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PubMed1991

Defense mechanisms of conifers : relationship of monoterpene cyclase activity to anatomical specialization and oleoresin monoterpene content.

Cell-free extracts from Pinus ponderosa Lawson (ponderosa pine) and Pinus sylvestris L. (Scotch pine) wood exhibited high levels of monoterpene synthase (cyclase) activity, whereas bark extracts of these species contained no detectable activity, and they inhibited cyclase activity when added to extracts from wood, unless polyvinylpyrrolidone was included in the preparation. The molecular mass of the polyvinylpyrrolidone added was of little consequence; however, polyvinylpolypyrrolidone (a cross-linked insoluble form of the polymer) was ineffective in protecting enzyme activity. Based on these observations, methods were developed for the efficient extraction and assay of monoterpene cyclase activity from conifer stem (wood and bark) tissue. The level of monoterpene cyclase activity for a given conifer species was shown to correlate closely with the monoterpene content of the oleoresin and with the degree of anatomical complexity of the specialized resin-secreting structures. Cyclase activity and monoterpene content were lowest in the stems of species containing only isolated resin cells, such as western red cedar (Thuja plicata D. Don). Increasing levels of cyclase activity and oleoresin monoterpenes were observed in advancing from species with multicellular resin blisters (true firs [Abies]) to those with organized resin passages, such as western larch (Larix occidentalis Nutt.), Colorado blue spruce (Picea pungens Engelm.) and Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco). The highest levels of cyclase activity and oleoresin monoterpenes were noted in Pinus species that contain the most highly developed resin duct systems. The relationship between biosynthetic capacity, as measured by cyclase activity, monoterpene content, and the degree of organization of the secretory structures for a given species, may reflect the total number of specialized resin-producing cells per unit mass of stem tissue.

Journal Article↗

PubMed2001

Mediterranean climate effects. I. Conifer water use across a Sierra Nevada ecotone.

Xylem water potential of the midelevation conifers Pinus jeffreyi, Pinus lambertiana, Abies concolor, and Calocedrus decurrens, the higher elevation Pinus monticola and Abies magnifica, and co-occurring evergreen angiosperm shrubs, together with soil moisture under these plants, were monitored at three sites on the Kern Plateau in the southernmost Sierra Nevada Range of California. Site locations spanned the ecotone between the mid- and upper montane forests at elevations of 2230-2820 m. Measurements were made through a low-snowfall year and a heavy-snowfall year.In the Mediterranean climate of the Sierra Nevada, the heavy winter snowpack persists into late spring, after precipitation has effectively stopped. We found the subsequent depletion of soil moisture due to plant water uptake to result in predawn xylem water potentials for conifers more negative by 0.6-1.4 MPa than those for shrubs or inferred soil potentials. Shrubs generally depleted soil moisture more rapidly and ultimately extracted a greater fraction of the available soil moisture than did the conifers. This depletion of soil moisture by shrubs, particularly Arctostaphylos patula, may limit conifer growth and regeneration by prematurely terminating growth on the shallow soils studied. The conifers all generally showed similar patterns of soil moisture use, except that A. magnifica extracted moisture more rapidly early in the season.

Journal Article↗

PubMed2001

Mediterranean climate effects. II. Conifer growth phenology across a Sierra Nevada ecotone.

Growth and xylem water potential of the lower elevation conifers Pinus jeffreyi and Abies concolor and the higher elevation Pinus monticola and Abies magnifica were monitored in their montane Mediterranean habitat of the southernmost Sierra Nevada mountains of California. Measurements were made across the ecotone between the midmontane and upper montane forests and through light and heavy snowfall years.Radial stem growth, averaging ∼1.5 mm/yr, started 2 wk after snow melt, providing that maximum air temperatures had reached 21°C, and ended when predawn water potentials fell rapidly at the onset of the summer drought. Leader growth started on or after a fixed date, providing that minimum air temperatures were above -4°C for Pinus species or +2.5°C for Abies species. The cue for leader growth was inferred to be photoperiodic. Leader growth ended when either a determinate internode length of ∼1 mm was reached or predawn water potentials fell rapidly. Abies magnifica grew more rapidly than the low-elevation species, but had a shorter growth period; its annual leader growth, as a consequence, was only 35 mm/yr vs. 50 mm/yr for the low-elevation species. Needle growth was similarly determinate in the absence of early drought. This growth phenology contributes to determining species distribution across the ecotone.

