Showing papers by "Forest Research Institute published in 1999"
TL;DR: In this paper, the authors used evidence from 15 N-tracer studies in nine forests to show that elevated nitrogen deposition is unlikely to be a major contributor to the putative CO2 sink in forested northern temperature regions.
Abstract: Humans have altered global nitrogen cycling such that more atmospheric N2 is being converted (‘fixed’) into biologically reactive forms by anthropogenic activities than by all natural processes combined1. In particular, nitrogen oxides emitted during fuel combustion and ammonia volatilized as a result of intensive agriculture have increased atmospheric nitrogen inputs (mostly NO3 and NH4) to temperate forests in the Northern Hemisphere2,3,4. Because tree growth in northern temperate regions is typically nitrogen-limited5, increased nitrogen deposition could have the effect of attenuating rising atmospheric CO2 by stimulating the accumulation of forest biomass. Forest inventories indicate that the carbon contents of northern forests have increased concurrently with nitrogen deposition since the 1950s6,7,8. In addition, variations in atmospheric CO2 indicate a globally significant carbon sink in northern mid-latitude forest regions9,10,11,12. It is unclear, however, whether elevated nitrogen deposition or other factors are the primary cause of carbon sequestration in northern forests. Here we use evidence from 15N-tracer studies in nine forests to show that elevated nitrogen deposition is unlikely to be a major contributor to the putative CO2 sink in forested northern temperature regions.
735 citations
TL;DR: In infarct-related coronary arteries, the number of degranulated mast cells in the adventitia backing ruptured plaques is increased and may reach the media, where it may locally provoke coronary spasm and thus contribute to the onset of MI.
Abstract: Background—Histamine, a product of mast cells, is an effective vasoconstrictor of atherosclerotic coronary arteries. Because it has been suggested that coronary spasm plays a role in acute coronary syndromes such as myocardial infarction (MI), we quantified and characterized the mast cells in the adventitia of infarct-related coronary arteries. Methods and Results—In a series of 17 autopsied MI patients, we identified the segment of the left coronary artery with ruptured plaque responsible for the infarction. More distal segments from the infarct-related coronary artery, either with nonruptured plaques or with normal intima, were also studied. Corresponding segments taken from left coronary arteries obtained from 17 patients who had died of noncardiac causes served as controls. Adventitial mast cells in the infarct-related and the control coronary arteries were identified immunohistochemically by staining for tryptase. In the infarct-related coronary arteries, we also stained for chymase and histamine. Mo...
343 citations
TL;DR: The Pasoh forest is more stable than BCI's in another way: few of its tree populations changed much over the eight-year census interval; the faster species turnover at BCI can probably be attributed to severe droughts that have plagued the forest periodically over the past 30 years; Pasoh has not suffered such extreme events recently.
Abstract: Dynamics of the Pasoh forest in Peninsular Malaysia were assessed by drawing a comparison with a forest in Panama, Central America, whose dynamics have been thoroughly described. Census plots of 50 ha were established at both sites using standard methods. Tree mortality at Pasoh over an eight-year interval was 1.46% yr(-1) for all stems > or = 10 mm diameter at breast height (dbh), and 1.48% yr(-1) for stems > or = 100 mm dbh. Comparable figures at the Barro Colorado Island site in Panama (BCI) were 2.55% and 2.03%. Growth and recruitment rates were likewise considerably higher at BCI than at Pasoh. For example, in all trees 500-700 mm in dbh, mean BCI growth over the period 1985-1995 was 6 mm yr(-1), whereas mean Pasoh growth was about 3.5 mm yr(-1). Examining growth and mortality rates for individual species showed that the difference between the forests can be attributed to a few light-demanding pioneer species at BCI, which have very high growth and mortality; Pasoh is essentially lacking this guild. The bulk of the species in the two forests are shade-tolerant and have very similar mortality, growth and recruitment. The Pasoh forest is more stable than BCI's in another way as well: few of its tree populations changed much over the eight-year census interval. In contrast, at BCI, over 10% of the species had populations increasing or decreasing at a rate of >0.05 yr(-1) compared to just 2% of the species at Pasoh). The faster species turnover at BCI can probably be attributed to severe droughts that have plagued the forest periodically over the past 30 years; Pasoh has not suffered such extreme events recently. The dearth of pioneer species at Pasoh is associated with low-nutrient soil and slow litter breakdown, but the exact mechanisms behind this association remain poorly understood.
220 citations
TL;DR: This work compared the occurrence of cardiomyocyte apoptosis in explanted hearts with the progression of severe heart failure until the need for transplantation.
Abstract: Background
Cardiomyocyte apoptosis has been found in congestive heart failure, but its clinical significance has been difficult to study. We compared the occurrence of cardiomyocyte apoptosis in explanted hearts with the progression of severe heart failure until the need for transplantation.
