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At least 865 records · Page 48Linked to original sources
PubMed1993

The presence of two types of gene that encode the chlorophyll a/b-binding protein (LHCPII) and their light-independent expression in pine (Pinus thunbergii).

A cDNA clone (pPDLHC3117) for LHCPII of pine (Pinus thunbergii) was isolated and sequenced. From a comparison of the deduced amino acid sequence with those of proteins from other seed plants, pPDLHC3117 was identified as encoding a type I LHCPII. Specific probes for genes for type I and type II LHCPII were made from pPDLHC3117 and a type II cDNA (pPDLHC2176), respectively. Northern blotting with the specific probes showed that both types of LHCPII were expressed in dark-grown seedlings of pine.

Amino Acid Sequence↗
PubMed1994

Inhibition of platelet aggregation by diterpene acids from Pinus massoniana resin.

The acidic fraction of the resin of Pinus massoniana Lamb. from China was converted to the p-nitrophenyl esters, and the esters separated by chromatography. The separated p-nitrophenyl esters were individually hydrolysed by potassium hydroxide in acetone-water at room temperature to 8 diterpene acids of the pimarane and abietane groups: pimaric acid (8(14),15-pimaradien-18-oic acid) (1), levopimaric acid (8(14),12-abietadien-18-oic acid) (2), palustric acid (8,13-abietadien-18-oic acid) (3), neobietic acid (8(14),13(15)-abietadien-18-oic acid) (4), abietic acid (7,13-abietadien-18-oic acid) (5), dehydroabietic acid (8,11,13-abietatrien-18-oic acid) (6), 7-oxodehydroabietic acid (7-oxo-8,11,13-abietatrien-18-oic acid) (7) and 7 alpha-hydroxydehydroabietic acid (7 alpha-hydroxy-8,11,13-abietatrien-18-oic acid) (8). The structure (and stereochemistry) of the diterpene acids were substantiated by nuclear magnetic resonance spectroscopy (proton and carbon-13, one and two dimensional), by mass spectrometry (electron impact and methane chemical ionization) and by rotation measurements. The 8 diterpene acids were tested for their ability to inhibit the aggregation of washed rabbit platelets induced by platelet activating factor (PAF), adenosine diphosphate (ADP) and by calcium ionophore A23187. With platelet aggregation induced by the latter two agonists, activities comparable with or higher than linolenic acid were given by the first 4 acids. With aggregation induced by PAF, the first 3 acids show activity, but at a level significantly lower than that of linolenic acid. Levopimaric acid has the highest activity among the diterpene acids tested. It is proposed that this activity is related to the folded shape of the molecule.

Adenosine Diphosphate↗
PubMed1994

Monoterpene synthases of Pinus contorta and related conifers. A new class of terpenoid cyclase.

A cell-free extract from the xylem of lodgepole pine (Pinus contorta) catalyzes the conversion of [1-3H1]geranyl pyrophosphate to a variety of monoterpene olefins found in lodgepole pine oleoresin. This monoterpene synthase activity is similar to previously described terpenoid cyclases from grand fir (Abies grandis) and other higher plants in molecular mass (67 +/- 2 kDa as estimated by size-exclusion chromatography), Km for geranyl pyrophosphate (7.8 +/- 1.9 microM), and isoelectric point (4.75 +/- 0.2 as determined by isoelectric focusing), but the cyclases from both lodgepole pine and grand fir are unlike previously characterized terpenoid cyclases from angiosperms and fungi, in that they have an alkaline pH optimum (pH 7.8), are activated by K+, Rb+, Cs+, or NH+4 (Li+ and Na+ are not effective), require either Mn2+ or Fe2+ as divalent metal ion cofactors (Mg2+ is not effective), and are not protected by the substrate-metal ion complex against inhibition by the histidine-directed reagent diethyl pyrocarbonate. Chromatography of the pine xylem extracts on a quaternary amino anion-exchange resin results in the separation of four similar, but distinct, multiple product monoterpene synthases that produce sabinene, beta-phellandrene, 3-carene, and beta-pinene as the principal components, respectively. The major cyclase (phellandrene synthase) was subsequently purified by hydroxyapatite chromatography and electrophoresis. V8 proteolysis provided a peptide map significantly different from that obtained with limonene synthase from spearmint (Mentha spicata), and limited NH2-terminal sequencing of the phellandrene synthase fragments revealed no significant similarity to the deduced amino acid sequence of the angiosperm limonene synthase, the only monoterpene cyclase to be cloned and sequenced thus far. Furthermore, polyclonal antibodies raised against the angiosperm limonene synthase did not detectably cross-react with any proteins in extracts from either lodgepole pine or grand fir by immunoblotting analysis. In addition to these structural differences between cyclases from conifers and herbaceous angiosperms, the unusual pH optimum, mono- and divalent metal ion requirement, and reactivity toward histidine carbethoxylation indicate that monoterpene cyclases isolated from conifers may also have a different complement of active-site amino acid residues involved in substrate binding and catalysis than those of terpenoid cyclases previously isolated from angiosperms.

