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PubMed2003

Comparison of selection methods for optimizing genetic gain and gene diversity in a red pine ( Pinus resinosa Ait.) seedling seed orchard.

Four selection methods, individual selection (IS), family selection (FS), family plus within-family selection (FWFS) and combined selection (CS), were used to estimate genetic gain [ E( g)] for stem volume and gene diversity ( GD) for ten theoretical selection intensities in a 108-family, 12-year-old red pine seedling seed orchard. Estimated genetic gain for stem volume ranged from 4.6% to 11.8% across all selection methods and intensities with CS consistently having the highest gains and FS the lowest for any given selection intensity. Genetic diversity ranged from 0.9797 to 0.9954 across all selection methods and intensities. Individual selection was the best selection method for retaining GD, especially at the higher selection intensities, while FWFS was more efficient at the lowest selection intensity. An optimization point, which maximized E( g) and GD relative to each other, was calculated for each selection method. In all cases the optimization point indicated that both E( g) and GD would be favorably high when optimized relative to each other. The implications for volume gain, genetic diversity and potential inbreeding in red pine, a species with inherently low levels of genetic variation, are discussed.

Biological Evolution↗
PubMed2004

An auxin-inducible gene from loblolly pine (Pinus taeda L.) is differentially expressed in mature and juvenile-phase shoots and encodes a putative transmembrane protein.

We have isolated a gene from loblolly pine, 5NG4, that is highly and specifically induced by auxin in juvenile loblolly pine shoots prior to adventitious root formation, but substantially down-regulated in physiologically mature shoots that are adventitious rooting incompetent. 5NG4 was highly auxin-induced in roots, stems and hypocotyls, organs that can form either lateral or adventitious roots following an auxin treatment, but was not induced to the same level in needles and cotyledons, organs that do not form roots. The deduced amino acid sequence shows homology to the MtN21 nodulin gene from Medicago truncatula. The expression pattern of 5NG4 and its homology to a protein from Medicago involved in a root-related process suggest a possible role for this gene in adventitious root formation. Homology searches also identified similar proteins in Arabidopsis thaliana and Oryza sativa. High conservation across these evolutionarily distant species suggests essential functions in plant growth and development. A 38-member family of genes homologous to 5NG4 was identified in the A. thaliana genome. The physiological significance of this redundancy is most likely associated with functional divergence and/or expression specificity of the different family members. The exact biochemical function of the gene is still unknown, but sequence and structure predictions and 5NG4::GFP fusion protein localizations indicate it is a transmembrane protein with a possible transport function.

Amino Acid Sequence↗
PubMed2005

Association between tree-ring and needle delta13C and leaf gas exchange in Pinus halepensis under semi-arid conditions.

Associations between delta13C values and leaf gas exchanges and tree-ring or needle growth, used in ecophysiological compositions, can be complex depending on the relative timing of CO2 uptake and subsequent redistribution and allocation of carbon to needle and stem components. For palaeoenvironmental and dendroecological studies it is often interpreted in terms of a simple model of delta13C fractionation in C3 plants. However, in spite of potential complicating factors, few studies have actually examined these relationships in mature trees over inter- and intra-annual time-scales. Here, we present results from a 4 years study that investigated the links between variations in leaf gas-exchange properties, growth, and dated delta13C values along the needles and across tree rings of Aleppo pine trees growing in a semi-arid region under natural conditions or with supplemental summer irrigation. Sub-sections of tissue across annual rings and along needles, for which time of formation was resolved from growth rate analyses, showed rapid growth and delta13C responses to changing environmental conditions. Seasonal cycles of growth and delta13C (up to approximately 4 per thousand) significantly correlated (P < 0.01) with photosynthetically active radiation, vapour pressure deficit, air temperature, and soil water content. The irrigation significantly increased leaf net assimilation, stomatal conductance and needle and tree-ring growth rate, and markedly decreased needle and tree-ring delta13C values and its sensitivity to environmental parameters. The delta13C estimates derived from gas-exchange parameters, and weighted by assimilation, compared closely with seasonal and inter-annual delta13C values of needle- and tree-ring tissue. Higher stomatal conductances of the irrigated trees (0.22 vs. 0.08 mol m(-2) s(-1) on average) corresponded with approximately 2.0 per thousand lower average delta13C values, both measured and derived. Derived and measured delta13C values also indicated that needle growth, which occurs throughout the stressful summer was supported by carbon from concurrent, low rate assimilation. For Aleppo pine under semi-arid and irrigated conditions, the delta13C of tree-ring and needle material proved, in general, to be a reasonable indicator of integrated leaf gas-exchange properties.