Design
Using the TUNEL assay, apoptotic cardiomyocytes were quantified in explanted failing hearts from patients with either idiopathic dilated cardiomyopathy (n = 21) or ischaemic heart disease (n = 14). The percentage was compared with the clinical severity and progression of end-stage heart failure. Samples obtained at autopsy and during open heart surgery served as controls.
Results
The number of apoptotic cardiomyocytes was significantly increased in failing hearts regardless of aetiology (medians 0.075% in ischaemic heart disease and 0.119% in dilated cardiomyopathy) compared with control myocardium. In patients with dilated cardiomyopathy, apoptotic cardiomyocytes were more numerous in subjects with a rapidly deteriorating clinical course (0.192%, n = 10) than in patients with intermediate (0.093%, n = 6, P = 0.03) or slow (0.026%, n = 5, P = 0.003) progression. No such association was observed in patients with ischaemic heart disease, in whom we found significantly increased cardiomyocyte apoptosis adjacent to scars of previous infarctions (0.576%) in contrast to the diffuse distribution seen in dilated cardiomyopathy. Expression of Bcl-2, an antiapoptotic protein, was increased in all failing hearts by immunohistochemistry.
Conclusion
Cardiomyocyte apoptosis is a consistent feature of end-stage heart failure in man and appears to be quantitatively related to the clinical severity of deterioration in dilated cardiomyopathy. Increased expression of Bcl-2 in cardiomyocytes indicates activation of an antiapoptotic response. These observations suggest that cardiomyocyte apoptosis is a clinically relevant and potentially modifiable pathophysiological phenomenon in severe heart failure.
215 citations
TL;DR: These studies suggest that genetic-based plant traits affect the distribution of many species and that the variation in hybrids can be used as tools to examine the genetic components of community structure and biodiversity.
Abstract: Plant hybrid zones are dynamic centers of ecological and evolutionary processes for plants and their associated communities. Studies in the wild and in gardens with synthetic crosses showed that hybrid eucalypts supported the greatest species richness and abundances of insect and fungal taxa. In an updated review of 152 case studies of taxa associated with diverse hybridizing systems, there were 43 (28%) cases of hybrids being more susceptible than their parent species, 7 (5%) resistant, 35 (23%) additive, 35 (23%) dominant, and 32 (21%) showed no response to hybridization. Thus, most taxa respond to hybrids in ways that result in equal or greater abundance, and hybrids tend to accumulate the taxa of their parent species. These studies suggest that genetic-based plant traits affect the distribution of many species and that the variation in hybrids can be used as tools to examine the genetic components of community structure and biodiversity. Several patterns have emerged thus far. (1) Genetic variation between classes of hybrids (e.g., F1’s vs. backcrosses) may equal or even exceed that found between species. (2) As a reflection of this genetic variation, herbivores are more likely to differentiate between hybrid classes than they are to differentiate between pure plant species. (3) The communities associated with different hybrid classes can differ from one another as well as from their parental species. (4) Generalist and specialist herbivores predictably vary in their responses to hybrids. (5) Plant hybrid zones may represent essential habitat for some arthropod species. (6) Even nesting birds respond to hybridizing plants. (7) Including multiple trophic levels and taxa from microbes to vertebrates, susceptible hybrid genotypes support greater biodiversity than resistant genotypes. (8) The effects of hybridization on common or keystone species can either positively or negatively affect biodiversity. The indirect impacts of hybridization on biodiversity may exceed the direct impacts and may result in “apparent” herbivore resistance or susceptibility at the community level. (9) Although hybrids are often maligned, exotic or problem hybrids generally result from human disturbances, whereas native hybrids are part of natural ecosystems and should be conserved.
Three predictions are made: (1) Intermediate genetic differences between the parental species will result in the greatest genetic variation in the hybrid zone, which in turn will have a positive effect on biodiversity. (2) Bidirectional introgression enhances species richness on hybrids, whereas F1 sterility and unidirectional introgression limit the accumulation of species on hybrids. (3) Although susceptible hybrids are likely to support the greatest biodiversity, the impacts of hybridization on keystone species will be crucial in determining the overall effect.
202 citations
TL;DR: In this article, fuel characteristics of 12 tree species grown under a short rotation forestry regime were analyzed, including basic density, volatile matter content, 91.5-95.1%, fixed carbon content, 4.2-7.3%, and extractives content, 3.3-11.9%.
