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D. Don (d + don)
Selected AbstractsPatterns of isozyme variation as indicators of biogeographic history in Pilgerodendron uviferum (D. Don) FlorínDIVERSITY AND DISTRIBUTIONS, Issue 2 2002A. C. Premoli Abstract. The effects of Pleistocene glaciations on the genetic characteristics of the most austral conifer in the world, Pilgerodendron uviferum, were analysed with specific reference to the hypothesis that the species persisted locally in ice-free areas in temperate South America. It was expected that genetic variation would decrease with latitude, given that ice fields were larger in southern Patagonia and thus refugia were probably located towards the northern distributional limit of the species as suggested by the fossil record. In addition, an increase in among-population genetic divergence was expected with increasing distance to putative glacial refugia. We examined the relationship between location and within-population variability indices of 20 Pilgerodendron populations derived from isozyme analyses. We analysed possible refugia hypotheses by the distribution of allele frequencies using multivariate discriminant analysis. The degree of genetic differentiation with geographical distance between all population pairs was investigated by Mantel tests. Results indicated that Pilgerodendron populations are highly monomorphic, probably reflecting past population bottlenecks and reduced gene flow. Southernmost populations tend to be the least genetically variable and were therefore probably more affected by glacial activity than northern ones. Populations located outside ice limits seem to have been isolated during the glacial period. The presence of centres of genetic diversity, together with the lack of a significant correlation between genetic and geographical distances and the absence of geographical patterns of allelic frequencies at most analysed alleles, may indicate that Pilgerodendron did not advance southward after the last glaciation from a unique northern refugium, but spread from several surviving populations in ice-free areas in Patagonia instead. [source] The lethal effects of gamma irradiation on larvae of the Huhu beetle, Prionoplus reticularis: a potential quarantine treatment for New Zealand export pine treesENTOMOLOGIA EXPERIMENTALIS ET APPLICATA, Issue 3 2000Philip J. Lester Abstract Gamma irradiation was investigated as a possible method for disinfestation of huhu beetle larvae, Prionoplus reticularis White, in Pinus radiata D. Don. Larvae of four representative size classes were irradiated at six doses, and the lethal dose (LD99) calculated from mortality data 3 days and 10 days post treatment. All larval size classes showed a similar sensitivity to gamma irradiation and required 3677 Gray (Gy) and 2476 Gy for a LD99 3 and 10 days post-treatment, respectively. The penetration of gamma irradiation into pine wood was found to be lowest in freshly cut logs, and decreased linearly at a rate of 0.698 Gy mm,1 of wood. The penetration was greatest in wood that had been stored for 2 years, and decreased 0.512 Gy mm,1 of wood. These results are likely to be correlated with wood moisture content. Gamma irradiation appears to be a potential alternative method to fumigation for quarantine treatment of P. reticularis. [source] A short synthesis of the monoterpenes (,)-6,-hydroxy- carvotanacetone and (,)-6,-hydroxycarvotanacetone from (R)-(,)-carvoneFLAVOUR AND FRAGRANCE JOURNAL, Issue 4 2001R. B. dos Santos Abstract 6-Hydroxycarvotanacetone[2-methyl-5-(1-methylethyl)-6-hydroxycyclohex-2-en-1-one] has been isolated in small amounts from the essential oil of Laggera alata (D. Don) Sch. Bip. ex Oliv., although its absolute stereostructure has not yet been unequivocally established. A short synthesis of two diastereomers of 6-hydroxycarvotanacetone from (R)-(,)-carvone via regioselective epoxidation of its dienylsilyl ether is described. Copyright © 2001 John Wiley & Sons, Ltd. [source] Site history affects soil and plant 15N natural abundances (,15N) in forests of northern Vancouver Island, British ColumbiaFUNCTIONAL ECOLOGY, Issue 3 2000S. X. Chang Abstract 1.,About 10 years after establishment, plantations of Western Redcedar (Thuja plicata Donn ex D. Don) on northern Vancouver Island, British Columbia become nutrient deficient and chlorotic, grow slowly, and are susceptible to invasion by the ericaceous shrub Salal (Gaultheria shallon Pursh.). 2.,To test the hypothesis that ,15N can be related to site histories (site disturbance, soil N dynamics and plant development), we measured soil and foliar ,15N in the summer of 1992 in 3-year-old (nutrient-sufficient) and 10-year-old (nutrient-deficient) plantations and in old-growth stands. The foliar and soil ,15N values of the plantations and old-growth forests were different and closely reflected site histories. Salal invasion and nutrient deficiency interacted to depress the growth of Redcedar in 10-year-old plantations. 