Paul-Gerhard Gülz

Epicuticular Leaf Waxes in the Evolution of the Plant Kingdom

Summary Needle waxes of conifer trees consist of homologues of fatty acids, nonacosan-10-ol and predominantly bifunctional lipids with chain lengths C 12 to C 16 , the α-ω-diols and above all the ω-OH-fatty acids, free or in form of their inner esters, the estolides. On young needles crystalloids in the shape of small round tubules formed by nonacosan-10-ol always can be observed. Leaf waxes of deciduous trees have a quite different composition. They consist mostly of homologous series of hydrocarbons, wax esters, aldehydes, alcohols and fatty acids. Further lipids are found on occasion, for example benzyl acyl esters or acetates and often triterpenoids as well. The surface wax ultrastructures of deciduous trees differ from species to species according to wax composition. Liriodendron leaves have surface crystalloids in the shape of transversally ridged rodlets formed by hentriacontan-16-one, Tilia leaves show quandrangular rodlets formed by β-amyrenyl acetate, Quercus has fringed edged platelets formed by tetracosanol. Fagus and Castanea trees have no wax crystalloids, but only a sculptured surface structure on the upper leaf side. Gingko leaf waxes have an intermediate composition. Dominant are the homologue lipid components similar to those of deciduous trees, but nonacosan-10-ol is also present and thus the surface ultrastructure shows small round tubules like those of conifer needles. There are fundamental differences between epicuticular leaf waxes of gymnosperms and angiosperms, fundamental evolutionary influences are found to affect the wax compositions and surface ultrastructures of these different plant classes.

Developmental and seasonal variations in the epicuticular waxes of Tilia tomentosa leaves

The epicuticular waxes of Tilia tomentosa were analysed continuously over one vegetation period. The rolled leaves in buds contain waxes quite different in composition from those of mature leaves. Waxes of very young unfolded leaves are composed of homologous series of hydrocarbons, alkyl esters, triterpenol esters, acetates, alcohols, fatty acids and α- and β-amyrin. After 15 days of leaf unfolding, the biosynthesis of β-amyrenyl acetate and later on aldehydes commenced. A rapid biosynthesis of epicuticular waxes was observed from April to June. Wax content doubled or tripled in that time. An increasing trend was found for the synthesis of hydrocarbons, aldehydes, alcohols, fatty acids, β-amyrin and β-amyrenyl acetate during the active biosynthetic phase. The synthesis of wax esters and acetates, however, had almost stopped after the unfolding of leaves. During leaf development β-amyrenyl acetate became the dominant epicuticular wax component comprising ca 44% of the wax. From July to November the wax amount and composition remained nearly constant.

Epicuticular Flavonoid Aglycones in the Genus Cistus, Cistaceae

Summary The epicuticular leaf resins of 16 species and 3 subspecies of the genus Cistus were analysed with regard to their flavonoids. A total of 51 different flavonoids including flavanones, flavones, and flavonols could be identified. Many of these compounds are common and widespread flavonoid methyl ethers, some 6- and 8-O-methylated flavonols, several myricetin methyl ethers found, however, are rare natural products. In addition to the flavonoids two coumarin derivatives were identified in the leaf resins of several species. The flavonoid patterns elucidated are more or less species specific. Based on the flavonoid pattern we are able to comment on several difficult inter- and intraspecific taxonomic problems in the genus Cistus .

Surface structures and epicuticular wax composition of spruce needles after long-term treatment with ozone and acid mist.

Epicuticular wax structures and epicuticular wax composition were studied in needles of Picea abies (L.) Karst. plants after a long-term fumigation experiment. SEM observations showed aggregated as well as undamaged waxes without any relation to treatments. The chemical wax analysis revealed clone specific differences, but only one compound, the nonacosan-10-ol (C(29)-ol), was found enriched in ozone/acid mist treatments.

Epicuticular waxes from leaves of Quercus robur

Abstract The surface waxes from the leaves of Quercus robur L. were comprised largely of the common wax lipids in homologous series namely hydrocarbons (6.4%), esters (1.1%), aldehydes (38.8%), primary alcohols (36.0%) and fatty acids (6.1 %). In addition, triterpenols (3.6%), namely taraxerol, β-amyrin, α-amyrin and lupeol and the corresponding triterpenol esters (0.5%) were also found in smaller amounts.

Leaf trichomes in the genus Cistus

Summary Leaf trichomes of fifteen Cistus species and three C. incanus subspecies are studied in detail by scanning electron microscopy (SEM). All Cistus species secrete resin and essential oils in different amounts. All Cistus species therefore have secretorial trichomes, referred to as glands, all over the leaf surfaces. These are of three distinct shapes: 1. short stalked small heads, 2. long ball-headed tubes, and 3. long tubes. In addition, stellate hairs in different lengths and density, mostly on the upper as well as on the lower leaf surface are found on leaves of all other Cistus species with the exception of C. populifolius . Three species however, show stellate hairs only on the lower surface of the leaf; C. laurifolius , C. ladanifer and C. palhinhae . In addition six Cistus species have very long simple and mostly singular hairs. Only C. clusii shows a speciality in form of tuft hairs. These different shapes of leaf trichomes are very useful for a taxonomic classification of Cistus species.