Abstract: Fuel characteristics of biomass from 12 tree species grown under a short rotation forestry regime were analysed. E. globulus, E. nitens and A. dealbata had the biggest trees while A. glutinosa, P. tomentosa and S. matsudana × alba 1002 had the smallest trees when the trees were harvested at the age of 3, 4 and 5 years. Higher heating value (HHV) ranged from 19.6–20.5 MJ/kg for wood, 17.4–20.6 MJ/kg for bark, and 19.5–24.1 MJ/kg for leaves, with the highest values for wood and bark being obtained from Pinus radiata . Wood basic density ranged from 250–500 kg/m 3 ; ash content, 0.7–1.4%; volatile matter content, 91.5–95.1%; fixed carbon content, 4.2–7.3%; and extractives content, 3.3–11.9%. Wood properties were significantly different from those of bark, and also different from those of leaves. Except basic density and the proportion of bark on the stem, properties of wood did not vary with either cutting age or stocking density. Wood from coppice crops did not differ from that of single stem, first harvest crops. Differences in tree size for species planted at similar plant populations determine species yields. Variations in properties between species and between tree parts have implications for feedstock handling, transport, drying, storage, and on the design of conversion systems.
181 citations
TL;DR: In this article, a series of trembling aspen (Populus tremuloides Michx) clones differing in O3 sensitivity have been identified from OTC studies and the responses of these same clones exposed to O3 under field conditions along a natural O3 gradient and in a Free-Air CO2 and O3 Enrichment (FACE) facility.
Abstract: Over the years, a series of trembling aspen (Populus tremuloides Michx.) clones differing in O3 sensitivity have been identified from OTC studies. Three clones (216 and 271[(O3 tolerant] and 259 [O3 sensitive]) have been characterized for O3 sensitivity by growth and biomass responses, foliar symptoms, gas exchange, chlorophyll content, epicuticular wax characteristics, and antioxidant production. In this study we compared the responses of these same clones exposed to O3 under field conditions along a natural O3 gradient and in a Free-Air CO2 and O3 Enrichment (FACE) facility. In addition, we examined how elevated CO2 affected O3 symptom development. Visible O3 symptoms were consistently seen (5 out of 6 years) at two of the three sites along the O3 gradient and where daily one-hour maximum concentrations were in the range of 96 to 125 ppb. Clonal differences in O3 sensitivity were consistent with our OTC rankings Elevated CO2 (200 ppm over ambient and applied during daylight hours during the growing season) reduced visible foliar symptoms for all three clones from 31 to 96% as determined by symptom development in elevated O3 versus elevated O3 + CO2 treatments. Degradation of the epicuticular wax surface of all three clones was found at the two elevated O3 gradient sites. This degradation was quantified by a coefficient of occlusion which was a measure of stomatal occlusion by epicuticular waxes. Statistically significant increases in stomatal occlusion compared to controls were found for all three clones and for all treatments including elevated CO2, elevated O3, and elevated CO2 + O3. Our results provide additional evidence that current ambient O3 levels in the Great Lakes region are causing adverse effects on trembling aspen. Whether or not elevated CO2 in the future will alleviate some of these adverse effects, as occurred with visible symptoms but not with epicuticular wax degradation, is unknown.
131 citations
TL;DR: The present results show that cryoprotectants may cause a risk for genetic fidelity of plant material and thus, monitoring it is important in the breeding of the long-living conifers, since the effects of occasional mutations or genetic rearrangements may be readily observed in young plants but expressed substantially later on in mature trees.
110 citations
TL;DR: Protection was demonstrated to be pathogen nonspecific, as trees that had been pretreated with a medium dosage of the root rot fungus Heterobasidion annosum showed enhanced resistance to challenge inoculation with C. polonica.
Abstract: Norway spruce ( Picea abies ) trees (approximately 16 m high) of a single clone were used to study the effects of fungal infection and wounding on induction of resistance to the bark beetle-associated bluestain fungus Ceratocystis polonica . A dose-response experiment was designed involving three different dosages of fungal (fungus and wound) and sterile agar (wound) pretreatment inoculations (10, 50, or 100 inoculations/m 2 on the stem between 0.8 and 2.0 m high). Three weeks after pretreatment, trees were challenged with a massive C. polonica inoculation (400 inoculations/m 2 ). Control trees that received no pretreatment were heavily colonized and killed by the challenge inoculation. The high and medium fungal pretreatments reduced subsequent fungal colonization success by 76% to 97% relative to the control, and fungal pretreatments protected the trees much more efficiently than sterile agar pretreatments. The protection was demonstrated to be local and not systemic in a subsequent experiment, where trees were pretreated with the medium fungal dosage on the lower bole and challenge inoculated further up the stem. Protection was also demonstrated to be pathogen nonspecific, as trees that had been pretreated with a medium dosage of the root rot fungus Heterobasidion annosum showed enhanced resistance to challenge inoculation with C. polonica .
94 citations
TL;DR: In human cardiac membranes, the most critical step in kinin metabolism, that is, inactivation of BK, appears to be mediated mostly by NEP, which suggests a role for NEP in the local control of Bk concentration in heart tissue.
