Showing papers on "Bark published in 1991"

Photoperiod Control of Poplar Bark Storage Protein Accumulation

Abstract: Bark storage proteins (BSPs) accumulate in the inner bark parenchyma of many woody plants during autumn and winter. We investigated the effect of a short-day (SD) photoperiod on the accumulation of the 32-kilodalton bark storage protein of poplar (Populus deltoides Bart. ex Marsh.) under controlled environmental and natural growing conditions. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and protein gel blot analysis revealed that 10 days of SD exposure (8 hours of light) resulted in a 20% increase in the relative abundance of the 32-kilodalton bark storage protein of poplar. After 17 days of SD exposure, the 32-kilodalton bark storage protein accounted for nearly one-half of the soluble bark proteins. In natural field conditions, accumulation of the 32-kilodalton bark storage protein was observed to start by August 18 (daylength 14.1 hours). Immunoprecipitation of in vitro translation products with anti-BSP serum revealed that the SD protein accumulation was correlated with changes in the pool of translatable mRNA. A survey of poplar clones from different geographic origins revealed the presence of the 32-kilodalton BSP in the dormant bark of all the clones tested. These results demonstrate that a SD photoperiod induces, whether directly or indirectly, rapid changes in woody plant gene expression, leading to the accumulation of BSP.

Mechanisms of resistance in Eucalyptus against larvae of the eucalyptus longhorned borer (Coleoptera: Cerambycidae)

Abstract: First instars of the eucalyptus longhorned borer, Phoracantha semipunctata (F.), were not capable of colonizing bark of vigorous standing trees of two Eucalyptus species. The lack of a kino gum reaction after the introduction of larvae into the bark of E. grandis Hill ex Maiden and E. tereticornis Small strongly indicates that this gum does not play an important role in the initial defense against borer attack. Larvae were also not able to colonize the bark of logs that were maintained at high moisture content but were able to colonize the bark of dry logs and artificially water-stressed trees that had reduced bark moisture content. We propose that bark moisture content plays a critical role in the resistance of eucalyptus trees against colonization by eucalyptus longhorned borer larvae.

Antimalarial activity of Tanzanian plants and their active constituents: the genus Uvaria.

Abstract: Petroleum ether, dichloromethane, and methanol extracts of leaves, stem, and root bark of nine Uvaria species: U. dependens, U. faulknerae, U. kirkii, U. leptocladon, U. lucida ssp. lucida, Uvaria sp. (Pande)k U scheffleri, and U. tanzaniae were tested for their in vitro activity against the multidrug resistant K1 strain of Plasmodium falciparum. The IC50 values of the extracts varied between 5 and 500 micrograms/ml. The most active extracts were obtained from the stem and root bark of U. lucida ssp. lucida and Uvaria sp. (Pande) and the root bark of U. scheffleri, all of which had IC50 values between 5 and 9 micrograms/ml. Among the compounds isolated, uvaretin, diuvaretin, and (8',9'-dihydroxy)-3-farnesylindole were the most active (IC50 = 3.49, 4.20, and 2.86 micrograms/ml, respectively).

Decomposition of sawdust and bark treated with cellulose-decomposing microorganisms

Abstract: The decomposition of coniferous sawdust and bark with added N and P was studied in relation to its capacity to serve as a substrate for plant growth. With sawdust as a substrate, there was more microbial biomass, greater CO2 evolution, more ammonification and more actinomycetes but less nitrification and less fungi compared with bark. All groups and activities were greater in sawdust and bark compared with soil used as the substrate. Inoculation with cellulolytic strains of Bacillus sp. Cephalosporium sp. and Streptomyces sp. sometimes increased these activities but only marginally. The derived sawdust and bark composts increased the yields of tomato compared with soil to which the same nutrients had been added.

Qualitative Structural Changes during Bark Development in Quercus Robur, Ulmus Glabra, Populus Tremula and Betula Pendula

Abstract: The development of bark structure of Quercus robur L., Ulmus glabra Huds., Populus tremula L. and Betula pendula Roth is being described. Profound structural changes can be observed during the first years after secondary growth has started. In all four species the epidermis is replaced by a periderm, the cortex shows intensive dilatation growth, and the groups of primary bark fibres are pushed apart. The collapse of sieve tube members starts with the second year. With proceeding secondary growth, the specific formation of sclerenchymatic tissue, especially sclereids, and the dilatation growth are processes which strongly affect the bark structure of Quercus robur, Populus tremula and Betula pendula. In addition, wide, fused phloem rays develop in Quercus robur. The structure of Ulmus glabra bark is affected by the formation of phloem fibre-/sclereid-like cells and mucilage cells and by dilatation growth. The histological pattern of Ulmus glabra bark stabilises to a great extent after the first few years, the other barks investigated show further developmental processes over many years. In all species the formation of a rhytidome is the last distinct modification of bark structure.

