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1.
Elevated CO(2) and ozone effects were studied singly and in combination on the crown structure of two Betula pendula clones. Measurements were made at the end of the second fumigation period in an open-top-chamber experiment with 9-year-old trees. Shoot ramification (number of long and short daughter shoots), shoot length, and number of metamers, leaves and buds were measured at four positions in every tree. As a result of increased temperature, trees in chambers had longer shoots and more frequent shoot ramification than control trees not enclosed in chambers. Ozone treatment decreased shoot ramification significantly. Additionally, ozone treatment resulted in an increased number of metamers in one clone. There was no statistically significant interaction between ozone effect and crown position; however, there was a slight tendency for the lower crown to be more affected by ozone. Elevated CO(2) caused a significant increase in the number of long-shoot metamers. Therefore, 2x ambient CO(2) concentration partly ameliorated the negative effect of ozone because the increased number of leaves per shoot counteracted the decreased branching. Although the main effects of elevated ozone and CO(2) were similar in the two clones, slight, statistically insignificant, differences appeared in their responses when interactions with crown position were considered. 相似文献
2.
The effects of nitrogen (N) fertilisation and elevated [CO2] on lipid biosynthesis and carbon isotope discrimination in birch (Betula pendula Roth.) transplants were evaluated using seedlings grown with and without N fertiliser, and under two concentrations of atmospheric
CO2 (ambient and ambient+250 μmol mol-1) in solar dome systems. N fertilisation decreased n-fatty acid chain length (18:0/16:0) and the ratios of α-linolenate (18:2)/linoleate (18:1), whereas elevated [CO2] showed little effect on n-fatty acid chain length, but decreased the unsaturation (18:2+18:1)/18:0. Both N fertilisation and elevated [CO2] increased the quantity of leaf wax n-alkanes, whilst reducing that of n-alkanols by 20–50%, but had no simple response in fatty acid concentrations. 13C enrichment by 1–2.5‰ under N fertilisation was observed, and can be attributed to both reduced leaf conductance and increased
photosynthetic consumption of CO2. Individual n-alkyl lipids of different chain length show consistent pattern of δ13C values within each homologue, but are in general 5–8‰ more depleted in 13C than the bulk tissues. Niether nitrogen fertilisation and elevated CO2 influenced the relationship between carbon isotope discrimination of the bulk tissue and the individual lipids.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
3.
Ontogenetic patterns of leaf CO2 exchange, morphology and chemistry in Betula pendula trees 总被引:3,自引:0,他引:3
J. Oleksyn R. Żytkowiak P. B. Reich M. G. Tjoelker P. Karolewski 《Trees - Structure and Function》2000,14(5):271-281
In order to explore ontogenetic variation in leaf-level physiological traits of Betula pendula trees, we measured changes in mass- (A
mass) and area-based (A
area) net photosynthesis under light-saturated conditions, mass- (RSmass) and area-based (RSarea) leaf respiration, relative growth rate, leaf mass per area (LMA), total nonstructural carbohydrates (TNC), and macro- and
micronutrient concentrations. Expanding leaves maintained high rates of A
area, but due to high growth respiration rates, net CO2 fixation occurred only at irradiances >200 μmol photons m–2 s–1. We found that full structural leaf development is not a necessary prerequisite for maintaining positive CO2 balance in young birch leaves. Maximum rates of A
area were realized in late June and early July, whereas the highest values of A
mass occurred in May and steadily declined thereafter. The maintenance respiration rate averaged ≈8 nmol CO2 g–1 s–1, whereas growth respiration varied between 0 and 65 nmol CO2 g–1 s–1. After reaching its lowest point in mid-June, leaf respiration increased gradually until the end of the growing season. Mass
and area-based dark respiration were significantly positively correlated with LMA at stages of leaf maturity, and senescence.
Concentrations of P and K decreased during leaf development and stabilized or increased during maturity, and concentrations
of immobile elements such as Ca, Mn and B increased throughout the growing season. Identification of interrelations between
leaf development, CO2 exchange, TNC and leaf nutrients allowed us to define factors related to ontogenetic variation in leaf-level physiological
traits and can be helpful in establishing periods appropriate for sampling birch leaves for diagnostic purposes such as assessment
of plant and site productivity or effects of biotic or abiotic factors.
Received: 29 December 1998 / Accepted: 26 July 1999 相似文献
4.
