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1.
Eva Ritter 《Plant and Soil》2007,295(1-2):239-251
Afforestation has become an important tool for soil protection and land reclamation in Iceland. Nevertheless, the harsh climate
and degraded soils are growth-limiting for trees, and little is know about changes in soil nutrients in maturing forests planted
on the volcanic soils. In the present chronosequence study, changes in C, N and total P in soil (0–10 and 10–20 cm depth)
and C and N in foliar tissue were investigated in stands of native Downy birch (Betula pubescens Enrh.) and the in Iceland introduced Siberian larch (Larix sibirica Ledeb.). The forest stands were between 14 and 97 years old and were established on heath land that had been treeless for
centuries. Soils were Andosols derived from basaltic material and rhyolitic volcanic ash. A significant effect of tree species
was only found for the N content in foliar tissue. Foliar N concentrations were significantly higher and foliar C/N ratios
significantly lower in larch needles than in birch leaves. There was no effect of stand age. Changes in soil C and the soil
nutrient status with time after afforestation were little significant. Soil C concentrations in 0–10 cm depth in forest stands
older than 30 years were significantly higher than in heath land and forest stands younger than 30 years. This was attributed
to a slow accumulation of organic matter. Soil N concentrations and soil Ptot were not affected by stand age. Nutrient pools in the two soil layers were calculated for an average weight of soil material
(400 Mg soil ha−1 in 0–10 cm depth and 600 Mg soil ha−1 in 10–20 cm depth, respectively). Soil nutrient pools did not change significantly with time. Soil C pools were in average
23.6 Mg ha−1 in the upper soil layer and 16.9 Mg ha−1 in the lower soil layer. The highest annual increase in soil C under forest compared to heath land was 0.23 Mg C ha−1 year−1 in 0–10 cm depth calculated for the 53-year-old larch stand. Soil N pools were in average 1.0 Mg N ha−1 in both soil layers and did not decrease with time despite a low N deposition and the uptake and accumulation of N in biomass
of the growing trees. Soil Ptot pools were in average 220 and 320 kg P ha−1 in the upper and lower soil layer, respectively. It was assumed that mycorrhizal fungi present in the stands had an influence
on the availability of N and P to the trees.
Responsible Editor: Hans Lambers. 相似文献
2.
Sílvia Fernanda Mardegan Gabriela Bielefeld Nardoto Niro Higuchi Marcelo Zacharias Moreira Luiz Antonio Martinelli 《Trees - Structure and Function》2009,23(3):479-488
Addressing spatial variability in nitrogen (N) availability in the Central Brazilian Amazon, we hypothesized that N availability
varies among white-sand vegetation types (campina and campinarana) and lowland tropical forests (dense terra-firme forests) in the Central Brazilian Amazon, under the same climate conditions.
Accordingly, we measured soil and foliar N concentration and N isotope ratios (δ15N) throughout the campina-campinarana transect and compared to published dense terra-firme forest results. There were no differences between white-sand vegetation
types in regard to soil N concentration, C:N ratio and δ15N across the transect. Both white-sand vegetation types showed very low foliar N concentrations and elevated foliar C:N ratios,
and no significant difference between site types was observed. Foliar δ15N was depleted, varying from −9.6 to 1.6‰ in the white-sand vegetations. The legume Aldina heterophylla had the highest average δ15N values (−1.5‰) as well as the highest foliar N concentration (2.1%) while the non-legume species had more depleted δ15N values and the average foliar N concentrations varied from 0.9 to 1.5% among them. Despite the high variation in foliar
δ15N among plants, a significant and gradual 15N-enrichment in foliar isotopic signatures throughout the campina–campinarana transect was observed. Individual plants growing in the campinarana were significantly enriched in 15N compared to those in campina. In the white-sand N-limited ecosystems, the differentiation of N use seems to be a major cause of variations observed in
foliar δ15N values throughout the campina–campinarana transect. 相似文献
3.
