| a comparison of internal standards for plant cytophotometry. | plant cell nuclei were compared with chicken erythrocyte nuclei for use as internal standards for microspectrophotometry. the amount of dna per nucleus and the coefficient of variation for measurement of individual nuclei were determined for cells from dormant embryos of pinus taeda and pinus coulteri, from onion root tips and from chicken erythrocytes. the chicken erythrocytes had the least variability and thus were best suited for use as a standard. onion root tips were least suitable, with a ... | 1986 | 3787672 |
| effects of nutrition on age determination using eye lens weights. | populations of hispid cotton rats (sigmodon hispidus) were studied in 6 young loblolly pine (pinus taeda) plantations in south carolina, usa. each plantation had 2, 1-ha, live-trapping grids; 1 to sample a sigmodon population which continually received supplemental food, the other to sample a control population. after 15 months of live-trapping, the sigmodon were killed and their eye lenses removed, dried and weighed. birth dates were calculated for 425 sigmodon which were first captured when yo ... | 1986 | 3803993 |
| genetic analysis of cinnamyl alcohol dehydrogenase in loblolly pine: single gene inheritance, molecular characterization and evolution. | the gene encoding the monolignol biosynthetic enzyme cinnamyl alcohol dehydrogenase (cad, e.c. 1.1.1.195) can be expressed in response to different developmental and environmental cues. control of cad gene expression could involve either differential regulation of more than one cad gene or, alternatively combinatorial regulation of a single cad gene. in loblolly pine (pinus taeda l.), we found several electrophoretic variants (allozymes) of cad and a high level of heterozygosity (he = 0.46). ana ... | 1995 | 7603432 |
| lipid transfer protein genes of loblolly pine are members of a complex gene family. | a loblolly pine (pinus taeda l.) cdna with properties of a nonspecific lipid transfer protein (nsltp) is reported. in contrast to simple family structures reported for a variety of angiosperm nsltp genes, the putative pine nsltp gene is a member of a complex family. | 1994 | 7811979 |
| electrophoretic analysis of coniferyl alcohol oxidase and related laccases. | gradient gel electrophoretic methods enabled a distinction to be made between coniferyl alcohol oxidase (cao) of lignifying cell walls and a pi approximately 9 pine "laccase" recently implicated in lignification (science 1993 260, 672). following treatment of a partially purified protein mixture from developing xylem of pinus strobus with 2-[n-morpholine]ethanesulfonic acid (mes) buffer, isoelectric focusing and sodium dodecyl sulphate-polyacrylamide gel electrophoresis indicated that cao had be ... | 1994 | 7859710 |
| xylem-specific gene expression in loblolly pine. | two genes preferentially expressed in differentiating xylem of loblolly pine (pinus taeda l.) were cloned from cdna and genomic libraries and designated ptx3h6 and ptx14a9. transcripts of ptx3h6 and ptx14a9 are very abundant in differentiating xylem, less abundant in needles, and very low or non-detectable in embryos and megagametophytes. ptx3h6 contains a putative signal peptide, a threonine-rich region, a proline-rich region, and a hydrophobic tail. repeats of pro-pro-pro-val-x-x are similar t ... | 1995 | 7888618 |
| identification of quantitative trait loci influencing wood specific gravity in an outbred pedigree of loblolly pine. | we report the identification of quantitative trait loci (qtl) influencing wood specific gravity (wsg) in an outbred pedigree of loblolly pine (pinus taeda l.). qtl mapping in an outcrossing species is complicated by the presence of multiple alleles (> 2) at qtl and marker loci. multiple alleles at qtl allow the examination of interaction among alleles at qtl (deviation from additive gene action). restriction fragment length polymorphism (rflp) marker genotypes and wood specific gravity phenotype ... | 1994 | 7896107 |
| lignification in cell suspension cultures of pinus taeda. in situ characterization of a gymnosperm lignin. | pinus taeda suspension cultures grown in medium containing 2,4-dichlorophenoxyacetic acid showed only primary cell wall formation and essentially no lignification, as determined by histochemical, ultrastructural, chemical, and nmr spectroscopic analyses. however, these cultures maintained a functional phenylpropanoid pathway as demonstrated by formation of the lignans (-)-matairesinol and (-)-pinoresinol. administration of [1-13c]phe to these cultures, followed by solid-state carbon-13 nmr spect ... | 1993 | 8407945 |
| nitrogen metabolism in lignifying pinus taeda cell cultures. | the primary metabolic fate of phyenylalanine, following its deamination in plants, is conscription of its carbon skeleton for lignin, suberin, flavonoid, and related metabolite formation. since this accounts for approximately 30-40% of all organic carbon, an effective means of recycling the liberated ammonium ion must be operative. in order to establish how this occurs, the uptake and metabolism of various 15n-labeled precursors (15n-phe, 15nh4cl, 15n-gln, and 15n-glu) in lignifying pinus taeda ... | 1996 | 8647837 |
| cloning of a cdna for a chitinase homologue which lacks chitin-binding sites and is down-regulated by water stress and wounding. | a cdna clone (plp6) of a gene which is repressed under water deficit was isolated from a loblolly pine (pinus taeda l.) cdna library and characterized. the predicted polypeptide encoded by plp6 bears strong resemblance to a number of class i chitinases. however, lp6 lacks most of the amino-terminal and, consequently the signal peptide, cysteine-rich chitin-binding domain and glycine/proline-rich "hinge' region, diagnostic of class i chitinases, are absent. although the cdna is similar in size to ... | 1996 | 8790302 |
| survey of microsatellite dna in pine. | a large insert genomic library from eastern white pine (pinus strobus) was probed for the microsatellite motifs (ac)n and (ag)n, all 10 trinucleotide motifs, and 22 of the 33 possible tetranucleotide motifs. for comparison with a species from a different subgenus, a loblolly pine (pinus taeda) genomic library was also probed with the same set of di- and tri-nucleotide repeats and 11 of the tetranucleotide repeats. the four most abundant microsatellite motifs in both species were (ac)n, (ag)n, (a ... | 1997 | 9061909 |
| regulation of two loblolly pine (pinus taeda l.) isocitrate lyase genes in megagametophytes of mature and stratified seeds and during postgerminative growth. | two full-length cdnas encoding the glyoxysomal enzyme isocitrate lyase (icl) were isolated from a lambda zap cdna library prepared from megagametophyte mrnas extracted from seeds imbibed at 30 degrees c for 8 days. the cdnas, designated ptbs icl 8 and ptbs icl 12, have open reading frames of 1740 and 1719 bp, with deduced amino acid sequences of 580 and 573 residues, respectively. the predicted amino acid sequences of ptbs icl 8 and ptbs icl 12 exhibit a 79% identity with each other, and have a ... | 1997 | 9132051 |
| analysis of xylem formation in pine by cdna sequencing. | secondary xylem (wood) formation is likely to involve some genes expressed rarely or not at all in herbaceous plants. moreover, environmental and developmental stimuli influence secondary xylem differentiation, producing morphological and chemical changes in wood. to increase our understanding of xylem formation, and to provide material for comparative analysis of gymnosperm and angiosperm sequences, ests were obtained from immature xylem of loblolly pine (pinus taeda l.). a total of 1,097 singl ... | 1998 | 9689143 |