Carbon Dioxide↗
PubMed2006

Tree height and age-related decline in growth in Scots pine (Pinus sylvestris L.).

Growth and seasonal water use was measured amongst trees growing in an old growth Scots pine forest in the Scottish Highlands. Three sites which differed in their recent management history and contained old and naturally regenerated young trees growing together were monitored in the field. Our results showed a clear decrease in growth efficiency with age, from values of around 0.25 kg m(-2) leaves year(-1) in approximately 25-year-old trees to less than 0.1 kg m(-2) leaves year(-1) in trees over 200 years old. When the old trees in one of the field sites were released from competition by thinning, their growth efficiency reverted to that of coexisting young trees, indicating that the decline in growth was reversible. This is consistent with the results of a parallel study showing that cambial age had no effect on the physiology or growth of grafted seedlings originating from the same population studied here (Mencuccini et al. 2005). Our detailed study of tree water use in the field showed an overall decrease in whole-tree hydraulic conductance and stomatal canopy conductance with tree height in the unthinned stands, in agreement with the hydraulic limitation hypothesis. However, the effect of this reduction in hydraulic efficiency on growth was comparatively small, and old trees also showed consistently lower nitrogen concentrations in needles, suggesting that hydraulic and nutritional factors combined to produce the decline in growth efficiency with age observed in the studied populations.

Pinus sylvestris↗
PubMed2003

Variation in nitrogen source utilisation by nine Amanita muscaria genotypes from Australian Pinus radiata plantations.

The abilities of nine genotypes of Amanita muscaria (L.:Fr) Pers. to utilise a range of inorganic and organic nitrogen sources for growth was examined in axenic liquid cultures. Considerable intraspecific variation was observed in biomass yields on all substrates; however biomass yield was highest on glutamine and/or NH4+ for all genotypes. Yields on aspartic acid, glutamic acid and histidine were generally low relative to NH4+, while utilisation of arginine and glycine showed marked variation between genotypes. Eight genotypes produced significantly less biomass on bovine serum albumin than on NH4+, raising questions regarding classification of A. muscaria as a 'protein fungus'.

Amanita↗
PubMed2004

Pezizalean mycorrhizas and sporocarps in ponderosa pine (Pinus ponderosa) after prescribed fires in eastern Oregon, USA.

Post-fire Pezizales fruit commonly in many forest types after fire. The objectives of this study were to determine which Pezizales appeared as sporocarps after a prescribed fire in the Blue Mountains of eastern Oregon, and whether species of Pezizales formed mycorrhizas on ponderosa pine, whether or not they were detected from sporocarps. Forty-two sporocarp collections in five genera (Anthracobia, Morchella, Peziza, Scutellinia, Tricharina) of post-fire Pezizales produced ten restriction fragment length polymorphism (RFLP) types. We found no root tips colonized by species of post-fire Pezizales fruiting at our site. However, 15% (6/39) of the RFLP types obtained from mycorrhizal roots within 32 soil cores were ascomycetes. Phylogenetic analyses of the 18S nuclear ribosomal DNA gene indicated that four of the six RFLP types clustered with two genera of the Pezizales, Wilcoxina and Geopora. Subsequent analyses indicated that two of these mycobionts were probably Wilcoxina rehmii, one Geopora cooperi, and one Geopora sp. The identities of two types were not successfully determined with PCR-based methods. Results contribute knowledge about the above- and below-ground ascomycete community in a ponderosa pine forest after a low intensity fire.