The effect of elevated carbon dioxide and fertilization on primary and secondary metabolites in birch,Betula pendula (Roth) 总被引:5,自引:0,他引:5
Seedlings of European white birch (Betula pendula Roth) were grown in growth chambers for one growth season under four carbon dioxide regimes (350, 700, 1050 and 1400 ppm) and at three fertilization levels (0, 100 and 500 kg ha–1 monthly). The soluble carbohydrates and secondary phenolics in the leaves and stems were analysed. It was found that fertilizer addition reduced the amounts of glucose and fructose while sucrose remained almost unaffected. The sugar content of leaves increased at 700 ppm and 1050 ppm of CO2 and decreased at the highest CO2 concentration (1400 ppm). The amounts of proanthocyanidins and flavonoids in leaves decreased with fertilization addition and increased with CO2 enrichment. The production of simple phenolic glucosides varied according to the fertilization and CO2 treatments. The triterpenoid content of stems seemed to increase with fertilization and CO2-addition. Our results indicate that the production of phytochemicals in the birch seedlings is very sensitive to both fertilization and CO2 addition, which is in agreement with earlier studies, and thus provide some support for the hypothesis of carbon allocation to plant defence when there is an excess of carbon and nutrient. The considerable variation in the production of secondary components may indicate that the synthesis of these defensive metabolites can be regulated by a plant to certain extent, depending on the ability of the plant to acclimate to changes in the physical environment. 相似文献
5.
K. Kuokkanen P. Niemelä J. Matala R. Julkunen-Tiitto† J. Heinonen‡ M. Rousi§ H. Henttonen¶ J. Tahvanainen† S. Kellomäki 《Global Change Biology》2004,10(9):1504-1512
The effects of elevated CO2 and temperature on the resource allocation pattern and resistance against mammalian herbivores of silver birch (Betula pendula Roth) were studied. Birch seedlings were grown through two growing seasons in closed‐top chambers exposed to four different treatments: ambient CO2 and temperature, elevated atmospheric CO2 (700 ppm) and ambient temperature, elevated temperature (+3°C above ambient) and ambient CO2, and a combination of elevated CO2 and temperature. After winter hardening of the seedlings, the growth of the seedlings was measured and the concentration of secondary compounds such as phenolics and papyriferic acid determined. The top parts of the stem were fed to hares, and the basal parts of the same stems were offered to voles. Elevated CO2 increased the height and basal diameter of the shoots, shoot biomass and total biomass of the seedlings but did not have any effect on secondary chemistry. Elevated temperature increased the height and shoot biomass, but did not have a significant effect on the total biomass of the seedlings. Elevated temperature decreased the concentration of condensed tannins and their precursor, (+)‐catechin, in the top part of the stems, but only the concentration of (+)‐catechin in the basal part of the stems. There were no significant interactive effects between CO2 and temperature on phenolics in the stems, while the concentration of papyriferic acid showed significant interaction in the top part of the stems. This indicates high accumulation of papyriferic acid in ambient CO2 under increased temperature. Consequently, elevated temperature increased the resistance of birch against hares, but did not affect the resistance of the basal parts of the same birches to voles. Our results indicate that the predicted climatic change will not necessarily lead to increased browsing damage by the mountain hare and the field vole to silver birch. 相似文献
6.
Three-year-old birch (Betula pendula Roth.) seedlings were exposed, in the field, to supplemental levels of UV-B radiation. Control seedlings were exposed to ambient levels of UV radiation, using arrays of unenergized lamps. A control for UV-A radiation was also included in the experiment. Enhanced UV-B radiation had no significant effects on height growth, and shoot and root biomass of birch seedlings. Leaf expansion rate increased transiently in the middle of the growing period in enhanced UV-B- and UV-A-exposed plants; however, final leaf size and relative growth rate remained unaffected. Leaf thickness and spongy intercellular spaces were increased in UV-B-exposed seedlings along with increased density of glandular trichomes. At the ultrastructural level, enhanced UV-B increased the number of cytoplasmic lipid bodies, and abnormal membrane whorls were found. Both enhanced UV-B and UV-A radiation induced swelling of chloroplast thylakoids. Stomatal density and conductance were significantly increased by elevated UV-B radiation. UV-A radiation increased the length and width of stomata, whereas UV-B radiation had only a marginal effect on stomatal size. UV-A and enhanced UV-B radiation attenuated the appearance of necrotic spots in autumn, probably caused by the fungus Pyrenopeziza betulicola, suggesting a direct harmful effect of UV on pathogens or reduced susceptibility to pathogens in UV-exposed seedlings. Secondary metabolite analysis showed increases in (+)-catechin, quercetin, cinnamic acid derivative, apigenin and pentagalloylglucose in birch leaves under enhanced UV-B radiation. Negative correlations between apigenin, and particularly quercetin concentrations and lipid peroxidation levels indicated an antioxidant role of secondary metabolites in birch leaves exposed to UV-B radiation. 相似文献
7.
