SEARCH · PubMed Health

Results for “Pinus”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 595 records · Page 33Linked to original sources

PubMed1990

Effects of ozone on three open-pollinated families of Pinus taeda L. grown in two substrates.

Seedlings from three open-pollinated loblolly pine (Pinus taeda L.) families grown in a mixture of commercial peat moss and grade 3 vermiculite (1:3 by volume) or a mixture of mineral soil and peat (1:1 by volume) were exposed to 0, 160 or 320 ppb ozone (O3) for 6h/day, 4 days/week for 8 weeks beginning 12 weeks after transplanting. Before exposures began, seedlings grown in the vermiculite-peat substrate were taller but smaller in diameter than those grown in the mineral soil-peat substrate. After 8 weeks of exposure, seedlings grown in the mineral soil-peat substrate were significantly larger in diameter and total biomass than those grown in the vermiculite-peat substrate. Primary needle and secondary needle injury increased with increasing O3 concentrations. Suppression of diameter growth, shoot weight and root weight was linear as O3 concentration increased. The effect of O3 on height or diameter growth or shoot biomass was not influenced by substrate type; but the suppression of root biomass due to O3 was dependent on substrate, with greater suppression in biomass occurring in the vermiculite-peat substrate. Foliar injury due to O3 was slightly greater in family 8-103, but growth suppression due to O3 was not significantly different among the families. Based on root biomass, response of seedlings to O3 was substrate-dependent.

Journal Article↗

PubMed1991

Effects of ammonium and aluminium on the development and nutrition of Pinus nigra in hydroculture.

Application of ammonium and aluminium to young Pinus nigra var. maritima (Ait.) Melville trees resulted in a variety of negative effects. Excess ammonium led to an increase in shoot/root ratio. The biomass of the fine roots declined, resulting in an increase of the coarse/fine root ratio. The degree of mycorrhizal infection of the roots decreased. The nitrogen content of the trees increased considerably, whereas particularly the levels of calcium magnesium, manganese and zinc decreased sharply. Excess aluminium resulted in a simultaneous reduction of root and shoot biomass, a decline of the fine root system, an increase in the coarse/fine root ratio and a decrease in the degree of mycorrhizal infection. Uptake of the divalent cations calcium, magnesium, iron, manganese and zinc was restricted substantially, The nitrogen and phosphorus contents of the trees were hardly affected, whilst the potassium content of the shoot increased and of the roots decreased. This implicates that a deteriorating fine root system has to supply water and nutrients to a more demanding shoot. In the long term, high ammonium inputs and aluminium dissolution in forest ecosystems will lead to substantial nutrient deficiencies, just as has been found in the field.

Journal Article↗

PubMed1991

Growth response of loblolly pine (Pinus taeda L.) seedlings to ozone fumigation.

Twenty-two week-old Pinus taeda L. (loblolly pine) seedlings of 30 open-pollinated and five full-sib families, representing a wide range in geographic origin, were grown in charcoal-filtered (CF) air or CF-air supplemented with 160 or 320 nl liter(-1) ozone for 8 h day(-1), 4 days week(-1), for 9 weeks. Visible foliar injury (banded chlorosis, tip burn and premature senescence) was apparent in many families after 3 weeks in 320 nl liter(-1) and 6 weeks in 160 nl liter(-1) ozone. Decreases in relative height and root collar diameter growth rates, total dry weight, root dry weight, shoot dry weight, and root/shoot ratios were evident after 9 weeks of treatment with both 160 and 320 nl liter(-1) ozone. For relative height growth rates, family differences in response to ozone were observed. By the study's end, net photosynthesis rates were 15% less for the 320 nl liter(-1) ozone treatment as compared to the CF-air treatment. Total soluble sugar and total starch content of roots were not changed after 9 weeks of ozone exposure.

Journal Article↗

PubMed1991

High nitrogen deposition causes changes in amino acid concentrations and protein spectra in needles of the scots pine (Pinus sylvestris).

