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61.
A new fraction has been isolated by chromatographic methods from the wax of the Bulgarian oil-bearing rose. According to its IR, NMR and MS it was characterized as an homologous series of γ-diols, from C17 to C33 with the major homologues those containing an odd number of carbon atoms. Nonacosane-5,8-diol is the major constituent. 相似文献
62.
Leaf architecture and epidermal characters in Zelkova, Ulmaceae 总被引:4,自引:0,他引:4
YU-FEI WANG DAVID K. FERGUSON REINHARD ZETTER THOMAS DENK GIUSEPPE GARFI 《Botanical journal of the Linnean Society. Linnean Society of London》2001,136(3):255-265
Zelkova , with six extant species in Eurasia - three in East Asia (Z. schneideriana, Z. serrata, Z. sinica) , one in south-western Asia (Z. carpinifolia) and two in southern Europe (Z. abelicea, Z. sicula) - was investigated with respect to leaf architecture and epidermal characters by LM and SEM. The leaf venation of Zelkova is relatively uniform, while leaf size and shape are highly variable. Characters such as teeth and epidermal cells, trichomes and stomata provide useful specific distinctions. Beginning in the Miocene, increasing aridity in Central Asia would appear to have been responsible for isolating the eastern Asiatic species from their European/western Asiatic counterparts. The European range underwent further changes in response to Quaternary climatic oscillations. 相似文献
63.
Carolina Elejalde-Palmett Ignacio Martinez San Segundo Imène Garroum Laurence Charrier Damien De Bellis Antonio Mucciolo Aurore Guerault Jie Liu Viktoria Zeisler-Diehl Asaph Aharoni Lukas Schreiber Bénédicte Bakan Mads H. Clausen Markus Geisler Christiane Nawrath 《Current biology : CB》2021,31(10):2111-2123.e9
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64.
The presence of a substantial proportion of branched, in addition to normal compounds, was confirmed in the alkyl ester and primary alcohol components 相似文献
65.
Abstract We investigated how insects use wax as a defence against visual predators, using a New Zealand salticid species, Marpissa marina, as the predator and Eriosoma lanigerum, an aphid that covers itself with wax, as the prey. For live‐prey testing, the predator was presented with two aphids, one with its wax covering intact and one with its wax removed. The predator ate more of the waxless than wax‐covered aphids. The predators were presented with two lures at a time: (1) one that was fully covered with wax (hid the aphid's head) compared with one that was without wax (waxless) or (2) one that was fully covered with wax compared with one that was only partially covered with wax (the head of the prey exposed), or (3) one that was waxless compared with one that was partially covered with wax. The predators stalked waxless prey more often than they stalked prey that was fully or partially covered with wax. When wax only partially covered the prey (i.e., when the prey's head was left exposed), the predator more often stalked than when the insect was fully covered. These findings suggest that the aphid's wax covering functions in part to hide prey‐identification cues from vision‐guided predators. 相似文献
66.
Takafumi Mizuno Masayuki Hayashi Toshiharu Akino 《Ethology : formerly Zeitschrift fur Tierpsychologie》2018,124(7):468-474
Coccinellid pupae have various defensive traits, such as keeping their final‐instar larval exuviae and secreting droplets containing defensive chemicals at the tips of glandular hairs. Although each of these traits has been described separately in different species, it is unclear how each defensive trait functions when more than one trait coexists. We found that pupae of the ladybird Scymnus posticalis have two different types of traits; they were partially covered with their own final‐instar larval exuviae, with thick wax structures, and had many glandular hairs secreting transparent droplets on the exposed parts of the body without waxy exuviae (head and medial parts of thoracic and abdominal dorsum). In this study, the defensive effects of these two traits were evaluated against two ant species, Tetramorium tsushimae and Lasius japonicus, which are potential predators. When encountering a pupa, neither ant species were able to make frequent physical contact with the exposed parts of the pupa because of the presence of the waxy exuviae. When touching the exposed body part that was covered with droplets, both ant species immediately stepped backward and then swept their antennae. The droplets suppressed ant feeding when mixed with sucrose solution, suggesting that the droplets contain repellent chemicals. These results indicate that the two traits of S. posticalis pupae (the larval waxy exuviae and the droplets) effectively play defensive roles against ants, functioning as a physical obstruction and a chemical repellent, respectively. 相似文献
67.