Cations, Divalent↗
PubMed1977

[Patterns in the cellular organization of ovule growth in the pine, Pinus silvestris L. II. Growth processes in nucellus and integument].

The dynamics of growth processes was studied in the integument and nucellus of Pinus silvestris during the year of fertilization. The growth of two parts of the nucellus and integument under study is described by an S-shaped curve but the dynamics of growth processes and the ratio of cell reproduction and elongation differ in each tissue. The growth of micropylar part of the nucellus and integument proceeds, mainly at the expense of cell proliferation. At the first stages of growth the cell size remains constant, then during a short period the reproduction and elongation of cells occur simultaneously, and after the fertilization the growth proceeds at the expense of cell elongation only, since the cell division arrests completely. In the part of nucellus concrescent with the integument, the mitotic activity disappears still prior to fertilization and the growth proceeds, mainly, at the expense of cell elongation. Differences in the cell size are observed both between tissues and between different regions of the same tissue. The larges nuclei are situated in the micropylar part of nucellus. The nuclear size suffers insignificant changes during the growth of the tissues under study.

Growth↗
PubMed1997

Antiinflammatory activities of procyanidin-containing extracts from Pinus pinaster Ait. after oral and cutaneous application.

Orally in liquid diet administered procyanidin-containing extracts from Pinus pinaster Ait. decreased the croton oil-induced ear edema in mice or the compound 48/80-induced hind paw edema in rats to a statistically significant extent. Most effective were the extracts containing mainly oligomeric procyanidins with chain lengths greater then 4 units (extracts A or B). Further, the different extracts incorporated in various concentrations (1.0, 3.0 or 0.1%) in 5% hydroxyethylcellulose gel and applied topically on the shaved back of rats, inhibited significantly the ultraviolet radiation-induced increased capillary permeability. In these experiments, normalisation of capillary permeability was not correlated with the content of the extracts on higher oligomeric procyanidins.

Administration, Oral↗
PubMed1997

On the specific pattern of long chain polyprenols in green needles of Pinus mugo Turra.

In green needles of Pinus mugo the most abundant polyprenols occur as a mixture of prenologues in which the dominant alcohol is built of 16 isoprene units. The characteristic spectrum of polyprenols (prenol-15, -16 and -17) was the same irrespective of the location of plant and of distinct morphological differences observed in the various selected forms of this species. The constant pattern of the polyprenols spectrum was preserved throughout the 2-year life span of needles, although the level of polyprenols was increased 2-3-fold. The polyprenol pattern in Pinaceae family differs from species to species, thus it may serve as chemotaxonomic criterion within this systematic group.

Alcohols↗
PubMed1976

Biochemical changes in Pinus pinea seeds. III. The effect of growth substances and steroidal hormones on nucleic acids.

The effects of exogenous growth factors (indolacetic acid, gibberellic acid and kinetin and steroidal hormones (estrone, estradiol and testosterone on the germination pattern of Pinus pinea seeds were studied. Nucleic acids metabolism during the stages before germination, has also been investigated. Seeds sown in the presence of all these substances, showed a higher growth rate and a higher germination degree than their respective controls; kinetin and estradiol were the most active factors. The level of total nucleic acids was studied in seeds after one day soaking and on the 1rst, 3rd, 5th, and 7th day after sowing. Megagametophytes contained a higher amount of acids when growth factors and steroidal hormones were present, specially after one day soaking. In embryos; after the 3rd day, a similar result was obtained. The RNA fraction increased the most.

DNA↗
PubMed2002

Two endophytic fungi in different tissues of scots pine buds (Pinus sylvestris L.).

Two fungal species were isolated with different frequencies from pine tissue cultures originating from buds. One species was detected in 33.1% of the cultures initiated in March, and another was present in 1.7% of cultures initiated in June. Based on analyses of phylogenetic and physiological characteristics these fungi were identified as Hormonema dematioides (isolated in March) and Rhodotorula minuta (isolated in June). Probes targeted towards the 18S rRNA of H. dematioides and R. minuta were made. When in situ hybridizations were performed on pine bud tissue, R. minuta was detected inside the cells of meristematic tissue in 40% of the samples, in contrast to H. dematioides, which was not found in this tissue. Using light microscopy, H. dematioides was found to be localized in the scale tissues of the buds. Fungal endophytes have previously been detected in scale tissues, but not in the meristematic tissues of buds. The habitats of these fungi may reflect their different roles in the plant.