CO2浓度和温度升高对红桦根际微生物的影响 总被引:7,自引:0,他引:7
应用自控、封闭、独立的生长室系统,研究升高的大气CO2浓度(环境CO2浓度 350(±25)μmol.mol-1,EC)和温度(环境温度 2.0(±0.5)℃,ET)及其交互作用(ECT)对不同栽植密度条件下红桦根际土壤可培养微生物数量的影响。结果表明:(1)EC显著增加了高密度条件下根际细菌数量;在整个生长季中,最大的根际细菌数量增加出现在7月份;而EC对低密度处理的根际细菌数量影响不显著。除了5月和6月份,ET在其余月份均显著增加了根际细菌数量,但是与密度处理没有有意义的相关;ECT对高低密度处理的根际细菌数量均未产生有统计意义的影响。(2)EC对低密度条件下的根际放线菌数量有显著增加,而对高密度条件下的根际放线菌数量无显著影响;ET和ECT对高低密度条件下的根际放线菌数量均未产生有统计意义的影响。(3)EC和ET对高低密度条件下的根际真菌数量无显著增加,而ECT显著增加了根际真菌数量。 相似文献
8.
采用控制环境生长室,研究了CO2浓度升高对2个种植密度下红桦幼苗生长和氮(N)、磷(P)含量的影响。试验设置CO2浓度为350和700μmol.mol-12个水平,每个CO2浓度水平下又设密度28和84株.m-22个水平。结果表明:CO2浓度升高,红桦株高和叶面积指数(LAI)均增加,净同化率(NAR)值增加,叶质比(LMR)和比叶面积(SLA)均下降,但相对生长率(RGR)提高。CO2浓度增加,红桦幼苗茎枝、叶、根和总生物量提高,氮(N)、磷(P)含量降低,但单株N、P总吸收量均增加。CO2浓度升高,氮磷利用效率(NUE和PUE)提高,氮磷累积速率(NAcR和PAcR)显著增加。CO2浓度升高,红桦幼苗体内N、P浓度下降是由于生物量迅速增加引起的稀释效应造成的,而NUE和PUE的提高可以有效缓解CO2浓度升高后,亚高山和高山地区森林土壤中养分元素不足对森林生产力的限制。CO2浓度升高导致的植物生长的增加量会随植株密度的增加而降低,不同器官养分吸收量的增加量在低密度条件下比高密度条件下大得多,主要是因为高种植密度显著降低了植株各部位的干质量。 相似文献
9.
Birch seedlings (Betula pendula) were grown for four months in a greenhouse at three nutrient levels (fertilization of 0, 100 and 500 kg ha-1 monthy) and at four CO2 concentrations (350, 700, 1050 and 1400 ppm). The effect of CO2 concentration on the biomass production depended on the nutrient status. When mineralization of the soil material was the only source of nutrients (0 kg ha-1), CO2 enhancement reduced the biomass production slightly, whereas the highest production increase occurred at a fertilization of 100 kg ha-1, being over 100% between 350 and 700 ppm CO2. At 500 kg ha-1 the production increase was smaller, and the production decreased beyond a CO2 concentration of 700 ppm. The CO2 concentration had a slight effect on the biomass distribution, the leaves accounting for the highest proportion at the lowest CO2 concentration (350 ppm). An increase in nutrient status led to a longer growth period and increased the nutrient concentrations in the plants, but the CO2 concentration had no effect on the growth rhythm and higher CO2 reduced the nutrient concentrations. 相似文献
10.
The response to aluminium concentrations was evaluated for birch seedlings ( Betula pendula Roth, formerly Betula verrucosa Ehrh.) by using a growth technique that provides stable internal concentrations of nutrients in plants. Aluminium was added as aluminium nitrate and aluminium chloride and pH was kept at 3.8±0.2 by adding HCl or NaOH. The seedlings were grown in two different series of nutrient treatments, either with near-optimum conditions (relative addition rate 25% day−1 ) or with constant nutrient stress (relative addition rate 10% day−1 ) before the aluminium addition. Growth reduction occurred at aluminium concentrations greater than 3 m M , and lethal effects at aluminium concentrations greater than 15 m M . In plants subjected to near-optimum conditions before aluminium addition, the internal nutrient concentrations decreased with increasing aluminium concentration for all macronutrients. The concentration of the macronutrients N, K and P decreased gradually with increasing aluminium concentration, while the concentration of Ca and Mg decreased fairly abruptly when aluminium concentrations exceeded 1 m M . The same tendency was observed in nutrient stressed birch seedlings, but the pattern was more scattered. Relative growth rate of the seedlings was not affected by a low Ca/Al ratio. In all treatments, the molar Ca/Al ratio in/on the roots was below 0.2 at the end of the experiments. As decrease in growth occurs only at high aluminium concentrations, there is no reason to suggest that aluminium in acid soils is growth limiting for natural birch stands. 相似文献
11.
