Tracheid length variation in a single tree ofPinus kesiya Royle ex Gord.     

Jeffrey Burley 《Wood Science and Technology》1969,3(2):109-116

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Light availability influences root carbohydrates, and potentially vigor, in white oak advance regeneration     

Dylan N. Dillaway  Jeffrey W. Stringer  Lynne K. Rieske 《Forest Ecology and Management》2007,250(3):227-233

Oaks (Quercus spp.) are experiencing recurring regeneration failures associated with pervasive mid- and under-story strata of shade tolerant species in intact, undisturbed forests. Where oak regeneration occurs, inadequate vertical height and depleted root carbohydrate stores impede the ability of regenerating oaks to respond when light does become available. A variety of silvicultural techniques have been developed to increase the penetration of diffuse light, enhancing the light environment on the forest floor, and thereby increasing the likelihood of regenerating oaks to successfully respond to increased light transmittance. We measured shoot and root characteristics, and root soluble non-structural carbohydrate concentrations of white oak (Q. alba L.) advance regeneration exposed to enhanced light intensities associated with a mid-story removal and a clearcut, and compared white oak regeneration vigor to untreated controls.

Root diameter and soluble non-structural carbohydrates increased with increasing light availability. Our data suggest that white oak responds to increases in light transmittance by building below-ground biomass and carbohydrates in the root system prior to an above-ground response. Our study shows that white oak regeneration vigor increases with only modest increases in light. In the absence of other pressures, enhancing the light environment to the forest floor should contribute to successful regeneration of this species.  相似文献   

Rheological Studies on the Reaction of Zein with Polyethylenemaleic Anhydride     

Gordon W. Selling  Jeffrey A. Byars  Kelly D. Utt 《Cereal Chemistry》2016,93(2):145-149

There continues to be interest in developing solvent‐resistant articles from biobased renewable materials to successfully compete with petrochemical products. It was previously shown that reaction of zein with polyethylenemaleic anhydride (PEMA) provides articles that are solvent resistant. The gelation kinetics for the reaction of PEMA with zein was investigated rheologically to better understand this chemistry. The reaction of the nucleophilic groups on zein with the anhydrides on PEMA is the main cause for the gelation reaction. The gelation time was defined as being the point when the elastic modulus (G′) and viscous modulus (G″) cross. In this work, the rate of reaction, in terms of time to gelation, was studied in N,N‐dimethylformamide solution for which the amount of PEMA, the reaction temperature, and the overall reaction concentration were varied. Exponential relationships were found between the gelation time and % PEMA, temperature, and % solids, as well as between elastic modulus with either % PEMA or % solids. The concentration of PEMA had the largest impact on gelation time, for which going from 2.5% PEMA to 6% PEMA reduced the gelation time from 63,114 to 1,576 s. The temperature dependence of this gelation reaction was well described by an Arrhenius plot with an apparent activation energy of 50.5 kJ/mol.  相似文献   

A robust set of black walnut microsatellites for parentage and clonal identification     

Rodney L. Robichaud  Jeffrey C. Glaubitz  Olin E. Rhodes Jr.  Keith Woeste 《New Forests》2006,32(2):179-196

We describe the development of a robust and powerful suite of 12 microsatellite marker loci for use in genetic investigations of black walnut and related species. These 12 loci were chosen from a set of 17 candidate loci used to genotype 222 trees sampled from a 38-year-old black walnut progeny test. The 222 genotypes represent a sampling from the broad geographic distribution of the species. Analysis of the samples using the 12 loci revealed an average expected heterozygosity of 0.83, a combined probability of identity of 3×10⁻¹⁹, and a combined probability of exclusion for paternity analysis of >0.999. The 222 genotyped trees from the progeny test comprised 39 open-pollinated families, 29 of which (having at least five sampled progeny) were used to estimate the outcrossing rate for the progeny trial. The same 29 families were used to construct a Neighbor-Joining dendrogram based upon allele sharing between individuals. The multilocus estimate of the outcrossing rate was 100% (standard error of zero), higher than the 90% level found in previous studies at the embryo stage, suggesting that both artificial and natural selection against selfs may have occurred over the 38-year lifespan of the progeny trial. In the Neighbor-Joining dendrogram, the majority of the putative siblings grouped together in 21 out of the 29 families, showing that the microsatellites were able to discern most of the family structure in the dataset. Our results indicate that errors were sometimes committed during the establishment of the progeny test. This set of microsatellite loci clearly provides a powerful tool for future applications in black walnut.  相似文献   

Detecting endotoxin activity in bovine serum using an automated testing system     

Kazuyuki SUZUKI  Toshio SHIMAMORI  Ayano SATO  Kenji TSUKANO  Masakazu TSUCHIYA  Jeffrey LAKRITZ 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2015,77(8):977-979

The aim of the present study was to compare the ability of the commercially available portable test system (PTS^TM) to detect endotoxin activity in bovine serum, with that of the traditional LAL-kinetic turbidimetric (KT) and chromogenic (KC) assays. Prior to testing, serum samples, which were obtained from endotoxin-challenged cattle, were diluted 1:20 in endotoxin-free water and heated to 80°C for 10 min. The performance of the PTS^TM was not significantly different from that of the traditional LAL-based assays. The results using PTS^TM correlated with those using KT (r²=0.963, P<0.001) or KC assays (r²=0.982, P<0.001). Based on these findings, the PTS^TM could be applied as a simplified system to assess endotoxin activity in bovine serum.  相似文献   

Development of a new method for the complete extraction of carotenoids from cereals with special reference to durum wheat (Triticum durum Desf.)     

