Showing papers on "Bark published in 1995"

Interaction of pre-attack and induced monoterpene concentrations in host conifer defense against bark beetle-fungal complexes.

Abstract: Two pine species (Pinus resinosa, P. banksiana) responded to inoculation with fungi carried by bark beetles by rapidly increasing monoterpene concentrations at the entry site. Changes in total monoterpenes were more pronounced than changes in proportionate compositions. The extent and rate of host response was affected by fungal species, the viability of the inoculum, and host tree species. In general, host responses were highest to fungi that are phytopathogenic and consistently associated with the major bark beetles in the study region. Simple mechanical wounding cannot account for the observed allelochemical changes, as aseptic inoculations elicited only minor reactions. Similarly, inoculation with autoclaved inviable fungi generally elicited intermediate responses, suggesting that both structural and metabolic fungal properties are important. Responses by jack pine, P. banksiana, were generally more rapid and variable than those of red pine, P. resinosa. Dose-toxicity experiments with synthetic compounds demonstrated that monoterpene concentrations present in vivo only a few days after simulated attack are lethal to most beetles. Constitutive (pre-attack) monoterpene levels can also exert some toxicity. Because bark beetles engage in pheromone-mediated mass attacks that can deplete host defenses, constitutive monoterpene levels, while a necessary early phase of successful plant defense, appear insufficient by themselves. Such interactions between constitutive and induced defense chemistry may be important considerations when evaluating general theories of plant defense.

Host-Tree Chemistry Affecting Colonization in Bark Beetles

Abstract: Bark beetles (order Coleoptera: family Scolytidae) comprise a taxonomic group of species that look similar although they differ widely in their ecology and biochemical adaptations to host trees. This diversity of bark beetle biology, in which each species is adapted to only one or a few host-tree species, has probably resulted from natural selection due to the great variety of trees and their biochemicals. It also is likely that each species of tree has coevolved various chemicals to defend against the herbivorous selection pressures of bark beetles and other insects (Erlich and Raven, 1965; Feeny, 1975; Cates, 1981; Berryman et al., 1985). Host-plant chemicals can be attractive, repellent, toxic, or nutritious to bark beetles and have effects on: (1) finding and accepting the host tree (host selection and suitability); (2) feeding stimulation and deterrence; (3) host resistance; (4) pheromone/allomone biosynthesis and communication; and (5) attraction of predators, parasites, and competitors of bark beetles.

Structural and Immunological Characterization of the Vaccine Adjuvant QS-21

Abstract: QS-21 is a triterpene glycoside “saponin” isolated from the bark of the Quillaja saponaria Molina tree, a species native to South America The bark of this tree, particularly the saponin fraction present in the bark, has long been known as a source of immune stimulators that can be used as vaccine adjuvants Espinet (1951) noted the adjuvant activity of plant saponins to enhance the potency of foot-and-mouth disease vaccines A number of commercially available complex saponin extracts were developed for adjuvant use Not all of these extracts were effective as adjuvants Dalsgaard (1970) showed that a correlation exists between adjuvant activity and the source of the saponin, and that the most adjuvantactive extracts were derived from the tree Quillaja saponaria The use of Quillaja saponins as adjuvants has been reviewed by Campbell and Peerbaye (1992)

Effects of biotic and abiotic stress on induced accumulation of terpenes and phenolics in red pines inoculated with bark beetle-vectored fungus

Abstract: This study characterized the chemical response of healthy red pine to artificial inoculation with the bark beetle-vectored fungusLeptographium terebrantis. In addition, we sought to determine whether stress altered this induced response and to understand the implications of these interactions to the study of decline diseases. Twenty-five-year-old trees responded to mechanical wounding or inoculation withL. terebrantis by producing resinous reaction lesions in the phloem. Aseptically wounded and wound-inoculated phloem contained higher concentrations of phenolics than did constitutive tissue. Trees inoculated withL. terebrantis also contained higher concentrations of six monoterpenes,α-pinene,β-pinene, 3-carene, limonene, camphene, and myrcene, and higher total monoterpenes than did trees that were mechanically wounded or left unwounded. Concentrations of these monoterpenes increased with time after inoculation. Total phenolic concentrations in unwounded stem tissue did not differ between healthy and root-diseased trees. Likewise, constitutive monoterpene concentrations in stem phloem were similar between healthy and root-diseased trees. However, when stem phloem tissue was challenged with fungal inoculations, reaction tissue from root-diseased trees contained lower concentrations ofα-pinene, the predominant monoterpene in red pine, than did reaction tissue from healthy trees. Seedlings stressed by exposure to low light levels exhibited less extensive induced chemical changes when challenge inoculated withL. terebrantis than did seedlings growing under higher light. Stem phloem tissue in these seedlings contained lower concentrations ofα-pinene than did nonstressed seedlings also challenge inoculated withL. terebrantis. It is hypothesized that monoterpenes and phenolics play a role in the defensive response of red pine against insect-fungal attack, that stress may predispose red pine to attack by insect-fungal complexes, and that such interactions are involved in red pine decline disease. Implications to plant defense theory and interactions among multiple stress agents in forest decline are discussed.