Ascomycota↗
PubMed2006

Polysomes are associated with microtubules in fertilized eggs of Chinese pine (Pinus tabulaeformis).

Transmission electron microscopy of immunogold-labeled Chinese pine egg cells before and after fertilization revealed that polysomes are associated with microtubules (MTs) from fertilization to the 2-nucleate embryo stage. Ribosome aggregates of various size and shape were randomly distributed in the cytoplasm of the eggs before fertilization. Single MTs or clusters were observed to be free of polysomes at this stage. Upon fertilization, all polysomes were attached to MTs, and this association persisted until the formation of the polarized embryo. Thereafter, the polysomes spread into the cytoplasm and no polysome-MT association was observed in the embryo. Some of the polysomes were attached to one end of the MTs, while others appeared to form contacts along their entire length. No polysome-microfilament association was observed at any stage of the development. The polysome-MT association may provide a mechanism for MT-dependent mRNA localization in early embryo development of this plant.

Cell Polarity↗
PubMed2006

Searching for a new putative cryptic virus in Pinus sylvestris L.

Double-stranded RNAs (dsRNAs) were detected in different pine populations in Germany and Hungary. Two dsRNA species of 1.5 and 1.58 kbp, respectively, persisted in the same trees for at least 2 years and their presence was not associated with any symptoms. The dsRNAs were found to sediment in the VLP (virus-like particles) fraction and to be protected by protein(s) against RNase A digestion at low salt. cDNA cloning and sequencing of the smaller segment (dsRNA2) led to the identification of a putative RNA-dependent RNA-polymerase (RdRp) containing the GDD, as well as three other, conserved motifs. Sequence comparison with different RNA viruses and phylogenetic analysis indicates that the putative RdRp from pine shows highest similarity to the homologous proteins of Beet cryptic virus 3 and of a cryptic virus of Pyrus pyrifolia. On the basis of these results we suggest that the 1.5 and 1.58 kbp dsRNAs in P. sylvestris may represent the genomic segments of a new plant cryptic virus, Cryptoviruses have not yet been reported to occur in Gymnosperms.

Amino Acid Motifs↗
PubMed2005

Deposition velocities to Sorbus aria, Acer campestre, Populus deltoides X trichocarpa 'Beaupré', Pinus nigra and X Cupressocyparis leylandii for coarse, fine and ultra-fine particles in the urban environment.

Trees are effective in the capture of particles from urban air to the extent that they can significantly improve urban air quality. As a result of their aerodynamic properties conifers, with their smaller leaves and more complex shoot structures, have been shown to capture larger amounts of particle matter than broadleaved trees. This study focuses on the effects of particle size on the deposition velocity of particles (Vg) to five urban tree species (coniferous and broadleaved) measured at two field sites, one urban and polluted and a second more rural. The larger uptake to conifers is confirmed, and for broadleaves and conifers Vg values are shown to be greater for ultra-fine particles (Dp < 1.0 microm) than for fine and coarse particles. This is important since finer particles are more likely to be deposited deep in the alveoli of the human lung causing adverse health effects. The finer particle fraction is also shown to be transported further from the emission source; in this study a busy urban road. In further sets of data the aqueous soluble and insoluble fractions of the ultra-fines were separated, indicating that aqueous insoluble particles made up only a small proportion of the ultra-fines. Much of the ultra-fine fraction is present as aerosol. Chemical analysis of the aqueous soluble fractions of coarse, fine and ultra-fine particles showed the importance of nitrates, chloride and phosphates in all three size categories at the polluted and more rural location.

Acer↗
PubMed2005

Long-term evaluation of the needle surface wax condition of Pinus sylvestris around different industries in Lithuania.