Growth of the Scots pine (Pinus sylvestris) suffered considerably in forests close to fur farms in western Finland, with the occurrence of winter time dieback in the youngest shoots and leading to a bush-like, flat crown canopy. One reason for this growth disturbance may be a serious imbalance in nitrogen metabolism caused by the extra N supply, emitted as NH3 from the dung of the animals. Total N and NH4+ concentrations in the needles and soluble nitrogen concentration in the soil increased considerably in the vicinity of the fur farms. The extra N in the needles was bound in the first place in arginine, the concentration of which increased 10(2)-10(3) fold compared with control trees, and to a lesser extent in glutamine and other amino acids. Alterations in the quantitative and qualitative protein patterns of the needles were obtained. The extra N increased the concentration of total soluble proteins, although it inhibited the formation of certain polypeptides (particularly in the areas of 30, 38, 50 and 65-90 kDa) which were possibly essential for the normal wintering processes. One reason for the winter time dieback in the high N area could thus be found in the altered protein profiles.

Journal Article↗

PubMed1993

Effects of acidic fog on seedlings of Pinus ponderosa and Abies concolor: foliar injury, physiological and biochemical responses.

Seedlings of Pinus ponderosa (ponderosa pine) and Abies concolor (white fir) were exposed to acidic fog (pH 2.0, 3.0 or 4.0) in open-field plots for six weeks. The two species exhibited dissimilar injury responses; neither current year nor previous year needles of ponderosa pine were injured by pH 2.0 fog, but current year needles exhibited higher membrane permeability responses (i.e. needle extract conductivity, K+ concentration). In comparison, both needle age classes in white fir were significantly injured by pH 2.0 fog, but no significant effects on membrane permeability were observed. For both species, whole-study average rates of net photosynthesis in previous year needles were lower in plants exposed to pH 2.0 fog than in plants treated with pH 4.0 fog. While decreased process rates coincided with leaf necrosis in white fir, stomatal closure appeared to be the mechanism of inhibition in ponderosa pine with pH 2.0 fog (i.e. no visible injury). The findings of the present study provide evidence that frequent applications of highly acidic fog (i.e. pH 2.0-3.0) can cause temporal alterations in membrane permeability and gas exchange rates in western conifer seedlings, in the presence or absence of visible injury. However, because incipient effects on other measures of foliage health were species-specific (i.e. concentrations of starch, photosynthetic pigments, inorganic nutrients), a general mechanism of phytotoxicity could not be identified.

Journal Article↗

PubMed1996

The individual and combined effects of ozone and simulated acid rain on growth, gas exchange rate and water-use efficiency of Pinus armandi Franch.

The seedlings of Pinus armandi Franch. were exposed to ozone (O(3)) at 300 ppb for 8 h a day, 6 days a week, and simulated acid rain of pH 3.0 or 2.3, 6 times a week, alone or in combination, for 14 weeks from 15 June to 20 September 1993. The control seedlings were exposed to charcoal-filtered air and simulated rain of pH 6.8 during the same period. Significant interactive effects of O(3) and simulated acid rain on whole plant net photosynthetic rate were observed, but not on other determined parameters. The exposure of the seedlings to O(3) caused the reductions in the dry weight growth, root dry weight relative to the whole plant dry weight, net photosynthetic rate, transpiration rate in light, water-use efficiency and root respiration activity, and increases in shoot/root ratio, and leaf dry weight relative to the whole plant dry weight without an appearance of acute visible foliar injury, but did not affect the dark respiration rate and transpiration rate in the darkness. The decreased net photosynthetic rate was considered to be the major cause for the growth reduction of the seedlings exposed to O(3). On the other hand, the exposure of the seedlings to simulated acid rain reduced the net photosynthetic rate per unit chlorophyll a + b content, but did not induce the significant change in other determined parameters.

Journal Article↗

PubMed1996

Effects of oxidant air pollution on Pinus maximartinezii Rzedowski in the México City region.

The response of Pinus maximartinezii Rzedowski to photochemical oxidant air pollution was examined using 100 trees, during a 1 year cycle, at Vivero de Coyoacán, a tree nursery located in the south central part of México City, where exposure to polluted air masses has been continuous. The tree response assessment method was based upon documented symptoms of pollutant injury on the foliage. The results showed a homogeneous pattern of health and vigor and only medium sensitivity (based on foliar injury) to photochemical oxidants, although the trees maintained their needles through a three and not the normal 5 year period as at its geographic location of origin (different habitat or environment). Nevertheless, these data suggest that this species of pine could be proposed as good planting material for reforestation in the urban metropolitan area of México city.

Journal Article↗

PubMed1988

Purification and properties of peroxidase from Pinus pinaster needles.

