The plant cuticle as an interface between leaves and air-borne pollutants

Material deposited on leaf surfaces may be taken up into the interior either by the stomata! or the cuticular pathway. The uptake of non-volatile substances is restricted to the penetration of the cuticle. The objective of the collaborative work reported here was to characterise important aspects of the interactions between air-borne pollutants and the cuticle of trees. The amounts and composition of the cuticular waxes of the needles of Picea abies and the leaves of Fagus sylvatica were investigated with special attention to the effects of age and environmental factors. The transport properties of plant cuticles were studied using a variety of techniques covering uptake into intact needles, permeability of isolated cuticular membranes and the mobility of permeants in reconstituted cuticular waxes. Effects of polluted sea-spray on the needle surfaces of conifers growing close to the Mediterranean Sea were also investigated

Multivariate patterns of antioxidative and photoprotective defence compounds in Spruce needles at two Central European forests sites of different elevation

In this work we measured a set of antioxidative and photoprotective compounds (chlorophylls, carotenoids, tocopherol, ascorbate and glutathione), which were suggested previously as stress markers in conifer needles, at two spruce forest sites at different elevation in Saxony, Germany. Most variables differed significantly between current and 1-year-old needles, but only the content of the xanthophyll cycle per mg total chlorophyll and the oxidation state of glutathione were significantly different between the sites. We applied principal component analysis (PCA) to address the question if underlying accumulated variables are similar to the ones found in spruce needles across Alpine elevation profiles and/or for pines in Mediterranean ecosystems. Four principal components (accumulated variables, PC) representing 68% of the total variance of the dataset were extracted. PC 1 encompassed total chlorophyll, lutein, and β-carotene contents, PC 2 combined the epoxidation state of xanthophylls, ascorbate content and redox state, and glutathione content, PC 3 represented the content of xanthophylls and the redox state of glutathione, and PC 4 encompassed the content of β-carotene and the epoxidation state of xanthophylls. Only PC 3 was significantly different between sites. The PCA structure shows many similarities to corresponding findings in studies on spruce in mountain forests in the Alps and pines in Mediterranean systems. This corroborates the interpretation of PCs as indicative for underlying physiological processes. However, separation of the two investigated sites by PCs was in the present case study not superior to the separation by single input variables. © Springer Science+Business Media B.V. 2007