Ben Bond-Lamberty Stith T. Gower Chuankuan Wang Pascal Cyr Hugo Veldhuis 《Biogeochemistry》2006,81(1):1-16
This study examined the nitrogen (N) dynamics of a black spruce (Picea mariana (Mill.) BSP)-dominated chronosequence in Manitoba, Canada. The seven sites studied each contained separate well- and poorly drained stands, originated from stand-killing wildfires, and were between 3 and 151 years old. Our goals were to (i) measure total N concentration ([N]) of all biomass components and major soil horizons; (ii) compare N content and select vegetation N cycle processes among the stands; and (iii) examine relationships between ecosystem C and N cycling for these stands. Vegetation [N] varied significantly by tissue type, species, soil drainage, and stand age; woody debris [N] increased with decay state and decreased with debris size. Soil [N] declined with horizon depth but did not vary with stand age. Total (live + dead) biomass N content ranged from 18.4 to 99.7 g N m−2 in the well-drained stands and 37.8–154.6 g N m−2 in the poorly drained stands. Mean soil N content (380.6 g N m−2) was unaffected by stand age. Annual vegetation N requirement (5.9 and 8.4 g N m−2 yr−1 in the middle-aged well- and poorly drained stands, respectively) was dominated by trees and fine roots in the well-drained stands, and bryophytes in the poorly drained stands. Fraction N retranslocated was significantly higher in deciduous than evergreen tree species, and in older than younger stands. Nitrogen use efficiency (NUE) was significantly lower in bryophytes than in trees, and in deciduous than in evergreen trees. Tree NUE increased with stand age, but overall stand NUE was roughly constant (∼
∼150 g g−1 N) across the entire chronosequence. 相似文献
4.
Net Primary Production and Canopy Nitrogen in a Temperate Forest Landscape: An Analysis Using Imaging Spectroscopy, Modeling and Field Data 总被引:4,自引:0,他引:4
Understanding spatial patterns of net primary production (NPP) is central to the study of terrestrial ecosystems, but efforts
are frequently hampered by a lack of spatial information regarding factors such as nitrogen availability and site history.
Here, we examined the degree to which canopy nitrogen can serve as an indicator of patterns of NPP at the Bartlett Experimental
Forest in New Hampshire by linking canopy nitrogen estimates from two high spectral resolution remote sensing instruments
with field measurements and an ecosystem model. Predicted NPP across the study area ranged from less than 700 g m−2 year−1 to greater than 1300 g m−2 year−1 with a mean of 951 g m−2 year−1. Spatial patterns corresponded with elevation, species composition and historical forest management, all of which were reflected
in patterns of canopy nitrogen. The relationship between production and elevation was nonlinear, with an increase from low-
to mid-elevation deciduous stands, followed by a decline in upper-elevation areas dominated by evergreens. This pattern was
also evident in field measurements and mirrored an elevational trend in foliar N concentrations. The increase in production from low-to mid-elevation deciduous stands runs counter to the generally accepted
pattern for the northeastern U.S. region, and suggests an importance of moisture limitations in lower-elevation forests.
Field measurements of foliar N, wood production and leaf litterfall were also used to evaluate sources of error in model estimates and to determine how
predictions are affected by different methods of acquiring foliar N input data. The accuracy of predictions generated from remotely sensed foliar N approached that of predictions driven by field-measured foliar N. Predictions based on the more common approach of using aggregated foliar N for individual cover types showed reasonable agreement in terms of the overall mean, but were in poor agreement on a plot-by-plot
basis. Collectively, these results suggest that variation in foliar N exerts an important control on landscape-level spatial patterns and can serve as an integrator of other underlying factors
that influence forest growth rates. 相似文献
5.
S. M. Ghaderian A. Mohtadi R. Rahiminejad R. D. Reeves A. J. M. Baker 《Plant and Soil》2007,293(1-2):91-97
Serpentine soils, which contain relatively high concentrations of nickel and some other metals, are the preferred substrate
for some plants, especially those that accumulate Ni in their tissues. In temperate regions more Ni-hyperaccumulator plants
are found in Alyssum than in any other genus. In this study, serpentine soils of two areas (Marivan and Dizaj) in the west/northwest of Iran and
also perennial Alyssum plants growing on these soils were analyzed for Ni and some other metals. The highest concentrations of total metals in the
soils of these areas for Ni, Cr, Co and Mn were 1,350, 265, 94 and 1,150 μg g−1, respectively, while concentrations of Fe, Mg and Ca reached 3.55%, 16.8% and 0.585% respectively. The concentration of exchangeable
Ni in these soils is up to 4.5 μg g−1. In this study two Alyssum species, A. inflatum and A. longistylum, have been collected from Marivan and Dizaj, respectively. Analysis of leaf dry matter shows that they can contain up to
3,700 and 8,100 μg Ni g−1, respectively. This is the first time that such high Ni concentrations have been found in these species. The concentrations
of other metals determined in these species were in the normal range for serpentine plants, except for Ca, which was higher,
up to 5.3% and 3.5%, respectively 相似文献
6.