Abstract: Background—Since kinins kallidin (KD) and bradykinin (BK) appear to have cardioprotective effects ranging from improved hemodynamics to antiproliferative effects, inhibition of kinin-degrading enzymes should potentiate such effects. Indeed, it is believed that this mechanism is partly responsible for the beneficial effects of angiotensin-converting enzyme (ACE) inhibitors. In the heart, enzymes other than ACE may contribute to local degradation of kinins. The purpose of this study was to investigate which enzymes are responsible for the degradation of KD and BK in human heart tissue. Methods and Results—Cardiac membranes were prepared from the left ventricles of normal (n=5) and failing (n=10) hearts. The patients had end-stage congestive heart failure as the result of coronary heart disease or idiopathic dilated cardiomyopathy. Heart tissue was incubated with KD or BK in the presence or absence of enzyme inhibitors. We found no difference in the enzymes responsible for kinin metabolism or their activitie...
80 citations
TL;DR: Magnesium (Mg) nutrition and photosynthesis were studied in clones of Pinus radiata D. Don grown in sand culture for 21 weeks and found significant clonal variation in Mg nutrition of P. radiata.
Abstract: Magnesium (Mg) nutrition and photosynthesis were studied in clones of Pinus radiata D. Don grown in sand culture for 21 weeks at four Mg concentrations (0.008, 0.04, 0.2 and 0.4 mM) and three potassium (K) concentrations (0.25, 0.5 and 2.5 mM). We found significant clonal variation in Mg nutrition of P. radiata. Plants grown at 0.04 mM [Mg] or less showed pronounced visible symptoms of foliar Mg deficiency. Net photosynthetic rate and leaf conductance were closely related to shoot Mg concentrations below a concentration of 0.6 mg Mg g(DW) (-1). Potassium enhanced the development of visible symptoms of foliar Mg deficiency. At the lowest Mg concentration tested (0.008 mM), the severity of needle chlorosis and necrosis increased with increasing K concentration in the culture solution. With increasing Mg concentration, 2.5 mM [K] in the culture solution markedly increased root Mg concentration, but decreased shoot Mg concentration, suggesting that excessive K inhibited Mg mobilization from roots to shoots. Rates of growth and photosynthesis were both severely inhibited at 0.008 mM [Mg].
TL;DR: High-frequency direct shoot proliferation was induced in aseptic seed cultures of D. asper on modified Murashige and Skoog's (1962) medium supplemented with 1.0–10.0 mg/l benzyladenine to achieve efficient and reproducible propagation of Dendrocalamus asper.
Abstract: An efficient and reproducible procedure for the large-scale propagation of Dendrocalamus asper is described. High-frequency direct shoot proliferation was induced in aseptic seed cultures of D. asper on modified Murashige and Skoog's (1962) medium supplemented with 1.0–10.0 mg/l benzyladenine (BA). Multiple shoots (1–25) were formed within 5 weeks of seed culture without root formation. The shoot-forming capacity of seeds was influenced by the BA concentration in the medium. Proliferating shoot cultures were established by repeatedly subculturing shoots in propagules of 3 shoots each. A multiplication rate of 15–16 fold was achieved on MS medium +3.0 mg/l BA. Roots were formed on excised propagules of 3–5 shoots when transferred to MS medium containing 10.0 mg/l indole-3-butyric acid (IBA) or 3.0 mg/l 1-naphthaleneacetic acid (NAA). Plantlets were hardened, acclimatized and established in soil, where they exhibited normal growth.
TL;DR: It is concluded that N reallocation and acclimation of PSII to self-shading occurred even in mature leaves, whereas the change in photosynthetic capacity with leaf age was more conservative.
Abstract: In the tropical canopy tree, Dryobalanops aromatica Gaertn. f., upper-canopy leaves (UL) develop under sunlit conditions but are subjected to self-shading within the crown as they age. In contrast, lower-canopy leaves (LL) are exposed to uniform dim light conditions throughout their life span. By comparing leaf morphology and physiology of UL and LL, variations in leaf characteristics were related to leaf age and self-shading. Mass-based chlorophyll (chl) concentration and the chlorophyll/nitrogen (chl/N) ratio were lower and the chl a/b ratio was higher in UL than in LL. In UL, the chl/N ratio gradually increased and the chl a/b ratio gradually decreased with leaf aging, whereas these ratios remained unchanged with leaf age in LL. The effective quantum yield of photosystem II (PSII) (DeltaF/F(m)') at a given irradiance remained unchanged with leaf age in LL, whereas DeltaF/F(m)' changed with leaf age in UL. These data indicate N reallocation within the leaves from carbon fixation components to light harvesting components and a dynamic regulation of photochemical processes of PSII in response to increased self-shading of UL. Despite the difference in light environment with leaf age between UL and LL, maximum photosynthetic rates and nitrogen-use efficiency decreased with leaf aging in both UL and LL. Constancy in the chl/N ratio with leaf age in LL indicated that the decrease in photosynthetic capacity was caused by effects other than shading, such as leaf aging. We conclude that N reallocation and acclimation of PSII to self-shading occurred even in mature leaves, whereas the change in photosynthetic capacity with leaf age was more conservative.