3.,Site preparation destroyed the top soil organic layers (fresh and decaying litter) and forced Salal (ecto- and ericoid mycorrhizal) into the humus layer, where it was in direct competition with Redcedar, thereby disadvantaging arbuscular mycorrhizal/non-mycorrhizal Redcedar in its nutrient acquisition during a period when N and P are severely limited. 4.,There was a large seasonal range of foliar ,15N (5·5 and 4·3, for 10-year-old Redcedar and Salal, respectively), and there was no relationship between foliar ,15N and measured rooting depth, demonstrating that rooting depths cannot be used to explain foliar ,15N variation among coexisting woody taxa. 5.,Foliar and soil ,15N declined with site age and with a presumed change from ,open' to ,closed' N cycling; the 15N-depleting effects of mycorrhizal N transformations contributed to the observed ,15N decline. [source] Evaluation of soil saturation, soil chemistry, and early spring soil and air temperatures as risk factors in yellow-cedar declineGLOBAL CHANGE BIOLOGY, Issue 3 2006D. V. D'AMORE Abstract Yellow-cedar (Callitropsis nootkatensis (D. Don) Oerst.) is a valuable tree species that is experiencing a widespread decline and mortality in southeast Alaska. This study evaluated the relative importance of several potential risk factors associated with yellow-cedar decline: soil saturation, soil aluminum (Al) toxicity or calcium (Ca) deficiency, and air and soil temperature. Data were collected from permanent vegetation plots established in two low-elevation coastal forests exhibiting broad ranges of cedar mortality. Measurements of each risk factor were contrasted among classified forest zones to indicate if there were strong links with decline. Hydrology alone is weakly associated with yellow-cedar decline, but could have a predisposing role in the decline by creating exposed conditions because of reduced forest productivity. Yellow-cedar decline is not strongly associated with soil pH and extractable Al and Ca, but there appears to be Ca enrichment of surface soils by feedback from dead yellow-cedar foliage. Air and soil temperature factors are strongly associated with decline. Based on these results, an hypothesis is presented to explain the mechanism of tree injury where exposure-driven tree mortality is initiated in gaps created by soil saturation and then expands in gaps created by the tree-mortality itself. The exposure allows soils to warm in early spring causing premature dehardening in yellow-cedar trees and subsequent freezing injury during cold events. Yellow-cedars growing in the protection of shade or snow are not preconditioned by this warming, and thus not as susceptible to cold injury. Yellow-cedar decline appears to be associated with regional climate changes, but whether the cause of these changes is related to natural or human-induced climate shifts remains uncertain. Management implications, the possible role of climate, and recommended research are discussed. [source] The solute budget of a forest catchment and solute fluxes within a Pinus radiata and a secondary native forest site, southern ChileHYDROLOGICAL PROCESSES, Issue 13 2002Geertrui Y. P. Uyttendaele Abstract Solute concentrations and fluxes in rainfall, throughfall and stemflow in two forest types, and stream flow in a 90 ha catchment in southern Chile (39°44,S, 73°10,W) were measured. Bulk precipitation pH was 6·1 and conductivity was low. Cation concentrations in rainfall were low (0·58 mg Ca2+ l,1, 0·13 mg K+ l,1, 0·11 mg Mg2+ l,1 and <0·08 mg NH4,N l,1), except for sodium (1·10 mg l,1). Unexpected high levels of nitrate deposition in rainfall (mean concentration 0·38 mg NO3,N l,1, total flux 6·3 kg NO3,N ha,1) were measured. Concentrations of soluble phosphorous in bulk precipitation and stream flow were below detection limits (<0·09 mg l,1) for all events. Stream-flow pH was 6·3 and conductivity was 28·3 ,s. Stream-water chemistry was also dominated by sodium (2·70 mg l,1) followed by Ca, Mg and K (1·31, 0·70 and 0·36 mg l,1). The solute budget indicated a net loss of 3·8 kg Na+ ha,1 year,1, 5·4 kg Mg2+ ha,1 year,1, 1·5 kg Ca2+ ha,1 year,1 and 0·9 kg K+ ha,1 year,1, while 4·9 kg NO3,N ha,1 year,1 was retained by the ecosystem. Stream water is not suitable for domestic use owing to high manganese and, especially, iron concentrations. Throughfall and stemflow chemistry at a pine stand (Pinus radiata D. Don) and a native forest site (Siempreverde type), both located within the catchment, were compared. Nitrate fluxes within both forest sites were similar (1·3 kg NO3,N ha,1 year,1 as throughfall). Cation fluxes in net rainfall (throughfall plus stemflow) at the pine stand generally were higher (34·8 kg Na+ ha,1 year,1, 21·5 kg K+ ha,1 year,1, 5·1 kg Mg2+ ha,1 year,1) compared with the secondary native forest site (24·7 kg Na+ ha,1 year,1, 18·9 kg K+ ha,1 year,1 and 4·4 kg Mg2+ ha,1 year,1). However, calcium deposition beneath the native forest stand was higher (15·9 kg Ca2+ ha,1 year,1) compared with the pine stand (12·6 kg Ca2+ ha,1 year,1). Copyright © 2002 John Wiley & Sons, Ltd. [source] Below-ground ectomycorrhizal community structure in a recently burned bishop pine forestJOURNAL OF ECOLOGY, Issue 6 2000P. Grogan Summary 1,The effects of wildfire ash on ectomycorrhizal (EM) associations were investigated by sampling bishop pine (Pinus muricata, D. Don) seedlings from control and ash-removed plots 1.5 years after a severe fire in a northern Californian P. muricata forest. The below-ground community composition of EM at the site was characterized using molecular techniques (PCR-RFLP and nucleotide sequencing). 