Current and one-year-old foliage was collected from sixty-five red spruce trees growing in thirteen stands at different elevations
in the Green Mountains of Vermont and Adirondacks of New York. Sample trees were randomly selected from visually healthy trees
at each site. Foliage was analyzed for major and minor elements. In July 1984, foliar Ca, Mg, and Zn concentrations were significantly
greater at low than at high elevations. In October 1984, Ca, Mg, and Zn concentrations were higher at low elevations and Ca
and Mg concentrations varied significantly among locations within elevational groups. Nitrogen concentration was significantly
higher in the high-elevation group in July but not in October. The average red spruce foliar Mg concentration at the end of
the growing season in the high elevation stands (442 mg kg−1) is much lower than values reported for other mature red spruce stands in the eastern United States. 相似文献
7.
Fernando DR Woodrow IE Jaffré T Dumontet V Marshall AT Baker AJ 《The New phytologist》2008,177(1):178-185
Hyperaccumulation by plants is a rare phenomenon that has potential practical benefits. The majority of manganese (Mn) hyperaccumulators discovered to date occur in New Caledonia, and little is known about their ecophysiology. This study reports on natural populations of one such species, the endemic shrub Maytenus founieri. Mean foliar Mn concentrations of two populations growing on ultramafic substrates with varying soil pHs were obtained. Leaf anatomies were examined by light microscopy, while the spatial distributions of foliar Mn in both populations were examined by qualitative scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS). Plants growing on two different substrates were found to have very different mean dry weight (DW) foliar Mn concentrations. Light microscopy showed that the leaves had very distinct thick dermal structures, consisting of multiple layers of large cells in the hypodermis. In vivo X-ray microprobe analyses revealed that, in both populations, Mn sequestration occurred primarily in these dermal tissues. The finding here that foliar Mn is most highly localized in the nonphotosynthetic tissues of M. founieri contrasts with results from similar studies on other woody species that accumulate high Mn concentrations in their shoots. 相似文献
8.
The chemical composition of rainwater is altered upon its passage through tree canopies. In order to investigate how rainwater
chemistry is affected by canopy-dependent processes in characteristic forest types of Northwest German sandy lowland regions
– oak–birch-forests, Betula pubescens Ehrh. swamp forests, and stands of Pinus sylvestris L. – comparative studies on the chemical composition of throughfall were carried out at seven forest sites, situated in close
proximity within a nature reserve. Additionally, rainwater was sampled at three heathland sites for analysis of open-field
precipitation and at three sites along an oak–birch-forest edge. Throughfall concentrations of most of the parameters analysed
were significantly higher than open-field concentrations, especially with regard to electric conductivity, NH4-N, K+, and KMnO4-index. Ion concentrations in throughfall were the lowest in a 10-year-old stand of Betula pendula Roth. and Pinus sylvestris and in a Betula pubescens swamp forest and were highest beneath a stand of Pinus sylvestris. Except for Na+, Cl−, and NO3−, ion concentrations in both throughfall and open-field precipitation increased during the growing season (May–October). In
throughfall, Ca2+, Mg2+, K+, and Mn2+ were strongly correlated. Enrichment ratios between throughfall and open-field deposition varied among sites and elements
and were the highest for K‰+, Mg2‰+, and Mn2‰+. Estimates of canopy leaching indicated high leaching rates of K‰+ and Mn2‰+ and moderate leaching of Mg2‰+. The contribution of foliar leaching to throughfall deposition was higher at the deciduous than at the coniferous stands. 相似文献
9.
