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Morphological and anatomical traits of the Vinca leaf were examined using microscopy techniques. Outdoor Vinca minor and V. herbacea plants and greenhouse cultivated V. major and V. major var. variegata plants had interspecific variations. All Vinca species leaves are hypostomatic. However, except for V. minor leaf, few stomata were also present on the upper epidermis. V. minor leaf had the highest stomatal index and V. major had the lowest, while the distribution of trichomes on the upper epidermis was species-specific. Differentiated palisade and spongy parenchyma tissues were present in all Vinca species’ leaves. However, V. minor and V. herbacea leaves had a more organized anatomical aspect, compared to V. major and V. major var. variegata leaves. Additionally, as a novelty, the cellular to intercellular space ratio of the Vinca leaf’s mesophyll was revealed herein with the help of computational analysis. Lipid droplets of different sizes and aspects were localized in the spongy parenchyma cells. Ultrastructural characteristics of the cuticle and its epicuticular waxes were described for the first time. Moreover, thick layers of cutin seemed to be characteristic of the outdoor plants only. This could be an adaptation to the unpredictable environmental conditions, but nevertheless, it might influence the chemical composition of plants.

The cuticle is regarded as a non-living tissue; it remains unknown whether the cuticle could be reversibly modified and what are the potential mechanisms. In this study, three tea germplasms (Wuniuzao, 0202-10, and 0306A) were subjected to water deprivation followed by rehydration. The epicuticular waxes and intracuticular waxes from both leaf surfaces were quantified from the mature 5th leaf. Cuticular transpiration rates were then measured from leaf drying curves, and the correlations between cuticular transpiration rates and cuticular wax coverage were analyzed. We found that the cuticular transpiration barriers were reinforced by drought and reversed by rehydration treatment; the initial weak cuticular transpiration barriers were preferentially reinforced by drought stress, while the original major cuticular transpiration barriers were either strengthened or unaltered. Correlation analysis suggests that cuticle modifications could be realized by selective deposition of specific wax compounds into individual cuticular compartments through multiple mechanisms, including in vivo wax synthesis or transport, dynamic phase separation between epicuticular waxes and the intracuticular waxes, in vitro polymerization, and retro transportation into epidermal cell wall or protoplast for further transformation. Our data suggest that modifications of a limited set of specific wax components from individual cuticular compartments are sufficient to alter cuticular transpiration barrier properties.

Wax layer formation accompanies the processes of epidermis and cuticle formation. To examine these changes, observationsalong current-year long shoots of four woody species (Acer negundo, A. rufinerve, Gymnocladus dioica, and Gingko biloba) were made. Long shoots are suitable objects for such observations, because from the same stem, several samples can be obtained that represent a well-defined sequence of fragments of different ages. The data that were obtained from different and sometimes distant stem regions suggest that epicuticular wax crystals appear on the stems very early and quickly, since they are found near the stem apex during intensive plant growth. This was confirmed for the four examined species. Some differences, however, were noted. Very rapid production of prominent wax crystals was observed in stems. In an experiment involving mechanical wax removal from the A. negundo stem surface and subsequent analysis of the surface after several days via scanning electron microscopy (SEM), it was shown that wax regenerates very quickly. After only several hours, new emerging crystals were observed and their morphologies were essentially the same. Nearly full regeneration was observed several days after removal.

The paper deals with the study of damage to the assimilatory apparatus of silver birch (Betula pendula Roth) using the study of changes of epicuticular waxes in the period 1997 to 2009. During the period, changes in the air pollution spectrum occurred in the area of the Ore Mountains. At the beginning of the monitoring, above-limit concentrations of sulphur oxides were the main anthropogenic factor. These concentrations resulted in the degradation of epicuticular waxes. Statistical evaluations demonstrated the high dependence of damage to epicuticular waxes on high concentrations of sulphur oxides. Damage to epicuticular waxes by air pollution increased with the increasing altitude of a forest stand. Since 2001, measured values of SO2 decreased to a minimum but a new phenomenon appeared damaging the assimilatory apparatus of forest stands, namely above-limit concentrations of ground ozone. These above-limit concentrations of ground ozone damage the assimilatory apparatus including epicuticular waxes at all silver birch stands occurring at altitudes above 800 m. This finding was also proved by the high coefficient of determination.