The aim of our study was to evaluate the annual dynamics of needle surface wax erosion and wettability in Scots pines exposed to a gradient of industrial pollutants emitted from the main factories of Lithuania: a nitrogen fertilizer factory, an oil refinery and a cement factory. Decreased emissions (in the case of the oil refinery and the cement factory) were reflected in the increased structural surface area (SSA, i.e. area covered by tubular waxes) on the needles. The nearly constant amount of emissions from the nitrogen fertilizer factory within the 1994-2000 period corresponded to negligible annual differences in SSA. Annual changes in the hydrophobicity of needles on the investigated transects were small. Despite the decreased pollution within the 7-year period, industrial emissions are still causing significantly accelerated wax erosion and increased wettability in needles sampled from the stands most heavily affected by pollutants.

Ecology↗
PubMed2006

Quantification of ozone uptake at the stand level in a Pinus canariensis forest in Tenerife, Canary Islands: an approach based on sap flow measurements.

Ozone uptake was studied in a pine forest in Tenerife, Canary Islands, an ecotone with strong seasonal changes in climate. Ambient ozone concentration showed a pronounced seasonal course with high concentrations during the dry and warm period and low concentrations during the wet and cold season. Ozone uptake by contrast showed no clear seasonal trend. This is because canopy conductance significantly decreased with soil water availability and vapour pressure deficit. Mean daily ozone uptake averaged 1.9 nmol m(-2) s(-1) during the wet and cold season, and 1.5 nmol m(-2) s(-1) during the warm and dry period. The corresponding daily mean ambient ozone concentrations were 42 and 51 nl l(-1), respectively. Thus we conclude that in Mediterranean type forest ecosystems the flux based approach is more capable for risk assessment than an external, concentration based approach.

Atlantic Islands↗
PubMed2004

Multigene phylogenies of Ophiostoma clavigerum and closely related species from bark beetle-attacked Pinus in North America.

Leptographium pyrinum, Leptographium terebrantis, Ophiostoma aureum, Ophiostoma clavigerum, and Ophiostoma robustum are very similar in morphology, host trees choice, and the way they are disseminated by bark beetles. Their phylogenetic relationships were clarified using rDNA and protein coding genes including actin, beta-tubulin, and translation elongation factor-1alpha. Protein coding gene trees showed better resolution than the rDNA tree, which generated three clades: O. clavigerum, L. terebrantis/L. pyrinum, and O. robustum/O. aureum. A combined gene phylogenetic tree, which was supported by high bootstrap values, showed that O. aureum, L. pyrinum, O. robustum, and O. clavigerum each formed distinct clades while L. terebrantis was paraphyletic to O. clavigerum. The higher variability of the protein coding genes and the congruity in their phylogenetic results suggested that these genes may be better markers for identifying closely related species. These gene trees have also facilitated the description of the evolutionary relationships among these species.

Actins↗
PubMed2005

Uranium distribution and cycling in Scots pine (Pinus sylvestris L.) growing on a revegetated U-mining heap.

We determined the uranium distribution in soil and its allocation in compartments of 35-year-old Scots pine developed on a revegetated U-mining heap. The processes controlling the dynamics of U recycling were identified and further quantified in terms of annual fluxes. As pine developed, an acid humus layer emerged leading to weathering of the alkaline mining debris but this had little effect on U mobility in the soil profile. Increased U mobility mainly involved a translocation of U to metal-humus chelates in surface layers. The root compartment accounted for 99.3% of the U budget in tree, thus serving as an effective barrier which restricts U uptake. The current root uptake and transfer of U to upper parts of the tree amounted to about 3g ha(-1) y(-1), i.e. less than 0.03% of the current NH4-exchangeable U pool in the soil (0-30 cm). Allocation and translocation pattern made it clear that a dominant fraction of the translocated U moves passively with the ascent xylem sap, most likely as a soluble complex, and steadily accumulates in the needles. Consequently, 97% of the U annual uptake is returned to the soil through litterfall. At the studied site, the risk of U dissemination due to biomass turnover or trunk harvest was low when considered in relation to the current "exemption level" for U.

Biodegradation, Environmental↗
PubMed2004

Processes, dynamics and modelling of radiocaesium cycling in a chronosequence of Chernobyl-contaminated Scots pine (Pinus sylvestris L.) plantations.