| loblolly pine (pinus taeda l.) contains multiple expressed genes encoding light-dependent nadph:protochlorophyllide oxidoreductase (por). | nadph:protochlorophyllide oxidoreductase (por) catalyzes the light-dependent reduction of protochlorophyllide (pchlide) to chlorophyllide (chlide), a key regulatory step in chlorophyll biosynthesis. in most angiosperms, por is encoded by a small nuclear gene family, containing at least two differentially-expressed genes designated pora and porb. we have demonstrated that the pors of loblolly pine (pinus taeda l.), a gymnosperm, are encoded by a large multigene family, composed of two distinct su ... | 1998 | 9787456 |
| evolution of plant defense mechanisms. relationships of phenylcoumaran benzylic ether reductases to pinoresinol-lariciresinol and isoflavone reductases. | pinoresinol-lariciresinol and isoflavone reductase classes are phylogenetically related, as is a third, the so-called "isoflavone reductase homologs." this study establishes the first known catalytic function for the latter, as being able to engender the nadph-dependent reduction of phenylcoumaran benzylic ethers. accordingly, all three reductase classes are involved in the biosynthesis of important and related phenylpropanoid-derived plant defense compounds. in this investigation, the phenylcou ... | 1999 | 10066819 |
| differential expression of genes encoding the light-dependent and light-independent enzymes for protochlorophyllide reduction during development in loblolly pine. | the expression patterns of the two distinct subfamilies of genes (designated pora and porb) encoding the light-dependent nadph:protochlorophyllide oxidoreductases (pors) in loblolly pine (pinus taeda l.) were examined. transcripts arising from both gene subfamilies were shown to be present at high levels in the cotyledons of dark-grown pine seedlings and to a lesser extent in their stems. exposure of dark-grown seedlings to light resulted in increased levels of both pora and porb transcripts, as ... | 1999 | 10092184 |
| expansins are conserved in conifers and expressed in hypocotyls in response to exogenous auxin. | differential display reverse transcription-polymerase chain reaction was used to detect the induction of gene expression during adventitious root formation in loblolly pine (pinus taeda) after treatment with the exogenous auxin indole-3-butyric acid. a blast search of the genbank database using one of the clones obtained revealed very strong similarity to the alpha-expansin gene family in angiosperms. a near-full-length loblolly pine alpha-expansin sequence was obtained using 5'- and 3'-rapid am ... | 1999 | 10398718 |
| multi-site modulation of flux during monolignol formation in loblolly pine (pinus taeda). | loblolly pine (pinus taeda l.) cell suspension cultures secrete monolignols when placed in 8% sucrose/20 mm ki solution, and these were used to identify phenylpropanoid pathway flux-modulating steps. when cells were provided with increasing amounts of either phenylalanine (phe) or cinnamic acid, cellular concentrations of immediate downstream products (cinnamic and p-coumaric acids, respectively) increased, whereas caffeic and ferulic acid pool sizes were essentially unaffected. increasing phe c ... | 1999 | 10441481 |
| the dfrc method for lignin analysis. 4. lignin dimers isolated from dfrc-degraded loblolly pine wood. | sixteen lignin dimers were directly isolated by gel permeation and reversed-phase tlc and hplc from loblolly pine (pinus taeda l.) sapwood following large-scale application of the new derivatization followed by reductive cleavage (dfrc) procedure. their structures were elucidated by gc/ms and nmr. these dimers included representatives from all of the common interunit linkages in softwood lignins (beta-1, beta-beta, 5-5, beta-5, and 5-o-4). the dfrc procedure efficiently cleaves beta-aryl ethers, ... | 1998 | 10554276 |
| stand-level allometry in pinus taeda as affected by irrigation and fertilization. | changing environmental conditions have the potential to alter allometric relationships between plant parts, possibly leading to ecosystem-level feedbacks. we quantified allometric shifts in field-grown loblolly pine (pinus taeda l.) in response to altered resource availability based on data from multiple harvests to correct for size-related changes in biomass partitioning. a replicated factorial arrangement of irrigation and fertilization treatments was applied for 4 years to an 8-year-old loblo ... | 1999 | 10562392 |
| effects of co2 enrichment on the photosynthetic light response of sun and shade leaves of canopy sweetgum (liquidambar styraciflua) in a forest ecosystem. | to investigate whether sun and shade leaves respond differently to co2 enrichment, we examined photosynthetic light response of sun and shade leaves in canopy sweetgum (liquidambar styraciflua l.) trees growing at ambient and elevated (ambient + 200 microliters per liter) atmospheric co2 in the brookhaven national laboratory/duke university free air co2 enrichment (face) experiment. the sweetgum trees were naturally established in a 15-year-old forest dominated by loblolly pine (pinus taeda l.). ... | 1999 | 10562393 |
| monoterpene synthases of loblolly pine (pinus taeda) produce pinene isomers and enantiomers. | the turpentine fraction of conifer oleoresin is a complex mixture of monoterpene olefins and plays important roles in defense and in the mediation of chemical communication between conifer hosts and insect predators. the stereochemistry of the turpentine monoterpenes is critical in these interactions, influencing host recognition, toxicity, and potency of derived pheromones, and the stereochemical composition of these compounds lends insight into their biogenetic origin, with implications for th ... | 1999 | 10562434 |
| use of haploid mixtures and heteroduplex analysis enhance polymorphisms revealed by denaturing gradient gel electrophoresis. | pcr-based codominant genetic markers were developed by using primer sequences designed from cdna clones of loblolly pine (pinus taeda l.). such markers offer certain advantages relative to simple-sequence repeat (ssr), also known as short-tandem repeat (str) markers, and include the ability to quantify and map dna polymorphisms in expressed genes. however, detecting these dna polymorphisms is more problematic because many dna polymorphisms in genes involve base substitutions rather than insertio ... | 2000 | 10649781 |
| purification and cloning of an arabinogalactan-protein from xylem of loblolly pine. | an arabinogalactan-protein (agp) was purified from differentiating xylem of loblolly pine (pinus taeda l.) and the n-terminal sequence used to identify a cdna clone. the protein, ptaagp3, was not coded for by any previously identified agp-like genes. moreover, ptaagp3 was abundantly and preferentially expressed in differentiating xylem. the encoded protein contains four domains, a signal peptide, a cleaved hydrophilic region, a region rich in serine, alanine, and proline/hydroxyproline, and a hy ... | 2000 | 10787065 |
| whole-genome characterization of embryonic stage inbreeding depression in a selfed loblolly pine family. | inbreeding depression is important in the evolution of plant populations and mating systems. previous studies have suggested that early-acting inbreeding depression in plants is primarily due to lethal alleles and possibly epistatic interactions. recent advances in molecular markers now make genetic mapping a powerful tool to study the genetic architecture of inbreeding depression. we describe a genome-wide evaluation of embryonic viability loci in a selfed family of loblolly pine (pinus taeda l ... | 2000 | 10790407 |
