Interspecific variation in leaf wax of Dudleya

The distribution of the pentacylic triterpenoids, β-amyrin acetate and taraxerone, in the glaucous epicuticular wax of Dudleya subgenus Dudleya is correlated with both the geographic distribution and corolla tube length of a particular species. This is significant in a genus with many systematic problems.     

Triterpenoids of Cnidosculus urens

The ethanol extract of Cnidosculus urens yielded β-amyrin cinnamate and germanicol acetate. Also, using ¹³C NMR spectroscopy, mixtures of β-amyrin, germanicol and lupeol as well as their acetates were identified.     

Hydrocarbons from epicuticular waxes of Citrus peels

The hydrocarbon fraction of the epicuticular wax layer of peel from 5 cultivars of Citrus was monitored at various stages of fruit development. GLC     

Triterpenoids from Hyptis suaveolens roots

A new natural triterpenoid, 3β-hydroxylup-12-en-28-oic acid, has been isolated from the roots of Hyptis suaveolens in addition to α- and β-amyrin.     

Epicuticular waxes of two sorghum varieties

The epicuticular waxes of the two sorghum varieties Alliance A and SD 102 have been analyzed, after separation of the leaf blades from the sheaths. The major constituents were found to be free fatty acids but small amounts of esters, aldehydes, alcohols, n-alkanes and sterols were also detected. The typical chain lengths of aldehydes, free alcohols and free fatty acids were C₂₈ and C₃₀.     

Seed epicuticular wax of avena sativa

The main fractions in oat seed wax are β-diketones (15.5%), alkanols (14.4%), hydroxy-β-diketones (12.2%), esters (11.1%) and fatty esters (7.2%).     

Alkane distribution in epicuticular wax of epacridaceae

Alkane distribution pattern was determined in the epicuticular wax of leaves of 39 species and in the flower wax of three species of Epacridaceae. Uniform patterns were observed within some genera (Monotoca, Styphelia) whereas in others no common pattern was apparent. There was no difference between the alkane patterns of the two subfamilies Epacrideae and Styphelieae. The pattern was not affected by the presence of new growth, and there was no correlation with the season, habitat, climate, nature of soil, or the presence or absence of flowers.     

Epicuticular waxes of albino maize

Epicuticular wax of albino maize seedlings contains alkanes (9.5 %), esters (23.3 %), aldehydes (14.1 %) and free alcohols (53.1 %). The wax compositio     

13CNMR Spectra of β-diketones from waxes of the gramineae

The ¹³CNMR spectra of six β-diketones and seven oxygenated β-diketones have been measured. The β-dicarbonyl grouping has the following effects on the chemical shifts of the neighbouring carbons: α-, + 8.72; β-, ? 3.98; γ-, ?0.42; δ-, ?0.33; ?-,?0.20; ζ-,?0.09; η-, ?0.05; θ-, ?0.03 ppm. The effects indicate the position of the grouping up to the 10,12-position. The positions of hydroxyl and oxo groups, up to the eighth carbon from the end of the chain, are also shown by long-range effects. The relative positions of a β-diketone grouping and another oxygen-containing group can be established from the ¹³CNMR spectrum with little ambiguity when they are separated by six or fewer methylene groups. For these structures NMR spectroscopy is more reliable than mass spectroscopy, which gives results which are difficult to interpret when groups are close together.Components of mixtures of hydroxy β-diketones, from grass waxes, are identified and proportions indicated by the NMR spectra.     

Volatiles from the epicuticular wax of watercress (Rorippa nasturtium-aquaticum)

Volatiles from the epicuticular wax of watercress were collected by ether washing and examined using gas chromatographic and mass spectrometric analysi     

p-Hydroxybenzaldehyde as a major constituent of the epicuticular wax of seedling Sorghum bicolor

p-Hydroxybenzaldehyde is present in concentrations up to 30% in the wax of Sorghum bicolor seedlings. It is highly deterrent to locusts, reducing their normal feeding by 90%.     

Epicuticular waxes of Sorghum and some compositional changes with plant age

Epicuticular wax from mature plants of Sorghum bicolor SD-102 was compared with that from panicles and seedlings of the same variety at the fourth-fifth leaf stage of growth. The composition of wax from SD-102 panicles was quite different from that of mature leaf blades and sheaths. Free fatty alcohols were the dominant class of wax from SD-102 seedlings and C₃₂ was the major homologue of alcohols and aldehydes. For comparison purposes, the epicuticular waxes from whole plants of two other S. bicolor varieties, Alliance A and Martin A, grown up to the tasseling stage, have been analysed. The major wax components were free fatty acids. The typical chain lengths of aldehydes, free alcohols and free fatty acids were C₂₈ and C_30.p-Hydroxybenzaldehyde was not a wax component of the studied varieties of sorghum.     

Epicuticular waxes of hexaploid and octaploid triticales

Leaf and stem wax of triticales contain alkanes, esters, aldehydes, free alcohols, free acids, β-diketones and hydroxy gb-diketones. The wax compositions of the triticales investigated are closer to that of wheat than to that of rye.     

Effect of leaf age on epicuticular wax alkanes in Rhododendron

Alkane distribution pattern in epicuticular wax of Rhododendron fortunei cv Admiral Piet Hein leaves remains unchanged from the age of 6 weeks to abscission.     

Micromorphology of epicuticular waxes in Centrosperms

Epidermal surfaces of about 500 species from some 250 genera of centrospermous families plus some possibly related families were examined by scanning electron microscopy. The micromorphology of their epicuticular waxes is described under taxonomic aspects. In general, Centrosperms tend to develop wax platelets on their cuticle. Shape and size of these platelets are highly diverse, but specific for some taxa. Particular forms of rodlets and thick wax plates occur only in few taxa. The systematic and taxonomic applicability of wax micromorphology is limited, but tentatively family characterizations are given. The data presented provide additional information concerning the familiar and suprafamiliar classification ofCaryophyllales. Dedicated to the enthusiast of succulent Centrosperms, Prof. DrK. E. Wohlfarth-Bottermann (Director of the Institute of Cytology and Micromorphology, University of Bonn) on the occasion of his 65th birthday in May 1988.