TL;DR: In this paper, the mechanistic Windermere humic aqueous model (WHAM) was applied to describe the solubility of Al and organic matter as observed in a batch equilibrium study with a forest floor Oe horizon.
Abstract: Several studies suggest that solution concentration of Al in organic surface soils are controlled by complexation with organic matter. The authors applied the mechanistic Windermere humic aqueous model (WHAM) to describe the solubility of Al and organic matter as observed in a batch equilibrium study with a forest floor Oe horizon. WHAM is unique in that it considers interactions of soil organic matter with protons and metals. They also compared WHAM with a previously proposed linear regression model that describes Al solubility. A range of soil Al contents was established by adding different amounts of Al in batch prior to titration with acid or base. The soil Al content was described by the bound Al ratio (BAR), defined as the equivalent ratio of organically bound Al and carboxyl groups. The bound Al ratio and pH ranged from 0.1 to 3, and from 1.7 to 6.3, respectively. Solutions were undersaturated with respect to Al(OH){sub 3}, except at BAR {ge} 2 and pH {ge} 4.5. Aluminum solubility increased with increasing BAR. Organic matter solubility was greatest at low BAR and high pH. WHAM reproduced the observed pH and Al concentrations, using parameters derived from experimental data. At BAR {lt} 0.7, pH-pAl relationshipsmore » were approximately linear. At BAR {ge} 0.7, there was a nonlinear increase in {Delta}pAl/{Delta}pH with pH. WHAM simulated the changing slope of the pH-pAl curves satisfactorily and reproduced observed trends in dissolved organic C (DOC) concentrations. This supports the hypotheses and assumptions concerning mechanisms for binding Al to soil organic matter in a forest floor, as embodied in WHAM.« less
TL;DR: Evidence is provided that the ability of collagen to bind LDL in vitro is greatly enhanced by decorin, a collagen-binding small proteoglycan that also is present in atherosclerotic lesions, which provides a novel mechanism for retention of LDL in collagen-rich regions of the arterial intima.
TL;DR: The results support the hypothesis that many of the reproductive processes in the angiosperms and gymnosperms were inherited from a common ancestor.
Abstract: We describe the isolation and characterization of 13 cDNA clones that are differentially expressed in male cones of Pinus radiata (D. Don). The transcripts of the 13 genes are expressed at different times between meiosis and microspore mitosis, timing that corresponds to a burst in tapetal activity in the developing anthers. In situ hybridization showed that four of the genes are expressed in the tapetum, while a fifth is expressed in tetrads during a brief developmental window. Six of the seven cDNAs identified in database searches have striking similarity to genes expressed in angiosperm anthers. Seven cDNAs are homologs of defense and pathogen response genes. The cDNAs identified are predicted to encode a chalcone-synthase-like protein, a thaumatin-like protein, a serine hydrolase thought to be a putative regulator of programmed cell death, two lipid-transfer proteins, and two homologs of the anther-specific A9 genes from Brassica napus and Arabidopsis. Overall, our results support the hypothesis that many of the reproductive processes in the angiosperms and gymnosperms were inherited from a common ancestor.
TL;DR: In this paper, the scaling of water absorption and water loss by seeds on various soil surfaces was simulated using seed analogues constructed with paper pulp, and the scaling coefficients between the amount of absorbed water by an analogue seed and seed mass were usually lower than 1: small seeds absorbed water more rapidly than large ones.
Abstract: Scaling of water absorption and water loss by seeds on various soil surfaces was simulated using seed analogues constructed with paper pulp. Three sizes of analogue seeds (large, medium and small) were laid on three types of soil surface (coarse, medium and fine texture). To estimate the amount of water absorbed by a seed during a fixed time interval, the difference in seed weight from the start of the experiment was used. The scaling of water absorption necessary for germination was also studied using actual seeds of 14 species representing a range of seed sizes. Scaling coefficients between the amount of absorbed water by an analogue seed (net water gain) and seed mass were usually lower than 1: small seeds absorbed water more rapidly than large ones. The water loss of analogue seeds was also correlated with seed mass with a scaling coefficient lower than 1, but the amount of water loss itself was far smaller than the absorption. On the other hand, the germination of actual seeds revealed that the amount of water necessary to start germination was proportional to seed mass. Thus, smaller seeds have an advantage over larger seeds in more rapidly attaining the water content necessary for germination. Moreover, small seeds can penetrate through small cracks in the soil surface and thus enjoy a double advantage in a microsite that promotes water absorption and minimizes desiccation.
TL;DR: The significance of the genetic background of the explants and the initiation medium indicate that it might be possible to improve the initiation rates by using explants from controlled crossings between competent genotypes, and by developing more specific media for important seed families.