Peroxidase (Ec 1.11.1.7) was purified from needles of Pinus pinaster to apparent homogeneity by DE-52 cellulose chromatography with a final recovery of enzyme activity of about 85%. The purified enzyme (A402/A275 = 1.05) had a specific activity of about 948 U/mg of protein and ran as a single protein band both on SDS-PAGE and native PAGE with Mr of 37,000 and 151,000, respectively. Both native PAGE and isoelectric focusing gels of the purified enzyme were stained for activity which coincided with the protein band. The pI of the purified enzyme was found to be 3.2 by isoelectric focusing on an ultrathin polyacrylamide gel. The enzyme has an optimum pH of activity of 5.0 and temperature optimum of 30 degrees C. Stability studies of the enzyme as a function of pH and temperature suggest that it is most stable at pH 5.0 and 0-40 degrees C, respectively.

Chromatography, Ion Exchange↗

PubMed2005

Molecular characterization of a glutathione transferase from Pinus tabulaeformis (Pinaceae).

Glutathione transferases (GSTs) play important roles in stress tolerance and detoxification metabolism in plants. To date, studies on GSTs in higher plants have focused largely on agricultural plants. In contrast, there is virtually no information on the molecular characteristics of GSTs in gymnosperms. The present study reports for the first time the cloning, expression and characteristics of a GST gene (PtGSTU1) from a pine, Pinus tabulaeformis, which is widely distributed from northern to central China covering cold temperate and drought regions. The PtGSTU1 gene encodes a protein of 228 amino acid residues with a calculated molecular mass of 26.37 kDa. Reverse transcription PCR revealed that PtGSTU1 was expressed in different tissues, both above and below ground, of P. tabulaeformis. The over-expressed recombinant PtGSTU1 showed high activity towards the substrates 1-chloro-2,4-dinitrobenzene (CDNB) and 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole (NBD-Cl). Kinetic analysis with respect to CDNB as substrate revealed a Km of 0.47 mM and Vmax of 169.1 micromol/min per mg of protein. The recombinant PtGSTU1 retained more than 60% of its maximum enzymatic activity from 15 degrees C to 45 degrees C with a broad optimum Tm range of 25 degrees C - 35 degrees C. The enzyme had a maximum activity at approximately pH 8.5 - 9.0. Site-directed mutagenesis revealed that Ser13 in the N-terminal domain is a critical catalytic residue, responsible for stabilisation of the thiolate anion of enzyme-bound glutathione. Based on comparative analyses of its amino acid sequence, phylogeny and predicted three-dimensional structure, the PtGSTU1 should be classified as a tau class GST.

4-Chloro-7-nitrobenzofurazan↗

PubMed2003

Removal of Cd(II) and Pb(II) ions, from aqueous solutions, by adsorption onto sawdust of Pinus sylvestris.

Fixation of heavy metal ions (Cd(II) and Pb(II)) onto sawdust of Pinus sylvestris is presented in this paper. Batch experiments were conducted to study the main parameters such as adsorbent concentration, initial adsorbate concentration, contact time, kinetic, pH solution, and stirring velocity on the sorption of Cd(II) and Pb(II) by sawdust of P. sylvestris. Kinetic aspects are studied in order to develop a model which can describe the process of adsorption on sawdust. The equilibrium of a solution between liquid and solid phases is described by Langmuir model. Scanning electronic microscopy (SEM) coupled with energy dispersive X-ray analysis (EDAX) and X-ray photoelectron spectroscopy (XPS) shows that the process is controlled by a porous diffusion with ion-exchange. The capacity of the metal ions to bind onto the biomass was 96% for Cd(II), and 98% for Pb(II). The sorption followed a pseudo-second-order kinetics. The adsorption of these heavy metals ions increased with the pH and reached a maximum at a 5.5 value. From these results, it can be concluded that the sawdust of P. sylvestris could be a good adsorbent for the metal ions coming from aqueous solutions. Moreover, this material could also be used for purification of water before rejection into the natural environment.

Adsorption↗

PubMed2001

Phytoalexins from Pinus strobus bark infected with pinewood nematode, bursaphelenchus xylophilus.

