Building a Barrier: The Influence of Different Wax Fractions on the Water Transpiration Barrier of Leaf Cuticles

Waxes are critical in limiting non-stomatal water loss in higher terrestrial plants by making up the limiting barrier for water diffusion across cuticles. Using a differential extraction protocol, we investigated the influence of various wax fractions on the cuticular transpiration barrier. Triterpenoids (TRPs) and very long-chain aliphatics (VLCAs) were selectively extracted from isolated adaxial leaf cuticles using methanol (MeOH) followed by chloroform (TCM). The water permeabilities of the native and the solvent-treated cuticles were measured gravimetrically. Seven plant species (Camellia sinensis, Ficus elastica, Hedera helix, Ilex aquifolium, Nerium oleander, Vinca minor, and Zamioculcas zamiifolia) with highly varying wax compositions ranging from nearly pure VLCA- to TRP-dominated waxes were selected. After TRP removal with MeOH, water permeability did not or only slightly increase. The subsequent VLCA extraction with TCM led to increases in cuticular water permeabilities by up to two orders of magnitude. These effects were consistent across all species investigated, providing direct evidence that the cuticular transpiration barrier is mainly composed of VLCA. In contrast, TRPs play no or only a minor role in controlling water loss.

Biological Potential and Chemical Profile of European Varieties of Ilex

Plants of the genus Ilex are widespread throughout the world, with its best-known representative being Ilex paraguraiensis from South America. The European species Ilex aquifolium shows similarities in its terpenoid, sugar and phenolic acid profiles. Using aqueous extracts of Ilex aquifolium as a supplement in Wistar rats showed that, despite the lack of caffeine, it had strong hypocholesterolemic effects. In addition, a reduction in oxidative lipid degradation and a decrease in hepatic steatosis in histopathological studies were observed. The results of this study suggest that extracts from the European species Ilex aquifolium may have potential as an alternative treatment for hyperlipidemia.

Water Sorption and Desorption of Isolated Cuticles From Three Woody Species With Focus on Ilex aquifolium

The cuticle is a lipid-rich layer that protects aerial plant organs against multiple stress factors such as dehydration. In this study, cuticle composition and structure in relation to water loss are examined in a broad ecophysiological context, taking into consideration leaf age and side from Ilex aquifolium (holly) in comparison with Eucalyptus globulus (eucalypt) and Prunus laurocerasus (cherry laurel). Enzymatically isolated cuticular membranes from holly leaves were studied under three treatment conditions: natural (no chemical treatment), after dewaxing, and after methanolysis, and the rate of water loss was assessed. Structural and chemical changes were evaluated using different microscopy techniques and by Fourier transform infrared (FTIR) spectroscopy. The potential mechanisms of solute absorption by holly leaves were additionally evaluated, also testing if its prickly leaf margin may facilitate uptake. The results indicate that the treatment conditions led to structural changes, and that chemical composition was hardly affected because of the occurrence of cutan. Structural changes led to more hydrophilic adaxial surfaces, which retained more water and were more efficient than natural cuticles, while changes were not significant for abaxial surfaces. Across natural cuticles, age was a significant factor for eucalypt but not for holly. Young eucalypt cuticles were the group that absorbed more water and had the lowest water loss rate. When comparing older leaf cuticles of the three species, cherry laurel was found to absorb more water, which was, however, lost more slowly, compared with the other species. Evidence was gained that holly leaves can absorb foliar-applied solutes (traced after calcium chloride application) through the adaxial and abaxial surfaces, the adaxial mid veins, and to a lower extent, the spines. In conclusion, for the species examined, the results show variations in leaf cuticle composition and structure in relation to leaf ontogeny, and water sorption and desorption capacity.

Vegetative Propagation and ISSR-Based Genetic Identification of Genotypes of Ilex aquifolium ‘Agrifoglio Commune’

The market demand for interesting varieties and cultivars of Ilex aquifolium necessitates the exploration and sustainable exploitation of plant individuals thriving in nature without human care. In this work, an effort was made to develop a simple and reliable protocol for vegetative propagation of I. aquifolium plants, with desirable-for-market characteristics, grown in a mountain area of Halkidiki, Greece, and at the same time to proceed with their genetic identification using molecular markers. From these plants, new plants were vegetatively produced which afterward were used as stock plants for providing the needed shoot cuttings for the experiments of rooting and leaves for their genetic analysis. Factors studied in formulating a propagation protocol included the season of cutting collection and the application of 0.2% 1-naphthaleneacetic acid (NAA), as well as the type of shoot cuttings (terminal, subterminal) and the application of auxin. It was found that application of NAA was crucial for rooting response and number of roots formed, whereas the season effect was not significant on rooting. Terminal cuttings treated with 0.2% NAA exhibited the highest rooting percentage (100%) and formed abundant roots (25.7) compared to subterminal ones. All rooted cuttings, after being potted and transferred to acclimatization greenhouse, were successfully hardened. In the spring of the next year, the produced plants blossomed abundantly and formed fruits (bright red berries) presenting their characteristic ornamental appearance that was maintained until Christmas. For the identification procedure, the genotypic profile of the stock plants was also investigated by inter-simple sequence repeat (ISSR) genetic analysis, revealing that they were genetically the same both among themselves and when compared with a certified I. aquifolium ‘Agrifoglio Commune’ individual, but they differed genetically from I. aquifolium ‘Argentea Marginata’ and I. aquifolium ‘Hellas’.