| effects of intensive forest management practices on insect infestation levels and loblolly pine growth. | intensive forest management practices have been shown to increase tree growth and shorten rotation time. however, they may also lead to an increased need for insect pest management because of higher infestation levels and lower action thresholds. to investigate the relationship between intensive management practices and insect infestation, maximum growth potential studies of loblolly pine, pinus taeda l., were conducted over 4 yr using a hierarchy of cultural treatments. the treatments were herb ... | 2000 | 10826182 |
| lignin structure in a mutant pine deficient in cinnamyl alcohol dehydrogenase. | cinnamyl alcohol dehydrogenase (cad) activity is deficient in loblolly pine (pinus taeda l.) harboring a mutated allele of the cad gene (cad-n1). we compared lignin structure of cad-deficient and wild-type pines, both types segregating within full-sib families obtained by controlled crosses. the type and frequency of lignin building units and distribution of interunit bonds were determined from the gc-ms analysis of thioacidolysis monomers and dimers. while the lignin content was only slightly r ... | 2000 | 10888545 |
| low-copy microsatellite markers for pinus taeda l. | eighteen low-copy and genomic microsatellite markers were tested for mendelian inheritance and then assayed in 41 pinus taeda l. samples drawn from five regions in the southern united states. the pcr products had multiple alleles, high levels of polymorphism, and little non-specific priming. fifteen of the 18 markers were informative for a p. taeda three-generation rflp (restriction fragment length polymorphism) pedigree, and a p. taeda population survey revealed three to 28 alleles per locus. t ... | 2000 | 10902720 |
| effect of different daytime and night-time temperature regimes on the foliar respiration of pinus taeda: predicting the effect of variable temperature on acclimation. | the objectives of this study were to determine the acclimation of loblolly pine (pinus taeda l.) foliar respiration to different night-time low temperatures, daytime high temperatures, and daily mean temperatures, and then to use the responses of temperature acclimation to various temperature regimes to predict acclimation under fluctuating temperatures. experiments were conducted on two-year-old seedlings in growth chambers using different combinations of day and night-time temperatures. the fi ... | 2000 | 11053463 |
| the influence of elevated carbon dioxide and water availability on herbaceous weed development and growth of transplanted loblolly pine (pinus taeda). | loblolly pine (pinus taeda l.) seedlings were grown in competition with native weeds using soil and seed bank collected from recently chopped and burned areas near appomattox, virginia. one-year-old seedlings were planted and weeds allowed to germinate from the native seed bank while being exposed to co(2) (ambient and elevated - approximately 700 ppm) and water (water stressed and well watered) treatments for approximately one growing season in a greenhouse. elevated co(2) did not influence tot ... | 2000 | 11064039 |
| evaluation of major genetic loci contributing to inbreeding depression for survival and early growth in a selfed family of pinus taeda. | the magnitude of fitness effects at genetic loci causing inbreeding depression at various life stages has been an important question in plant evolution. we used genetic mapping in a selfed family of loblolly pine (pinus taeda l.) to gain insights on inbreeding depression for early growth and viability. two quantitative trait loci (qtls) were identified that explain much of the phenotypic variation in height growth through age 3 and may account for more than 13% inbreeding depression in this fami ... | 2000 | 11108586 |
| response to auxin changes during maturation-related loss of adventitious rooting competence in loblolly pine (pinus taeda) stem cuttings. | hypocotyl cuttings (from 20- and 50-day-old pinus taeda l. seedlings) rooted readily within 30 days in response to exogenous auxin, while epicotyl cuttings (from 50-day-old seedlings) rarely formed roots within 60 days. responses to auxin during adventitious rooting included the induction of cell reorganization and cell division, followed by the organization of the root meristem. explants from the bases of both epicotyl and hypocotyl cuttings readily formed callus tissue in response to a variety ... | 2001 | 11240922 |
| deladenus siricidicola, bedding (neotylenchidae) parasitism evaluation in adult sirex noctilio, fabricius, 1793 (hymenoptera: siricidae). | this work aimed to evaluate the deladenus siricidicola, bedding (neotylenchidae) parasitism in adults sirex noctilio, fabricius, 1793 (hymenoptera: siricidae). timber was sampled by cutting out pieces of 0.80 m in length in sirex noctilio attacked and deladenus siricidicola inoculated pinus taeda. longs were 15-20 cm in diameter, according to the tree age. samples were packed in gauze-cages, for daily observations, till s. noctilio adults emergence. the emerged insects were transported, in plast ... | 2000 | 11241969 |
| production efficiency of loblolly pine and sweetgum in response to four years of intensive management. | we tested the hypothesis that productivity of intensively managed loblolly pine (pinus taeda l.) and sweetgum (liquidambar styraciflua l.) stands is dependent not only on leaf area, but also on foliar photosynthetic rate. effects of irrigation (irrigation treatment), irrigation with a fertilizer solution (fertigation treatment), and fertigation + pest control (loblolly pine only; fertigation + pest control treatment) on leaf physiology and growth were compared with control plots during the third ... | 2001 | 11282576 |
| rising co2 levels and the fecundity of forest trees. | we determined the reproductive response of 19-year-old loblolly pine (pinus taeda) to 4 years of carbon dioxide (co2) enrichment (ambient concentration plus 200 microliters per liter) in an intact forest. after 3 years of co2 fumigation, trees were twice as likely to be reproductively mature and produced three times as many cones and seeds as trees at ambient co2 concentration. a disproportionate carbon allocation to reproduction under co2 enrichment results in trees reaching maturity sooner and ... | 2001 | 11292871 |
| influence of elevated co2 and mycorrhizae on nitrogen acquisition: contrasting responses in pinus taeda and liquidambar styraciflua. | an understanding of root system capacity to acquire nitrogen (n) is critical in assessing the long-term growth impact of rising atmospheric co2 concentration ([co2]) on trees and forest ecosystems. we examined the effects of mycorrhizal inoculation and elevated [co2] on root ammonium (nh4+) and nitrate (no3-) uptake capacity in sweetgum (liquidambar styraciflua l.) and loblolly pine (pinus taeda l.). mycorrhizal treatments included inoculation of seedlings with the arbuscular mycorrhizal (am) fu ... | 2001 | 11303652 |
| oxidase activity in lignifying xylem of a taxonomically diverse range of trees: identification of a conifer laccase. | in a diverse taxonomic range of tree species, including representative species of ancient families of angiosperms (magnolia x soulangiana soul.-bod.) and gymnosperms (ginkgo biloba l.), oxidase activity was associated with cell walls of developing xylem and was enriched in extracts of cell wall-associated glycoproteins. in all species where oxidase activity was detected histochemically, it was expressed in cell walls of lignifying, differentiating xylem cells and was absent from old wood, cambiu ... | 2000 | 11305458 |
| limited carbon storage in soil and litter of experimental forest plots under increased atmospheric co2. | the current rise in atmospheric co2 concentration is thought to be mitigated in part by carbon sequestration within forest ecosystems, where carbon can be stored in vegetation or soils. the storage of carbon in soils is determined by the fraction that is sequestered in persistent organic materials, such as humus. in experimental forest plots of loblolly pine (pinus taeda) exposed to high co2 concentrations, nearly half of the carbon uptake is allocated to short-lived tissues, largely foliage. th ... | 2001 | 11373676 |