Journal Article↗

PubMed2000

[Distribution patterns of root systems of main planting tree species in Weibei Loess Plateau].

The vertical patterns of root systems of Pinus tabulaeformis, Robinia pseudoacacia, Platycladus orientalis, Pinus sylvestris var. mongolica, Pinus armandi, Prunus armeniacia var. ansu planted in the Weibei Loess Plateau were studied with soil auger. Site conditions had a significant effect on the vertical root distribution of R. pseudoacacia, of which, soil moisture is the key factor. Soil species and soil structure also had great effect on the distribution. P. tabulaeformis had a maximum rooting depth at its young stage(8 years old), but the root density increased with age. There was a great difference in vertical root distribution among the tree species, of them, R. pseudoaccia rooted deepest, which negated the opinion that R. pseudoacacia is a shallow rooted tree species. According to the vertical root distribution of the tree species, the productivity of these species in the south-facing site of yellow loess soil would be in order of R. pseudoacacia > Prunus armeniacia var. ansu > P. tabulaeformis > P. sylvestris var. mongolica > P. armandi > Platycladus orientalis.

China↗

PubMed2000

[Characterization and fruit-body production of Neolentinus suffrutescens strains obtained by crossing in vitro in a pilot plant].

Dikaryotic strains of Neolentinus suffrutescens were obtained from crosses of 12 monosporous isolates. The monosporous breeding stocks and the crosses were evaluated on potato dextrose agar with a wood infusion of Pinus montezumae and growth rates at 12 days of incubation were determined. Eight crosses were selected and subsequently evaluated in vitro on Pinus spp. and P. montezumae wood chips. Crosses were not equal in performance to the original parental strain, however, on Pinus spp. wood, three of the crosses exceeded performance of the original parental strain. The parental strain and the selected crosses were cultivated in a pilot plant on the above mentioned substrates. The biological efficiency (BE) fluctuated between 4.85 to 14.60 % and the production rate (TP) between 0.07 to 0.19 % on the substrate I and on the substrate II, of 4.41 to 14.92 % and of 0.06 to 0.23 %, respectively.

English Abstract↗

PubMed1990

[Effect of cryopreservation on pollen viability].

The viability of pollen at room temperature lowers and disappears in few days; on the contrary the cryopreservation lengthens the pollen viability. Pollen of Pinus brutia, P. canariensis, P. halepensis, P. pinaster has been stored at -20 degrees C for one year with the aim of checking the variation of viability. The viability has been tested by fluorescein diacetate; the germination by in vitro culture for 96 hours has been observed and daily percentage of germinated pollen grains and maximum lengths of pollen tubes have been checked. The tests have been carried out at the drawing of pollen and then 6 months and 12 months after. The pollen viability lowers during this period but it does not disappear. The germination power decreases in Pinus canariensis and P. pinaster, while in Pinus brutia and P. halepensis it is increased by low temperature. Therefore the cryopreservation has to be considered an important method for the maintenance of the germplasm of those plants, like the pines, which are important from the naturalistic point of view.

Cell Survival↗

PubMed1977

[Isolation and properties of merodiploid strains with F-factor including the pts-region of the Escherichia coli K-12 chromosome].

A technique of hybridization of haploid methanol-utilizing yeast Pichia pinus MH4 is worked out using UV- and N-nitrosoguanidine-induced auxotrophic mutants. Vegetative diploid cultures are isolated. Tetrad analysis and random spore analysis have revealed a meiotic nature of spores, recombination of genetic material in the process of sporulation and the chromosomal nature of some mutations. A possibility to construct a genetic map of the yeast Pichia pinus MH4 is demonstrated on the basis of tetrad analysis. Three linkage groups are revealed. The life cycle in a homothalic haploid yeast, Pichia pinus, was demonstrated. They are capable to form zygotes and meiotic spores under conditions preventing vegetative growth.