Abstract: This is the first report on Scots pine (Pinus sylvestris L.) somatic embryo plants regenerated and growing in a greenhouse. The present work focused on improving somatic embryogenesis of the species by studying the factors affecting culture induction. Developmental stage of explants that were immature female gametophytes, including the zygotic embryos with suspensor tissues, was investigated in detail. The genetic background of the material, cold treatments (14 d, 1 or 2 months at +5 °C) of cones including explants, as well as the plant growth regulator composition of the initiation medium, were also examined. When initiation of somatic embryogenesis was successful, the zygotic embryos in the explants were either proembryos or early embryos. Cold treatment of the cones had no significant effect on induction, nor were there any differences among the treatments with different duration, thus improving the practical applicability of the culture technique. The explants in cold-stored cones probably retained their initiation capacity due to the conversion of starch to sugars. This was observed as decreased number and size of starch grains in the megagametophytes compared with the controls. The seed family and the medium significantly affected induction success, the medium with auxin (9.1 or 13.6 μM 2,4-dichlorophenoxyacetic acid) and cytokinin (2.2 μM 6-benzylaminopurine) being better than the medium with cytokinin (5 μM 6-benzylaminopurine) alone. The significance of the genetic background of the explants and the initiation medium indicate that it might be possible to improve the initiation rates by using explants from controlled crossings between competent genotypes, and by developing more specific media for important seed families.
TL;DR: It is shown that if the distortion is caused by a single viability gene or by sampling error, the estimate of recombination frequency in megagametophytes of selfed seeds would not be affected.
Abstract: A genetic map of Pinus radiata plus tree 850.55 was constructed using megagametophytes of S1 seeds. The map contained 19 linkage groups, with 168 RAPD and four microsatellite markers. The total map length was 1116.7 cM (Kosambi’s function) and was estimated to cover 56% of the genome. Of the 172 markers, 59 (34%) were distorted from the expected 1 : 1 ratio in megagametophytes (P<0.05). We show that if the distortion is caused by a single viability gene or by sampling error, the estimate of recombination frequency in megagametophytes of selfed seeds would not be affected.
TL;DR: Activated mast cells, by releasing heparin proteoglycans, possibly participate in the regulation of SMC growth in the human arterial intima, the site of atherogenesis.
Abstract: -Mast cells are present in the human arterial intima. To study whether mast-cell degranulation influences the rate of proliferation of smooth muscle cells, we cocultured sensitized (IgE-bearing) rat serosal mast cells and rat aortic smooth muscle cells (SMCs). When sensitized mast cells were stimulated to degranulate with antigen, the rate of proliferation of the cocultured SMCs decreased sharply. This inhibitory effect was found to be due mainly to the very high molecular weight (Mr) heparin proteoglycans (average Mr 750 000) released from the stimulated mast cells. When the heparin proteoglycans were purified from mast-cell granule remnants and added to the SMC culture, they were found to block the cell cycle at the G0-->S transition and the exit from the G2/M phase, their inhibitory effect resembling that of commercial heparin. However, in contrast to the reported dependence of the inhibitory effect of commercial heparin on the release of transforming growth factor-beta from serum, the inhibitory effect of the mast cell-derived heparin proteoglycans in the presence of serum was not transforming growth factor-beta dependent. Moreover, the effect of the mast cell-derived heparin proteoglycans was more efficient than that of commercial heparins of high (average Mr 15 000) and low (average Mr 5000) molecular weight. We also purified heparin glycosaminoglycans (average Mr 75 000) from the mast cell-derived heparin proteoglycans and found that they also inhibited SMC growth efficiently, although less strongly than their parent heparin proteoglycans. These results reveal, for the first time, that mast cells are able to regulate SMC growth. Thus, activated mast cells, by releasing heparin proteoglycans, possibly participate in the regulation of SMC growth in the human arterial intima, the site of atherogenesis.
TL;DR: In this article, the role of forest productivity in defining the sustainability of plantation forests in New Zealand is evaluated, where management practices lead to reductions in productivity, some form of amelioration is required and, as long as this is economically viable the practice is still sustainable.
TL;DR: Volatile constituents of Vitex negundo leaves growing in Dehra Dun (India) were analysed by gas chromatography-mass spectrometry (GC-MS) and showed the presence of sixty-six compounds, constituting 74.96% of the oil.
Abstract: Volatile constituents of Vitex negundo leaves growing in Dehra Dun (India) were analysed by gas chromatography-mass spectrometry (GC-MS) and showed the presence of sixty-six compounds. Such a study has not been done earlier on the Indian oil. Thirty-five compounds, constituting 74.96% of the oil, were identified. The main compounds are viridiflorol (19.55%), beta-caryophyllene (16.59%), sabinene (12.07%), 4-terpineol (9.65%), gamma-terpinene (2.21%), caryophyllene oxide (1.75%), 1-oceten-3-ol (1.59%), and globulol (1.05%). Viridiflorol is being reported for the first time in the oil of Vitex species.
