Characterization of Turkish <Emphasis Type="Italic">Quercus</Emphasis> L. Taxa Based on Fatty Acid Compositions of the Acorns

Total oil content and the composition of fatty acids were analyzed in the acorns of 16 Quercus taxa from Turkey. The range of total fat varied between 0.7 and 7.4%. Oleic (10.2–54.4%), linoleic (24.2–49.1%), palmitic (13.4–30.4%), alpha linolenic (1.5–8.6%) and stearic acid (1.5–4.5%) were major fatty acids for all taxa. Significantly differences at section level were found (p < 0.05) for palmitic, stearic and oleic acid concentration. Saturated (17.0–38.6%), mono unsaturated (11.0–55.5%) and unsaturated fatty acids (57.4–81.6%) in total oil were also significantly different between section Quercus, Cerris and Ilex (p < 0.05). In addition, sectional differences were significant (p < 0.02) for the relative concentrations of saturated fatty acids compared to mono, poly and total unsaturated fatty acids. Considerable variation of individual fatty acid levels were observed in related species and varieties. The species from section Ilex Loudon exhibited the highest levels of saturated fatty acid while the lowest levels were found in Q. brantii, Q. libani and Q. trojana from section Cerris Loudon. These species also had the highest levels of unsaturated fatty acids. Whereas the lowest values were detected in the species of section Ilex. Both varieties of Q. cerris showed significant differences (p < 0.05) from the other species in section Cerris for all parameters, except for stearic acid and exhibited little variations among their individual populations. Different concentrations of fatty acids may be useful biochemical markers for the characterization of Quercus at the infrageneric level. Interesting ratios of linoleic:α-linolenic acid especially in Q. robur ssp. robur, Q. hartwissiana, Q. vulcanica, Q. ithaburensis ssp. macrolepis and Q. libani also were detected with respect to dietary reference for fatty acid intake.     

Molecular basis ofMorinda citrifolia (L.): Toxicity on drosophila

The ripe fruit ofMorinda citrifolia, host plant forDrosophila sechellia is highly toxic for three closely related species (D. melanogaster, D. simulans, andD. mauritiana). Green and rotten fruits are not toxic for all species tested. Short fatty acids were found to be present in large quantities in the extract of the ripe fruit. The most abundant (octanoic acid) was tested pure for its toxicity in a dose-dependent manner;D. sechellia is five to six times more resistant thanD. melanogaster to octanoic acid. Octanoic acid alone seems to be sufficient to explain the toxic effect of the pulp. It is less abundant in the rotten fruit and absent in the green fruit.     

Degradation of Leaf Litter Phenolics by Aquatic and Terrestrial Isopods

To investigate species-specific decomposition rates of litter from native (Quercus faginea) and introduced (Eucalyptus globulus) tree species in Portugal, we monitored changes in the phenolic signature of leaf litter during decomposition as mediated by an aquatic, Proasellus coxalis (Isopoda: Asellota), and two terrestrial, Porcellio dispar and Eluma caelatum (Isopoda: Oniscidea), detritivores. Although the litter of Eucalyptus and Quercus did not differ in overall protein precipitation capacity, we detected differences in terms of contents of particular phenolic compounds and phenol oxidation products. Accordingly, we observed food-specific consumption rates in Proasellus, but not in the terrestrial isopods. Proasellus digested Eucalyptus at significantly higher rates than Quercus, whereas the opposite was the case for Eluma, and Porcellio digested both litter types equally well. Despite slight differences in detail, effects of Proasellus on changes in the signature of litter phenolics were similar for both litter types, whereas terrestrial isopods—Porcellio and Eluma, although they differed from each other—digestively degraded phenolic compounds in Eucalyptus and Quercus litter, respectively, in different ways. Overall, however, degradation of litter phenolics was similarly effective on both litter types. From these data, we conclude that decomposition of Eucalyptus litter does not proceed more slowly than of litter from native Portuguese trees.     