Biological Transport↗

PubMed2004

Cross-species transferability and mapping of genomic and cDNA SSRs in pines.

Two unigene datasets of Pinus taeda and Pinus pinaster were screened to detect di-, tri- and tetranucleotide repeated motifs using the SSRIT script. A total of 419 simple sequence repeats (SSRs) were identified, from which only 12.8% overlapped between the two sets. The position of the SSRs within their coding sequences were predicted using FrameD. Trinucleotides appeared to be the most abundant repeated motif (63 and 51% in P. taeda and P. pinaster, respectively) and tended to be found within translated regions (76% in both species), whereas dinucleotide repeats were preferentially found within the 5'- and 3'-untranslated regions (75 and 65%, respectively). Fifty-three primer pairs amplifying a single PCR fragment in the source species (mainly P. taeda), were tested for amplification in six other pine species. The amplification rate with other pine species was high and corresponded with the phylogenetic distance between species, varying from 64.6% in P. canariensis to 94.2% in P. radiata. Genomic SSRs were found to be less transferable; 58 of the 107 primer pairs (i.e. 54%) derived from P. radiata amplified a single fragment in P. pinaster. Nine cDNA-SSRs were located to their chromosomes in two P. pinaster linkage maps. The level of polymorphism of these cDNA-SSRs was compared to that of previously and newly developed genomic-SSRs. Overall, genomic SSRs tend to perform better in terms of heterozygosity and number of alleles. This study suggests that useful SSR markers can be developed from pine ESTs.

Base Sequence↗

PubMed2004

Volatiles associated with preferred and nonpreferred hosts of the Nantucket pine tip moth, Rhyacionia frustrana.

Ovipositing female Nantucket pine tip moth, Rhyacionia frustrana, prefer loblolly pine, Pinus taeda L., to slash pine, Pinus elliottii Engelm, except during the first spring following planting of seedlings. Host discrimination by R. frustrana increases as seedlings develop, suggesting that changes in the chemical composition of seedlings may mediate the moth's host preferences. Volatile compounds from slash and loblolly pine seedlings were collected using solid-phase microextraction (SPME) during the first year following planting. Four collection periods coincided with adult emergence and oviposition during each of four annual generations of R. frustrana in the Georgia Coastal Plain. Infestation of slash pine peaked during the second tip moth generation and was similar to the loblolly pine infestation level. By the fourth tip moth generation, slash pine infestation levels had declined and diverged considerably from those of loblolly pine. Significant differences in relative quantities of beta-pinene, alpha-phellandrene, limonene, beta-phellandrene, bornyl acetate, beta-caryophyllene, and an unidentified sesquiterpene occurred between slash and loblolly pine during the fourth generation. However, no strong correlation was observed between any individual compound and host damage that could readily explain the temporal changes in R. frustrana host preference. Gas chromatographic-electroantennographic detection (GC-EAD) analyses of standards identified 19 different seedling-associated compounds that elicited antennal responses from R. frustrana females, indicating that a blend of terpenoids may mediate host discrimination.

Animals↗

PubMed2005

Aluminum fractions in root tips of slash pine and loblolly pine families differing in Al resistance.

Aluminum (Al) distribution among several cellular fractions was investigated in root tips of seedlings of one Al-resistant and one Al-sensitive family of slash pine (Pinus elliottii Engelm.) and loblolly pine (Pinus taeda L.) grown in nutrient solution containing 100 microM AlCl3 (pH 4) for 167 h. Aluminum present in 5-mm-long root tips was fractionated into cell-wall-labile (desorbed in 0.5 mM citric acid), cell-wall-bound (retained after filtering disrupted cells through 20-microm mesh) and symplasmic (filtrate following cell disruption) fractions. When averaged across both species, 12% of Al absorbed by root tips appeared in the symplasmic fraction and 88% in the apoplasmic fraction (55% as cell-wall-labile, and 33% as cell-wall-bound). On a fresh mass basis, total Al in root tips was lower in loblolly pine than in slash pine, lower in the Al-resistant slash pine family than in the Al-sensitive slash pine family, and lower in the Al-resistant families than in the Al-sensitive families across species. Although the data support the hypothesis that Al-resistant plants limit Al uptake to root apices, they do not exclude other mechanisms of Al resistance. Differential Al resistance between the species and between slash pine families may also be associated with the size of the total non-labile and cell-wall-labile Al fractions, respectively. We were unable to identify the basis for differential Al resistance in loblolly pine.