Physiological, morphological and anatomical responses of Fraxinus mandshurica seedlings to flooding.

Abstract: Two-year-old Fraxinus mandshurica Rupr. var. japonica Maxim. seedlings were flooded to 8 cm above soil level for 70 days. The flooding treatment altered the growth, morphology, stem anatomy and ethylene production of the seedlings. Although flooding did not affect height growth, it stimulated diameter growth of the submerged stems by increasing both the number and size of wood fibers produced; however, the thickness of the cell walls of the wood fibers was reduced by flooding. In response to the flooding treatment, the seedlings formed abundant hyperhydric tissues, originating from the vicinity of lenticels on the surface of the flooded stems, and adventitious roots, which grew through the hyperhydric tissues. Aerenchyma tissues were observed in the bark of the adventitious roots. The flooding treatment did not affect dry weight increment of leaves and stems, but it reduced the total dry weight increment of the root system even though it promoted adventitious root formation. Flooding also enhanced ethylene production in the submerged portions of stems. The potential roles of flood-induced ethylene in cambial growth and adventitious root formation in flooded plants are discussed.

Chemical Evaluation of Betula Species in Japan. I.Constituents of Betula ermanii

Abstract: The constituents of Betula ermanii CHAM. in Japan were identified as follws. Fresh leaves : 20(S), 24(R)-epoxydammmaran-3β, 11α, 25-triol (1), 3-O-β-D-glucopyranoside of 1 (2), 2'-acetate of 2 (3), 11, 2'-diacetate of 2 (4), dammar-24-en-3β-, 11α-20(S)-triol (5), 3-O-β-D-2-O-acetylglucopyranoside of 5 (6). Outer bark : betulin (7), betulin 3-caffeate (8), oleanolic acid (9). Inner bark : (+)-lyoniresinol 3α-O-α-L-rhamnopyranoside (10), (-)-lyoniresinol 3α-O-β-D-xylopyranoside (11), 9, 9'di-O-feruloyl-(-)-secoisolariciresinol (12), acerogenin E (13), 3, 4, 5-trimethoxyphenol β-D-apiofuranosyl(1→6)-β-D-glucopyranoside (14), 4-(4-hydroxyphenyl)-2-butanol 2-O-β-D-apiofuranosyl-(1→6)-β-D-glucopyranoside (15), (+)-catechine 7-O-β-D-xylopyranoside (16), lupeol (17), monogynol A (18). Root outer bark : lupeol caffeate (19), betulin 3-caffeate (8), oleanolic acid caffeate (20), dammarendiol II 3-caffeate (21). Compounds 2, 3, 4, 6, 19 and 21 are new.

Evaluation of regional heavy metal deposition by multivariate analysis of element contents in pine tree barks

Abstract: The airborne immission of heavy metals in the conservation area “Dubener Heide” nearby Bitterfeld was evaluated by biomonitoring studies with bark samples of 60-years-old scots pine (Pinus sylvestris L.). Nitric acid digestion and hydrochloric acid extraction of bark was followed by ICP-AES and ICP-MS analysis of the elements Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb and Zn. Fe and especially Cr were only partly soluble in hydrochloric acid. These elements deposited mostly as insoluble oxides, and their contents in the bark correlate significantly with Ca and S as elements of alkaline and acid deposition. Factor and cluster analysis of all element contents are used for the characterization and evaluation of heavy metal deposition types, which is shown to be a useful tool in forest monitoring control.

Semiochemicals from bark beetles: New results, remarks, and reflections.

Abstract: A brief survey is given about recent results in the identification of semiochemicals in bark beetles: Males ofIps sexdentatus (Boern.), stressed by the attack on resinous trees produce large amounts of 3(S)-1-methyl-5-(1-hydroxyl-1-methylethyl)-cyclohexa-1,3-diene. The compound appears to be derived from Δ3-carene and acts as a repellent. Males ofIps typographus (L.), stressed through the attack on unsuitable host material release 3-methyl-7-methylene-1,3(E), 8-nonatriene, which seems to act as a repellent. The odor bouquet of three species ofPityogenes is described. The occurrence of (+)-grandisol and other compounds related to weevil pheromones points to a close relation between Scolytidae and Curculionidae. Females ofDendroctonus simplex (Le Conte) use (−)-frontalin as the main pheromone. 6-Methyl-6-hepten-2-one, a minor component among the volatile compounds released by the females, is regarded as a possible precursor of frontalin. Similarly, (2R,5S)-2(1-hydroxyl-1-methylethyl)-5-methyltetrahydrofuran, pityol, a pheromone ofPityophthorus spp., is regarded to at least share a common biogenetic precursor with 6-methyl-5-hepten-2-ol, sulcatol. A new bicylic acetal, 2-ethyl-1,5-dimethyl-6,8-dioxabicyclo[3.2.1]octane, is described as an aggregation pheromone of the beech bark beetle,Taphrorychus bicolor (Herbst). Structural relationships between bark beetle pheromones and plant volatiles are discussed.