From the bark of Pinus strobus infected with pinewood nematode, Bursaphelenchus xylophilus, a stilbenoid 3-O-methyldihydropinosylvin and a flavanone (2S)-pinocembrin were isolated as active principles of inducibly produced antifungal compounds. The structures of the compounds were determined on the basis of spectroscopic analyses. Close investigations of spectroscopic analyses led to the complete assignment of 13C NMR and 1H NMR chemical shifts for the former compound and to the determination of the stereochemistry of the latter compound from P. strobus to be 2S. Furthermore, the distribution and time course accumulation of the identified compounds were investigated. The former compound was demonstrated to be nematocidal and the concentrations of the compound in the inoculated branches were sufficient enough to inactivate the pinewood nematode within one week after inoculation.

Animals↗

PubMed1999

Proteolytic activity in relation to seasonal cambial growth and xylogenesis in Pinus banksiana.

Proteolytic activity in the cambial zone and developing xylem of Pinus banksiana Lamb. was investigated over an annual cycle of growth and dormancy. Highest proteolytic activity was associated with the most active period of primary-wall radial expansion of cambial derivatives, in early spring, before protoplasmic autolysis was initiated in developing earlywood. Three pH maxima of proteolytic activity, near pH 3.0, 6.5 and 9.5, were observed at that time. In general, activities measured at pH values below 7.0 were greater than those determined above pH 7.0 at all stages in the annual cycle, in both cambial zone and developing xylem, although elevated activity at alkaline pH was also observed during springtime growth. Polyvinylpolypyrollidone (PVP) treatment markedly enhanced pH 7.5 but not pH 4.0 proteolytic activity in the cambial zone, but not in developing xylem, indicating the presence of PVP-binding proteinase regulators in the cambium. By fractionation and effector studies total proteolysis was determined to comprise interactions between serine, cystine, aspartate and metallo-proteases having MWs, by gel chromatography, between 10 and 100 kDa. The observations point to a complex regulatory mechanism controlling the presence and catalytic rates of the distinct types of proteases in the cambial region throughout an annual cycle of growth and dormancy.

Cycadopsida↗

PubMed2000

Biotransformation of the Trichoderma metabolite 6-n-pentyl-2H-pyran-2-one by cell suspension cultures of Pinus radiata.

Cell suspension cultures of Pinus radiata metabolize the antifungal Trichoderma secondary metabolite 6-n-pentyl-2H-pyran-2-one (6PAP) (1) via hydroxylation of the pentyl side chain. Examination of the culture medium following dosing studies with 1 revealed that 79-85% of this bioactive compound had been metabolised after 144 h. At that time, 34-40% of the metabolized dose was recovered as a series of monohydroxylated isomers of 1, the principal metabolite being 5-(2-pyron-6-yl)pentan-5-ol (7).

Antifungal Agents↗

PubMed2000

Biochemical responses of the mycorrhizae in Pinus massoniana to combined effects of Al, Ca and low pH.

Biochemical responses of Pinus massoniana, with and without the inoculation mycorrhizal fungus Pisolithus tinctorius at the root, to artificial acid rain (pH 2.0) and various Ca/Al ratios were investigated. Some enzymes associated with the nutritive metabolism, such as acid phosphatase, alkaline phosphatase, nitrate reductase, mannitol dehydrogenase and trehalase, in the roots, stems and leaves of plant were obviously inhibited by the artificial acid rain and Al. After treatment with pH 2.0 + Ca/Al (0/1 or 1/10) artificial acid rain, the protein content in the organs was decreased. However, the activities of superoxide dismutase (SOD) and peroxidase (POD) and glutathione (GSH) concentrations were induced. It demonstrated that acid rain and Al could induce oxygen radicals in plant. Compared with the treatments with lower pH or Al, respectively, the combination of lower pH and Al concentration was more toxic to P. massoniana. Al toxicity could be ameliorated by the addition of Ca and the amelioration was the most when the ratio was 1/1 among the various Ca/Al ratio. Infection with mycorrhizal fungus P. tinctorius at the root of P. massoniana increased the ability of the plant to resist the toxicity of artificial acid rain and Al stress.

Acid Phosphatase↗

PubMed1976

Studies on the physiology of pollen and pollen tube growth. 1. pinus roxburghii.

Pollen grains and pollen tubes of Pinus roxburghii were subjected to histochemical technique with a view to determining the distributional pattern of reserve substances (ascorbic acid, proteins starch, polysaccharides, nucleic acids) and some enzymes (acid phosphatase, glucose-6-phosphatase, peroxidase, esterase, cytochrome oxidase, succinate dehydrogenase). An attempt is made to correlate the activity of different enzymes in relation to pollen tube growth.