2,A total of 30 fungal taxa were observed, many of which differed in their distribution between treatment and control seedlings. However, most of the taxa that were distinctive to either treatment or control seedlings occurred only once across the site, precluding statistical detection of potential ash effects on EM community composition. There were no significant effects of ash removal on plot-level mycorrhizal community richness or diversity, and there were no distinct treatment-related clusters in a principal components analysis. 3,Analysis of the combined data indicated that numbers of fungal taxa per seedling, numbers of successive root depth increments colonized by the same taxon, and distances to neighbouring seedlings colonized by the same taxon, were randomly distributed across the site for the majority of mycorrhizal fungi. These distributional patterns suggest that the post-fire mycorrhizal community structure on P. muricata arose primarily from successful colonization by randomly distributed point-source fungal inocula within the upper mineral soil layer of the forest floor. 4,By comparison with pre-fire studies from similar P. muricata sites nearby, our data indicate that severe wildfire disturbance resulted in marked changes in mycorrhizal community composition, and a sharp increase in the relative biomass of ascomycetous fungi. [source] Application of microscopy in authentication of traditional Tibetan medicinal plant Halenia ellipticaMICROSCOPY RESEARCH AND TECHNIQUE, Issue 1 2008Jie Li Abstract Halenia elliptica D. Don, a popularly used ethnodrug from Qinghai-Tibetan plateau, was studied to reveal the indispensable morphoanatomic details. The fixed, sectioned, and stained plant materials as well as the epidermis, powder, and maceration materials were studied using light microscope according to the usual microscopic techniques. The results of the microscopic features were systematic described and illustrated. In the root, an endodermal cell was divided into 8-16-22 and 38-50-62 daughter cells in transverse section and in face view, respectively, and 9-11-13 phloem strands were present in primary structure; in the stem, stone cells were observed in the cortex, pericycle, and external phloem while 17-19-21 internal phloem strands were present in an incontinuous ring; in the pedicel, 8-10-12 internal phloem strands were observed to form an incontinuous ring; anisocytic and anomocytic stomata were present in leaf and sepal epidermis; pollen grain was with three germinal apertures and furrows; a few tracheids, a large number of spiral vessels, and various fibers were observed. Also, semiquantitative and quantitative micrographic parameter tables were simultaneously presented. Further, the key authentication parameters were concluded. The study indicated that light microscopy and related techniques could be unambiguously applied to the authentication of Halenia elliptica. Microsc. Res. Tech., 2008. © 2007 Wiley-Liss, Inc. [source] Isolation and characterization of 19 microsatellite markers in a tropical and warm subtropical birch, Betula alnoides Buch.,Ham. ex D. DonMOLECULAR ECOLOGY RESOURCES, Issue 4 2008J. J. GUO Abstract Betula alnoides is an ecologically and economically important species in the tropics and warm subtropics. Nineteen polymorphic microsatellite markers were isolated from this species, which displayed three to 12 alleles per locus. The observed heterozygosities ranged from 0.100 to 0.905, and the expected heterozygosities from 0.510 to 0.893. These markers would be useful tools in genetic resource assessment, molecular marker-assistant breeding, parentage analysis and genetic diversity studies for this species. [source] Lithocarpuslongzhouicus comb. nov. (Fagaceae) from China: based on morphological and molecular dataNORDIC JOURNAL OF BOTANY, Issue 2 2009Li Chen The taxonomic position of Castanopsis longzhouica C. C. Huang & Y. T. Chang has been controversial. Various authors included it in Castanopsis (D. Don) Spach, or Lithocarpus Bl. based on morphology, palynology and wood anatomy. In order to investigate this issue, sequences of nuclear ITS and the chloroplast genes matK and trnL-F of C. longzhouica were analyzed together with 72 representatives of 7 genera within Fagaceae. As for species of Lithocarpus, there were a 1-bp insertion and two unique 3-bp deletions from ITS2 of C. longzhouica distinguishing it from Castanopsis. The phylogenetic analyses on the separate ITS data and the joint data (ITS+matK+ trnL-F) strongly supported a derived position of C. longzhouica within a clade consisting of members of Lithocarpus. The result is consistent with