| correlation between the individual heterozygosity of parents and their offspring. | specific formulations are derived for the correlation between the heterozygosity of a randomly mating parent and its offspring for a diallelic locus, and for the correlation when multiple loci are considered. the expected correlation is maximal, approaching r = 0.50, when allelic frequencies are highly asymmetric, and it is zero when the allelic frequencies are equal to 0.50. parent-offspring correlations, up to a maximum of 0.50 for diallelic loci, indicate that levels of heterozygosity can res ... | 1993 | 8360078 |
| a comparison of population differentiation across four classes of gene marker in limber pine (pinus flexilis james). | we examined genetic differentiation among seven populations of limber pine using four classes of gene marker. among-population differentiation was much higher for maternally inherited mitochondrial dna polymorphisms than for paternally inherited chloroplast dna, indicating that wind-dispersed pollen is the main agent of gene flow. chloroplast dna differentiation is consistent with gene flow estimated in a prior paternity analysis. using the estimates of seed and pollen flow derived from mtdna an ... | 1997 | 9215916 |
| isolation and structure elucidation of new pkcalpha inhibitors from pinus flexilis. | bioassay-guided fractionation of the ch2cl2-meoh extract of pinus flexilis using an assay for protein kinase c (pkc) inhibitory activity led to the isolation of the two new bioactive diarylheptanoids (3r)-1,7-bis(3, 4-dihydroxyphenyl)-3-(beta-d-glucopyranosyl)heptan-3-ol (1) and its aglycon (3r)-1,7-bis(3,4-dihydroxyphenyl)heptan-3-ol (2), together with the three known bioactive compounds, hirsutenone (3), oregonin (4), and hirsutanonol (5). the ic50 values of compounds 1-5 in the pkc assay were ... | 1998 | 9834165 |
| glacial refugia of limber pine (pinus flexilis james) inferred from the population structure of mitochondrial dna. | to make inferences about the glacial refugia that harboured the limber pine, pinus flexilis james, we examined the range-wide population structure of mitochondrial dna (mtdna) with eight size variants in the second intron of nad1. the data consisted of haplotypes from 704 trees collected from 40 localities. the value of fst for these populations was 0.80, which is a much larger value than has been reported for allozymes and chloroplast dna (cpdna) in limber pine, and it suggests that the number ... | 2000 | 10652078 |
| paternity and gene dispersal in limber pine (pinus flexilis james). | this study provides empirical information on intrapopulation gene dispersal via pollen, the size of genetic 'neighbourhoods', and interpopulation gene flow in a long-lived conifer, limber pine (pinus flexilis). we used allozyme loci for a paternity analysis of 518 seeds produced in an isolated population of limber pine located in north-eastern colorado, u.s.a., separated by 2 km from the nearest conspecific trees and nearly 100 km from populations in the rocky mountains. we also used indirect te ... | 2000 | 10762405 |
| morphological variation of pinus flexilis (pinaceae), a bird-dispersed pine, across a range of elevations. | limber pine (pinus flexilis james) grows across a wider range of elevations than any other tree species in the central rockies, from approximately 1600 m at pawnee buttes to >3300 m at rollins pass. in this study we investigated two possible explanations for limber pine's success across a broad range of elevations: (1) the sites on which it is found, although separated by >1000 m elevation, may not be very different with respect to environmental factors that affect tree growth, and (2) limber pi ... | 2000 | 11118417 |
| changes in whole-tree water relations during ontogeny of pinus flexilis and pinus ponderosa in a high-elevation meadow. | we measured sap flux in pinus ponderosa laws. and pinus flexilis james trees in a high-elevation meadow in northern arizona that has been invaded by conifers over the last 150 years. sap flux and environmental data were collected from july 1 to september 1, 2000, and used to estimate leaf specific transpiration rate (el), canopy conductance (gc) and whole-plant hydraulic conductance (kh). leaf area to sapwood area ratio (la/sa) increased with increasing tree size in p. flexilis, but decreased wi ... | 2002 | 12091149 |
| facilitation by pinus flexilis during succession: a hierarchy of mechanisms benefits other plant species. | studies of facilitation have primarily been limited to single mechanisms, species, or environments. we examined interacting mechanisms governing the facilitative effects of pinus flexilis on two later successional understory species, pseudotsuga menziesii and ribes cereum, in different microhabitats and seasons at the ecotone between the rocky mountain forests and great plains grasslands in montana, usa. in field surveys, 69% of pseudotsuga and 91% of ribes were located beneath p. flexilis even ... | 2006 | 16922330 |
| stable isotopes, ecological integration and environmental change: wolves record atmospheric carbon isotope trend better than tree rings. | large-scale patterns of isotope ratios are detectable in the tissues of organisms, but the variability in these patterns often obscures detection of environmental trends. we show that plants and animals at lower trophic levels are relatively poor indicators of the temporal trend in atmospheric carbon isotope ratios (delta13c) when compared with animals at higher trophic levels. first, we tested how differences in atmospheric delta13c values were transferred across three trophic levels. second, w ... | 2007 | 17686730 |
| trends in stomatal density and 13c/12c ratios of pinus flexilis needles during last glacial-interglacial cycle. | measurements of stomatal density and delta(13)c of limber pine (pinus flexilis) needles (leaves) preserved in pack rat middens from the great basin reveal shifts in plant physiology and leaf morphology during the last 30,000 years. sites were selected so as to offset glacial to holocene climatic differences and thus to isolate the effects of changing atmospheric co(2) levels. stomatal density decreased approximately 17 percent and delta(13)c decreased approximately 1.5 per mil during deglaciatio ... | 1994 | 17749021 |