Cynipid gall-wasp communities correlate with oak chemistry

Host-plant association data, gathered from field surveys conducted throughout Florida and from the literature, were used to identify the specificity of cynipid gall inducers to one or more of six Quercus species that occur at Archbold Biological Station, Lake Placid, Florida, USA, including the red oaks Q. laevis, Q. myrtifolia, and Q. inopina, and the white oaks Q. chapmanii, Q. geminata, and Q. minima. Quercus myrtifolia had the highest cynipid richness and diversity (37 cynipid species, Shannon H = 3.61, Simpson's D = 0.97), followed by Q. chapmanii, Q. laevis, Q. inopina, Q. geminata, and finally Q. minima (10 species, H = 2.30, D = 0.90). All cynipid species showed strong fidelity to a particular host plant or a restricted set of host plants. An ordination of gall-wasp host associations indicated that the cynipid communities of each oak species were distinct and specific to a given oak species. Leaf samples taken from each oak species were analyzed for condensed and hydrolyzable tannins, total phenolics, lignin, cellulose and hemicellulose, nitrogen, and carbon. All of these chemical traits, with the exception of carbon, differed by oak species, and the differences were strongly correlated with the axes of the cynipid--species ordination. These results suggest that gall-wasp occurrence is influenced by oak chemistry and imply that experimental studies of cynipid gall inducers that examine host-plant chemistry and female oviposition choice and larval performance will yield useful insights.     

Preference of meadow voles (Microtus pennsylvanicus) for conifer seedlings: Chemical components and nutritional quality of bark of damaged and undamaged trees

Meadow voles (Microtus pennsylvanicus Ord.) of the 1987–1988 population density peak left several seedling plantations of Norway spruce (Picea abies) and Norway pine (Pinus resinosa) severely damaged in southern Quebec, Canada, while white spruce (Picea glauca) and white pine (Pinus strobus) suffered no damage. We compared levels of crude protein, total nonstructural carbohydrates (TNC), total phenols, and monoterpenes in the bark to detect differences between damaged and undamaged seedlings within and between plantations. There were no significant differences in levels of nutritional components between both types of seedlings within the same plantation. However, differences were noted among tree plantations for protein, TNC, and phenolics content but these differences could not be assigned to the voles' selection for particular species. Quantitative and qualitative differences also were registered in monoterpene levels between species. -Myrcene and bornyl acetate were found only in seedlings of undamaged species. Moreover, the latter contained higher levels of limonene. We conclude that the presence of specific monoterpenes is more important in defense mechanisms of conifer seedlings than relative levels of nutrients (protein or TNC) or total phenolics.     

Can Acorn Tannin Predict Scrub-Jay Caching Behavior?

We tested the hypothesis that animals caching acorns for future food use may preferentially cache acorns high in tannin content. We used a population of Florida scrub-jays (Aphelocoma coerulescens) that cache acorns from four oak species. Tannin activity in acorns was measured by protein precipitating ability (PPA). Logistic regression models accurately predicted frequency of acorn caching among the oak species, using frequency of usable acorns and PPA loss during burial as predictor variables. Among the four oak species, frequency of caching increased with both increasing frequency of undamaged acorns at peak harvest time, and increasing loss of PPA during burial. Other regression models accurately predicted frequency of undamaged acorns for each species, using green acorn PPA and buried acorn PPA as predictor variables. Among the four oak species, frequency of usable acorns tended to increase with increasing green acorn PPA, and decreased with buried acorn PPA. We suggest that a deterrent effect of tannins on insect larvae is responsible for the differences in frequency of acorns usable to jays among oak species, and that jays select acorns for burial by assessing insect damage. Species differences in PPA change during burial probably reinforce this pattern of scrub-jay caching behavior.     

