The effects of dry O₃, SO₂ and NO₂ on reconstituted epicuticular wax tubules

Abstract

S i; M M A R YEpicuticular -^vax tubules were reconstituted in vitro by recrystallizing nonacosan-10-ol from the soluble cuticular lipids o(Piceapungens Engelm. on a glass support. Fumigation of these preparations for 100 h with dry O., (1-8%), SO, (100 °o) or for 1500h with NO^ (0-1%) did not change their composition or crystal habit. Exposure of reconstituted wax tubules to 1 % of dry NO^ yielded planar crystals of nonacosan-10-one after 100 h. Eurther exposure (264 h) resulted in the complete degradation of aggregates and the formation of nonadecanoic and eicosanoic acids. The same oxidation steps and the accompanying changes of crystal shapes could be induced by fumigation of nonacosan-10-ol tubules with 100°o of dry NO^ for 0-25-1 h and for 2 h, respectively. The oxidation of nonacosan-10-ol depended on the doses applied. At ambient concentrations, equivalent doses would accumulate onjy over thousands of years. Oxidative transformations alone can therefore not account for the in vivo degradation of wax tubules on conifer needles.

Early Responses to Acute Ozone Exposure in Two Fagus Sylvatica Clones Differing in Xeromorphic Adaptations: Photosynthetic and Stomatal Processes, Membrane and Epicuticular Characteristics

“…Clone-specific and quali-quantitative variations in wax chemistry exposed to O 3 have been detected in spruce needles (Lutz et al, 1990, Percy et al, 1992 and in poplar leaves (Percy et al, 2002). Chemical changes in wax composition were unlikely to induce the structural alteration of stomata, as oxidative transformations alone cannot account for the in vivo degradation of epicuticular wax tubules (Jetter, Riederer, & Lendzian, 1996). Ozone may alter the synthesis of cuticular components (Kerstiens & Lendzian, 1989) and affect the regeneration of epicuticular waxes in mature leaves.…”

Ozone sensing and early signaling in plants: An outline from the cloud

“…Alterations in EW structure and chemical composition were recently shown to affect plants' responses to abiotic and biotic stresses (Riikonen et al, 2010). Yet oxidative transformation alone cannot account for the in vivo degradation of wax tubules on conifer needles, even at O 3 concentrations well above ambient conditions (Jetter et al, 1996). Surface characteristics of leaves from different tree species -Betula papyrifera (Riikonen et al, 2010), Populus tremuloides (Mankovska et al, 2005), Picea abies (Lütz et al,1990), or Picea pungens (Jetter et al, 1996) -exposed to O 3 treatment were analyzed, and O 3 seemed to have no significant impact on EW biosynthesis, composition or crystal habit.…”

“…Yet oxidative transformation alone cannot account for the in vivo degradation of wax tubules on conifer needles, even at O 3 concentrations well above ambient conditions (Jetter et al, 1996). Surface characteristics of leaves from different tree species -Betula papyrifera (Riikonen et al, 2010), Populus tremuloides (Mankovska et al, 2005), Picea abies (Lütz et al,1990), or Picea pungens (Jetter et al, 1996) -exposed to O 3 treatment were analyzed, and O 3 seemed to have no significant impact on EW biosynthesis, composition or crystal habit. However, O 3 had a significant negative impact on aspen wax quality and this impact was more severe on O 3 -sensitive clones as rust colonization on leaf surfaces increased under O 3 exposure (Mankovska et al, 2005).…”

Notice of Retraction: Foliar Uptake of Atmospheric Nitrogen Dioxide

“…NO 2 can also be removed from the atmosphere by rain and wash-out thereby depositing as NO 3 -/NO 2 -on cuticles. Although knowledge of NO 2 flux via cuticles is rare, some evidence has suggested the significance of cuticles in controlling NO 2 deposition and re-emission [5]. In recent years, more work focused mainly on (i) the diffusive processes of leaf NO 2 uptake, involving NO 2 absorption by water films of various thicknesses [6], regulation of NO 2 uptake by stomatal dynamics [7], and reactions between NO 2 and apoplastic antioxidant [8], etc., and (ii) the metabolic processes of NO 2 -derived NO 3 -, including NO 3 -/NO 2 -transporters, accumulation and remobilization of NO 3 - [9], and downstream products of NO 2 -N assimilation [10], etc.…”