International audience; The waxy surfaces of three carnivorous plants, Nepenthes ventrata (Nepenthaceae), Brocchinia reducta and Catopsis berteroniana (Bromeliaceae), were compared using scanning electron microscopy (SEM). Their effects on attachment and locomotion of the fly Calliphora vomitoria were studied. The waxy surface of N. ventrata is comprised of a heterogeneous layer from which only platelet-shaped crystalloids could be detached by brushing. In the two bromeliads, the crystalloids are thread-shaped and form a homogenous dense network, which was entirely removable from the epidermis. Experimental data showed that none of the flies was able to walk across any of the waxy surfaces and only a few were able to take offfrom those surfaces. Both the absence of sites for claw anchorage, especially in N. ventrata, and the wax itself were shown to contribute to the trapping ability of the plants. Only half of the flies quickly recovered their locomotion ability on a glass surface after 20 min of being tested on waxy plant surfaces. SEM observations revealed that the wax of C. berteroniana formed a powder of broken crystals on the tenent setae of the flies’ pulvilli. In contrast, the waxes of B. reducta and N. ventrata appeared to have lost their crystal structure in contact with the tenent setae and formed an amorphous substance that adhered setae together. We hypothesize that wax interacts with adhesive fluids secreted by the fly pad and thereby prevents the tenent setae from functioning effectively. q 2003 Elsevier Ltd. All rights reserved.

The epicuticular leaf waxes from four glaucous and four non-glaucous species of Encephalartos were examined by GC-mass spectrometry and SEM techniques. The four glaucous-leaved species, E. horridus, E. lehmannii, E. princeps and E. trispinosus, all occurring in xeric conditions in the Eastern Cape Province of South Africa, were conspicuous in having leaf waxes containing a series of secondary alcohols. In addition to 10-nonacosanol as the principal wax component, minor amounts of C25C31 10-alkanols, 4,10-, 5,10- and 7,10-nonacosanediol and the ketone, 10-nonacosanone, were detected in these species. The adaxial leaflet surfaces of the glaucous species all showed a distinctive trabecular deposit of wax platelets when viewed microscopically. By contrast, secondary alcohols and ketones were absent in waxes from the non-glaucous species, and the surface of leaflets of these taxa were relatively featureless microscopically. Varying quantities of alkanes, fatty acids, primary alcohols, aldehydes and alkyl esters were present in all samples. Amongst the non-glaucous species, E. altensteinii, E. natalensis and E. woodii were similar in their wax composition, but differed from E. villosus. Alkanes were dominant in the latter species, which had high proportions of hentriacontane and tritriacontane in parallel with the most prominent oxygenated wax compounds, C32 and C34 fatty acids and aldehydes.

This is the first report on the composition and variability of the needle-wax n-alkanes in natural populations of Pinus nigra in Serbia. Samples of 195 trees from seven populations belonging to several infraspecific taxa (ssp. nigra, var. gocensis, ssp. pallasiana, and var. banatica) were analyzed. In general, the size of the n-alkanes ranged from C(16) to C(33) , with the exception of ssp. nigra, for which it ranged from C(18) to C(33) . The most abundant were C(23) -, C(25) -, C(27) -, and C(29) -alkanes. The needle waxes of Populations I-III and V were characterized by a higher content of C(23) -, C(25) -, and C(27) -alkanes and a lower content of C(24) -, C(26) -, C(28) -, and C(30) -alkanes, compared to the other populations, and the trees of these populations could be assigned to ssp. nigra. The samples of Population VI were characterized by higher amounts of C(22) -, C(24) -, C(30) -, and C(32) -alkanes and lower amounts of C(25) - and C(27) -alkanes, and the trees could be considered as ssp. pallasiana. The samples of Population VII, consisting of trees belonging to var. banatica, were richer in C(29) -, C(31) -, and C(33) -alkanes. The wax compositions of Populations IV and V, both composed of trees previously determined as P. nigra var. gocensis, showed a tendency of splitting. Indeed, the alkane composition of Population IV was closer to that of ssp. pallasiana pines, while that of Population V was more similar to that of ssp. nigra pines. From the results presented here, it is obvious that in the central part of the Balkan Peninsula, significant diversification and differentiation of the populations of black pine exists, and these populations could be defined as different intraspecific taxa. Our results also indicate the validity of n-alkanes as chemotaxonomic characters within this aggregate.

Leaves of Bruguiera gymnorrhiza (L.) Lam. growing at Beachwood Mangrove Nature Reserve (Durban) were removed just prior to leaf fall, placed in mesh litterbags and submerged in the creek of the swamp. At the time of collection the leaves were colonized by phylloplane fungi. The degree of decomposition of leaf material was studied over a period of 18 weeks by means of SEM and LM techniques. After a week’s submergence, the leaves appeared to be devoid of phenolic deposits and microbial colonization intensified. SEM studies indicated that fungi may have degraded the cuticular waxes but the cuticle was still intact at the end of the study. Degradation of the internal tissues was shown to be associated with fungal activities.