Interspecies differences and variability with time of protein precipitation activity of extractable tannins,crude protein,ash, and dry matter content of leaves from 13 species of Nepalese fodder trees

Dry matter, ash, crude protein, and protein precipitation activity (PPA) of 13 Nepalese tree fodder species were monitored in dried samples prepared monthly between November 1990 and May 1991, and additionally in November 1991, covering the season when they are particularly important as fodder. Monthly levels of dry matter, ash, and crude protein were fairly stable except when there was new leaf growth, although year to year differences in dry matter were found inBrassaiopsis hainla (Bh),Dendrocalamus strictus (Ds),Ficus roxburghii (Fr), andQuercus semecarpifolia (Qs). Tannin PPA fluctuated considerably inArtocarpus lakoocha (Al),Ficus glaberrima (Fg),F. nerrifolia (Fn), Fr,F. semicordata (Fs),Litsea polyantha (Lp), andPrunus cerasoides (Pc), and to a lesser extent in Bh,Castanopsis indica (Ci),C. tribuloides (Ct),Quercus lamellosa (Ql), and Qs. Similar fluctuations in PPA were observed in fresh leaf samples taken weekly. Ds did not have any detectable PPA. Trends in PPA fluctuation were generally similar for trees located at similar altitudes. Fr, Pc, Al, Fn, Ql, and Ci had falling PPAs before shedding leaves. Some of the fluctuations in Fr, Fs, Fg, Pc, and Lp were apparently due to changes in the extractability and quantity of condensed tannins. These fluctuations in PPA may affect the nutritive value of the fodders.     

Chemical and nutritional differences between two bird-dispersed fruits:Ilex opaca andIlex verticillata

Ilex opaca andIlex verticillata are woody species bearing lowquality, bird-dispersed fall fruits that persist for several months. Tests of secondary chemistry show that fruits of both species contain phenolics and saponins as major classes of secondary metabolites. Soluble carbohydrates are the major nutrients in both species. Ripe fruits from ten trees in both wild and cultivated populations of each species were collected during 1986, 1987, and 1988 and analyzed for phenolic and carbohydrate content using Folin-Denis and anthrone methods, respectively. Fruits from 1987 and 1988 were analyzed for saponin content using hemanalysis. Significant differences were found in the average content of the above chemical classes between the two species and among individuals within each species. The fruits ofIlex opaca are more persistent, higher in phenolics, and lower in saponins and carbohydrates thanJ. verticillata fruits. Generally, there are greater differences in fruit chemistry among plants within a year than within one individual between years. Mechanical defenses were tested by puncturing fruits in situ. No differences in decay were found between punctured and unpunctured fruits.     

Glucosinolate Content and Susceptibility for Insect Attack of Three Populations of Sinapis alba

Sinapis alba is less susceptible to damage by insect pests than Brassica napus. We investigated the composition and distribution of glucosinolates in different plant parts in three populations of S. alba; two populations selected for low-seed-glucosinolate content and one commercial cultivar. We have assessed the susceptibility of low-seed-glucosinolate content populations of S. alba to four insect pests, a flea beetle, a pollen beetle, and two species of aphids. Over 90% of the total glucosinolates in the cotyledons of the three populations of S. alba consisted of sinalbin. There was no difference in feeding damage by flea beetles on different S. alba populations at the cotyledon stage, nor was there a difference in sinalbin concentration of cotyledons. Total glucosinolate levels were highest in younger plant tissues. Sinalbin declined as a proportion of total glucosinolate content in later growth stages, especially in the low breeding lines. Reproduction by aphids was the same on all three populations despite differences in sinalbin content of the S. alba leaves at the growth stage tested. The specialist aphid, Brevicoryne brassicae, was found mainly on young tissues, while the generalist aphid, Myzus persicae, was found predominantly on older plant parts. There was no difference in oviposition by pollen beetles between the S. alba populations, despite the fact that on one population total glucosinolate concentration and the proportion of sinalbin found in the buds were much lower than on the other two populations.     

Developmental profile of sinalbin (p-hydroxybenzyl glucosinolate) in mustard seedlings,Sinapis alba L., and its relationship to insect resistance