Istraživanje korištenja, gospodarenja i zaštite prirodnih dobara u zakonom zaštićenim područjima

Ovo istraživanje potaknuto je istraživačkim pitanjem postoje li neki konkretni problemi pri provođenju Zakona o zaštiti prirode i Plana upravljanja u samom Parku prirode Medvednica, koji je ujedno sastavni dio ekološke mreže Natura 2000. U radu su prikazani su rezultati istraživanja stavova predstavnika Javne ustanove PP Medvednica te su anketirani stanovnici rubnih zona PP Medvednica vezano uz tematiku korištenja i gospodarenja prostorom u zakonom zaštićenom području. Rezultati su pokazali da postoje problemi u PP od kojih je najvažniji problem odlaganje otpada i veliki broj posjetitelja koji se ne ponašaju u skladu s pravilima ponašanja u zaštićenom području. Kao najveće prednosti PP Medvednica navodi se da je to prostor za odmor i rekreaciju te predstavlja "pluća" grada Zagreba. Sadržaj koji najviše privlače stanovništvo rubnih zona jesu raznolikost biljnog i životinjskog svijeta te mir i tišina, čist zrak. Od biljaka sezonski se sakupljaju uglavnom plodovi (kesten, kupina i šumska jagoda) te gljive. Najčešće spominjane zaštićene biljne vrste jesu: Taxus baccata, Galanthus nivalis, Ilex aquifolium i Primula auricula i njih se ne sakuplja. Zaključujemo da su ispitanici dobro upoznati sa sadašnjim stanjem i aktualnim problemima, te smatraju da bi bilo nužno poduzeti bolju kontrolu unutar područja PP Medvednica.

Noteworthy new floristic records from Greece

This contribution to the Greek flora includes distribution extensions and taxonomic notes for some noteworthy plant taxa. New records for certain phytogeographical regions of Greece are presented for: Arum cylindraceum, Convolvulus pentapetaloides. Cruciata taurica, Galanthus reginae-olgae subsp. vernalis, Ilex aquifolium, Linum decumbens, Lythrum thymifolia, Sedum praesidis, Silene congesta and Trifolium diffusum. Allium karistanum, Helichrysum amorginum, Limonium antipaxorum and L. cephalonicum have been recorded for the first time on some islands. New populations of Allium maniaticum and A. ritsii, previously known only from their loci classici, were discovered in the Peloponnese. Valeriana alliariifolia, Silene auriculata subsp. auriculata and Symphytum creticum were rediscovered in central Evvia, confirming long-lost historical records from previous centuries. The presence of V. alliariifolia in Greece and Europe is confirmed for the first time since the 19th century.

Upotreba božikovine (Ilex aquifolium L.) u urbanom krajobrazu

Porast gradskog stanovništva uz istovremeno smanjenje zelenih površina ima za posljedicu da se od urbanog zelenila traži da ispuni što veći broj funkcija. Osim ukrasne funkcije, od biljnih vrsta se traži da što više doprinose uslugama koje pruža urbani ekosustav, pokazuju otpornost na biotički i abiotički stres te imaju minimalni negativni utjecaj na čovjeka i okoliš. Zbog dugog životnog vijeka, podnošenja raznolikih okolišnih uvjeta, pridonošenja kvaliteti zraka i tla u gradu te visoke dekorativnosti, božikovina se može ubrojiti u multifunkcionalne biljne vrste pogodne za oblikovanje zelenih urbanih površina. Osim adaptiranosti na lokalne uvjete, kao hrvatska autohtona vrsta s dugom tradicijom primjene u uređenju interijera, privatnih i javnih zelenih površina, božikovina ujedno odražava karakter i običaje okruženja u kojem se koristi. Potencijalno štetni utjecaj vrste ogleda se u emisiji biogenih hlapivih organskih spojeva, otrovnosti te umjerenoj alergenosti muških primjeraka.

Selective Shrub Management to Preserve Mediterranean Forests and Reduce the Risk of Fire: The Case of Mainland Portugal

The recurrent rural fires that occur annually in Portugal have reached great proportions due to a lack of effective landscape management. Attempts to solve this problem led to the legal imposition to cut back the vegetation in the fuel management areas, which has had a negative effect on biodiversity. National legislation protects three native plant species (Quercus suber, Q. rotundifolia and Ilex aquifolium). European legislation, through the Habitats Directive, also identifies some plant species that require strict protection, although it leaves out several endemic and rare plants. In this work we aim to differentiate the types of shrub plant material and their pyrophilic behavior, since the physical and chemical characteristics of vegetation can enhance or inhibit the progression of fire. Thus, based on phytosociological science, specifically at the class level, the dynamics of potential climatophilous vegetation in Portugal are presented and the classes that should be prioritized for control are identified. Based on ecology, it was possible to identify morphological patterns of vegetation. In short, the genera targeted for control under the National Forest Fire Protection Plan belong to the furthest states from the mature potential of a forest, generally consisting of heliophile shrubs and typically growing in degraded soils. The shrub species to be valued belong to dynamic states closer to the mature potential, consisting mainly of broad-leaved shrubs and those growing in better-preserved soils.