The effects of the contents and chemical composition of the foliar epicuticular waxes of species from the caatinga (Aspidosperma pyrifolium, Capparis yco, Maytenus rigida and Ziziphus joazeiro) and cerrado (Aristolochia esperanzae, Didymopanax vinosum, Strychnos pseudoquina and Tocoyena formosa) were evaluated as to the resistance to water loss by means of an experimental device constructed for this purpose. In general, the waxes of the caatinga species investigated were more efficient against water loss than cerrado species. Increase of the thickness of the waxy deposits from 40 to 90m g.cm-2 had no significant effect on the resistance to water loss. The chemistry of the wax constituents was shown to be an important factor to determine the degree of resistance to evaporation. n-Alkanes and alcoholic triterpenes were the most efficient barriers, while hentriacontan-16-one (a ketone) and ursolic acid (an acid triterpene) revealed lowefficiency. The higher efficiency of the waxes of the leaves from caatinga species (mainly those of C. yco and Z. joazeiro) is probably accounted for the predominance of n-alkanes in their composition. The lower efficiency of the waxes of A. pyrifolium (caatinga), T. formosa and A. esperanzae (both species from the cerrado) is probably a consequence of the predominance of triterpenoids in the waxes of the two former species and hentriacontan-16-one in the latter.A influência do teor e da composição química das ceras epicuticulares foliares de espécies da caatinga (Aspidosperma pyrifolium, Capparis yco, Maytenus rigida e Ziziphus joazeiro) e do cerrado (Aristolochia esperanzae, Didymopanax vinosum, Strychnos pseudoquina e Tocoyena formosa) foram avaliadas em relação à resistência à perda de água, através de um dispositivo experimental construído para essa finalidade. Em geral, as ceras das espécies da caatinga foram mais eficientes contra a perda de água que as das espécies do cerrado. O aumento da espessura dos depósitos cerosos de 40 até 90 mg.cm-2 não alterou significativamente a resistência à evaporação. A natureza química dos componentes das ceras revelou-se um fator importante na determinação do grau de resistência à evaporação. n-Alcanos e triterpenos alcoólicos foram os constituintes mais eficientes como barreiras à evaporação, enquanto hentriacontan-16-ona (uma cetona) e ácido ursólico (triterpeno com função carboxílica) foram menos eficazes. A maior eficiência das ceras epicuticulares de duas espécies da caatinga (C. yco e Z. joazeiro) provavelmente se deve à predominância de n-alcanos em sua composição. A menor eficiência das ceras epicuticulares de A. pyrifolium (outra espécie da caatinga), T. formosa e A. esperanzae (ambas espécies do cerrado), à predominância em suas ceras de ácido ursólico para as duas primeiras e hentriacontan-16-para a última.

The wax hydrocarbon fractions of native Butia and Syagrus species collected from Palms in different regions of the of Rio Grande do Sul state (Brazil) and in Rocha (Uruguay) were analyzed to evaluate their potential as chemotaxonomic markers. The wax was extracted with chloroform and the resulting wax was fractionated by preparative TLC. The hydrocarbon fractions were analyzed by GC-MS. Statistical analyses were completed with the Statistica 5.0 program. The total crude wax yields averaged 0.31% w.w-1 dried leaves for Butia samples and 0.28% for Syagrus samples. The linear hydrocarbons represented on average 15% of the total waxes in the case of Butia samples and 13.7% in Syagrus samples. Hentriacontane and triacontane were the main components of all samples. The comparison of the means showed significant differences among Butia and Syagrus samples, and amongst Butia samples collected in different localities. In the case of the Syagrus collections no consistent groupings could be made. In the case of Butia samples the formation of three groupings could be observed, which were consistent with the species described for their geographical distribution. These results are discussed in the paper. Frações de hidrocarbonetos das ceras de espécies nativas de Butia e Syagrus coletadas de palmeiras em diferentes regiões do Rio Grande do Sul (Brasil) e em Rocha (Uruguai) foram analisadas para avaliar o seu potencial como marcadores quiomiotaxonômicos. As ceras foram extraídas com clorofórmio e fracionadas por TLC preparativo. As frações de hidrocarbonetos foram analisadas por CG-EM. As análises estatísticas foram realizadas com auxílio do programa Statistica 5.0. O rendimento total de cera das folhas secas foi de 0,31% g.g-1 para as amostras de Butia e de 0,28% para Syagrus. Os hidrocarbonetos lineares representaram em média 15 e 13% do total das ceras para Butia e Syagrus, respectivamente. Hentriacontano e triacontano foram os compostos majoritários em todas as amostras. A comparação de médias mostrou diferenças significativas entre as amostras de Butia e Syagrus e entre as amostras de Butia coletadas em diferentes localidades. As amostras de Syagrus não formaram agrupamentos relacionados com os locais de coleta. Já no caso de Butia, três agrupamentos puderam ser observados e são consistentes com a distribuição geográfica desta espécie. Estes resultados são discutidos no trabalho.