Biomass, morphology and nutrient contents of fine roots in four Norway spruce stands 总被引:2,自引:0,他引:2
Fine root systems may respond to soil chemical conditions, but contrasting results have been obtained from field studies in
non-manipulated forests with distinct soil chemical properties. We investigated biomass, necromass, live/dead ratios, morphology
and nutrient concentrations of fine roots (<2 mm) in four mature Norway spruce (Picea abies [L.] Karst.) stands of south-east Germany, encompassing variations in soil chemical properties and climate. All stands
were established on acidic soils (pH (CaCl2) range 2.8–3.8 in the humus layer), two of the four stands had molar ratios in soil solution below 1 and one of the four
stands had received a liming treatment 22 years before the study. Soil cores down to 40 cm mineral soil depth were taken in
autumn and separated into four fractions: humus layer, 0–10 cm, 10–20 cm and 20–40 cm. We found no indications of negative
effects of N availability on fine root properties despite large variations in inorganic N seepage fluxes (4–34 kg N ha−1 yr−1), suggesting that the variation in N deposition between 17 and 26 kg N ha−1 yr−1 does not affect the fine root system of Norway spruce. Fine root biomass was largest in the humus layer and increased with
the amount of organic matter stored in the humus layer, indicating that the vertical pattern of fine roots is largely affected
by the thickness of this horizon. Only two stands showed significant differences in fine root biomass of the mineral soil
which can be explained by differences in soil chemical conditions. The stand with the lowest total biomass had the lowest
Ca/Al ratio of 0.1 in seepage, however, Al, Ca, Mg and K concentrations of fine roots were not different among the stands.
The Ca/Al ratio in seepage might be a less reliable stress parameter because another stand also had Ca/Al ratios in seepage
far below the critical value of 1.0 without any signs of fine root damages. Large differences in the live/dead ratio were
positively correlated with the Mn concentration of live fine roots from the mineral soil. This relationship was attributed
to faster decay of dead fine roots because Mn is known as an essential element of lignin degrading enzymes. It is questionable
if the live/dead ratio can be used as a vitality parameter of fine roots since both longevity of fine roots and decay of root
litter may affect this parameter. Morphological properties were different in the humus layer of one stand that was limed in
1983, indicating that a single lime dose of 3–4 Mg ha−1 has a long-lasting effect on fine root architecture of Norway spruce. Almost no differences were found in morphological properties
in the mineral soil among the stands, but vertical patterns were apparently different. Two stands with high base saturation
in the subsoil showed a vertical decrease in specific root length and specific root tip density whereas the other two stands
showed an opposite pattern or no effect. Our results suggest that proliferation of fine roots increased with decreasing base
saturation in the subsoil of Norway spruce stands. 相似文献
10.
The changes in foliar concentrations of volatile terpenes in response to water stress, fertilization and temperature were
analyzed in Pinus halepensis and Quercus ilex. The most abundant terpenes found in both species were α-pinene and Δ3-carene. β-Pinene and myrcene were also abundant in both species. P. halepensis concentrations were much greater than those of Q. ilex in agreement with the lack of storage in the latter species (15205.60 ± 1140.04 vs. 0.54 ± 0.08 μg g−1 [d.m.]). The drought treatment (reduction to 1/3 of full watering) significantly increased the total terpene concentrations
in both species (54% in P. halepensis and 119% in Q. ilex). The fertilization treatment (addition of either 250 kg N ha−1 or 250 kg P ha−1 or both) had no significant effects on terpene foliar concentrations. The terpene concentrations increased from 0.25 μg g−1 [d.m.] at 30°C to 0.70 μg g−1 [d.m.] at 40°C in Q. ilex (the non-storing species) and from 2,240 μg g−1 [d.m.] at 30°C to 15,621 μg g−1 [d.m.] at 40°C in P. halepensis (the storing species). Both species presented negative relationship between terpene concentrations and relative water contents
(RWC). The results of this study show that higher terpene concentrations can be expected in the warmer and drier conditions
predicted for the next decades in the Mediterranean region. 相似文献
11.