Phase behaviour and crystallinity of plant cuticular waxes studied by Fourier transform infrared spectroscopy 总被引:1,自引:0,他引:1
The phase behaviour of cuticular waxes from leaves of Hedera helix L. and Juglans regia L. was studied by Fourier transform infrared spectroscopy. For this purpose reconstituted waxes, isolated cuticular membranes,
dewaxed polymer matrix membranes and whole leaves were studied in the horizontal attenuated total reflection and transmission
modes. Melting curves of cuticular waxes were derived from temperature-dependent changes in the absorption maximum of the
symmetric stretching mode of CH2 groups (νs, at approx. 2856–2848 cm−1). With increasing temperature absorption band doublets due to CH2 scissoring (δsciss) and rocking (δrock) movements (at approx. 1473–1471 and 730–720 cm−1, respectively) indicative of an orthorhombic arrangement of alkyl chains merged into a single peak. The area ratio of the
peaks at approx. 720 and 730 cm−1 was used as a measure for aliphatic crystallinity of plant cuticular waxes at a given temperature. The investigations of
reconstituted cuticular waxes and those still embedded in isolated cuticles or in situ on the leaf produced comparable results.
The findings are discussed in terms of the properties of the cuticular transport barrier.
Received: 21 March 1997 / Accepted: 25 April 1997 相似文献
68.
The microrelief of plant surfaces, mainly caused by epicuticular wax crystalloids, serves different purposes and often causes
effective water repellency. Furthermore, the adhesion of contaminating particles is reduced. Based on experimental data carried
out on microscopically smooth (Fagus sylvatica L., Gnetum gnemon L., Heliconia densiflora Verlot, Magnolia grandiflora L.) and rough water-repellent plants (Brassica oleracea L., Colocasia esculenta (L.) Schott., Mutisia decurrens Cav., Nelumbo nucifera Gaertn.), it is shown here for the first time that the interdependence between surface roughness, reduced particle adhesion
and water repellency is the keystone in the self-cleaning mechanism of many biological surfaces. The plants were artificially
contaminated with various particles and subsequently subjected to artificial rinsing by sprinkler or fog generator. In the
case of water-repellent leaves, the particles were removed completely by water droplets that rolled off the surfaces independent
of their chemical nature or size. The leaves of N. nucifera afford an impressive demonstration of this effect, which is, therefore, called the “Lotus-Effect” and which may be of great
biological and technological importance.
Received: 19 August 1996 / Accepted: 12 November 1996 相似文献
69.
Diffusion in plant cuticles as affected by temperature and size of organic solutes: similarity and diversity among species 总被引:7,自引:1,他引:6
Mobilities of lipophilic organic solutes in cuticular membranes (CM) isolated from mature leaves of Citrus aurantium L., Citrus grandis L., Hedera helix L., IIex aquifolium L., Ilex paraguariensis St.-Hil., Mains domestica Borkh., Prunus armeniaca L., Primus laurocerasus L., Pyrus communis L., Pyrus pyrifolia (Burm. f.) Nakai, Stephanotis florihunda Brongn. and Strophantus gratus Baill. were measured over a temperature range of 15–78°C. In this range, solute mobilities increased up to 1000-fold, which corresponds to temperature coefficients Q10 of 3 (IAA in P. armeniaca) to 14 (cholesterol in H. helix). For most species, Arrhenius graphs showed good linearity up to 40°C, and up to 78°C for some species, while for others activation energies declined with increasing temperature. However, no distinct phase transitions caused by sudden structural changes in the CM were observed. In three species we examined whether heating to 70°C changed solute mobility irreversibly by comparing Arrhenius graphs for two successive experiments with the same CM. The two graphs were very similar for P. laurocerasus, while mobilities in the second graph were somewhat reduced for C. aurantium and greatly increased (at 25 and 35°C) for H. helix. This indicates rearrangements of at least some wax constituents when heated to high temperatures. The activation energies of diffusion (ED) ranged from 75 to 189 KJ mol?11 depending on species and solute size. Size selectivity and variability between cuticles decreased with increasing temperature, and this is caused by differences in (ED). An excellent correlation between the pre-exponential factor of the Arrhenius equation and ED was observed, which is evidence that organic solutes differing greatly in molecular size (130–349 cm3 mol?1) and cuticle/water partition coefficient (25–108) use similar diffusion paths in the CM of all 12 plant species tested. Diffusion occurs in regions with identical physicochemical properties and differs only in magnitude. 相似文献
70.