previous suggestions based on wood anatomy, suggesting that C. longzhouica should be transferred to Lithocarpus. In addition, the shallow cup-shaped, loose incoherent-scale and indehiscent cupule and the concave scar of C. longzhouica suggests a close relationship to species of Lithocarpus. Based on these data, the new combination Lithocarpus longzhouicus (C. C. Huang & Y. T. Chang) J. Q. Li & L. Chen is proposed. [source] Antiproliferative effect of Scutellaria barbata D. Don. on cultured human uterine leiomyoma cells by down-regulation of the expression of Bcl-2 proteinPHYTOTHERAPY RESEARCH, Issue 5 2008Kyung-Woon Kim Abstract Scutellaria barbata D. Don (Lamiaceae; SB) inhibited the growth of leiomyomal cells (LM). A time-dependent antiproliferative effect was noted when 10,5m buserelin, gonadotrophin-releasing hormone (GnRH) agonist or 20,40 µg/mL SB was added. The inhibition of cell growth decreased with the addition of the PKC activator (12-O-tetradecanoylphorbor-13-acetate; TPA) much as it did with the addition of SB, and the decreases in the viable cells caused by the addition of SB were reversed completely by pretreatment with a protein kinase C (PKC) inhibitor (calphostin C). The findings suggest that SB inhibits cell proliferation in cultured human uterine leiomyoma cells accompanied by PKC activation. Next, the study investigated the effect of SB on fetal development for toxicity. Pregnant Sprague-Dawley rats, from gestation day 6,15, were administered 20 g/L or 50 g/L SB in the drinking water and then killed on day 20. No maternal toxicity was observed, however, embryonic loss in the treatment groups was double that of the controls (p < 0.05). No gross morphologic malformations were seen in the treated fetuses. Fetuses exposed to SB were found to be significantly heavier than the controls, an effect that was greater in female fetuses and was not correlated with increased placental size. The results suggest that the SB had no toxicity and that in utero exposure to SB resulted in increased early embryo loss with increased growth in surviving fetuses. On the other hand, Western blot analyses revealed that Bcl-2 protein of a 26 kDa was abundant in leiomyomal cells, but not in normal myometrial cells. The addition of progesterone (100 ng/mL) resulted in a striking increase in Bcl-2 protein expression in the cultured leiomyoma cells. However, the addition of SB (20 µg/mL) resulted in a significant reduction in Bcl-2 protein expression in the cells. The results indicated that human uterine leiomyomal cells express Bcl-2 protein and progesterone enhances its expression, however, SB reduces the expression of Bcl-2 protein in human uterine leiomyoma cells. Copyright © 2008 John Wiley & Sons, Ltd. [source] Identification of metabolites of adonifoline, a hepatotoxic pyrrolizidine alkaloid, by liquid chromatography/tandem and high-resolution mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 24 2009Aizhen Xiong Hepatotoxic pyrrolizidine alkaloid (HPA)-containing plants have always been a threat to human and livestock health worldwide. Adonifoline, a main HPA in Senecio scandens Buch.-Ham. ex D. Don (Qianli guang), was used officially as an infusion in cases of oral and pharyngeal infections in China. In this study in vivo metabolism of adonifoline was studied for the first time by identifying the metabolites of adonifoline present in bile, urine and feces of rats using liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI-MSn) (ion trap) as well as liquid chromatography/electrospray ionization high-resolution mass spectrometry (LC/ESI-HRMS) (quadrupole-time of flight). In total 19 metabolites were identified and, among them, retronecine- N -oxides were confirmed by matching their fragmentation patterns with their fully characterized synthetic compounds. These metabolites are all involved in both phase I and phase II metabolic processes and the principal in vivo metabolism pathways of adonifoline were proposed. Copyright © 2009 John Wiley & Sons, Ltd. [source] Primary growth and morphological markers of interannual growth limits in Cupressaceae from PatagoniaBOTANICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 3 2004JAVIER GROSFELD The present study shows experimentally that primary growth of the native Patagonian Cupressaceae Austrocedrus chilensis (D. Don) Pic.-Serm et Bizz., Fitzroya cupressoides (Molina) I. M. Johnst. and Pilgerodendron uviferum (D. Don) Florin is potentially continuous. External morphological markers of interannual growth limits have been identified for the main axes of these species after several years of observation. Such limits correspond with axis portions in which internodes are relatively short and leaves have a small distal free end forming an acute angle with the axis. The causality of these results and their utility for studying the productivity, adaptation to different environments, population management and conservation of these threatened species are discussed. © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society, 2004, 146, 285,293. [source] | |||||||||||||||||||||||||