| atmospheric carbon dioxide, irrigation, and fertilization effects on phenolic and nitrogen concentrations in loblolly pine (pinus taeda) needles. | concentrations of total soluble phenolics, catechin, proanthocyanidins (pa), lignin and nitrogen (n) were measured in loblolly pine (pinus taeda l.) needles exposed to either ambient co(2) concentration ([co(2)]), ambient plus 175 or ambient plus 350 micromol co(2) mol(-1) in branch chambers for 2 years. the co(2) treatments were superimposed on a 2 x 2 factorial combination of irrigation and fertilization treatments. in addition, we compared the effects of branch chambers and open-top chambers ... | 2001 | 11390305 |
| families of clustered microsatellites in a conifer genome. | microsatellite clustering may account for genetic maps which do not coalesce into the expected number of linkage groups. microsatellite organization within the large genome of pinus taeda (1c = 20,000 mb) was determined by (1) testing whether repeat motifs were sequestered within the low-copy dna kinetic component and (2) testing for repeat motif clusters within dna fragments regardless of copy number. within the low-copy kinetic component, either (ac)n or (ag)n repeat units were present in 32% ... | 2001 | 11405637 |
| regulation of loblolly pine (pinus taeda l.) arginase in developing seedling tissue during germination and post-germinative growth. | after seed germination, hydrolysis of storage proteins provides a nitrogen source for the developing seedling. in conifers the majority of these reserves are located in the living haploid megagametophyte tissue. in the developing loblolly pine (pinus taeda l.) seedling an influx of free amino acids from the megagametophyte accompanies germination and early seedling growth. the major component of this amino acid pool is arginine, which is transported rapidly and efficiently to the seedling withou ... | 2001 | 11414614 |
| in situ hybridization and immunolocalization of lignan reductases in woody tissues: implications for heartwood formation and other forms of vascular tissue preservation. | vascular plants have evolved with remarkable ways to form and protect the vasculature apparatus. in certain woody shrubs, the secondary xylem can have within its center a hollowed pith surrounded by secondary xylem, whereas in most trees there is a solid core of heartwood. both types of woody systems have, however, the commonality of accumulating so-called 'secondary' metabolites, albeit to different extents, whose roles are to protect and preserve the vascular (lignified) tissues. this investig ... | 2001 | 11423140 |
| mean canopy stomatal conductance responses to water and nutrient availabilities in picea abies and pinus taeda. | we compared sap-flux-scaled, mean, canopy stomatal conductance (gs) between picea abies (l.) karst. in sweden and pinus taeda (l.) in north carolina, both growing on nutritionally poor soils. stomatal conductance of picea abies was approximately half that of pinus taeda and the sensitivity of gs in picea abies to vapor pressure deficit (d) was lower than in pinus taeda. optimal fertilization increased leaf area index (l) two- and threefold in pinus taeda and picea abies, respectively, regardless ... | 2001 | 11498331 |
| triplet-repeat microsatellites shared among hard and soft pines. | vascular plant species have shown a low level of microsatellite conservation compared to many animal species. finding trans-specific microsatellites for plants may be improved by using a priori knowledge of genome organization. fifteen triplet-repeat microsatellites from hard pine (pinus taeda l.) were tested for trans-specific amplification across seven hard pines (p. palustris mill., p. echinata mill., p. radiata d. don., p. patula schiede et deppe, p. halepensis mill., p. kesiya royle), a sof ... | 2001 | 11535645 |
| towards the specification of consecutive steps in macromolecular lignin assembly. | when pinus taeda cell suspension cultures are exposed to 8% sucrose solution, the cells undergo significant intracellular disruption, irregular wall thickening/lignification with concomitant formation of an 'extracellular lignin precipitate. however, addition of potassium iodide (ki), an h202 scavenger, inhibits this lignification response, while the ability to synthesize the monolignols, p-coumaryl and coniferyl alcohols, is retained. lignin synthesis (i.e. polymerization) is thus temporarily c ... | 1995 | 11536693 |
| thigmomorphogenesis: anatomical, morphological and mechanical analysis of genetically different sibs of pinus taeda in response to mechanical perturbation. | twenty-three open pollinated families (half-sibs) and four controlled pollinated families (full-sibs) of pinus taeda l. (loblolly pine) were grown in a greenhouse and analyzed for changes induced by mechanical perturbation (mp). these changes included inhibition of stem and needle elongation, bracing of branch nodes, and increased radial growth in the direction of the mp. inhibition of stem elongation was the least variable feature measured. leaf extension and stem diameter were highly variab ... | 1986 | 11538655 |
| thigmomorphogenesis: the role of ethylene in the response of pinus taeda and abies fraseri to mechanical perturbation. | ethylene production was monitored for 48 h in two half-sibs of pinus taeda l. grown in the greenhouse and given mechanical perturbation (mp) by flexing; and for 22 h in abies fraseri (pursh) poir. grown in the field and exposed to wind-mediated mp. both species produced a peak of ethylene 18 h after mp. seedlings of p. taeda exposed to mp for the duration of the growing season (preconditioned) produced less ethylene compared to non-mp controls, with a peak production at 8 h. one half-sib whic ... | 1986 | 11538656 |
| functional genomics and cell wall biosynthesis in loblolly pine. | loblolly pine (pinus taeda l.) is the most widely planted tree species in the usa and an important tree in commercial forestry world-wide. the large genome size and long generation time of this species present obstacles to both breeding and molecular genetic analysis. gene discovery by partial dna sequence determination of cdna clones is an effective means of building a knowledge base for molecular investigations of mechanisms governing aspects of pine growth and development, including the comme ... | 2001 | 11554476 |
| stem growth and respiration in loblolly pine plantations differing in soil resource availability. | stem respiration and growth in 10-year-old loblolly pine (pinus taeda l.) plantations were measured monthly during the third year of fertilization and irrigation treatments to determine whether soil resource availability differentially altered growth and respiration in stem tissue. fertilized trees had significantly greater stem biomass, stem nitrogen concentration ([n]) and growth rate than unfertilized trees. stem respiration (rt) was significantly greater in fertilized trees when expressed on ... | 2001 | 11600340 |
| anchored reference loci in loblolly pine (pinus taeda l.) for integrating pine genomics. | anchored reference loci provide a framework for comparative mapping. they are landmarks to denote conserved chromosomal segments, allowing the synthesis of genetic maps from multiple sources. we evaluated 90 expressed sequence tag polymorphisms (estps) from loblolly pine (pinus taeda l.) for this function. primer sets were assayed for amplification and polymorphism in six pedigrees, representing two subgenera of pinus and a distant member of the pinaceae, douglas-fir (pseudotsuga menziesii [mirb ... | 2001 | 11606554 |