Summary An extensive number of biochemical and physiological measurements were made over the third and fourth years of the growth of birch (Betula pendula Roth.) in elevated CO2. Trees in elevated CO2 had 58% more biomass than trees grown in ambient CO2 although relative growth rate was not affected in the last year of the study. No changes in biomass allocation were observed. Elevated CO2 caused an increase in starch accumulation in the leaves that resulted in a series of feedback mechanisms to re-establish the source-sink balance of the trees. A decrease in Rubisco activity and to a lesser extent in chlorophyll and soluble proteins led to a decrease in the photosynthetic activity. Although the positive CO 2effect on photosynthetic activity was maintained in the field over the whole experiment, the photosynthetic capacity of the trees was reduced by long-term exposure to elevated CO2. Both maximum electron transport capacity (J max) and maximum carboxylation capacity (V emax) were reduced to a similar extent, so the ratio of J max:V cmax was not altered. Root biomass, fine root density and mycorrhizal infection were increased in elevated CO 2. The mycorrhizal species of fungi associated with the trees grown in elevated CO2 were late-successional species whereas the species associated with trees grown in ambient CO2 were early successional species. This lends support to the hypothesis of a CO2 effect on the ontogeny of the trees. 相似文献
12.
We have examined shoot and root growth and the concentration of carbohydrates in seedlings of a northern (67°N) and a southern (61°N) ecotype of Betula pendula Roth. cultivated at root-zone temperatures of 2, 6, 12 and 17°C. Three hydroponic experiments were conducted in controlled environments. We used three different pretreatments before seedlings were subjected to the experimental temperature treatments. Actively growing seedlings that were acclimated to the hydroponic solution for 3 weeks at a root temperature of 17°C, continued to grow at all the experimental temperatures, with an expected increase in growth from 2 to 17°C. However, if we started with ecodormant cold stored plants or used seedlings grown actively in perlite, no growth was observed at 2°C and only minor growth was found at 6°C. The highest root temperature always produced the best growth. The concentration of nonstructural carbohydrates was higher in seedlings grown at 2°C than at 17°C, and this is probably due to extensive incorporation of carbohydrates into cell walls and other structural elements at 17°C. We found no evidence for differences between the two ecotypes in root growth, in timing of bud burst, but shoot growth terminated in the northern ecotype in the first experiment because the natural photoperiod was below the critical value. Our study highlights the importance of post-transplantation stress (planting check) related to root growth, and that root threshold temperatures may change according to the way plants are pretreated. 相似文献
13.
14.
Effects of aluminium on growth and root reactions of phosphorus stressed Betula pendula seedlings 总被引:1,自引:0,他引:1
The impact of two constant non-toxic levels of Al stress (0.2 and 0.4 mM) on growth and 32P uptake capacity on sub-optimal (P-limited) Betula pendula seedlings grown in sand culture was examined.Seedling growth was under optimum controlled conditions in a growth chamber where nutrient additions were made at a predetermined relative addition rate (RA) of 10% day-1. Three treatment groups of seedlings 0, 0.2 and 0.4 mM Al were harvested at 15, 29 and 42 days. The excised roots were exposed to a 32P-labelled solution for 15 minutes to measure their capacity for P uptake. Growth was determined by weighing the roots, stems and leaves of the seedlings.Growth data showed that relative growth rate (RG) should equal the RA of P the most limiting nutrient, which was supplied at P/N 3% instead of an optimal 15%. Therefore, Ingestad's theory can also be used succesfully in sand culture and this may be particularly important for future studies of root and rhizosphere exudates. Low levels of Al (< 0.2 mM) in combination with low P supply significantly lowered the RG of the birch seedlings by further reducing P supply. However, previous studies of birch seedling growth and nutrient uptake using Ingestad's solution culture technique with optimumal P supply did not show any effect of Al on growth untill the Al was in excess of 3 mM. Aluminium was not directly toxic to the plants and therefore roots could respond to the 32P bioassay. 相似文献
15.