Burkhardt S  Böhm V 《Journal of agricultural and food chemistry》2007,55(21):8295-8301

Due to the growing interest in the role of carotenoids in human health, their qualitative and quantitative analysis in foods is becoming more and more important. High-performance liquid chromatography has become the method of choice for the determination of these phytochemicals. A crucial step prior to the chromatographic separation is the quantitative extraction from the food matrix which was proven to be impeded in durum wheat. To optimize the extraction procedure, several factors with influence on extractability of carotenoids were investigated. Finally, it was shown that soaking of samples in water for 5 min prior to extraction with organic solvents had the strongest impact on extraction yield and led to the most rapid and gentle method. Contents of carotenoids in the extracts of several durum wheat and corn samples were doubled by soaking in water before extracting with methanol/tetrahydrofuran (1/1, v/v). In light of these findings, literature data on contents of carotenoids in cereal grains have to be viewed critically regarding the extraction procedures employed.  相似文献   

Heritability of Latent Period Estimated from Wild-Type and Selected Populations of Puccinia triticina     

Lehman JS  Shaner G 《Phytopathology》2007,97(8):1022-1029

ABSTRACT Durability of partially resistant wheat cultivars to wheat leaf rust depends on the amount of genetic variation in parasitic fitness within populations of the pathogen Puccinia triticina. To assess the durability of partial resistance, selection experiments were used to explore quantitative variation in parasitic fitness of P. triticina. Fungal populations 881-WT and 882-WT were selected for shortened latent period on partially resistant cvs. CI 13277 and Sw 72469-6 for multiple generations. Fitness components were measured for wild-type and selected fungal populations. Responses to selection and selection differentials were calculated, and broad-sense, realized heritabilities for latent period were estimated for wild-type fungal populations on CI 13227 and on Sw 72469-6. Selected populations had fitness characteristics, not limited to latent period, that could provide greater fitness in nature. Generally, more cycles of selection had greater effects on fitness. In particular cases, selected populations on a partially resistant cultivar had values for latent period, uredinium area, and sporulation no different from those of a susceptible host-pathogen combination. Heritabilities of latent period of populations 881-WT and 882-WT on CI 13227 or populations 881-WT and 882-WT on Sw 72469-6 ranged from 0.65 to 0.76 and 0.17 to 0.24, respectively. Our results suggest the variation to overcome quantitative host resistance exists in extant populations of P. triticina. In addition, because more of the variation in latent period for populations of P. triticina on CI 13227 was genetic than for populations on Sw 72469-6, CI 13227 is likely to be more vulnerable to pathogen adaptation despite its exceptionally long latent period.  相似文献   

Projecting global and regional outlooks for planted forests under the shared socio-economic pathways     

Korhonen  Jaana  Nepal  Prakash  Prestemon  Jeffrey P.  Cubbage  Frederick W. 《New Forests》2021,52(2):197-216

New Forests - There is rising global interest in growing more trees in order to meet growing population, climate change, and wood energy needs. Using recently published data on planted forests by...  相似文献   

Starvation Induced Alterations in Hepatic Lysine Metabolism in Different Families of Rainbow Trout (<Emphasis Type="Italic">Oncorhynchus  mykiss</Emphasis>)     

Angela?D.?Higgins  Jeffrey?T.?Silverstein  Juanita?Engles  Matthew?E.?Wilson  Caird?E.?RexroadIII  Kenneth?P.?BlemingsEmail author 《Fish physiology and biochemistry》2005,31(1):33-44

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Contrasting the ability of data to make inferences regarding dispersal: case study of the Red-cockaded woodpecker (Picoides borealis)     

Douglas J. Bruggeman  Thorsten Wiegand  Jeffrey R. Walters  Fernando González Taboada 《Landscape Ecology》2014,29(4):639-653

Dispersal is a critical biological process that contributes to the persistence of species in complex and dynamic landscapes. However, little is known about the ability of different types of data to reveal how species interact with landscape patterns during dispersal. Further, application of process-based, landscape-scale models able to capture the influence of land use and climate change are limited by this lack of dispersal knowledge. Here we highlight a method for building such models when dispersal parameters are unknown, but information on the mating system and survival are available. We applied a common statistical framework, rooted in information theory, to contrast the ability of abundance, movement, and genetic data to estimate dispersal parameters for endangered Red-cockaded woodpecker (RCW), using an individual-based, spatially-explicit population model. Dispersal was modeled as a multifaceted process in which foray distance, long-distance dispersal, competition for mates, and landscape permeability were treated as uncertain. We found that movement data are three-times more powerful than abundance data collected at the same spatial and temporal scales. However, habitat occupancy data collected over much a shorter time scale but at regional spatial scales were very effective for estimating dispersal. We also found that one-year of abundance data provided a similar reduction in uncertainty as genetic differences among breeding groups estimated using a 24-year pedigree. Substituting population genetic data for movement and abundance data often led to the same parameter values, but not always. Our study highlights important differences in the information content of data commonly collected in the field.  相似文献