| wood contains a cell-wall structural protein. | a pine extensin-like protein (pelp) has been localized in metabolically active cells of differentiating xylem and in mature wood of loblolly pine (pinus taeda l.). this proline-rich glycosylated protein was purified from cell walls of differentiating xylem by differential solubility and gel electrophoresis. polyclonal rabbit antibodies were raised against the deglycosylated purified protein (dpelp) and purified antibody was used for immunolocalization. immunogold and alkaline phosphatase seconda ... | 1992 | 11607306 |
| agrobacterium-mediated transformation and assessment of factors influencing transgene expression in loblolly pine (pinus taeda l.). | this investigation reports a protocol for transfer and expression of foreign chimeric genes in loblolly pine (pinus taeda l.). transformation was achieved by co-cultivation of mature zygotic embryos with agrobacterium tumefaciens strain lba4404 which harbored a binary vector (pbi121) including genes for beta-glucuronidase (gus) and neomycin phosphotransferase (nptii). factors influencing transgene expression including seed sources of loblolly pine, concentration of bacteria, and the wounding pro ... | 2001 | 11642410 |
| regeneration of transgenic loblolly pine (pinus taeda l.) from zygotic embryos transformed with agrobacterium tumefaciens. | embryos of 24 open-pollinated families of loblolly pine (pinus teade l.) were used as explants to conduct in vitro regeneration. then, agrobacterium tumefaciens strain gv3101 harboring the plasmid ppcv6nfhyggusint was used to transform mature zygotic embryos of seven families of loblolly pine. the frequency of transformation varied among families infected with a. tumefaciens. the highest frequency (100%) of transient beta-glucuronidase (gus)-expressing embryos was obtained from family 11-1029 wi ... | 2001 | 11722135 |
| a chromosomal region promoting outcrossing in a conifer. | prefertilization mechanisms influencing selfing rates are thought to be absent in conifers. outcrossing in conifers is promoted via an embryo-lethal system, but the genetic mechanism is poorly understood. this study is the first experimental profile of the genetic mechanism promoting outcrossing in conifers. molecular dissection of a pinus taeda l. selfed pedigree detected a chromosomal region identified as pttx3020-rptest9. within this region, a semilethal factor was tightly linked (r = 0.0076) ... | 2001 | 11729169 |
| an aquaglyceroporin is abundantly expressed early in the development of the suspensor and the embryo proper of loblolly pine. | in contrast to angiosperms, pines and other gymnosperms form well-developed suspensors in somatic embryogenic cultures. this creates a useful system to study suspensor biology. in a study of gene expression during the early stages of conifer embryogenesis, we identified a transcript, ptnip1;1, that is abundant in immature loblolly pine (pinus taeda) zygotic and somatic embryos, but is undetectable in later-stage embryos, megagametophytes, and roots, stems, and needles from 1 year-old seedlings. ... | 2001 | 11743100 |
| [causal factors of decline disease in exotic pine (pinus taeda and p. elliottii) plantations]. | investigation on the cause of the decline of exotic pine plantations in anhui province was carried out from 1995 to 2000. the results showed that the cause might develop from the interaction of three or more sets of factors. the first group of factors called as predisposing factors were high and low temperature and rainfall, poor soil fertility, and excessive soil bulk density, soil moisture, and of stand density; the second group of factors called as inciting factors were insect defoliators, da ... | 2001 | 11758405 |
| [relationship between decline disease of exotic pines(pinus taeda and p. eliottii) and forest stand and environmental factors]. | the relationship between decline disease of exotic pines(pinus taeda and p. eliottii) plantations in anhui province and forest stand status and environmental factors was quantitatively analyzed. among 18 variable factors from 4 types of factors(climate, soil, stand status, and other diseases and insect pests), 10 factors contributed greatly to the state of illness. these were tree age, stand density, resin-tapping, rainfall, temperature, clay soil, stone soil, soil depth, water-logging, and othe ... | 2001 | 11758406 |
| ozone impacts on loblolly pine (pinus taeda l.) grown in a competitive environment. | one-year old, bare-root, loblolly pine (pinus taeda l.) seedlings grown in an early successional plant community, were exposed to four ozone treatments, 12 h day(-1) (09:00-21:59 h cst), 7 day week(-1) in east-central alabama for 2 years (1994-1995). treatments included aa=ambient air (open plot; no chamber), cf = carbon-filtered air (approximately 0.5xaa), 1x = non-filtered air, and 2x = twice ambient (aa) air. pine height and diameter were measured monthly for 2 years and total above-ground bi ... | 2002 | 11808552 |
| direct fluorescent primers are superior to m13-tailed primers for pinus taeda microsatellites. | | 2002 | 11808697 |
| development of a protocol for monitoring status and trends in forest soil carbon at a national level. | the national forest health monitoring (fhm) program requires protocols for monitoring soil carbon contents. in a pilot study, 30 fhm plots loblolly shortleaf (pinus taeda l./pinus echinata mill.) pine forests across georgia were sampled by horizon and by depth increments. for total soil carbon, approximately 40% of the variance was between plots, 40% between subplots and 20% within subplots. results by depth differed from those obtained by horizon primarily due to the rapid changes in carbon con ... | 2002 | 11833908 |
| influence of seedling roots, environmental factors and soil characteristics on soil co2 efflux rates in a 2-year-old loblolly pine (pinus taeda l.) plantation in the virginia piedmont. | to understand the role of managed forests in carbon sequestration an understanding of factors controlling soil co2 efflux will be necessary. this study examined the influence of seedling roots, environmental factors, nutrient availability, and soil characteristics on soil co2 efflux patterns in a 2-year-old pine plantation in the virginia piedmont. efflux rates were measured both near the base of seedlings and midway between rows in plots that had received fertilization and mulch treatments in a ... | 2002 | 11833922 |
| effects of forest management on soil carbon: results of some long-term resampling studies. | the effects of harvest intensity (sawlog, saw; whole tree, wth; and complete tree, cth) on biomass and soil c were studied in four forested sites in the southeastern us (mixed deciduous forests at oak ridge, tn and coweeta, nc; pinus taeda at clemson, sc: and p. eliottii at bradford, fl). in general, harvesting had no lasting effects on soil c. however, intensive temporal sampling at the nc and sc sites revealed short-term changes in soil c during the first few years after harvesting, and large, ... | 2002 | 11837236 |
| differential substrate inhibition couples kinetically distinct 4-coumarate:coenzyme a ligases with spatially distinct metabolic roles in quaking aspen. | 4-coumarate:coenzyme a ligase (4cl) activates hydroxycinnamates for entry into phenylpropanoid branchways that support various metabolic activities, including lignification and flavonoid biosynthesis. however, it is not clear whether and how 4cl proteins with their broad substrate specificities fulfill the specific hydroxycinnamate requirements of the branchways they supply. two tissue-specific 4cls, pt4cl1 and pt4cl2, have previously been cloned from quaking aspen (populus tremuloides michx.), ... | 2002 | 11842147 |