Aluminum↗

PubMed2006

Functional traits and plasticity in response to light in seedlings of four Iberian forest tree species.

We investigated the differential roles of physiological and morphological features on seedling survivorship along an experimental irradiance gradient in four dominant species of cool temperate-Mediterranean forests (Quercus robur L., Quercus pyrenaica Willd., Pinus sylvestris L. and Pinus pinaster Ait.). The lowest photochemical efficiency (F(v)/F(m) in dark-adapted leaves) was reached in deep shade (1% of full sunlight) in all species except Q. robur, which had the lowest photochemical efficiency in both deep shade and 100% of full sunlight. Species differed significantly in their survival in 1% of full sunlight but exhibited similar survivorship in 6, 20 and 100% of full sunlight. Shade-tolerant oaks had lower leaf area ratios, shoot to root ratios, foliage allocation ratios and higher rates of allocation to structural biomass (stem plus thick roots) than shade-intolerant pines. Overall phenotypic plasticity for each species, estimated as the difference between the minimum and the maximum mean values of the ecophysiological variables studied at the various irradiances divided by the maximum mean value of those variables, was inversely correlated with shade tolerance. Observed morphology, allocation and plasticity conformed to a conservative resource-use strategy, although observed differences in specific leaf area, which was higher in shade-tolerant species, supported a carbon gain maximization strategy. Lack of a congruent suite of traits underlying shade tolerance in the studied species provides evidence of adaptation to multiple selective forces. Although the study was based on only four species, the importance of ecophysiological variables as determinants of interspecific differences in survival in limiting light was demonstrated.

Light↗

PubMed2003

A novel sex-specific and inducible monoterpene synthase activity associated with a pine bark beetle, the pine engraver, Ips pini.

Ecological interactions of conifers and coniferophagous bark beetles are determined in part by terpenoids (isoprenoids), which are major defense metabolites of conifer oleoresin. Curiously, similar compounds are important aggregation pheromones of conifer-attacking bark beetles. Terpene synthases are responsible for generating the enormous variety of terpenoid carbon skeletons found in nature. These catalysts convert short-chain prenyl diphosphates to a diverse assortment of hemiterpene, monoterpene, sesquiterpene, and diterpene natural products. While terpene synthases have frequently been characterized from plant and microbial sources, they have not yet been described in animals. Here we report the discovery of a monoterpene synthase activity in an insect, the pine engraver, Ips pini (Say) (Coleoptera: Scolytidae). Cell-free assays of I. pini revealed that geranyl diphosphate (GDP) is converted to the acyclic monoterpene myrcene in whole-body extracts from males, but not females. Furthermore, the monoterpene synthase activity in males can be induced by prior treatment with juvenile hormone III (JH III) or by feeding on phloem from the host trees, Jeffrey pine (Pinus jeffreyi Grev. & Balf.) or red pine (Pinus resinosa Ait.). The sex-specificity and endocrine induction of this activity argue for its involvement in the biosynthesis of monoterpenoid pheromones mediated by enzymes from insect tissue. This discovery is the first example of a monoterpene synthase in the Metazoa and evokes exciting new questions about the origin, evolution, and occurrence of terpene synthases.

Animals↗

PubMed2002

Climatic and stream-flow controls on tree growth in a Western montane riparian forest.