Two xanthones from Root Bark of Calophyllum inophyllum.

Abstract: Two new xanthones, named caloxanthones A and B, were isolated from the root bark of Calophyllum inophyllum, in addition to known xanthones (macluraxanthone and 1,5-dihydroxyxanthone) and (−)-epicatechin. Their structures were determined by spectroscopic analysis, in particular, by 2D NMR techniques.

Chemical Composition of Essential Oil from the Root Bark of Sassafras albidum

Abstract: The root bark of Sassafras albidum (Nuttall) Nees (Lauraceae) was extracted at room temperature with hexane and chloroform as solvents. The isolated essential oils were analyzed with GC and GC/MS. Thirty compounds were identified, nine of which have not been previously reported from this species. The major compounds were safrole (85%), camphor (3.25%), and methyleugenol (1.10%). Ten sesquiterpenes were also identified.

Root browning in Pinus banksiana Lamb. and Eucalyptus pilularis Sm. 2: Anatomy and permeability of the cork zone

Abstract: The periderm in roots of Pinus banksiana Lamb. and the polyderm in roots of Eucalyptus pilularis Sm. originate from the pericycle. This occurs after the roots have turned brown due to deposition of tannins in the walls of cells external to the endodermis. In both species, cork cells form a continuous sheath around the vascular tissues. The cork cell walls are modified by the presence of suberin, lignin and tannin and it is the latter which imparts a brown colour to the tissue. The first layer of cork cells in both species constitutes an apoplastic barrier which prevents the fluorescent dye, berberine, from entering the vascular tissues, despite the absence of an identifiable Casparian band in the cells. Because the roots are still covered with the cortex and epidermis during early stages of periderm and polyderm formation, it is not possible to tell from the external aspect of the root when it makes a transition from the tannin zone to the cork zone.

Species interactions and substrate specificity among log-inhabiting bryophyte species'

Abstract: Fallen logs in temperate deciduous forests are a transient substrate on which a dozen or more bryophyte species can co-occur. This study aimed to assess whether establishment capabilities and species interactions determine the habitat specificity of these species. I performed a modified Dewit replacement series experiment on three moss species (Anomodon rostratus, typical on bark of hardwood logs ; Leucobryum albidum, characteristic of Pinus logs ; and Platygyrium repens, a generalist species) in order to evaluate their competitive interactions. The species were grown from leaf fragments sown on four substrates: Pinus bark and wood, and Quercus bark and wood. Substrate had a significant effect on establishment for all three species. However, only on Pinus bark was the frequency dependent on the species sown. Randomization test analogs of analysis of variance indicated that the biomass of Anomodon and Platygyrium grown in monoculture differed significantly across substrates, while that of Leucobryum did not. There was considerable variability in performance within bryophyte species and there was no evidence for significant interactions between pairs of species.

Distribution and retention of cleistothecia of Uncinula necator on bark of grapevines.

Abstract: Clesitothecia of Uncinula necator were dispersed by late summer and early autumn rain to the bark of grapevines. Rain-dispersed ascocarps accumulated rapidly on bark during a 10-wk period and were then retained on bark through subsequent rain events between leaf abscission and budbreak the following spring. The density of populations on bark was significantly correlated (r = 0.72-0.88) with catches of cleistothecia in filter-paper funnels attached to the trunk of grapevines. The density of populations on bark during winter was not correlated with several measures of disease incidence and severity from the previous growing season. We concluded that while incidence and severity may determine the potential population available for dispersal, rain events determine the actual efficiency of transfer from infected organs to the bark of the vine. The percentage of ascocarps that reacted positively with the fluorescent vital stain fluorescein diacetate ranged from 50 to 62% and did not change significantly during overwintering until cleistothecia began to dehisce in spring. Therefore, the density and viability of populations of cleistothecia on bark at the time of budbreak appear to have been determined at the time of leaf fall the previous autumn and were not modified by subsequent environmental conditions. The densest aggregations of cleistothecia occurred on the cordons of cordon-trained vines, with successively lower densities occurring on the bark of the upper and lower trunks. The pruning and training system of vines of Vitis labrusca cv. Concord did not affect the density of populations of cleistothecia on bark

Principle of the bark of Phellodendron amurense to suppress the cellular immune response.