| induced phenylpropanoid metabolism during suberization and lignification: a comparative analysis. | induction of the biosynthesis of phenylpropanoids was monitored at the enzyme level through measurement of the temporal change in the activity of two marker enzymes of phenylpropanoid metabolism, phenylalanine ammonia-lyase, (pal, e.c. 4.1.3.5) and 4-coumaryl-coa ligase (4-cl, e.c. 6.2.1.12) and two marker enzymes for hydroxycinnamyl alcohol biosynthesis, cinnamoyl-coa:nadp+ oxidoreductase (ccr, e.c. 1.2.1.44) and cinnamyl alcohol dehydrogenase (cad, e.c. 1.1.1.195) in both suberizing potato (so ... | 2000 | 11858251 |
| transcriptional control of monolignol biosynthesis in pinus taeda: factors affecting monolignol ratios and carbon allocation in phenylpropanoid metabolism. | transcriptional profiling of the phenylpropanoid pathway in pinus taeda cell suspension cultures was carried out using quantitative real time pcr analyses of all known genes involved in the biosynthesis of the two monolignols, p-coumaryl and coniferyl alcohols (lignin/lignan precursors). when the cells were transferred to a medium containing 8% sucrose and 20 mm potassium iodide, the monolignol/phenylpropanoid pathway was induced, and transcript levels for phenylalanine ammonia lyase, cinnamate ... | 2002 | 11891223 |
| plant expansins are a complex multigene family with an ancient evolutionary origin. | expansins are a group of extracellular proteins that directly modify the mechanical properties of plant cell walls, leading to turgor-driven cell extension. within the completely sequenced arabidopsis genome, we identified 38 expansin sequences that fall into three discrete subfamilies. based on phylogenetic analysis and shared intron patterns, we propose a new, systematic nomenclature of arabidopsis expansins. further phylogenetic analysis, including expansin sequences found here in monocots, p ... | 2002 | 11891242 |
| undermethylated dna as a source of microsatellites from a conifer genome. | developing microsatellites from the large, highly duplicated conifer genome requires special tools. to improve the efficiency of developing pinus taeda l. microsatellites, undermethylated (um) dna fragments were used to construct a microsatellite-enriched copy library. a methylation-sensitive restriction enzyme, mcrbc, was used to enrich for um dna before library construction. digested dna fragments larger than 9 kb were then excised and digested with rsai and used to construct nine dinucleotide ... | 2002 | 11908673 |
| sage profiling and demonstration of differential gene expression along the axial developmental gradient of lignifying xylem in loblolly pine (pinus taeda). | wood formation has been studied extensively at the cellular and biochemical levels, but remains poorly understood with respect to gene expression and regulation. as a first step toward identifying genes specifically involved in wood formation and characterizing their roles in determining wood quality, serial analysis of gene expression (sage) was used to quantify gene expression in lignifying xylem from a single, 10-year-old loblolly pine (pinus taeda l.). two sage libraries were generated based ... | 2002 | 11960754 |
| diurnal changes in gas exchange and carbon partitioning in needles of fast- and slow-growing families of loblolly pine (pinus taeda). | we investigated diurnal and seasonal changes in carbon acquisition and partitioning of recently assimilated carbon in fast- and slow-growing families of loblolly pine (pinus taeda l.) to determine whether fast-growing families exhibited greater carbon gain at the leaf level. since planting on a xeric infertile site in scotland county, nc, usa in 1993, five atlantic coastal plain (acp) and five "lost pines" texas (tx) families have been grown with either optimal nutrition or without fertilization ... | 2002 | 11986052 |
| the role of the megagametophyte in maintaining loblolly pine (pinus taeda l.) seedling arginase gene expression in vitro. | following loblolly pine (pinus taeda l.) seed germination, storage-protein breakdown in the megagametophyte and in the seedling results in a large increase in the seedling's free amino acid pool. a substantial portion of both the storage proteins and the amino acid pool is arginine, a very efficient nitrogen-storage compound. free arginine is hydrolyzed in the seedling by the enzyme arginase (ec 3.5.3.1), which is under strong developmental control. at present, regulation of arginase in conifers ... | 2002 | 12012247 |
| effects of phenology, water availability and seed source on loblolly pine biomass partitioning and transpiration. | one-year-old loblolly pine (pinus taeda l.) seedlings from four seed sources (arkansas, georgia, texas and virginia) grown in 1-m-deep sand-filled pits in two water regimes (well-watered and drought) were studied, to gain insight into the process of seedling establishment. whole-plant transpiration was measured biweekly from july to december. whole-plant harvests were conducted at 6-week intervals from april to december. whole-plant transpiration and transpiration per unit leaf and root area wer ... | 2002 | 12091155 |
| amino acid utilization in seeds of loblolly pine during germination and early seedling growth (i. arginine and arginase activity). | the mobilization and utilization of the major storage proteins in loblolly pine (pinus taeda l.) seeds following imbibition were investigated. most of the seed protein reserves were contained within the megagametophyte. breakdown of these proteins occurred primarily following radicle emergence and correlated with a substantial increase in the free amino acid pool in the seedling; the majority of this increase appeared to be the result of export from the megagametophyte. the megagametophyte was a ... | 1997 | 12223664 |
| purification and characterization of catalase from loblolly pine (pinus taeda l.) megagametophytes. | catalase (ec 1.11.1.6) was purified to near homogeneity from isolated megagametophytes of germinated loblolly pine (pinus taeda l.) seeds, and monospecific antibodies were elicited in rabbits. following a procedure that involved acetone extraction, (nh4)2so4 fractionation, and four chromatographic steps (i.e. de-52 cellulose, superdex-200, hydroxylapatite, and phenyl-sepharose cl-4b), catalase was purified about 140-fold to a final specific activity of 2215 mmol min-1 mg-1 of protein. cotton iso ... | 1993 | 12231955 |
| construction of an aflp genetic map with nearly complete genome coverage in pinus taeda. | de novo construction of complete genetic linkage maps requires large mapping populations, large numbers of genetic markers, and efficient algorithms for ordering markers and evaluating order confidence. we constructed a complete genetic map of an individual loblolly pine (pinus taeda l.) using amplified fragment length polymorphism (aflp) markers segregating in haploid megagametophytes and pgri mapping software. we generated 521 polymorphic fragments from 21 aflp primer pairs. a total of 508 fra ... | 1999 | 12238515 |
| radiation-use efficiency of a forest exposed to elevated concentrations of atmospheric carbon dioxide. | we compared radiation-use efficiency of growth (epsilon;), defined as rate of biomass accumulation per unit of absorbed photosynthetically active radiation, of forest plots exposed to ambient (approximately 360 micro l l-1) or elevated (approximately 560 micro l l-1) atmospheric co2 concentration ([co2]). large plots (30-m diameter) in a loblolly pine (pinus taeda l.) plantation, which contained several hardwood species in the understory, were fumigated with a free-air co2 enrichment system. bio ... | 2002 | 12359527 |
