Chemical Composition Of Epicuticular Wax Research Articles

Leaf surface traits related to differential particle adsorption – A case study of two tropical legumes

We aimed to test a set of epidermal traits in two legume species with contrasting chemical, physical, and micromorphological leaf-surface features to assess which ones would determine higher PM retention. For that, we performed a biomonitoring study in southeastern Brazil at the Steel Valley Metropolitan Region, where there is predominance of steel industry and one of the largest vehicle fleets in the country. A reference station was installed at a neighboring park. We evaluated leaf-surface roughness at two hierarchical levels, leaf wettability, epidermal-cell anticlinal-wall undulation, epidermal-cell perimeter, and the micromorphology and chemical composition of epicuticular waxes. Particle retention was significantly higher in Paubrasilia echinata than in Libidibia ferrea var. leiostachya, the former of which has lower roughness given by both the epidermal tissue (macro-roughness; 0.6 vs 2.6 μm) and epicuticular waxes (micro-roughness; 68 vs 220 nm), higher leaf wettability (82° vs 143°), lower epidermal-cell undulation index (1.2 vs 1.8), lower epidermal-cell perimeter (93 vs 146 μm), wax deposition in the form of a smooth layer (as opposed to densely aggregated rosettes of vertical platelets), and more polar wax chemical constitution (68% vs 47% of polar compounds). While all of the assessed traits contributed to particle retention, canonical loadings revealed that macro-roughness was the trait that contributed the most to the retention of PM2.5 (ca = 1.47; r = −0.56), PM10 (ca = 1.08; r = −0.61), PM100 (ca = −4.95; r = −0.39) and TSP (ca = 0.98; r = −0.62), although this trait was shown by factor analysis to be secondary in distinguishing between species (0.92 contribution to the second axis). Our findings shed new light on the criteria that should be considered when selecting species for green infrastructure aiming to reduce urban air pollution, as well as on novel possibilities for PM biomonitoring in the tropics.

Geographically Related Variation in Epicuticular Wax Traits of Pinusnigra Populations from Southern Carpathians and Central Balkans - Taxonomic Considerations.

The chemical composition of epicuticular waxes of nine populations from three Pinusnigra J. F. Arnold subspecies (namely subsp. nigra, subsp. banatica (Borbás) Novák, and subsp. pallasiana (Lamb.) Holmboe) from Southern Carpathians and central Balkan Peninsula were analyzed using GC/MS and GC/FID chromatography, and multivariate statistical techniques with respect to biogeography and taxonomy. In the needle waxes, four primary alcohols and 14 n-alkanes ranging from C21 to C33 were identified, and the most abundant compounds were the four odd-numbered n-alkanes C27 , C25 , C23 , and C29. Multivariate statistical analyses (CDA and CA) have shown existence of three P.nigra groups and suggested clinal differentiation as a mechanism of genetic variation across a geographic area: the first group consisted of the southernmost populations of subsp. pallasiana from Macedonia, the second consisted of the northernmost subsp. banatica populations from Romania, while all populations in Serbia described as three different subspecies (nigra, banatica, and pallasiana) formed the third group together with subsp. nigra population from Bosnia and Herzegovina. According to simple linear regression, geographic latitude and four bioclimatic parameters were moderately correlated with the contents of epicuticular wax compounds that are important in population discrimination, while stepwise multiple regression showed that latitude participated in most of the regression models for predicting the composition of the epicuticular waxes. These results agree with CDA and CA analysis, and confirmed the possibility of recognition of fine geographic differentiation of the analyzed P.nigra populations.

Composition of epicuticular wax layer of two species of Mandevilla (Apocynoideae, Apocynaceae) from Rio de Janeiro, Brazil

The chemical composition of epicuticular waxes of Mandevilla guanabarica and Mandevilla moricandiana was comparatively analyzed by extraction in n-hexane and chloroform. The mean wax content per unit of leaf area in the n-hexane extract was about 13–30 μg cm−2 for M. guanabarica, containing 20–28% n-alkanes and 55–63% triterpenes; for M. mori-candiana, the mean content was 19 μg cm−2, containing 73% n-alkanes and 14% triterpenes. In the chloroform extract, the wax yield was 40–80 μg cm−2 for M. guanabarica, with about 9–11% n-alkanes and 75–82% triterpenes; while for M. moricandiana, the wax yield was 110 μg cm−2, with 52% n-alkanes and 14% triterpenes. The major compounds identified were lupeol, pentacyclic triterpenes of the α- and β-amyrin class, and n-alkanes such as nonacosane, hentriacontane and tritriacontane. These results indicate that the quantitative chemical profiles of epicuticular waxes of M. guanabarica and M. moricandiana are distinct and could be used as an additional feature in taxonomic identification.