In a large forested area affected by the Chernobyl radioactive fallout, especially in CIS, the lasting recycling of radiocaesium (137Cs) by the trees is a source of long-term contamination of woody products. The quantitative description of the 137Cs dynamics in contaminated forest is a prerequisite to predictive modelling and further management of such territories. Three even-aged mono-specific Scots pine stands (17, 37 and 57 years old) were selected in a contaminated woodland in southeastern Belarus to constitute an adequate chronosequence. We determined the potassium and radiocaesium annual fluxes involved in the biological cycling in each stand using a well-documented calculation methodology. Qualitatively, 137Cs was shown to be rapidly recycled in trees through the same pathways as K and to redistribute similarly between the tree components. Compared to K, a higher fraction of 137Cs, corresponding to about the half of the annual uptake, is immobilised in perennial organs. With tree development, trunk wood and bark become prevailing sinks for 137Cs since they represent an increasing pool of biomass. In the pine chronosequence, the current root absorption, respectively, mobilizes 0.53, 0.32 and 0.31% year(-1) of the total 137Cs pool in soil. Variations in the 137Cs uptake do not reflect differences in the 137Cs balance between stands. In the two older stands, 51 and 71% of the current tree contamination are related to earlier accumulation subsequent to the initial fallout interception and recycling. The soil is the dominant source of long-term tree contamination. A simple modelling based on the measured 137Cs fluxes indicates that, for young stands, radioactive decay-corrected contamination would stabilize after reaching a maximum of 25 years after the 137Cs deposition. Stemwood presents a maximum of 15 years after the deposition and decrease afterwards mainly through radioactive decay. In the older stands, the decontamination is constant without local maximum of 137Cs level in the wood. The 137Cs contamination of tree components is the result of different influential processes like root uptake, internal translocation and immobilisation. For more accurate predictions, the calibration of existing models would be benefited by comparing with the 137Cs annual fluxes instead of the simple transfer factor coefficients. In the perspective of other applications, there is a need of such data for other radionuclides as well as for heavy metals.

Calibration↗
PubMed2005

Trace elements in fruiting bodies of ectomycorrhizal fungi growing in Scots pine (Pinus sylvestris L.) stands in Poland.

The trace metal contents in fruiting bodies of ectomycorrhizal (ECM) fungi, symbiotic partners of Scots pine, were studied on three sites situated in west-central Poland. Elements were determined by atomic absorption spectrometry in 123 samples of 16 species. The study explored the differences in metal accumulation in relation to site, fungal species, age and part of the fruiting body and results were related to metal content in soil and plant material (roots and needles). Soil analysis revealed that results were obtained under environmental conditions not subject to strong anthropogenic pressure. Median metal concentrations did not differ disparately between sites, although the concentrations of each of the tested metals in the individual species varied to a large extent. Extremely high levels of Al with a large bioconcentration factor (BCF) were found in sporocarps of Thelephora terrestris. The spread between the highest and the lowest concentration (max/min) was very wide in Al, Cd and Pb and these elements may be considered to be absorbed preferentially by fruiting bodies of some species whereas Fe, Mn and Zn, with relatively low values of max/min, are normally absorbed by the majority of fungi. There was no clear relationship between caps and stipes in metal content. However, a tendency to higher metal concentration in the caps was observed. The metal content in young and older fruiting bodies of five different fungi was species dependent. In order to estimate the degree of accumulation of each element by plant and mushrooms, bioconcentration factors (BCFs) were calculated. In plant material (roots and needles), highest values of BCFs were noted for essential metals, like Zn and Mn. Lead showed a definite exclusion pattern (BCF below 1). In fruiting bodies of tested fungi, especially in Amanita muscaria, cadmium was the most intensively accumulated metal. Lead was excluded by plants but was accumulated or excluded by fungi depending on the species. The significance of mycological observation and quantification of the metal content in monitoring of the forest ecosystem is discussed.

Age Factors↗