TL;DR: In this paper, the authors used permanent plots from permanent plots collected in 1931, 1961 and 1991 in a south boreal forest 20 km north of Oslo in southern Norway in order to investigate changes in vegetation composition during those 60 years.
Abstract: . Vegetation data from permanent plots were collected in 1931, 1961 and 1991 in a south boreal forest 20 km north of Oslo in southern Norway. Major changes were found in the vegetation composition during those 60 years. The main changes were a reduction in the frequency of species and the frequency of joint occurrences of vascular species such as Andromeda polifolia, Calluna vulgaris, Cornus suecica, Eriophorum vaginatum, Maianthemum bifolium, Melampyrum pratense, Trientalis europaea, Vaccinium uliginosum and V. oxycoccus, and mosses, e.g. Dicranum fuscescens, Hylocomium splendens, Pleurozium schreberi, Ptilidium ciliare and Ptilium crista-castrensis.
The observed changes were interpreted as being induced by internal processes e.g. notably a long-term change from paludified forest to mesic forest. In particular the growth of Picea abies seems to be a main driving force. The dominance of Picea abies and Vaccinium myrtillus appears to have rendered the conditions more unfavourable for other species. A doubling of the living stem biomass of P. abies during the last 67 yr shows that this old-growth forest has not yet reached a steady state. It was demonstrated that species such as Deschampsia flexuosa and Molinia caerulea did not increase in frequency in response to nitrogen deposition, as has occurred elsewhere in northern Europe. pH in the humus layer increased with 0.2 unit from 1961 to 1991.
The results of this study indicate that protection from logging has initiated the reduction of species in the field layer and bottom layer. This study questions if monitoring of forest vegetation should be restricted to protected forests as is the practice in Scandinavia today. We recommend that also areas with some kind of selective cutting will be used for monitoring of forest vegetation.
TL;DR: Linked dynamic programming formulations are developed that can be modified to maximise either total value of boards (incorporating quality) or total volume and results from simulations indicate that significant increases in value are possible when quality is considered.
Abstract: At sawmills logs are converted into boards by a series of cutting operations. Primary cuts reduce logs into slabs of wood, secondary cuts produce boards. Boards incorporating natural defects such as knots (branch sections) are inferior to clear boards. The aim of the sawmill is to cut logs to produce boards of greatest value. However, when logs are pruned, knots are only exposed after primary cutting. This complicates the conversion problem. To effectively convert logs into boards the interrelated effects of the cutting phases must be recognized. In this paper linked dynamic programming formulations are developed. The inner (secondary) formulation determines the optimal sequence for cutting a slab into boards. The result is passed to the master (primary) formulation that determines the optimal sequence for cutting the log into slabs. The objective functions can be modified to maximise either total value of boards (incorporating quality) or total volume. Results from simulations indicate that significant increases in value are possible when quality is considered.
TL;DR: It is concluded that during summer, when the forage quality of kermes oak shrubland declines, browse supplement with certain deciduous woody fodder plants allows weight gains similar to those of alfalfa pellets; thereby, improving grazing animal performance.
TL;DR: It is concluded that the reduced ability of granule remnant-treated HDL3 and granule remnants-treated plasma to induce cholesterol efflux from macrophage foam cells is caused by selective depletion by mast cell chymase of quantitatively minor A1- and A4-containing subpopulations of HDL.
Abstract: —Exposure of the LpA1-containing particles present in HDL 3 and plasma to a minimal degree of proteolysis by the neutral protease chymase from exocytosed rat mast cell granules (granule remnants) leads to a reduction in the high-affinity component of cholesterol efflux from macrophage foam cells In this study, we demonstrate for the first time, a role for mast cell chymase in the depletion of the lipid-poor minor components of HDL that are specifically involved in reverse cholesterol transport as initial acceptors of cellular cholesterol Thus, addition of proteolytically active granule remnants or human skin chymase to cholesterol-loaded macrophages of mouse or human origin incubated with human apoA1, ie, a system in which preβ 1 LpA1 is generated, resulted in a sharp reduction in the high-affinity cholesterol efflux promoted by apoA1 As determined by nondenaturing 2-dimensional polyacrylamide gradient gel electrophoresis, the granule remnants effectively depleted the preβ 1 LpA1, but not the αLpA1, in HDL 3 and in plasma during incubation at 37°C for 3 and granule remnant-treated plasma to induce cholesterol efflux from macrophage foam cells is caused by selective depletion by mast cell chymase of quantitatively minor A1- and A4-containing subpopulations of HDL Because these particles, ie, preβ 1 LpA1 and LpA4, are efficient acceptors of cholesterol from cell surfaces, their depletion by mast cells may block the initiation of reverse cholesterol transport in vivo and thereby favor foam cell formation in the arterial intima, the site of atherogenesis
TL;DR: In this paper, the effects of the addition of 35 kg N ha-1yr-1 (as NH4NO3) and interception of throughfall and litterfall by means of a roof on concentrations, chemical characteristics and dynamics of dissolved organic matter (DOM) in acid forest soils (podzols) were studied at Gardsjon, Sweden.