Humans have severely impacted riparian ecosystems through water diversions, impoundments, and consumptive uses. Effective management of these important areas is becoming an increasingly high priority of land managers, particularly as municipal, industrial, and recreational demands for water increase. We examined radial tree growth of four riparian tree species ( Pinus jeffreyi, Populus trichocarpa, Betula occidentalis, and Pinus monophylla) along Bishop Creek, California, and developed models relating basal area increment (BAI) and relative basal area increment (RBAI) to climatic and stream flow variables. Between years 1995-1999, univariate regression analysis with stream flow explained 29 to 61% of the variation in BAI and RBAI among all species except P. trichocarpa; growth by P. trichocarpa was not significantly related to stream flows over this period. Stepwise linear regression indicated that species responded differently to climatic variables, and models based on these variables explained between 33 to 86% of variation in BAI and RBAI during the decade of the 1990s. We examined branch growth of P. trichocarpa for sensitivity to differences in stream flow regimes and found that annual branch growth did not vary between a high- and low-flow site, but that annual branch growth was significantly higher in wet years with greater stream flows. Our results support the establishment of site-specific management goals by land managers that take into account all of the important tree species present in riparian ecosystems and their differential responses to altered hydrologic condition. Instream flow requirements for maintaining tree growth and vigor are only one of the species-specific responses that need to be evaluated, and these assessments should attempt to separate experimentally stream-flow (managed) controls from climatic (unmanaged) controls on growth.

Betula↗

PubMed2004

Molecular analysis of the 5'-upstream region of a gibberellin-inducible cytosolic glutamine synthetase gene (GS1b) expressed in pine vascular tissue.

The promoter region of the cytosolic glutamine synthetase GS1b gene was isolated from the conifer Pinus sylvestris L. (Scots pine). The 1,171-bp stretch of sequence lying immediately upstream of the transcriptional start site was sufficient to drive the expression of a reporter gene in a manner consistent with the expression pattern of the native GS1b gene. Computer analysis of putative cis elements in this promoter region revealed the presence of an AT box, an AC motif similar to those found in other genes expressed in the vascular tissue, and a gibberellin (GA)-responsive element. Consistent with the latter finding, GS1b gene expression was induced by exogenously supplied gibberellic acid (GA3) in germinating pine embryos and pine seedlings. In order to examine if the putative GA-response element found in the GS1b promoter could function in the regulation of GS1b expression, a series of deletions of the upstream gene region were fused to the uidA reporter gene, and transient expression analyzed either in untreated or in GA3-treated pine (Pinus pinaster Ait.) protoplasts. Deletion analysis revealed that sequences containing the GA-responsive element, located between -1005 and -724 bp were essential for the increased promoter activity observed in response to GA3. Furthermore, electrophoretic-mobility-shift assays showed that pine nuclear proteins bind to a 22-bp sequence that contains the GA-response element, located between -768 and -747 bp relative to the transcription start site.

5' Flanking Region↗

PubMed2003

Does tree diversity increase wood production in pine forests?

Recent experimental advances on the positive effect of species richness on ecosystem productivity highlight the need to explore this relationship in communities other than grasslands and using non-synthetic experiments. We investigated whether wood production in forests dominated by Aleppo pine (Pinus halepensis) and Pyrenean Scots pine (Pinus sylvestris) differed between monospecific and mixed forests (2-5 species) using the Ecological and Forest Inventory of Catalonia (IEFC) database which contains biotic and environmental characteristics for 10,644 field plots distributed within a 31,944 km(2) area in Catalonia (NE Spain). We found that in Pyrenean Scots pine forests wood production was not significantly different between monospecific and mixed plots. In contrast, in Aleppo pine forests wood production was greater in mixed plots than in monospecific plots. However, when climate, bedrock types, radiation and successional stage per plot were included in the analysis, species richness was no longer a significant factor. Aleppo pine forests had the highest productivity in plots located in humid climates and on marls and sandstone bedrocks. Climate did not influence wood production in Pyrenean Scots pine forests, but it was highest on sandstone and consolidated alluvial materials. For both pine forests wood production was negatively correlated with successional stage. Radiation did not influence wood production. Our analysis emphasizes the influence of macroenvironmental factors and temporal variation on tree productivity at the regional scale. Well-conducted forest surveys are an excellent source of data to test for the association between diversity and productivity driven by large-scale environmental factors.