Evaluation of Surface Free Energy of Various Fruit Epicarps Using Acid–Base and Zisman Approaches

Surface free energy (SFE; γSV) of 16 fruit epicarps present on the Chilean market was calculated by two approaches: the acid–base and Zisman. The results show that the fruit epicarps were low surface energy since the magnitude of γSV falls within a narrow range, between 37 and 44 mJ m − 2. Zisman approach gave a critical surface tension values, γcr lower than the SFE calculated by the acid–base approach. Significant differences in SFE between the fruits may be explained by the variation in the chemical composition of epicuticular waxes. The polar (\(\gamma^{\rm AB}_{\rm SV}\)) and apolar (\(\gamma^{\rm LW}_{\rm SV}\)) components of the SFE were also calculated and a mathematical relation was between both values was found. Values of \(\gamma^{\rm AB}_{\rm SV}\) and \(\gamma^{\rm LW}_{\rm SV}\) could also be associated with the fruit family and the tissue origins in the ovary region. Finally, it has been shown that fruit epicarps exhibited predominantly electron-donator behaviour since \(\gamma_{\rm SV}^- > \gamma_{\rm SV}^+\). We believe that the results reported here can potentially impact in food engineering because the compatibility of coatings and fruit epicarps depends on the interaction of their respective chemical and physical properties.

Composição química da cera epicuticular de biótipos de azevém resistente e suscetível ao glyphosate

Objetivou-se com este trabalho determinar a composição química da cera epicuticular dos biótipos de azevém (Lolium multiflorum) resistente e suscetível ao glyphosate, buscando relações entre suas características e a resistência dos biótipos ao herbicida. A cera epicuticular foi extraída e quantificada e os seus constituintes analisados por cromatografia em fase gasosa, acoplada a espectrômetro de massa (CG-EM). Para determinação da composição química, amostras de lâmina foliar foram retiradas 30 dias após a emergência das plantas, coletando-se a primeira folha com lígula totalmente visível. A quantidade de cera epicuticular extraída não diferiu entre os biótipos. Entre os compostos que constituem a cera epicuticular, os álcoois são os mais abundantes, sendo representados por apenas um composto: o hexacosan-1-ol (46,80% no biótipo resistente e 52,20% no biótipo suscetível). Ao comparar a polaridade da cera epicuticular dos biótipos de azevém, constatou-se que tanto no biótipo resistente quanto no suscetível a cera epicuticular apresentou mais de 50% de componentes polares (álcoois e aldeídos) em sua constituição, sendo esse valor igual a 69,80% no biótipo resistente e 64,94% no biótipo suscetível. Por meio da caracterização apresentada, pode-se afirmar que existem pequenas diferenças na cera epicuticular dos biótipos de azevém resistente e suscetível ao glyphosate; o biótipo resistente apresentou grau de polaridade pouco superior ao do biótipo suscetível, porém essa diferença não pode ser considerada marcante a ponto de determinar maior ou menor tolerância de um biótipo ou outro ao herbicida glyphosate.

Composição química da cera epicuticular e caracterização da superfície foliar em genótipos de cana-de-açúcar

Objetivou-se neste trabalho avaliar a composição química da cera epicuticular e caracterizar a superfície foliar dos cultivares de cana-de-açúcar RB855113 (sensível à mistura de herbicidas trifloxysulfuron-sodium + ametryn), SP80-1842 e SP80-1816, do clone RB957689 (com média sensibilidade à mistura de herbicidas) e do cultivar RB867515 (tolerante). A cera epicuticular foi extraída e quantificada e os seus constituintes analisados por cromatografia a gás, acoplada a espectrômetro de massa (CG-EM). Para determinação da composição química, assim como a caracterização da superfície foliar dos cultivares avaliados, amostras de lâmina foliar foram coletadas e submetidas à microscopia eletrônica de varredura, para caracterização das faces adaxial e abaxial. A análise das amostras revelou a presença de hidrocarbonetos, esteróides, ésteres graxos, álcoois e aldeídos. A cera do cultivar sensível à mistura (RB855113) apresentou menor número de componentes químicos e predominância de ésteres graxos de cadeia mais curta que os encontrados nos demais cultivares, bem como pequena proporção de esteróides e hidrocarbonetos. Nos cultivares com média sensibilidade (SP80-1842 e RB867515), a cera apresentou maior proporção de hidrocarbonetos e esteróides. A cera do cultivar RB855113 apresentou polaridade intermediária, porém menos polar que a cera do cultivar RB867515 (tolerante à mistura). Não foram observadas diferenças marcantes entre os cultivares no que se refere à micromorfologia foliar.

