Carbopack C 40/60 mesh (0.1 g) and Carbotrap X 20-40 mesh (0.1 g) adsorbents (Supelco). Even though the site usually experiences low ozone mix- ing ratios of 10-30 ppb (Noe et al, 2012), a catalytic Cu(II) ozone scrubbing system (Sun et al, 2012) was applied. Three constant-flow air sample pumps (1003-SKC, SKC Inc., Huston, TX, USA) and one multisample constant-flow air sample pump (224-PCXR8, SKC Inc., Huston, TX, USA) allowed four samples to be collected at the same time.…”

Estimations of isoprenoid emission capacity from enclosure studies: measurements, data processing, quality and standardized measurement protocols

“…Ekberg et al, 2009;Noe et al, 2011), and temperatures that high may constitute a significant stress for the plant. Analogously, temperatures are low in the beginning and end of the growing season when the emission measurements can be conducted at ambient temperatures at most of 10-15 • C (Hakola et al, 2006;Ruuskanen et al, 2007;Sun et al, 2009Sun et al, , 2011Tarvainen et al, 2005). Due to seasonal changes in the shape of the temperature response curve (Tarvainen et al, 2005), these low temperature measurements cannot be reliably extrapolated to 30 • C. Thus, in cooler climates, and in periods with lower temperatures, we suggest that standard temperatures lower than 30 • C be used for E S determination.…”