Enzymes↗

PubMed2000

Impacts of urban levels of ozone on Pinus halepensis foliage.

Between May and September, 1996, seedlings of Pinus halepensis were placed at a site adjacent to an automated air pollution monitoring station within the urban area of Florence. Additional 'control' plants were placed in chambers ventilated with charcoal/Purafil(R)-filtered air. All trees were well watered throughout the whole experimental period. During the exposure period, ambient levels of sulphur dioxide were very low, whilst the accumulated hourly exposure to ozone above 40 ppb (i.e. AOT40) exceeded 20000 ppb h(-1) - peak hourly ozone concentrations rising to levels above 100 ppb. Trees exposed to ambient levels of air pollution exhibited typical symptoms of ozone damage (chlorotic mottle) on previous year needles toward the end of the summer. Similar symptoms were not observed on equivalent trees exposed to filtered-air, nor were visible symptoms accompanied by insect or pest infestation. Anatomical and ultrastructural observations made on symptomatic needles revealed degeneration in mesophyll cells bordering sub-stomatal cavities and alterations in chloroplast ultrastructure (fat accumulation, starch and tannin pattern modifications). These observations are consistent with the known effects of air pollutants (namely ozone) recorded in the literature. Findings are discussed in relation to the impacts of ozone on P. halepensis in the Mediterranean region.

Journal Article↗

PubMed2000

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 total weed biomass; however, C(3) weed community development was favored over C(4) weed community development in elevated CO(2) regardless of water availability. This suggests that weed community composition may shift toward C(3) plants in a future elevated CO(2) atmosphere. Pine growth was significantly greater in the well watered and elevated CO(2) treatments compared to the water stressed and ambient treatments, respectively, even though they were competing with native herbaceous weeds for resources. There was a significant water and CO(2) interaction for pine root:shoot ratio. Under elevated CO(2), root:shoot ratio was significantly greater in the water stressed treatment than the well watered treatment. In contrast, there was no significant difference in the root:shoot ratio under the ambient CO(2) treatment for either water treatment. These results suggest that loblolly pine seedlings will respond favorably in an elevated CO(2) atmosphere, even under dry conditions and competing with herbaceous weeds.

Journal Article↗

PubMed2000

The influence of elevated ultraviolet-B radiation (UV-B) on tissue quality and decomposition of loblolly pine (Pinus taeda L.) needles.

Stratospheric ozone depletion is expected to elevate the influx of ultraviolet-B radiation (UV-B) to the biosphere. Increased levels of UV-B may, in turn, alter important ecosystem processes such as decomposition. Previous studies have shown that growth under elevated UV-B can alter leaf quality in angiosperm species and thereby indirectly change subsequent rates of leaf decay. In this experiment, we determined if elevated UV-B would alter the chemical composition and decay of needle tissue from two seed sources of the gymnosperm Pinus taeda L. Maryland and Virginia seed sources of P. taeda were grown in the field for 3 years beneath lampbanks supplying either ambient, low elevated or high elevated UV-B. These levels of UV-B corresponded to 0, 16 and 25% stratospheric ozone depletion at the experimental site in Beltsville, MD (39 degrees N). Needles were collected from six randomly chosen plants for each combination of seed source and UV-B level. The needle samples were analyzed for total C and N, UV-B absorbing compounds, and carbon fractions. Decay rates were also determined by measuring rates of CO(2) evolution from needle material decomposed under laboratory conditions. UV-B did not significantly alter the chemical composition of needles from the Virginia seed source. In contrast, needles from the Maryland seed source tended to have elevated lignin/N ratios and a lower holocellulose content when grown under the highest level of UV-B. Furthermore, while needles from the Virginia pines did not have UV-B altered decay rates, Maryland needles grown under low elevated UV-B conditions decomposed 36% more rapidly than needles from other treatments. Results from this experiment illustrate at least three characteristics about the indirect effect of UV-B on decomposition, (1) UV-B can modify decomposition of tissue from gymnosperms as well as angiosperms; (2) UV-B effects on tissue chemistry and decay may not only be species-specific but also seed-source specific; and (3) UV-B effects on decomposition may not increase with increasing UV-B dose.

Journal Article↗