| a survival model for unthinned loblolly pine plantations that incorporates non-planted tree competition, site quality, and incidence of fusiform rust. | future biomass yields are functionally related to the number of trees surviving at a given age. a stand level survival model was developed that incorporates competition of non-planted trees, site quality, and the incidence of fusiform rust (cronartium quercuum [berk.] miyabe ex shirai f. sp. fusiforme). the model consists of a system of two equations, one of which represents the number of surviving trees infected by fusiform rust while the other represents the number of trees not infected by fus ... | 2002 | 12365498 |
| branch growth and gas exchange in 13-year-old loblolly pine (pinus taeda) trees in response to elevated carbon dioxide concentration and fertilization. | we used whole-tree, open-top chambers to expose 13-year-old loblolly pine (pinus taeda l.) trees, growing in soil with high or low nutrient availability, to either ambient or elevated (ambient + 200 micromol mol-1) carbon dioxide concentration ([co2]) for 28 months. branch growth and morphology, foliar chemistry and gas exchange characteristics were measured periodically in the upper, middle and lower crown during the 2 years of exposure. fertilization and elevated [co2] increased branch leaf ar ... | 2002 | 12414369 |
| physical-mechanical properties and chemical composition of pinus taeda mature wood following a forest fire. | the objective of this study was to assess the effects of heat released during forest fires on wood properties of pinus taeda l. trees submitted to different burning levels (increasing fire intensity, i-iv). wood samples were collected from trees in each of the burning levels and also from trees not affected by fire (control). specimens were then extracted to evaluate the physical and mechanical wood properties; chemical composition was evaluated only for burning level iv and control. the analysi ... | 2003 | 12507861 |
| the effects of polyethylene glycol on gene expression of developing white spruce somatic embryos. | somatic embryogenic cultures of white spruce (picea glauca) represent a valuable system to study molecular mechanisms regulating embryo development because many embryos of defined developmental stages can be generated. the inclusion of polyethylene glycol (peg) in the maturation medium can improve the number and quality of embryos produced. to learn more about the mechanism of action of peg, we analyzed transcript profiles of stage-specific embryos matured without (control) or with (peg treated) ... | 2003 | 12529514 |
| identification and characterization of water-stress-responsive genes in hydroponically grown maritime pine (pinus pinaster) seedlings. | growth, development and productivity of long-lived organisms such as forest trees are continuously challenged by abiotic stresses, and may also be greatly affected by predicted climatic change. as a first step toward creating stress-resistant maritime pine (pinus pinaster ait.) varieties by marker-assisted breeding, we describe the identification and characterization of water-stress-responsive genes in hydroponically grown seedlings that were well watered (-0.08 mpa) or subjected to water depriv ... | 2003 | 12566267 |
| genetic analysis of growth curves for a woody perennial species, pinus taeda l. | inheritance of growth curves is critical for understanding evolutionary change and formulating efficient breeding plans, yet has received limited attention. growth curves, like other characters that change in concert with development, often have higher heritability than age-specific traits. this study compared genetic parameters of height-growth curves with those of age-specific heights for a conifer, pinus taeda l. growth curves were fitted with: (1) a linear regression model, and (2) a non-lin ... | 2002 | 12582501 |
| paternal chloroplast inheritance patterns in pine hybrids detected with trnl-trnf intergenic region polymorphism. | the inheritance patterns of the chloroplast genomes of shortleaf pine ( pinus echinata mill.), loblolly pine ( pinus taeda l.) and slash pine ( pinus elliottii engelm.) were investigated through the trnl-trnf intergenic spacer polymorphism analysis. the dna sequences of this spacer differ among these three closely related pinus species. a modified 'cold' pcr-sscp (single-strand conformation polymorphism) analysis of this spacer shows that the artificial hybrids (f1) from the shortleaf pine (seed ... | 2002 | 12582585 |
| identification of qtls influencing wood property traits in loblolly pine ( pinus taeda l.). ii. chemical wood properties. | chemical wood property traits were analyzed for the presence of quantitative trait loci (qtls) in a three-generation outbred pedigree of loblolly pine ( pinus taeda l.). these traits were assayed using pyrolysis molecular beam mass spectrometry and include mass spectrum peak intensities associated with carbohydrates, alpha-cellulose and hemicellulose sugars, and lignin. models for projection to latent structures (pls) were used to also estimate the chemical composition of cell walls (i.e., alpha ... | 2002 | 12582689 |
| cdna isolation, functional expression, and characterization of (+)-alpha-pinene synthase and (-)-alpha-pinene synthase from loblolly pine (pinus taeda): stereocontrol in pinene biosynthesis. | the complex mixture of monoterpenes, sesquiterpenes, and diterpenes that comprises oleoresin provides the primary defense of conifers against bark beetles and their associated fungal pathogens. monoterpene synthases produce the turpentine fraction of oleoresin, which allows mobilization of the diterpene resin acid component (rosin) and is also toxic toward invading insects; this is particularly the case for alpha-pinene, a prominent bicyclic monoterpene of pine turpentine. the stereochemistry of ... | 2003 | 12623076 |
| nutritional ecology of the formosan subterranean termite (isoptera: rhinotermitidae): growth and survival of incipient colonies feeding on preferred wood species. | the wood of 11 plant species was evaluated as a food source significantly impacting the growth and survival of incipient colonies of the formosan subterranean termite, coptotermes formosanus shiraki (isoptera: rhinotermitidae). colonies of c. formosanus feeding on pecan, carya illinoensis (wangenh.), and red gum, liquidambar styraciflua l., produced significantly more progeny than colonies feeding on other wood species tested. progeny of colonies feeding on pecan and american ash, fraxinus ameri ... | 2003 | 12650352 |
| effects of temperature and tissue nitrogen on dormant season stem and branch maintenance respiration in a young loblolly pine (pinus taeda) plantation. | we measured dormant season (november through february) maintenance respiration rates (r(m)) in stems and branches of 9-year-old loblolly pine (pinus taeda l.) growing in plots under conditions of controlled nutrient and water supply in an effort to determine the relationships between r(m) and tissue size (surface area, sapwood volume, sapwood dry weight), tissue nitrogen content and temperature. dormant season r(m) per unit size (i.e., surface area, &mgr;mol m(-2) s(-1); sapwood volume, &mgr;mol ... | 1998 | 12651294 |
| influence of rate of change in stomatal conductance to fluctuating irradiance on estimates of daily water use by pinus taeda leaves. | pinus taeda l. stomata respond slowly to changes in irradiance. because incident irradiance on a leaf varies constantly, the rate of change in stomatal conductance to fluctuating irradiance may have a large effect on plant water use. we estimated total daily water use of pinus taeda foliage for 10 days with very different irradiance patterns, assuming that rates of stomatal opening and closing were similar. to determine how the most extreme imbalance in rates of stomatal opening and closing affe ... | 1999 | 12651316 |