Abstract: We previously reported that Wen-Qing-Yin (Unsei-in), a traditional Chinese blended medicine, inhibited the induction phase of various kinds of delayed type hypersensitivity (DTH) and local graft-versus-host (GvH) reactions, but did not affect humoral immune responses or the effector phase of DTH in experimental animals. In another report, we demonstrated that Phellodendri Cortex (bark of Phellodendron amurense Rupr. Rutaceae) was a component having the most potent suppressive effect on the cellular immune response among the 8 medical plants composing Unsei-in. In the present study, we isolated OB-1 and OB-5 from Phellodendri Cortex as the biologically active principles to suppress local GvH reactions in mice. OB-1 and OB-5 are quaternary base alkaloids known as magnoflorine and phellodendrine, respectively. They suppressed the local GvH reaction, when given i.p. to the host mice at 5-20 mg/kg for 8 consecutive days from the day of spleen cell transfer to cause the reaction. Both OB-1 and OB-5 suppressed picryl chloride-induced delayed type hypersensitivity (PC-DTH) when given i.p. to mice at 10 and 20 mg/kg for 5 consecutive days from the day of the sensitization, but did not suppress it when given at the time of the challenge. These results suggest that OB-1 and OB-5 suppress the induction phase but not the effector phase of the cellular immune response. They are expected to have a value as a new type of immunosuppressor.

Further antibacterial diterpenes from the bark and leaves of Juniperus procera hochst. ex Endl

Abstract: The bark of Juniperus procera yielded three antibacterial diterpenoids, (+)-E-communic acid (1), (+)-Z-communic acid (2) and (+)-totarol (3). Compound 2 exhibited significant activity against Gram-positive bacteria, while 1 was found to be less active. Compound 3, on the other hand, demonstrated potent activity against Mycobacterium organisms, while its corresponding 3β-hydroxy-derivative 4 was found to be inactive. The chromatographic separation of (+)-Z-communic acid (2) from (+)-E-communic acid (1) and those previously unreported spectral data of 1 and 2 are described. In addition, the leaves yielded (+)-8α-acetoxyelemol, β-peltatin A methyl ether and deoxypodophyllotoxin.

Low molecular weight polyphenols in wood and bark of Eucalyptus globulus

Abstract: Polyphenols (mainly flavonoids and phenolic acids and aldehydes) were studied in wood and bark samples of Eucalyptus globulus. Gallic and ellagic acids, vanillin, syringaldehyde, sinapaldehyde, and quercetin were identified in wood; and gallic, protocatechuic, vanillic and ellagic acids, protocatechuic aldehyde, taxifolin, eriodictyol, quercetin, and naringenin in bark. Ellagitannins and some unidentified flavonols were also detected in both samples.

Is self-thinning in ponderosa pine ruled by Dendroctonus bark beetles?

Abstract: Stand density of even-aged stands of ponderosa pine in California seems to be ruled by Dendroctonus bark beetles, rather than the suppressioninduced mortality common for other tree species. Size-density trajectories were plotted for 155 permanent plots in both plantations and natural stands. Bark beetle kills created a limiting Stand Density Index of 365 which differed little between stands on poor sites east and good sites west of the crest of the Sierra Nevada and Cascade Range. Although good sites would be expected to carry a greater stand density than would poor sites, more explosive bark beetle populations and density-related stem breakage cancel this site advantage.

Adverse Effects of Epiphytic Crustose Lichens upon Stem Photosynthesis and Chlorophyll of Populus tremula L.

Abstract: Dry cork layer (phellem) in stems of Populus tremula transmitted 35–55 percent of incident irradiation, depending upon moisture content. A cover of crustose Lecanora lichens reduced transmission through phellem to 10 percent or less of incident irradiation. The bark contains photosynthetically active cells. Apparent quantum yield for photosynthetic O2-evolution was 0.017 in bark covered with dry Lecanora compared with 0.070 in naked bark. The capacity for gross photosynthesis in high light (1090 μmol photons m−2 s−1) was reduced by 50 percent in Lecanora-covered bark. Lecanora did not reduce the ratio between variable and maximal chlorophyll a fluorescence (Fv/Fm). Chlorophyll content per unit area was similar in leaves and naked bark of Populus tremula. The chlorophyll content in the bark decreased with increasing chlorophyll content in Lecanora. Chlorophyll a/b ratio was 2.5 in the bark compared with 4.0 in leaves and in Lecanora, and the ratio decreased down the stems. The a/b ratio was 2.3 in Lecanora covered bark compared with 2.6 in naked bark. The changes in bark photosynthesis below a Lecanora crust were probably due to acclimation of bark photosynthesis to shade, since the lichen acids in the measured lichens neither suppressed photosynthetic O2-evolution nor changed the Fv/Fm in bark disks.