Sinalbin was identified as a chemical component of insect anti-xenosis and antibiosis resistance mechanisms in seedlings ofSinapis alba by DEAE-Sephadex chromatography, HPLC, treatment with sulfatase and myrosinase, various feeding tests using artificial and natural substrates, and by measuring sinalbin concentrations in cotyledons and leaves during seedling development. The effects of sinaibin on feeding were dependent upon the insect species and upon the rapidly changing profile of sinaibin concentrations in the developing seedling. The high concentrations of sinalbin found in young cotyledons (up to 20 mM) and leaves (up to 10 mM) deterred the feeding of the flea beetle,Phyllotreta cruciferae Goeze and larvae of the bertha armyworm,Mamestra configurata Walker. The protection that sinalbin confers upon the vulnerable, newly emerged seedling (and upon tiny, young leaves) appears critical for the first few days of survival ofS. alba under feeding pressure from flea beetles in the field. The lower concentrations of sinaibin found in older cotyledons and leaves (2–3 mM) offer little or no protection againstP. cruciferae and may actually stimulate the feeding of this crucifer specialist. These concentrations of sinaibin, however, are still effective in reducing the level of feeding by larvae of the more generalist feederM. configurata.     

Venom chemistry of ants in the genusMonomorium

A comparative analysis of the venomous alkaloids produced by ant species in the subgenusMonomorium of the genusMonomorium has been undertaken. All species produce mixtures of unsymmetricaltrans-2,5-dialkylpyrrolidines, but the proportions of the constituents may vary considerably between species. All alkaloids contain both C₆ and C₉ side chains which are present as C₉-saturated. C₆-monounsaturated, and both C₆-and C₉-monounsaturated dialkylpyrrolidines. The structure of 2-(1-hex-5-enyl)-5-(1-non-8-enyl)pyrrolidine, a previously undescribed alkaloid, was proved by unambiguous synthesis after the location of the double bonds was established by the methoxymercuration-demercuration followed by mass spectrometry. The possible chemotaxonomic significance of the mixtures of venomous alkaloids produced by these species ofMonomorium is discussed.     

Lipid components in anal scent sacs of three mongoose species (Helogale parvula,Crossarchus obscurus,Suricata suricatta)

Anal sac secretions of three social mongoose species (Helogale parvula, Crossarchus obscurus, andSuricata suricatta) were chemically analyzed by means of gas chromatography-mass spectrometry. Compounds with high molecular weights (greater than 250) were found to distinguish the three species. Differences in composition suggest a possible species-specific role in scent marking. MaleH. parvula had vitamin E present in the anal sac, whereas it was absent in the females. This suggests a possible sex-specific function of vitamin E inH. parvula. No differences in chemical composition were found between male and femaleS. suricatta. Ten compounds were found in femaleC. obscurus that were not present in the male.     

Acorn (<Emphasis Type="Italic">Quercus</Emphasis> spp.) fruit lipids: Saponifiable and unsaponifiable fractions: A detailed study

The composition of the oils extracted from the acorn fruit of three species of Mediterranean oaks, Quercus ilex L., Q. suber L., and Q. faginea L., was characterized. Both major and minor components, including FA, TG, sterols, methyl sterols, triterpenic and aliphatic alcohols, tocopherols, and hydrocarbons, were identified by standard methods and MS. High-resolution GLC and HPLC were used for quantification. The FA profile, together with the equivalent carbon numbers and TG carbon numbers, was compared with data for other edible vegetable oils. Oil yield, expressed as wet weight, was 5% (w/w). Sterol content was remarkable for the three species (8,563–11,420 mg/kg), with β-sitosterol being the most abundant (80%). Oils were also high in tocopherol, with a wide variation between species (165–456 mg/kg) but with γ-tocopherol predominating in all three oils (90% of the total tocopherol content). Also, high terpenic alcohol contents were found (1527–2984 mg/kg), with dammaradienol and β-amyrin being the most abundant (33–60% of the total alcohol content). Bioactive properties and industrial applications of this underutilized native product are also discussed.     

Tissue culture of cocoa bean (Theobroma cacao L.): changes in lipids during maturation of beans and growth of cells and calli in culture

Callus cultures ofTheobroma cacao L., initiated from explants of immature cocoa bean cotyledons, contained 5.3%–6.4% lipids (dry wt basis). The major fatty acids were palmitic, oleic and linoleic acids. Cell suspensions contained 5.7–7.7% total lipids which had a higher polyunsaturated fatty acid content than total lipids of the calli. Phospholipids and glycolipids were the predominant lipid classes of calli and cell suspensions. Immature cocoa beans at early stages of development contained much higher polyunsaturated fatty acids, higher polar lipids and lower triglycerides than did mature ripe beans. Ripe cocoa beans contained 54% total lipids of which 96.8% where triglycerides. The fatty acid composition of total lipids of calli and cell suspensions were similar to those of the immature cocoa beans.     