Seasonal changes in chemical composition of epicuticular waxes from the leaves of Baccharis linearis

Abstract Extracts from the epicuticular waxes of leaves from Baccharis linearis collected at the same locality at different seasons of the year were compared in terms of relative yields, chemical composition and biological activity (feeding deterrancy against Spodoptera littoralis larvae and brine shrimp lethality bioassays). Variations detected in the concentration of some of the 13 secondary metabolites isolated in this study are discussed in connection with relevant seasonal changes of incidental environmental factors such as temperature, solar radiation, water stress and presence of predatory insects.

Epicuticular wax of subarctic Scots pine needles: response to sulphur and heavy metal deposition

summaryThe response of epicuticular wax of Scots pine (Pinus sylvestris L.) needles to dry‐ and wet‐ deposited sulphur and heavy metals was investigated at six sites located 10–110 km from the Monchegorsk Cu‐Ni smelter on the Kola Peninsula, North‐West Russia, and in a long‐term irrigation experiment where pines were exposed over four growing seasons (1991–1994) to either acid rain treatment at pH 3.1 (H2SO4), metal treatment at pH 5.7 (Cu and Ni) or a combination of these at pH 3.1. Needle wettability exhibited a closer relationship with epistomatal wax tube distribution (WTD) than with chemical composition of epicuticular wax. Water droplet contact angles (DCA) decreased towards the smelter, and significant differences due to site were noted for 26‐month‐old and 38‐month‐old needles. Significant differences due to site were determined for secondary alcohols, dehydroabietic acid and hydroxy fatty acids, the proportions of which ranged from 22–5 to 48.9%, 6.2 to 224% and 0.6 to 2.6% respectively, depending on site and needle age class. The proportion of dehydroabietic acid increased towards the smelter, but no gradient was observed in the proportion of secondary alcohols or hydroxy fatty acids. No major effect of experimentally applied pollutants on the chemical composition or structure of the epicuticular wax was observed. The effect of treatment on DCA was significant in 1993 and 1994 due to a 6.5–13.2 degree greater wettability of the 37–49–month‐old acid‐treated needles relative to the irrigated or dry controls. Sulphuric acid at pH 3.1 did not increase needle wettability when combined with copper and nickel sulphate in similar concentrations. These data indicate that S deposition, especially H2SO4, plays a more important role in needle surface deterioration than Cu and Ni. Pollutant‐induced changes in epicuticular wax structure and needle wettability mimic natural wax ageing, but at an accelerated rate. Changes in wax chemical composition might also be caused by pollutant‐induced metabolic changes in elongating needles.

Surface Structures and Chemical Composition of Epicuticular Waxes during Leaf Development of Fagus sylvatica L.

Abstract The surface structures of beech ( Fagus sylvatica) leaf waxes were studied by SEM and correlated with chemical compositions of the extracted wax lipids during one vegetation period. The very young leaflets just unfolding from buds contained already a wax layer without any wax sculptures or crystalloids. This wax layer is quite different in yield and composition to that of mature leaves. With the unfolding of beech leaves, a dynamic biosynthesis of several wax lipids was started, but the biosynthesis of wax esters was not continued further. Ten days after leaf unfolding the de novo biosynthesis of aldehydes could be detected for the first time. Aldehyde amount increased rapidly to about 13% of the wax. The predominant individual wax lipids synthesized were aldehydes, alcohols and fatty acids with C28 and hydrocarbons with C27 chain lengths, respectively. The biosynthesis of wax lipids in beech leaves was completed at the end of May and remained nearly constant in quantity and com position during the remaining season. At the same time when aldehydes were found for the first time, wax sculptures were observed on beech leaf waxes coming out of the continuous wax layer, exclusively on the upper leaf side. These wax sculptures increased in size and quantity in the following time and were present on the upper leaf side all over the season, only some wax sculptures show a trend to crystalline forms.

Content and chemical composition of epicuticular wax of ‘Navelina’ Oranges and ‘Satsuma’ Mandarins as Related to Rindstaining of Fruit

AbstractChanges in the content and chemical composition of epicuticular wax of susceptible and non‐susceptible ‘Navelina’ orange and non‐susceptible ‘ Satsuma’ mandarin fruits to rindstaining, growing in the area of Valencia (Spain), were studied. The epicuticular wax content of the susceptible Navelina fruits increases with ripening from 30 μg cm−2 in July to 110 μg cm−2 in January. The epicuticular wax content of the non‐susceptible Navelina fruits was similar to that of the susceptible ones. The epicuticular wax content of the Satsuma mandarin fruits was lower than that of Navelina orange fruits; it changed from 20 μg cm−2 in July to 40 μg cm−2 in January. In this study, no correlation between epicuticular wax content and susceptibility to rindstaining of the orange fruits was found. In general, alkanes, aldehydes and fatty acids are the major wax constituents, whereas the primary alcohols and the triterpenoids are the minor ones. The maximum incidence of rindstaining occurs at the end of October and the beginning of November, immediately after the major rate of increase of the fruit surface. Such an increase also concurs with the major hardening and facility of cracking of the wax layer.