Ecosystem↗

PubMed2002

Ultrastructure of vascular cambial cell cytokinesis in pine seedlings preserved by cryofixation and substitution.

Trees depend on the secondary vascular cambium to produce cells for new xylem and phloem. The fusiform cells of this lateral meristem are long and narrow, presenting special challenges for arranging the mitotic spindle and phragmoplast. Fusiform cambial cells of Pinus ponderosa and Pinus contorta were studied by cryofixation and cryosubstitution which preserved ultrastructure and phases of cytokinesis with a resolution not previously attained. Membranous structures including the plasma membrane, tonoplast, and those of other organelles were smooth and unbroken, indicating that they were preserved while the protoplasm was in a fully turgid state. Mitotic spindles separated daughter chromosomes diagonally across the radial width of the cells. The cell plate was initiated at an angle to the cell axis between the anaphase chromosomes by a microtubule array which organized vesicles at the phragmoplast midline. Within the phragmoplast, vesicles initially joined across thin tubular projections and then amalgamated into a tubulo-vesicular network. Axial expansion of the cell plate generated two opposing phragmoplasts connected by a thin, extended bridge of cell plate and cytoplasm that was oriented along the cell axis. In the cytoplasmic bridge trailing each phragmoplast, the callose-rich tubular network gradually consolidated into a fenestrated plate and then a complete cell wall. Where new membrane merged with old, the parent plasmalemma appeared to be loosened from the cell wall and the membranes joined via a short tubulo-vesicular network. These results have not been previously reported in cambial tissue, but the same phases of cytokinesis have been observed in cryofixed root tips and suspension-cultured cells of tobacco.

Cell Membrane↗

PubMed2005

Higher plants as bioindicators of sulphur dioxide emissions in urban environments.

The evaluation of certain vascular plants that grow in the city of Madrid as biomonitors of SO(2) air pollution in urban environments has been carried out. Total concentration of sulphur in leaves of the chosen higher plants as well as other parameters in close relation to this contaminant (visible injury symptoms, chlorophyll a- and b-content and peroxidase activity) have been determined in order to study the spatial distribution and temporal changes in SO(2) deposition. Results obtained show that coniferous species such as Pinus pinea, were more sensitive to SO(2) atmospheric concentration than leafy species as Quercux ilex subspecies ballota and, in the same way, bush species, such as Pyracantha coccinea and Nerium oleander, were more sensitive than wooded species, such as Cedrus deodara and Pinus pinea, respectively. There is a higher accumulation of sulphur in vegetable species located near highways and dense traffic incidence roads and near areas with high density of population. The minimum values for accumulation of SO(2) were registered in winter and spring seasons (from January to April) due to the vegetative stop; while maximum values are obtained during the summer season (from June to September), due to the stoma opening. The highest increments in sulphur concentration, calculated as the difference between two consecutive months, are obtained in May and June for all considered species except for Cedrus deodara and Pyracantha coccinea, both species have few seasonal changes during the whole year. Some species are more sensitive to natural washing than others, showing a decrease in sulphur concentration after rainfall periods.

Air Pollutants↗

PubMed2005

Relationship between density and ultrasonic velocity in Brazilian tropical woods.

In this study, the effect of density on the velocity of an ultrasonic wave in wood is investigated. The aim of the present study was to analyze the influence of density on the longitudinal velocity of an ultrasonic wave, propagated in the longitudinal direction. Experiments were conducted on 5cm x 5cm x 5cm wood specimens selected from the following species: pinus caribea (Pinus caribea var. caribea), eucalyptus citriodora (Eucalyptus citriodora), eucalyptus grandis (Eucalyptus grandis), cupiúba (Goupia glabra) and jatobá (Hymenaea sp.). The relationship between density and velocity was analyzed in two different manners: between and within species. The results obtained between species indicated that ultrasonic velocity tends to increase with increasing density. The results obtained within species also showed an increasing trend in ultrasonic velocity as density increased, but the relationship was not as significant as it was for between species.

Brazil↗