Ascomycota↗
PubMed2002

Seasonal responses of photosynthetic electron transport in Scots pine (Pinus sylvestris L.) studied by thermoluminescence.

The potential of photosynthesis to recover from winter stress was studied by following the thermoluminescence (TL) and chlorophyll fluorescence changes of winter pine needles during the exposure to room temperature (20 degrees C) and an irradiance of 100 micromol m(-2) s(-1). TL measurements of photosystem II (PSII) revealed that the S(2)Q(B)(-) charge recombinations (the B-band) were shifted to lower temperatures in winter pine needles, while the S(2)Q(A)(-) recombinations (the Q-band) remained close to 0 degrees C. This was accompanied by a drastically reduced (65%) PSII photochemical efficiency measured as F(v)/ F(m,) and a 20-fold faster rate of the fluorescence transient from F(o) to F(m) as compared to summer pine. A strong positive correlation between the increase in the photochemical efficiency of PSII and the increase in the relative contribution of the B-band was found during the time course of the recovery process. The seasonal dynamics of TL in Scots pine needles studied under field conditions revealed that between November and April, the contribution of the Q- and B-bands to the overall TL emission was very low (less than 5%). During spring, the relative contribution of the Q- and B-bands, corresponding to charge recombination events between the acceptor and donor sides of PSII, rapidly increased, reaching maximal values in late July. A sharp decline of the B-band was observed in late summer, followed by a gradual decrease, reaching minimal values in November. Possible mechanisms of the seasonally induced changes in the redox properties of S(2)/S(3)Q(B)(-) recombinations are discussed. It is proposed that the lowered redox potential of Q(B) in winter needles increases the population of Q(A)(-), thus enhancing the probability for non-radiative P680(+)Q(A)(-) recombination. This is suggested to enhance the radiationless dissipation of excess light within the PSII reaction center during cold acclimation and during cold winter periods.

Acclimatization↗
PubMed2002

The true distribution and accumulation of radiocaesium in stem of Scots pine (Pinus sylvestris L.).

The radial and vertical distributions of radiocaesium, potassium and calcium were determined in two Scots pine stands (17 and 58 yr old) similarly affected by the Chernobyl fallout. For both age classes, concentrations are always the lowest in the stemwood, highest in the inner bark and intermediary levels were observed for the outer bark. Due to the cumulative character of its biomass. however. stemwood is a long-term major reservoir of 137Cs. With tree development, changes in the 137Cs radial distribution are well described by variations in the sap ascent pattern and reveal an important transfer between tree rings. It is shown that. both the biomass evolution and knowledge of the evolution of the 137Cs radial gradient are important to predicting 137Cs accumulation in wood with time. According to the common transfer factor (TF) approach, one would expect a decrease in radiocaesium accumulation with time (from 0.0047 +/- 0.0013 to 0.0035 +/- 0.0008 m2kg(-1) for the 17 and 58 yr old trees, respectively). With the wood immobilisation potential (WIP) approach, it was, however, clearly shown that additional annual uptake was highest for the older stand (3.12 +/- 0.23 Bq cm(-3) yr(-1) for the 58-year-old stand compared to 1.99 +/- 0.30 Bq cm(-3) yr(-1) for the younger stand). Following the WIP approach, it was moreover possible to distinguish between the 137Cs incorporated via the root uptake process and a possible lasting effect of interception. It is shown that, whereas for the younger stand (5 yr old at the time of the accident) root uptake contributed exclusively to the wood contamination, the former process explained only 48% of the measured total 137Cs content in the wood of the older tree.

Age Factors↗
PubMed2002

Effect of fertilisation on the potassium and radiocaesium distribution in tree stands (Pinus sylvestris L.) and peat on a pine mire.

This paper compares the effects of single and repeated fertilisation on the contents of potassium, 134Cs and 137Cs in different Scots pine compartments at different levels above ground and in the peat profile 9 years after the Chernobyl disaster. The material was collected from a ditch spacing and fertilisation experiment in Finland. Above a needle potassium concentration of 3.0 mg g(-1) in composed crown samples, 137Cs and 134Cs concentrations remained at about the same level but below that the values were higher on average. This potassium value corresponded to the potassium concentrations of 3.5-3.6 mg g(-1) in the current-year needles of two topmost whorls. The result indicates an enhanced radiocaesium uptake by pine trees under severe potassium deficiency. Fertilisation with potassium-containing fertilisers decreased the caesium uptake considerably. The inhibiting effect of fertilisation on caesium uptake by trees seemed to be fairly long lasting. Fertilisation had sped up the penetration of caesium downwards in the peat profile and its moving out of the active circulation of elements between soil and plants.