Comparisons of three woodland sites in NW Britain differing in richness of the epiphytic Lobarion pulmonariae community and levels of wet acidic deposition

Abstract: The environment of three Quercus petraea-dominated woodlands differing in species richness of the epiphytic Lobarion pulmonariae alliance was surveyed. Data on occurrence of epiphytes, air pollution and bark- and soil-chemistry are presented. Within a given wood, individuals (of Q. petraea or Fraxinus excelsior) that support the growth of Lobaria spp. were found to have higher bark pH and higher bark Ca, K and Mg contents than individuals lacking these lichens. The most acidic bark was found at Seatoller Wood (Cumbria), a site which experiences strongly acidic rainfall. However, Old Garrock Wood (SW Scotland), although receiving acidic precipitation, had high bark pH and cation contents possibly due to the high levels of exchangeable cations in the soil. The results suggest that while bark pH is important in determining the occurrence of Lobaria spp., bark chemistry is determined by a combination of factors including tree species, atmospheric chemistry and soil nutrient status.

Triterpenoid extractives in the outer bark of Betula lenta (black birch)

Abstract: Birch bark represents an abundant, and currently unutilized, natural resource. In this study, the triterpenoid composition of the outer bark of the darkbarked birch species, Betula lenta, was investigated. Lupeol was the most abundant triterpene. Betulin, lupenone, betulone, betulinic acid, betulin-3-caffeate, Iup-20(29)-ene-3ß,30-diol, lup-20(29)-ene-3ß-ol-30-al, lup-20(29)-ene-3ß,28-diol-30-al, and lupan-3ß,20diol were also isolated and identified.To our knowledge, betulone (lup-20(29)-ene-28-ol-3-one) and lup20(29)-ene-3ß,28-diol-30-al, previously prepared synthetically, are new natural products.

Extractives yields, Stiasny values and polyflavanoid contents in barks from six Acacia species in Australia

Abstract: Summary Bark samples of 30 individual trees were collected from six potentially important Acacia species; A. falciformis, A. implexa, A leucoclada, A. parramattensis, A. sylvestris and A. trachyphloia in New South Wales and Australian Capital Territory, Australia, and the yields, Stiasny values, and the polyflavanoid contents of the hot water extractives were determined. The bark samples from A. parramattensis gave the highest mean (50.2% of bark dry weight) of the extractives yield, while the lowest mean (21.9%) was obtained from barks of A. leucoclada. The two highest mean Stiasny values from A. falciformis (88.0%) and from A. parramattensis (82.8%) were not significantly different. The highest mean polyflavanoid content from A. parramattensis (41.7%) was significantly different from others. The bark quality of A. parramattensis for wood adhesives would be comparable to that of A. mearnsii provenances in New South Wales, Australia.

Preliminary investigations on phenolics as a response of Scots pine phloem to attacks by bark beetles and associated fungi

Abstract: Two fungus and one bark beetle species were introduced into Scots pine phloem. The phenolic composition of the induced reaction zone in the phloem, studied by two dimensional thin layer chromatography, greatly differed from that of the uninjured phloem. The concentration of three compounds increased, one of them considerably, while the concentration of four others decreased. These modifications were the same irrespective of the nature of the aggressor.

Infection of pruning and small bark wounds in almond by Ceratocystis fimbriata.

Abstract: Ceratocystis fimbriata caused cankers at pruning cuts on branches of Nonpareil almond trees inoculated in all months from September through February. Pruning cuts were susceptible when 0-14 days old, and canker length was greatest where fresh wounds were inoculated. Small dead or living twigs of Mission almond trees, broken without visible exposure of the subtending branch cambium, and wounds inflicted with a lancet became infected when inoculated in alternate months throughout the year. Superficial abrasions of the periderm were less susceptible than were full- and half-depth penetrations of the bark

Relationship of matric water potential and air-filled porosity of container media to development of Phytophthora root rot of rhododendron

Abstract: Matric water potential and air-filled porosity were determined at four sampling dates during the growing season for trickle-irrigated pine bark and peat-based media that differed in composition and particle size distribution. At low and high inoculum densities (nine and 30 infested oat grains per container) of Phytophthora cinnamomi, severity of Phytophthora root rot of Rhododendron sp. was significantly less in pine bark media than in peat/sand/soil. Differences in root rot severity between the pine bark media and the peat/sand/soil medium were best explained by differences in air-filled porosity and matric water potential among media (...)

Developmental changes in the bark lectin of Sophora japonica L.