| a seed predator drives the evolution of a seed dispersal mutualism. | although antagonists are hypothesized to impede the evolution of mutualisms, they may simultaneously exert selection favouring the evolution of alternative mutualistic interactions. we found that increases in limber pine (pinus flexilis) seed defences arising from selection exerted by a pre-dispersal seed predator (red squirrel tamiasciurus hudsonicus) reduced the efficacy of limber pine's primary seed disperser (clark's nutcracker nucifraga columbiana) while enhancing seed dispersal by ground-f ... | 2008 | 18460433 |
| seed predation and selection exerted by a seed predator influence subalpine tree densities. | strongly interacting species often have pronounced direct and indirect effects on other species. here we focus of the effects of pine squirrels (tamiasciurus spp.), which are a dominant pre-dispersal seed predator of many conifers including limber pines (pinus flexilis) and whitebark pines (p. albicaulis). pine squirrels depress seed abundance by harvesting most limber and whitebark pine cones on their territories. pine squirrels further reduce seed availability for clark's nutcrackers (nucifrag ... | 2008 | 18959333 |
| conflicting selection from an antagonist and a mutualist enhances phenotypic variation in a plant. | the raw material for evolution is variation. consequently, identifying the factors that generate, maintain, and erode phenotypic and genetic variation in ecologically important traits within and among populations is important. although persistent directional or stabilizing selection can deplete variation, spatial variation in conflicting directional selection can enhance variation. here, we present evidence that phenotypic variation in limber pine (pinus flexilis) cone structure is enhanced by c ... | 2010 | 19817846 |
| ecophysiological variation in two provenances of pinus flexilis seedlings across an elevation gradient from forest to alpine. | climate change is predicted to cause upward shifts in forest tree distributions, which will require seedling recruitment beyond current forest boundaries. however, predicting the likelihood of successful plant establishment beyond current species' ranges under changing climate is complicated by the interaction of genetic and environmental controls on seedling establishment. to determine how genetics and climate may interact to affect seedling establishment, we transplanted recently germinated se ... | 2011 | 21757486 |
| regional patterns of genetic diversity in pinus flexilis (pinaceae) reveal complex species history. | pinus flexilis (limber pine) is patchily distributed within its large geographic range; it is mainly restricted to high elevations in the rocky mountains and the basin and range region of western north america. we examined patterns of allozyme diversity in 30 populations from throughout the species' range. overall genetic diversity (h(e) = 0.186) was high compared with that of most other pine species but was similar to that of other pines widespread in western north america. the proportion of ge ... | 2002 | 21665679 |
| pinus flexilis and picea engelmannii share a simple and consistent needle endophyte microbiota with a potential role in nitrogen fixation. | conifers predominantly occur on soils or in climates that are suboptimal for plant growth. this is generally attributed to symbioses with mycorrhizal fungi and to conifer adaptations, but recent experiments suggest that aboveground endophytic bacteria in conifers fix nitrogen (n) and affect host shoot tissue growth. because most bacteria cannot be grown in the laboratory very little is known about conifer-endophyte associations in the wild. pinus flexilis (limber pine) and picea engelmannii (eng ... | 2014 | 25071746 |
| defense traits in the long-lived great basin bristlecone pine and resistance to the native herbivore mountain pine beetle. | mountain pine beetle (mpb, dendroctonus ponderosae) is a significant mortality agent of pinus, and climate-driven range expansion is occurring. pinus defenses in recently invaded areas, including high elevations, are predicted to be lower than in areas with longer term mpb presence. mpb was recently observed in high-elevation forests of the great basin (gb) region, north america. defense and susceptibility in two long-lived species, gb bristlecone pine (pinus longaeva) and foxtail pine (p. balfo ... | 2017 | 27612209 |
| mountain pine beetles use volatile cues to locate host limber pine and avoid non-host great basin bristlecone pine. | the tree-killing mountain pine beetle (dendroctonus ponderosae hopkins) is an important disturbance agent of western north american forests and recent outbreaks have affected tens of millions of hectares of trees. most western north american pines (pinus spp.) are hosts and are successfully attacked by mountain pine beetles whereas a handful of pine species are not suitable hosts and are rarely attacked. how pioneering females locate host trees is not well understood, with prevailing theory invo ... | 2015 | 26332317 |
| efficacy of verbenone and green leaf volatiles for protecting whitebark and limber pines from attack by mountain pine beetle (coleoptera: curculionidae: scolytinae). | to develop safe and effective methods to protect whitebark pines, pinus albicaulis engelmann, and limber pines, pinus flexilis james, from attack by mountain pine beetle, dendroctonus ponderosae hopkins (coleoptera: curculionidae), we compared verbenone and verbenone plus green leaf volatiles (glvs) for prevention of beetle attack. we used two strategies: area-wide protection where semiochemical-releasing flakes are dispersed over the forest floor, and individual tree tests where flakes are appl ... | 2014 | 25003785 |