Salix gracilistyla is one of the dominant plants in the riparian vegetation of the upper-middle reaches of rivers in western Japan. This species
colonizes mainly sandy habitats, where soil nutrient levels are low, but shows high potential for production. We hypothesized
that S.␣gracilistyla uses nutrients conservatively within stands, showing a high resorption efficiency during leaf senescence. To test this hypothesis,
we examined seasonal changes in nitrogen (N) and phosphorus (P) concentrations in aboveground organs of S. gracilistyla stands on a fluvial bar in the Ohtagawa River, western Japan. The concentrations in leaves decreased from April to May as
leaves expanded. Thereafter, the concentrations showed little fluctuation until September. They declined considerably in autumn,
possibly owing to nutrient resorption. We converted the nutrient concentrations in each organ to nutrient amounts per stand
area on the basis of the biomass of each organ. The resorption efficiency of N and P in leaves during senescence were estimated
to be 44 and 46%, respectively. Annual net increments of N and P in aboveground organs, calculated by adding the amounts in
inflorescences and leaf litter to the annual increments in perennial organs, were estimated to be 9.9 g and 0.83 g m−2 year−1, respectively. The amounts released in leaf litter were 6.7 g N and 0.44 g P m−2. These values are comparable to or larger than those of other deciduous trees. We conclude that S. gracilistyla stands acquire large amounts of nutrients and release a large proportion in leaf litter. 相似文献
12.
Exotic diseases have fundamentally altered the structure and function of forest ecosystems. Controlling exotic diseases across
large expanses of forest has proven difficult, but fire may reduce the levels of diseases that are sensitive to environmental
conditions. We examined Cornus florida populations in burned and unburned Quercus–Carya stands to determine if burning prior to anthracnose infection has reduced the impacts of an exotic fungal disease, dogwood
anthracnose, caused by Discula destructiva. We hypothesized that fire has altered stand structure and created open conditions less conducive to dogwood anthracnose.
We compared C. florida density, C. florida health, and species composition and density among four sampling categories: unburned stands, and stands that had burned once,
twice, and 3 times over a 20-year period (late 1960s to late 1980s). Double burn stands contained the greatest density of
C. florida stems (770 stems ha−1) followed by triple burn stands (233 stems ha−1), single burn stands (225 stems ha−1) and unburned stands (70 stems ha−1; P < 0.01). We observed less crown dieback in small C. florida trees (<5 cm diameter at breast height) in burned stands than in unburned stands (P < 0.05). Indicator species analysis showed that burning favored species historically associated with Quercus–Carya forests and excluded species associated with secondary succession following nearly a century of fire suppression. Our results
suggest that fire may mitigate the decline of C. florida populations under attack by an exotic pathogen by altering forest structure and composition. Further, our results suggest
that the burns we sampled have had an overall restorative effect on forest communities and were within the fire return interval
of the historic fire regime. Consequently, prescribed fire may offer a management tool to reduce the impacts of fungal disease
in forest ecosystems that developed under historic burning regimes. 相似文献
13.
D. S. Choi H. O. Jin D. J. Chung K. Sasa T. Koike 《Trees - Structure and Function》2008,22(5):729-735
To evaluate the effect of ectomycorrhizal colonization on growth and physiological activity of Larix kaempferi seedlings grown under soil acidification, we grew L. kaempferi seedlings with three types of ectomycorrhizae for 180 days in acidified brown forest soil derived from granite. The soil
had been treated with an acid solution (0 (control), 10, 30, 60, and 90 mmol H+ kg−1). The water-soluble concentrations of Ca, Mg, K, Al, and Mn increased with increasing amounts of H+ added to the soil. Ectomycorrhizal development significantly increased in soil treated with 10 and 30 mmol H+ kg−1 but was significantly reduced in soil treated with 60 and 90 mmol H+ kg−1. The concentrations of Al and Mn in needles or roots increased with increasing H+ added to the soil. The total N in seedlings significantly increased with increasing H+ in soil and colonization with ectomycorrhiza. The maximum net photosynthetic rate at light and CO2 saturation (P
max) was greater in soil treated with 10 mmol H+ kg−1 than in controls, and was less is soils treated with greater than with 30 mmol H+ kg−1, especially with 60 and 90 mmol H+ kg−1. However, colonization with ectomycorrhiza significantly reduced the concentration of Al and Mn in needles or roots and increased
the values of P
max and total dry mass (TDM). The relative TDM of L. kaempferi seedlings was approximately 40% at a (BC, base cation)/Al ratio of 1.0. However, ectomycorrhizal seedlings had a 100–120%
greater TDM at a BC/Al ratio of 1.0 than non-ectomycorrhizal seedlings, even though the acid treatment reduced their overall
growth. 相似文献
14.