Cesium Radioisotopes↗
PubMed2002

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 factorial combination. Soil CO2 efflux rates were consistently higher near the base of seedlings, fertilization increased seedling growth with no significant effect on rates. and mulching increased winter efflux rates. In a regression analysis of seasonal soil CO2 efflux, soil temperature explained 42.2% of the variance followed by the interaction of soil temperature and moisture and of soil temperature and plot position, which together explained an additional 9.8% of the observed variance in seasonal rates. During March 2000 measurements, the spatial pattern of soil CO2 efflux between plots was most influenced by differences in soil nitrogen and pine root biomass. Furthermore, spatial differences observed in mean annual efflux rates were found to be highly influenced by the amount of soil coarse fragments in the upper soil profile.

Biomass↗
PubMed2002

Shift in ectomycorrhizal community composition in Scots pine (Pinus sylvestris L.) seedling roots as a response to nickel deposition and removal of lichen cover.

Scots pine seedlings were exposed to wet-deposited nickel (Ni) and removal of lichen cover in a dry heath Scots pine forest. Ni deposition affected the colonization of roots by indigenous ectomycorrhizal fungi in contrasting ways in intact and skimmed quadrats. Highest frequencies of tubercle morphotypes of ectomycorrhiza were found in quadrats exposed to 100 mg m(-2) year(-1) Ni in lichen covered treatment, while in skimmed quadrats these peaked after the treatment with 10 mg Ni m(-2) year(-1). Removal of the lichen layer increased the value of diversity index (H') of ectomycorrhizal fungal community, probably due to the increase in the evenness of the morphotype distribution. Lichen removal seemed also to improve the condition of the short roots, as the frequencies of poor and senescent short roots were decreased by the removal.

Analysis of Variance↗
PubMed2003

Feeding response of Ips paraconfusus to phloem and phloem metabolites of Heterobasidion annosum-inoculated ponderosa pine, Pinus ponderosa.

In studies of feeding by the bark beetle, Ips paraconfusus, two pine stilbenes (pinosylvin and pinosylvin methyl ether), ferulic acid glucoside, and enantiomers of the four most common sugars present in ponderosa pine phloem (sucrose, glucose, fructose, and raffinose) did not stimulate or reduce male feeding when assayed on wet alpha-cellulose with or without stimulatory phloem extractives present. When allowed to feed on wet alpha-cellulose containing sequential extracts (hexane, methanol, and water) of ponderosa pine phloem, methanol and water extractives stimulated feeding, but hexane extractives did not. Males confined in wet alpha-cellulose containing aqueous or organic extracts of culture broths derived from phloem tissue and containing the root pathogen. Heterobasidion annosum, ingested less substrate than beetles confined to control preparations. In an assay using logs from uninoculated ponderosa pines, the mean lengths of phloem in the digestive tracts increased as time spent feeding increased. Males confined to the phloem of basal logs cut from ponderosa pines artificially inoculated with H. annosum ingested significantly less phloem than beetles in logs cut from trees that were (combined) mock-inoculated or uninoculated and did not contain the pathogen. However, individual pathogen-containing treatments were not significantly different from uninoculated controls. It was concluded that altered feeding rates are not a major factor which may explain why diseased ponderosa pines are colonized by I. paraconfusus.

Animals↗
PubMed2001

[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, damaging diseases of needles, late spring frost, severe drought, and excessive resin-tapping, and the third group of factors called as contributing factors were several biotic agents such as shoot blight infected by Sphaeropsis sapinea, decay wood and root rot by fungi, and bark beetles and wood borers.

Causality↗
PubMed2002

[Natural regeneration of Pinus sylvestris var. mongolica plantation on sandy land].

By employing comparison analysis and field survey, the natural regeneration of Mongolian pine plantations on sandy soil was investigated. In plantation areas where regeneration can take place naturally, natural regeneration of Mongolian pine varied temporally and spatially. Natural regeneration wasn't temporally continuous; it had a close relationship with autumn precipitation in particular years. In spatial aspect, there were three regeneration types: regeneration in forest gaps, regeneration on edges of a forest, regeneration under young broadleaf forest. There was no significant difference between the growth of regeneration saplings and plantation trees.

Agriculture↗