Surface Structure and Chemical Composition of Epicuticular Waxes during Leaf Development of Tilia tomentosa Moench

Abstract The very young leaflets of silver lime trees (Tilia tomtentosa), just unfolding from buds, con ­ tained a continuous wax layer without any wax sculptures. The wax on young leaves is quite different in yield and composition than that of mature leaves. After unfolding of leaves a very dynamic biosynthesis of most wax lipids was started. Fifteen days after leaf unfolding the de novo biosynthesis of β-amyrenyl acetate and later on of aldehydes could be detected for the first time. The biosynthesis of wax components in silver lime leaves was finished at the end of June and the wax remained nearly constant in amount and composition during the remaining season. At the same time, when β-amyrenyl acetate was found for the first time, wax sculptures were observed in silver lime leaf waxes coming out of the continuous wax layer, exclusively on the upper leaf side. These wax sculptures increased in quantity in the next weeks and resulted in a crystalloid shape of most solitaire quadrangular rodlets. These crystals were remained all over the season and were formed from β-amyrenyl acetate, the dominating main wax compo­nent {ca. 49% wax).

Epicuticular waxes of maize as affected by the interaction of mutantgl8 withgl3, gl4 andgl15.

Chemical composition of epicuticular waxes from double mutants of maizegl2gl8, gl3gl8, gl4gl8 andgl15gl8 is compared to that of the wild type and of the single mutants. The wax composition was moderately affected in the double mutants studied. Meanwhile, free fatty acids became a normal class constituent of the waxes. The sites of action of the single mutants as deduced from previous studies are confirmed. The influence ofgl2, gl3 andgl4 on the terminal steps of the chain elongation process ingl2gl8, gl3gl8 andgl4gl8 genotypes is presented and discussed. The study ofgl3gl8 waxes also confirms that the mutantgl3 induces a metabolic defect defiitely different from those ofgl2 andgl4. The pattern of alkanes fromgl15gl8 is unusual, supporting the thesis thatgl15 controls mainly alkane synthesis. However, based on variations induced on wax composition, its manner of action is difficult to account for. Taken together, the available data on single and double mutants affecting wax synthesis in maize suggest that elongases might be heteromeric enzymes.

Chemical composition of epicuticular wax in cabbage plants grown in vitro

The chemical composition of epicuticular wax from cabbage plants grown in vitro was compared with that from plants grown in a greenhouse. There was a greater percentage of polar compounds (fatty acids, primary alcohols, aldehydes, and esters) and less alkanes and secondary alcohols in wax from cultured plants relative to those from greenhouse plants. Homologues in each class were more evenly distributed and had a greater range of chain lengths in wax from cultured plants. The high proportion of polar components in wax from cultured plants might be a factor in water loss when the plants are transferred to the greenhouse. Possible explanations for the altered wax composition in plants grown in vitro include increased relative humidity and decreased light intensity characteristic of in vitro conditions.

A survey of epicuticular waxes among genera of Triticeae. III. Synthesis and conclusion

Characteristics of ultrastructural morphology and chemical composition of epicuticular waxes on glumes of Triticeae were combined for two series of numerical taxonomic analyses. The first, incorporating within-genus variability, utilized frequencies and information radius. The information radius matrix was subjected to Jardine–Sibson Bk clustering, then transformed to Euclidean distances for distance Wagner and principal-coordinate analyses. The second series employed a table of average character values for each genus which was subjected to four ordinations: (i) principal-component analysis of the correlation matrix, (ii) principal-component analysis of the variance-covariance matrix, (iii) principal-coordinate analysis, and (iv) nonmetric multidimensional scaling. The results are compared and general inferences are drawn. Occurrence of wax filaments on the glumes was highly correlated with presence of appreciable amounts of β-diketones in wax from the whole plant. While some genera, such as Triticum and Aegilops, appeared less closely related than expected from classification based on morphology, this procedure has suggested relationships between other genera, such as Roegneria and Hordeum and Secale and Elymus. The genera Leymus, Elymus, and Aneurolepidium were also closely related to each other and more distantly to Elytrigia, Triticum, and Agropyron. A relatively close relationship was also shown between the seven genera, Crithopsis, Eremopyron, Heteranthelium, Hordelymus, Psathyrostachys, Sitanion, and Taeniatherum, which have waxes which do not contain any β-diketones.