Abstract: Effects of (1) the addition of 35 kg N ha-1yr-1(as NH4NO3) and (2) interception of throughfall and litterfall by means of a roof on concentrations, chemical characteristics and dynamics of dissolved organic matter (DOM) in acid forest soils (podzols) were studied at Gardsjon, Sweden. A non-manipulated catchment served as a reference. After 4 yr of treatment no significant effects of either manipulation were found on concentrations and characteristics of dissolved organic carbon (DOC) and dissolved organic nitrogen (DON). The variability of these parameters within catchments appeared to be of the same order of magnitude as the variability between catchments. At all sites, DON contributed more than 70% of the total dissolved nitrogen. In general, the proportion of hydrophilic DOC increased with depth. In contrast, to other studies the C/N ratio of DOM at Gardsjon did not show a clear pattern with depth. Other studies in SE U.S.A. have suggested that relatively low C/N ratios at depth are due to increased contribution of hydrophilic neutrals to DOC. However, this fraction appears to be small in temperate and boreal spruce forest soils, including Gardsjon.
TL;DR: In this article, the relationship between the soil's dielectric constant (K a ) and water content (θ) was measured by time domain reflectometry (TDR) for sandy volcanic soils on the North Island of New Zealand.
Abstract: To measure soil water content (θ) by time domain reflectometry (TDR), one must know the relationship between the soil's dielectric constant (K a ) and θ. Our objective was to determine K a -θ calibrations for sandy volcanic soils on the North Island of New Zealand. We collected samples from 24 horizons and 6 soil profiles. The soils were sandy loam and loamy sand textured, with bulk densities between 0.55 and 1.34 Mg m 3 . Samples were air-dried and packed to their field bulk density in plastic boxes. Time domain reflectometry probes (100 mm long) were inserted, and TDR waveforms were recorded and analyzed. Water contents were increased in approximate steps of 0.05 m 3 m 3 volume to the liquid limit, which varied between 0.33 and 0.57 m 3 m 3 . Samples were then submerged to obtain water contents as great as 0.646 m 3 m 3. Measured water contents were greater that those predicted by the Topp equation, but the differences varied according to soil texture. Pooled data from 17 of the samples provided a third-order polynomial calibration with an R 2 of 0.977 and root mean square error (RMSE) of 0.026 m m 3 . A third-order mixing model and a linear K a -θ expression gave greater mean errors. Although the calibration applied to a range of sandy volcanic soils, there were also two small groups of samples that showed distinct calibrations. These were coarser tephras, with at least 75% of particles >0.125 mm diam. by mass, and with bulk densities > 1.0 Mg m -3 .
TL;DR: In this paper, the authors used the multivariate cointegration method of Johansen instead of the bivariate method commonly used in earlier studies to test the existence of the law of one price for imports of soft sawnwood from Finland, Sweden, Canada and Russia.
Abstract: The law of one price states that prices of homogenous commodities, defined in a common currency, are equal throughout the world. It implies cointegration of prices. In the present study, the law was tested for imports of soft sawnwood to the United Kingdom from Finland, Sweden, Canada and Russia using the concept of cointegration. The data are quarterly and cover the period 1978–1992. The study used the multivariate cointegration method of Johansen instead of the bivariate method commonly used in earlier studies. The existence of the law was tested simultaneously for all four import prices and separately for pairs of prices. The results do not support the “law”but instead indicate the existence of differences over the long run between different suppliers’ sawnwood prices. This suggests that imperfect competition models should be used in explaining and forecasting UK sawnwood imports. The results also raise an important issue concerning testing for competition in forest products markets, which is not usually done in connection with the modeling of markets.
TL;DR: In this article, the CIRAD-Fort% growth strain gauge was used for estimating stein growth stress, and the relationship of longitudinal growth strain with log-end splitting, sawn timber distortion and other tree and wood properties was studied in 23 ten-year-old Eucalyptus cloeziana trees.
Abstract: SYMMARY To assess the utility of the CIRAD-Fort% growth strain gauge for estimating stein growth stress, the relationship of longitudinal growth strain (LGS) with log-end splitting, sawn timber distortion and other tree and wood properties was studied in 23 ten-year-old Eucalyptus cloeziana trees. The CIRAD-Foret growth strain gauge appears to be useful as a means of predicting sawn timber distortion in young E. cloeziana trees. LGS correlated well with bow and spring and accounted for 50 and 30% of the respective total variation. The relationships of LGS with log end splitting, wood density, tree diameter and height were weak. However, distinct differences in wood density and sawtimber distortion were observed between trees with low and high strain. Trees with high growth strain were generally smaller with wood of significantly higher basic density and bow. Sampling position around the stem was not important and LGS increased with tree height.