M. A. Nogueira U. Nehls R. Hampp K. Poralla E. J. B. N. Cardoso 《Plant and Soil》2007,298(1-2):273-284
Excess manganese (Mn) in soil is toxic to crops, but in some situations arbuscular mycorrhizal fungi (AMF) alleviate the toxic
effects of Mn. Besides the increased phosphorus (P) uptake, mycorrhiza may affect the balance between Mn-reducing and Mn-oxidizing
microorganisms in the mycorrhizosphere and affect the level of extractable Mn in soil. The aim of this work was to compare
mycorrhizal and non-mycorrhizal plants that received extra P in relation to alleviation of Mn toxicity and the balance between
Mn-oxidizing and Mn-reducing bacteria in the mycorrhizosphere. A clayey soil containing 508 mg kg−1 of extractable Mn was fertilized with 30 mg kg−1 (P1) or 45 mg kg−1 (P2) of soluble P. Soybean (Glycine max L. Merrill, cv. IAC 8-2) plants at P1 level were non-inoculated (CP1) or inoculated with either Glomus etunicatum (GeP1) or G. macrocarpum (GmP1), while plants at P2 level were left non-inoculated (CP2). Plants were grown in a greenhouse and harvested after 80 days.
In the mycorrhizosphere of the GmP1 and GeP1 plants a shift from Mn-oxidizing to Mn-reducing bacteria coincided with higher
soil extractability of Mn and Fe. However, the occurrence of Mn-oxidizing/reducing bacteria in the (mycor)rhizosphere was
unrelated to Mn toxicity in plants. Using 16S rDNA sequence homologies, the Mn-reducing isolates were consistent with the
genus Streptomyces. The Mn-oxidizers were homologous with the genera Arthrobacter, Variovorax and Ralstonia. While CP1 plants showed Mn toxicity throughout the whole growth period, CP2 plants never did, in spite of having Fe and
Mn shoot concentrations as high as in CP1 plants. Mycorrhizal plants showed Mn toxicity symptoms early in the growth period
that were no longer visible in later growth stages. The shoot P concentration was almost twice as high in mycorrhizal plants
compared with CP1 and CP2 plants. The shoot Mn and Fe concentrations and contents were lower in GmP1 and GeP1 plants compared
with the CP2 treatment, even though levels of extractable metals increased in the soil when plants were mycorrhizal. This
suggests that mycorrhiza protected its host plant from excessive uptake of Mn and Fe. In addition, higher tissue P concentrations
may have facilitated internal detoxification of Mn in mycorrhizal plants. The exact mechanisms acting on alleviation of Mn
toxicity in mycorrhizal plants should be further investigated. 相似文献
15.
J. T. Moraghan 《Plant and Soil》1987,104(1):121-127
The influence of FeEDDHA (0, 0.2 and 2 μg Fe g−1 soil) and NaH2PO4·H2O (0 and 120 μg Pg−1 soil) on the growth of two Fe-ineffective soybean (Glycine max L. Merr.) varieties (anoka and T203) on a calcareous soil at two soil temperatures (16 and 24°C) was compared under greenhouse
conditions. The two soybean varieties differed in the following respects: (a) T203 accumulated smaller concentrations of Fe
in washed tops than Anoka under comparable conditions; (b) T203 was more susceptible to Fe deficiency and its accentuation
by high levels of fertilizer P than Anoka; (c) T203 accumulated lower quantities of Mn in tops than Anoka under comparable
conditions; (d) T203, but not Anoka, developed Mn deficiency symptoms when treated with P and 2 μg Fe g−1 at 16°C. Fe deficiency was more severe in both varieties at the higher soil temperature due apparently to: (a) greater plant
concentration of P in tops at 24°C; and/or (b) an increased rate of plant growth and greater dilution of Fe in young tissue
at 24°C. Foliar P concentration was increased much more than foliar Fe concentration by an increase in soil temperature. Severely
Fe deficient T203 plants grown without FeEDDHA at 24°C accumulated less foliar Mn than their FeEDDHA counterparts. Comparisons
of Fe effectiveness of various soybean cultivars based on relative responses to FeEDDHA can be influenced by differential
effects on Mn nutrition. 相似文献
16.