Field Trials with the Synthetic Sex Pheromone of the Oak Processionary Moth Thaumetopoea processionea

The biological activity of synthetic (Z,Z)-11,13-hexadecadienyl ace- tate, the major pheromone component found in female gland extracts of the oak processionary moth Thaumetopoea processionea, was evaluated in field trials. Traps baited with 10 mg of the chemical efficiently attracted a large number of males provided they were placed in the upper crown region of the oaks. Devices positioned 10–15 m high in the trees attracted significantly more males than those traps installed at 2 or 6–8 m above the ground. Pherocon traps were slightly more efficient than Delta traps, and lower or higher amounts of the attractant in the baits did not significantly influence the number of moths caught. The importance of the stereomeric purity of the lure and the easy isomerization of the (Z,Z)-acetate to other isomers, particularly to the E,E isomer, should be considered for the development of efficient formulations in the field.     

Phenolic Compounds in Red Oak and Sugar Maple Leaves Have Prooxidant Activities in the Midgut Fluids of <Emphasis Type="Italic">Malacosoma disstria</Emphasis> and <Emphasis Type="Italic">Orgyia leucostigma</Emphasis> Caterpillars

Phenolic compounds are generally believed to be key components of the oxidative defenses of plants against pathogens and herbivores. However, phenolic oxidation in the gut fluids of insect herbivores has rarely been demonstrated, and some phenolics could act as antioxidants rather than prooxidants. We compared the overall activities of the phenolic compounds in red oak (Quercus rubra) and sugar maple (Acer saccharum) leaves in the midgut fluids of two caterpillar species, Malacosoma disstria (phenolic-sensitive) and Orgyia leucostigma (phenolic-tolerant). Three hypotheses were examined: (1) ingested sugar maple leaves produce higher levels of semiquinone radicals (from phenolic oxidation) in caterpillar midgut fluids than do red oak leaves; (2) O. leucostigma maintains lower levels of phenolic oxidation in its midgut fluids than does M. disstria; and (3) phenolic compounds in tree leaves have overall prooxidant activities in the midgut fluids of caterpillars. Sugar maple leaves had significantly lower ascorbate:phenolic ratios than did red oak leaves, suggesting that phenolics in maple would oxidize more readily than those in oak. As expected, semiquinone radicals were at higher steady-state levels in the midgut fluids of both caterpillar species when they fed on sugar maple than on red oak, consistent with the first hypothesis. Higher semiquinone radical levels were also found in M. disstria than in O. leucostigma, consistent with the second hypothesis. Finally, semiquinone radical formation was positively associated with two markers of oxidation (protein carbonyls and total peroxides). These results suggest that the complex mixtures of phenolics in red oak and sugar maple leaves have overall prooxidant activities in the midgut fluids of M. disstria and O. leucostigma caterpillars. We conclude that the oxidative defenses of trees vary substantially between species, with those in sugar maple leaves being especially active, even in phenolic-tolerant herbivore species.     

Chemical Ecology of Fruit Bat Foraging Behavior in Relation to the Fruit Odors of Two Species of Paleotropical Bat-Dispersed Figs (<Emphasis Type="Italic">Ficus hispida</Emphasis> and <Emphasis Type="Italic">Ficus scortechinii</Emphasis>)