Abstract: Lectin is the major protein in the phloem tissue of S. japonica. By immunohistochemistry using anti-seed lectin antibody it was demonstrated that the lectin was localized in the ray and the axial parenchyma. Neither lectin nor other cross-reactive materials were observed in the cambium, sieve tubes and companion cells. The distribution and localization changed in relation to tissue development. Lectin content in the bark changed during the year, the average in summer being about 50% of that in winter. The distribution of lectin in the bark in winter was similar from the innermost (youngest) to the outermost (oldest) region. In contrast, in summer the innermost region hardly contained any lectin, and the outermost region contained less lectin than the middle. Lectin localization in tissues and cells differed also depending on tissue age. In new tissue, produced in the current year, lectip was absent in summer, was located in the cytoplasmic layer between cell wall and vacuole in autumn, and sequestered in the vacuoles in winter. On the other hand, lectin in old tissue (formed in the previous year) was located throughout the year mainly within the vacuoles, with only very small contents in the cytoplasmic layer in autumn. Within the outermost (oldest) region, in which the lectin content was low in summer, the cells which bordered the outer bark never contained any lectin in summer. The intracellular localization in autumn in new tissue, determined by immunogold electron microscopy, was in the lumen of the endoplasmic reticulum and vesicles, with gold particles hardly present in the cytoplasm. From these findings we conclude that lectin is synthesized on the endoplasmic reticulum and most vigorously in the new tissue in autumn, and that it is mainly consumed in the outermost bark regions, where dilatation occurs and-or where cork cambium is differentiated.

Triterpenes from the outer bark of Betula nigra

Abstract: Twelve pentacyclic triterpenes were isolated from the outer bark of river birch, Betula nigra. 3β-Acetoxyolean-11-oxo-12-ene-28-oic acid was isolated for the first time from a Betula species. 3β-Caffeatoxyolean-12-ene-28-oic acid has been spectrally characterized for the first time. 3β-Acetoxyolean-12-ene-28-oic acid and 3β-acetoxyolean-11-oxo-12-ene-28-oic acid have been demonstrated to be active as antifeedants for the Colorado potato beetle, Leptinotarsa decemlineata.

Bark consumption by voles in relation to mineral contents

Abstract: Recent field experiments with impregnated wooden sticks have demonstrated a pronounced use by small rodents of mineral supplies, especially sodium, and such findings seemed related to vole damage to forestry seedlings. Consumption of the bark of experimentally introduced aspen twigs and of sodium-impregnated sticks by voles (mainly or onlyMicrotus agrestis) correlated significantly on clear-cuts but not on unmanipulated abandoned fields. Such a correlation appeared when abandoned fields were cut continuously in summer. At vole peak densities, bark of pine seedlings experimentally fertilized with sodium was consumed but not bark of seedlings fertilized with calcium or control seedlings. Field pine seedlings attacked by voles had significantly higher levels of calcium, sodium, and phosphorus than the nearest untouched seedling. However, sodium and phosphorus contents correlated strongly. Sodium and calcium supply to voles in laboratory feeding trials did not diminish the moderate interest in pine bark. Such conditions are, however, assumed to mimic a situation of bark sampling in low-density populations. Sodium, and possibly also calcium, requirements are concluded to be partial determinants of the destructive bark consumption by voles at the peaks of their multiannual population cycles.

Proanthocyanidins from Quercus petraea Bark.

Abstract: Flavanols and oligomeric proantho-cyanidins were isolated from oak bark ( QUERCUS PETRAEA) and characterized by acid hydrolysis, gel permeation chromatography, haemanalysis, and complete as well as partial thiolytic degradation. The proantho-cyanidins had an average polymerization degree of 6.1 and a procyanidin: prodelphinidin ratio of 6:4. The prevailing units of the oligomeric chains were (+)-catechin, (-)-epicatechin, and (+)-gallocatechin, minor units were (-)-epicatechin 3- O-gallate and (-)-epigallocatechin 3- O-gallate. The bark contains both hydrolyzable and condensed tannins. Although only 23% of the water-soluble oak bark tannins consisted of oligomeric proanthocyanidins, these contributed with 55% to the astringency of the total tannin fraction.

Bark Beetle-Fire Associations in the Greater Yellowstone Area

Abstract: The large forest fires in and around Yellowstone National Park in 1988 bring up many ecological questions, including the role of bark beetles. Bark beetles may contribute to fuel buildup over the years preceding a fire, resulting in stand replacement fires. Fire is important to the survival of seral tree species and bark beetles that reproduce in them. Without fire, seral species are ultimately replaced by climax species. Following fire, barkand wood-boring beetles respond to fire-injured trees. Because of synchrony of the fires and life cycles of the beetles, beetle infestation in 1988 was not observed in fire-injured trees. However, endemic populations of beetles, upon emergence in 1989, infested large numbers of fire-injured trees. Of the trees examined in each species, 28 to 65 percent were infested by bark beetles: Pinus contorta (28 percent) by ~ ci!:!i; Pseudotsuga menziesii (32 percent) by Dendroctonus pseudotsugae; Picea engelmannii (65 percent) by Dendroctonus rufipennis; and Abies lasiocarpa (35 percent) by Buprestidae and Cerambycidae. Most trees infested by bark beetles had 50 percent or more of their basal circumference killed by fire. Bark beetle popUlations probably will increase in the remaining