Stem-growth response of Pinus sylvestris and Picea abies to nitrogen fertilization as related to needle nitrogen concentration 总被引:2,自引:0,他引:2
U. Sikström Hans-Örjan Nohrstedt Folke Pettersson Staffan Jacobson 《Trees - Structure and Function》1998,12(4):208-214
Responses of stem-volume growth to N application were evaluated in relation to foliar N concentrations. Data from N-fertilization
experiments in 28 Pinus sylvestris stands and 21 Picea abies stands were used. Relative stem-growth responses were negatively related to concentrations of N in current-year needles of
unfertilized trees. There appeared to be a threshold value of 15–16 mg (g DM)–1 N in current-year needles, above which N-application is unlikely to stimulate growth. However, relations were non-significant
between N concentrations in current-year needles and the absolute stem-growth response [dm3 ha–1 (5 years)–1]. The indicated threshold values are discussed in relation to other variables reflecting the N richness of the environment.-->
Received: 20 December 1996 / Accepted: 30 September 1997 相似文献
17.
Spatial patterns of foliar stable carbon isotope compositions of C<Subscript>3</Subscript> plant species in the Loess Plateau of China 总被引:1,自引:0,他引:1
The spatial pattern of foliar stable carbon isotope compositions (δ13C) of dominant species and their relationships with environmental factors in seven sites, Yangling, Yongshou, Tongchuan, Fuxian,
Ansai, Mizhi and Shenmu, standing from south to north in the Loess Plateau of China, was studied. The results showed that
in the 121 C3 plant samples collected from the Loess Plateau, the foliar δ13C value ranged from −22.66‰ to −30.70‰, averaging −27.04‰. The foliar δ13C value varied significantly (P<0.01) among the seven sites, and the average δ13C value increased by about 1.69‰ from Yangling in the south to Shenmu in the north as climatic drought increased. There was
a significant difference in foliar δ13C value among three life-forms categorized from all the plant samples in the Loess Plateau (P<0.001). The trees (−26.74‰) and shrubs (−26.68‰) had similar mean δ13C values, both significantly (P<0.05) higher than the mean δ13C value of herbages (−27.69‰). It was shown that the trees and shrubs had higher WUEs and employed more conservative water-use
patterns to survive drier habitats in the Loess Plateau. Of all the C3 species in the Loess Plateau, the foliar δ13C values were significantly and negatively correlated with the mean annual rainfall (P<0.001) and mean annual temperature (P<0.05), while being significantly and positively correlated with the latitude (P<0.001) and the annual solar radiation (P<0.01). In general, the foliar δ13C values increased as the latitude and solar radiation increased and the rainfall and temperature decreased. The annual rainfall
as the main influencing factor could explain 13.3% of the spatial variations in foliar δ13C value. A 100 mm increment in annual rainfall would result in a decrease by 0.88‰ in foliar δ13C values. 相似文献
18.
Michael Nahm Andreas Matzarakis Heinz Rennenberg Arthur Geßler 《Trees - Structure and Function》2007,21(1):79-92
During the growing season of the exceptionally dry and warm year 2003, we assessed seasonal changes in nitrogen, carbon and
water balance related parameters of mature naturally grown European beech (Fagus sylvatica L.) along a North–South transect in Europe that included a beech forest stand in central Germany, two in southern Germany
and one in southern France. Indicators for N balance assessed at all four sites were foliar N contents and total soluble non-protein
nitrogen compounds (TSNN) in xylem sap, leaves and phloem exudates; C and water balance related parameters determined were
foliar C contents, δ13C and δ18O signatures. Tissue sampling was performed in May, July and September. The N related parameters displayed seasonal courses
with highest concentrations during N remobilization in May. Decreased total foliar N contents as well as higher C/N ratios
in the stands in central Germany and southern France compared to the other study sites point to an impaired N nutrition status
due to lower soil N contents and precipitation perception. TSNN concentrations in leaves and phloem exudates of all study
sites were in ranges previously reported, but xylem sap content of amino compounds in July was lower at all study sites when
compared to literature data (c. 1 μmol N mL−1). In September, TSNN concentrations increased again at the two study sites in southern Germany after a rain event, whereas
they remained constant at sites in central Germany and southern France which hardly perceived precipitation during that time.