We investigated the fruit odors of two bat-dispersed fig species in the Paleotropics, in relation to the foraging behavior of fruit bats, to test the following hypotheses: 1) fruit odor plays a critical role for detection and selection of ripe figs by fruit bats; 2) bat-dispersed fig species are characterized by the same, or similar, chemical compounds; and 3) total scent production, in bat-dispersed figs, increases when fruits ripen. We performed bioassays to test the effect of both natural and synthetic fig fruit odors on the foraging behavior of the short-nosed fruit bat (Cynopterus brachyotis)—an important disperser of figs within the study area. Fruit bats responded to both visual and chemical (olfactory) cues when foraging for figs. However, the strongest foraging reaction that resulted in a landing or feeding attempt was almost exclusively associated with the presence of a ripe fruit odor—either in combination with visual cues or when presented alone. Fruit bats also used fruit odors to distinguish between ripe and unripe fruits. By using gas chromatography (GC) and GC/mass spectrometry (MS), a total of 16 main compounds were identified in the ripe fruit odor of Ficus hispida and 13 in the ripe fruit odor of Ficus scortechinii—including alcohols, ketones, esters, and two terpenes. Additional compounds were also recorded in F. hispida, but not identified—four of which also occurred in F. scortechinii. Total scent production increased in both species when fruits ripened. Both natural and synthetic fruit odors resulted in feeding attempts by bats, with no feeding attempts elicited by unscented controls. Reaction rates to natural fruit odors were higher than those to synthetic blends.     

Some aspects of oviposition site selection inMonochamus notatus andM. scutellatus (Coleoptera: Cerambycidae)

The composition of monoterpene hydrocarbons and water content of freshly felled white pine logs (unattractive toMonochamus for oviposition) was compared to that of the same logs after aging long enough to become attractive toMonochamus. No significant differences were found. Variations between trees was the greatest source of variance in the data. If monoterpenes are used in host selection they are probably used to locate the host species and not to identify logs suitable for oviposition.     

Headspace Volatiles from 52 oak Species Advertise Induction, Species Identity, and Evolution, but not Defense

Leaf volatiles convey information about a plant to other organisms in their proximity. Despite increasing interest in understanding the relevance of volatile emissions for particular ecological interactions, there has been relatively little effort to assess generally what information volatile profiles transmit. We surveyed the volatile profiles of wounded and unwounded leaves of 52 oak (Quercus) species. We used phylogenetic comparison and multivariate techniques to assess in what circumstances oak individuals advertised their species identity, evolutionary history, direct defenses, or damage. We found that both species identity and evolutionary history were advertised when leaves were wounded, but species could not be differentiated by odor when leaves were not wounded. Various fatty-acid derivative compounds showed the strongest phylogenetic signal suggesting that they may best disclose taxonomic affiliations in oaks. We tested whether oak volatile composition or diversity advertised high defensive investment, but we found no evidence for this. Wounded leaves disclose much about an oak species’ identity and taxonomic affiliation, but unwounded leaves do not. This is consistent with the idea that volatile information is targeted toward natural enemy recruitment.     

Comparison between two controlled-release fertilizers on selected foliage plants in an artificial potting mix

A series of trials compared Osmocote^® and a recently available controlled-release fertilizer (CRF) product, Nutricote^®, at the same rates of N per container. Comparable formulations (e.i. 3–4 months) were compared on a variety of tropical foliage plants including:Impatiens, palms (Chamaedorea seifrizii, Chrysalidocarpus lutescens, Phoenix roebelinii, Rhapis excelsa andChamaedorea elegans) andSpathiphyllum; at 10 rates of N from 0 to 2–3 times the manufacture's recommended rate in a 1:1 (v:v) peat:perlite mix amended with dolomitic lime and a commercial micronutrient mixture. The plants were grown in a shade house, watered with overhead spray stakes and pest control measures used as required. Growth parameters used were plant height, growth index and top dry weight, along with tissue analysis and NO ₃ ^- concentrations. Overall plant height of the majority of plants tested was found to be comparable for the two CRF sources. However, there were some differences in top dry weight and leaf green color which were species specific. These results suggest that the release rate and availability of specific nutrients during the various plant growth phases may be more important for optimum plant growth and quality than the fertilizer formulation used. In general, both CRF products resulted in satisfactory plant growth and quality under the conditions of these trials.Additional studies are needed on the other factors affecting the use of these fertilizer products, such as water quality, media, media temperature, light, fertilizer placement, and economics. Once these factors are fully understood it will be possible to fully take advantage of this newer fertilizer technology and to customize the fertilizer to the plant species and its growing conditions.Hawaii Institute of Tropical Agriculture and Human Resources Journal Series No. 3905.