| mineral nutrition, resin flow and phloem phytochemistry in loblolly pine. | southern pine beetles and associated pathogenic fungi represent the largest biotic threat to pine forests in the southeastern usa. the two primary defensive mechanisms of the tree to the beetle-fungal complex are the primary oleoresin flow and the concentrations of preformed and induced secondary compounds. we compared oleoresin flow and concentrations of phloem nutrients, soluble sugars, starch, total phenolics and proanthocyanidins in pinus taeda l. trees in fertilized and control plots in the ... | 1999 | 12651321 |
| analyses of assumptions and errors in the calculation of stomatal conductance from sap flux measurements. | we analyzed assumptions and measurement errors in estimating canopy transpiration (e(l)) from sap flux (j(s)) measured with granier-type sensors, and in calculating canopy stomatal conductance (g(s)) from e(l) and vapor pressure deficit (d). the study was performed in 12-year-old pinus taeda l. stands with a wide range in leaf area index (l) and growth rate. no systematic differences in j(s) were found between the north and south sides of trees. however, j(s) in xylem between 20 and 40 mm from t ... | 2000 | 12651422 |
| seasonal co(2) assimilation and stomatal limitations in a pinus taeda canopy. | net co(2) assimilation (a(net)) of canopy leaves is the principal process governing carbon storage from the atmosphere in forests, but it has rarely been measured over multiple seasons and multiple years. i measured midday a(net) in the upper canopy of maturing loblolly pine (pinus taeda l.) trees in the piedmont region of the southeastern usa on 146 sunny days over 36 months. concurrent data for leaf conductance and photosynthetic co(2) response curves (a(net)-c(i) curves) were used to estimate ... | 2000 | 12651439 |
| differential expression of genes encoding cell wall proteins in vascular tissues from vertical and bent loblolly pine trees. | differential expression of cell wall proteins during plant development and in response to biotic or abiotic stress suggests that these proteins may contribute in different ways to plant cell wall architecture. because the wood of loblolly pine (pinus taeda l.) is highly specialized in the formation of secondary cell walls, it is an ideal tissue for studying these proteins. the cdnas coding for six novel cell wall associated proteins, as well as a homologue for a phytocyanin, were identified and ... | 2000 | 12651441 |
| diurnal changes in water conduction in loblolly pine (pinus taeda) and virginia pine (p. virginiana) during soil dehydration. | we studied diurnal changes in water conduction during soil dehydration in 37-month-old seedlings of one virginia pine (pinus virginiana mill.) and two loblolly pine (p. taeda l.) sources, one from north carolina (nc) and the other from the "lost pines" areas of texas (tx), in an environmentally controlled growth chamber. for seedlings of similar biomass, the tx source had higher values of transpiration, needle conductance, and plant hydraulic conductivity under well-watered conditions than the n ... | 1999 | 12651531 |
| acclimation of loblolly pine (pinus taeda) seedlings to high temperatures. | to determine the extent to which loblolly pine seedlings (pinus taeda l.) acclimate to high temperatures, seedlings from three provenances-southeastern texas (mean annual temperature 20.3 degrees c), southwestern arkansas (mean annual temperature 16.2 degrees c) and chesapeake, maryland (mean annual temperature 12.8 degrees c)-were grown at constant temperatures of 25, 30, 35 or 40 degrees c in growth chambers. after two months, only 14% of the seedlings in the 40 degrees c treatment survived, s ... | 1999 | 12651542 |
| photosynthetic responses of loblolly pine (pinus taeda) needles to experimental reduction in sink demand. | sink strength in loblolly pine (pinus taeda l.) was experimentally manipulated on two sun-exposed branches on each of two neighboring trees by excising the emerging terminal cohort (second flush of 1996) during a period of rapid needle expansion. in addition, export of photosynthate was restricted on one of these branches from each tree by removal of bark and phloem just below the second flush of 1995. treatment-induced changes in needle biochemistry were measured in 3-month-old (first flush of ... | 1999 | 12651566 |
| simulated nitrogen cycling response to elevated co(2) in pinus taeda and mixed deciduous forests. | interactions between elevated co(2) and n cycling were explored with a nutrient cycling model (nucm, johnson et al. 1993, 1995) for a pinus taeda l. site at duke university, north carolina, and a mixed deciduous site at walker branch, tennessee. the simulations tested whether n limitation would prevent growth increases in response to elevated co(2), and whether growth responses to co(2) in n-limited systems could be facilitated by increasing the biomass/n ratio (reducing n concentration) or incr ... | 1999 | 12651575 |
| thinning, fertilization, and crown position interact to control physiological responses of loblolly pine. | to examine physiological responses to thinning, fertilization, and crown position, we measured net photosynthesis (p(n)), transpiration (e), vapor pressure difference (vpd), stomatal conductance (g(s)), and xylem pressure potential (psi(1)) between 0930 and 1130 h under ambient conditions in the upper and lower crowns of a 13-year-old loblolly pine (pinus taeda l.) plantation six years (1994) after the treatments were applied. photosynthetic photon flux density (ppfd) and air temperature (t(a)) ... | 1999 | 12651587 |
| loblolly pine arginase responds to arginine in vitro. | following germination of loblolly pine (pinus taeda l.) seeds, storage proteins in the embryo and megagametophyte are broken down to provide nitrogen, in the form of amino acids, to the developing seedling. a substantial portion of the free amino acids released in this process is arginine. arginine is hydrolyzed in the cotyledons of the seedling by the enzyme arginase (ec 3.5.3.1), which is under developmental control. it has been shown previously that the seedling is able to initiate arginase g ... | 2003 | 12684785 |
| regional assessment of ozone sensitive tree species using bioindicator plants. | tropospheric ozone occurs at phytotoxic levels in the northeastern and mid-atlantic regions of the united states. quantifying possible regional-scale impacts of ambient ozone on forest tree species is difficult and is confounded by other factors, such as moisture and light, which influence the uptake of ozone by plants. biomonitoring provides an approach to document direct foliar injury irrespective of direct measure of ozone uptake. we used bioindicator and field plot data from the usda forest ... | 2003 | 12691526 |
| haplotypic qtl mapping in an outbred pedigree. | an offspring genome can be viewed as a mosaic of chromosomal segments or haplotypes contributed by multiple founders in any quantitative trait locus (qtl) detection study but tracing these is especially complex to achieve for outbred pedigrees. qtl haplotypes can be traced from offspring back to individual founders in outbred pedigrees by combining founder-origin probabilities with fully informative flanking markers. this haplotypic method was illustrated for qtl detection using a three-generati ... | 2003 | 12693682 |
| apparent homology of expressed genes from wood-forming tissues of loblolly pine (pinus taeda l.) with arabidopsis thaliana. | pinus taeda l. (loblolly pine) and arabidopsis thaliana differ greatly in form, ecological niche, evolutionary history, and genome size. arabidopsis is a small, herbaceous, annual dicotyledon, whereas pines are large, long-lived, coniferous forest trees. such diverse plants might be expected to differ in a large number of functional genes. we have obtained and analyzed 59,797 expressed sequence tags (ests) from wood-forming tissues of loblolly pine and compared them to the gene sequences inferre ... | 2003 | 12771380 |