Thus, TSNN concentrations in the xylem sap might be indicative for water balance related N supply in the beech trees. TSNN
profiles at all study sites, however, did not indicate drought stress. Foliar δ13C, but not foliar C and δ18O followed a seasonal trend at all study sites with highest values in May. Differences in foliar δ13C and δ18O did not reflect climatic differences between the sites, and are attributed to differences in altitude, photosynthesis and
δ18O signatures of the water sources. Except of low TSNN concentrations in the xylem sap, no physiological indications of drought
stress were detected in the trees analysed. We suppose that the other parameters assessed might not have been sensitive to
the drought events because of efficient regulation mechanisms that provide a suitable physiological setting even under conditions
of prolonged water limitation. The uniform performance of the trees from southern France and central Germany under comparably
dry climate conditions denotes that the metabolic plasticity of mature beech from the different sites studied might be similar. 相似文献
19.
Jacqueline A. Aitkenhead-Peterson Jess E. Alexander Jana Albrechtová Pavel Krám Barrett Rock Pavel Cudlín Jakub Hruška Zuzana Lhotaková Ryan Huntley Filip Oulehle Tomáš Polák William H. McDowell 《Plant and Soil》2006,283(1-2):187-201
Dissolved organic carbon and nitrogen (DOC and DON) produced in the forest floor are important for ecosystem functions such
as microbial metabolism, pedogenesis and pollutant transport. Past work has shown that both DOC and DON production are related
to litterfall and standing stocks of C and N in the forest floor. This study, conducted in spring, 2003, investigated variation
in forest floor water extractable DOC (WEDOC) and DON (WEDON) and forest floor C and N as a function of lignin, cellulose
and N contained in live canopy foliage across eight Picea abies [L.] Karst stands in northern Bohemia. Based on Near Infrared Spectroscopy (NIR) analysis of foliar materials, lignin:N and
cellulose:N content of the youngest needles (those produced in 2002) were positively and significantly related to WEDOC (R2 = 0.82–0.97; P<0.01) and to forest floor C:N ratio (R = 0.72–0.78; P<0.01). Foliar N was strongly and negatively related to WEDOC and C:N ratio (R = −0.91 and 0.72; P<0.05) among our study sites. WEDON was positively correlated to foliar lignin:N (R = 0.48; P<0.05; n=40). Forest floor C pools were not positively correlated with foliar lignin and cellulose and forest floor N pools were not
positively correlated with foliar N. Instead, a significant negative correlation was found between forest floor N pools and
foliar cellulose (R=−0.41; P<0.05), and between forest floor C pools and foliar N (R = −0.44; P<0.05). From a remote sensing standpoint, our results are important because canopy reflectance properties are primarily influenced
by the most recent foliage, and it was the chemistry of the most recently produced needles that showed a stronger relationship
with forest floor WEDOC and C:N ratio suggesting forest floor production of WEDOC can be calculated regionally with remote
sensing. 相似文献
20.
Roberta Fusconi Mirna Januária Leal Godinho Nelma Regina Segnini Bossolan 《World journal of microbiology & biotechnology》2005,21(8-9):1425-1431
Summary The actinomycete strain Lg, which was isolated from groundwater contaminated with leachate flowing out of a former municipal
landfill site (upstate S?o Paulo, Brazil) and found to produce exopolysaccharides, was analysed by polyphasic taxonomy. The
growth of this strain on sugarcane molasses, at various concentrations from 2% to 10%, and on the standard glucose-yeast-maltose
(GYM) medium was observed by monitoring the optical density of the culture at 600 nm. Lg was found to be Gram-positive, catalase-positive,
oxidase-negative, non-motile, non-sporing and did not reduce nitrate. Morphological, biochemical, chemotaxonomic and molecular
tests indicated that Lg has properties typical of Gordonia polyisoprenivorans and this new strain was thus named G. polyisoprenivorans CCT 7137. Growth of the bacterium in the experimental media was notably affected by the molasses content, being fastest at
2% and 3%, the lowest contents, the maximum specific growth-rates being 0.157 h−1 and 0.168 h−1, respectively. These rates were greater than those achieved at higher concentrations and of the same order as the rate in
GYM medium, 0.175 h−1. CCT 7137 is one of six strains of G. polyisoprenivorans so far isolated and recorded in the literature, and one of the two found in contaminated groundwater. This is the first known
study of the growth of a strain of G. polyisoprenivorans in GYM medium and on sugarcane molasses as sole source of nutrients. The latter is proposed as a potential substrate for
production of this strain. 相似文献