Normale und verzweigte alkane in chloroplastenpräparaten und blättern von Antirrhinum majus

Zusammenfassung Aus Chloroplastenpraparaten und Blattern von Antirrhinum majus wurde ein Alkangemisch isoliert, das uber Molekularsiebe in eine normale und eine verzweigte Alkanfraktion aufgetrennt werden konnte. Mit Hilfe der Gaschromatographie und der Massenspektrometrie gelang es, die einzelnen Komponenten als eine Reihe von langkettigen normalen und verzweigten Alkanen zu identifizieren. Es wurden alle n -Alkane der Kettenlange C 16 -C 35 gefunden. In den Chloroplastenpraparaten bestehen sie zu 22 Prozent aus n -Heptacosan, zu 14 Prozent aus n -Nonacosan, zu 21 Prozent aus n -Hentriacontan und zu 21 Prozent aus n -Tritriacontan. In den Blattern dominieren n -Hentriacontan mit 25 Prozent und n -Tritriacontan mit 36 Prozent. Von den verzweigten Alkanen wurden die Kohlenwasserstoffe mit einer Kettenlange von C 25 -C 35 naher identifiziert. Wie bei den normalen Alkanen uberwiegen auch hier die Komponenten mit ungerader Kohlenstoffzahl. Bei den Chloroplastenpraparaten bestehen die verzweigten Alkane aus 19 Prozent Nonacosan, 25 Prozent Hentriacontan und 25 Prozent Tritriacoatan. In den Blattern setzen sich die Hauptkomponenten wie folgt zusammen: 14 Prozent Nonacosan, 24 Prozent Hentriacontan und 31 Prozent Tritriacontan. Die untersuchten verzweigten Alkane sind bei gleicher Kohlenstoffzahl sowohl als 2-Methyl- wie auch als 3-Methyl-Verzweigungen in etwa gleicher Konzentration anzutreffen. Eine Ausnahme bilden 2-Methyl-octacosan und 2-Methyl-triacontan, von denen 3-Methyl-Isomere nicht gefunden wurden. In den Chloroplastenpraparaten sind die Alkane zu 0,20 Prozent enthalten. Ihre Zusammensetzung weist keine qualitativen Unterschiede zu den aus Blattern isolierten Alkanen (0,18 Prozent) auf.

Pentacyclic Triterpenoids in Epicuticular Waxes from Euphorbia lathyris L., Euphorbiaceae

Abstract The chemical composition of the leaf surface wax of Euphorbia lathyris L. was analysed using TLC, GC, GC-MS and NMR. A predominance of pentacyclic triterpenoids and primary alcohols was observed. They together constituted 60% of the total wax. Seven triterpenols: taraxerol, β-amyrin, lupeol, isomotiol, a-fernenol, simiarenol. Ψ-taraxasterol and eight triterpenones: taraxerone, β-amyrinone, lupenone, isomotione, a- and β-fernenone, simiarenone and filicanone were isolated. Among them , β-amyrin and lupeol were found esterified with homologous series of fatty acids. The minor part of wax was formed by long chained and predominantly saturated alkanes, wax esters, aldehydes and free fatty acids.

UV radiation dependent flavonoid accumulation of Cistus laurifolius L.

Abstract Epicuticular and in tracellular flavonoids of Cistus laurifolius grown with and without UV radiation in a phytotron as well as under natural garden conditions in the field were studied. The amount of intracellular flavonoid glycosides of leaves receiving UV -A radiation was two fold higher than that measured in the absence of UV -A radiation , whether grown in the phytotron or in the field. Exposure of previously protected leaves to UV -A radiation increased the intracellular flavonoid glycoside content to that of unprotected leaves. The qualitative composition of intracellular flavonoid glycosides showed a reduced amount of quercetin-3-galactoside to the myricetin monosides when the leaves were grown without UV-A radiation in the field and in the phytotron . Epicuticular flavonoid aglycones were not influenced by UV radiation significantly.

Isomeric alkyl esters in Quercus robur leaf cuticular wax

Abstract Cuticular wax of Quercus robur leaves contains a homologous series of alkyl esters ranging in chain lengths front C36 to C52. GC-MS analysis showed that each carbon chain length was represented by a mixture of isomers arising from different combinations of long chain 1-alkanols and long chain alkanoic acids. Both even- and odd- numbered chain lengths were found with the even-numbered ones clearly being predominant.