The effects of long-term elevated UV-B on the growth and phenolics of field-grown silver birch (Betula pendula) 总被引:2,自引:0,他引:2
The effects of long‐term elevated UV‐B radiation on silver birch (Betula pendula Roth) seedlings were studied over three growing seasons in an outdoor experiment in Finland started 64 days after germination. One group of seedlings was exposed to a constant 50% increase in UV‐BCIE radiation, which corresponds to 20–25% of ozone depletion; another group received a small increase in UV‐A radiation and a third (the control group) received ambient solar radiation. Changes in growth appeared during the third growing season; the stems of the UV‐B treated seedlings were thinner and their height tended to be shorter compared with that of the control seedlings. In contrast, there were no UV‐B effects on biomass, bud burst, bud dry weights, leaf area, rust frequency index or chlorophyll concentrations in any of the summers. During the three‐year study, the flavonols were significantly increased by the elevated UV‐B only in the first growing season. The responses varied greatly among individual compounds; the most induced were the quercetin glycosides, while the main flavonols, myricetins, were reduced by the UV‐A control treatment. In the second summer phenolic acids, such as 3,4′‐dihydroxypropiophenone‐3‐glucoside, neochlorogenic acid and 5‐coumarylquinic acid, were increased by the UV‐B treatment. In the third year, the constitutive concentrations of phenolics were not affected by the UV‐B treatment. 相似文献
16.
Betula pendula pollen, under laboratory conditions, was exposed to three atmospheric pollutants: carbon monoxide (CO), ozone (O3) and sulphur dioxide (SO2). Two levels of each pollutant were used; the first level corresponds to a concentration on the atmospheric hour-limit value acceptable for human health protection in Europe, the second level to a higher, at least more than double of the first, concentration level. Experiments were done under artificial solar light with controlled temperature and relative humidity. Our results indicate that, in urban areas, concentrations of CO, O3 and SO2 on the limits established for human protection, can affect pollen fertility. We verified a decrease in the viability and germination of the pollen, indicating damage to the pollen membrane system. Also, a general decreasing trend in the total protein content of the exposed samples when compared with the control samples was observed, which suggests alterations in the antigenic characteristics of pollen. 相似文献
17.
The effect of elevated atmospheric CO2 and nutrient supply on elemental composition and decomposition rates of tree leaf litter was studied using litters derived from birch (Betula pendula Roth.) plants grown under two levels of atmospheric CO2 (ambient and ambient +250 ppm) and two nutrient regimes in solar domes. CO2 and nutrient treatments affected the chemical composition of leaves, both independently and interactively. The elevated CO2 and unfertilized soil regime significantly enhanced lignin/N and C/N ratios of birch leaves. Decomposition was studied using field litter-bags, and marked differences were observed in the decomposition rates of litters derived from the two treatments, with the highest weight remaining being associated with litter derived from the enhanced CO2 and unfertilized regime. Highly significant correlations were shown between birch litter decomposition rates and lignin/N and C/N ratios. It can be concluded, from this study, that at levels of atmospheric CO2 predicted for the middle of the next century a deterioration of litter quality will result in decreased decomposition rates, leading to reduction of nutrient mineralization and increased C storage in forest ecosystems. However, such conclusions are difficult to generalize, since tree responses to elevated CO2 depend on soil nutritional status. 相似文献
18.
Niche differentiation in soil horizons, host species and natural nutrient gradients contribute to the high diversity of ectomycorrhizal fungi in boreal forests. This study aims at documenting the diversity and community composition of ectomycorrhizal fungi of Norway spruce ( Picea abies ) and silver birch ( Betula pendula ) seedlings in five most abundant microsites in three Estonian old-growth forests. Undisturbed forest floor, windthrow mounds and pits harboured more species than brown- and white-rotted wood. Several species of ectomycorrhizal fungi were differentially represented on either hosts, microsites and sites. Generally, the most frequent species in dead wood were also common in forest floor soil. Ordination analyses suggested that decay type determined the composition of EcM fungal community in dead wood. Root connections with in-growing mature tree roots from below affected the occurrence of certain fungal species on seedling roots systems in dead wood. This study demonstrates that ectomycorrhizal fungi differentially establish in certain forest microsites that is attributable to their dispersal and competitive abilities. Elevated microsites, especially decayed wood, act as seed beds for both ectomycorrhizal forest trees and fungi, thus affecting the succession of boreal forest ecosystems. 相似文献
19.
Here, the aim was to estimate loads imposed on the apoplastic ascorbate (ASC) pool by enzymatic and nonenzymatic reactions in Betula pendula exposed to doubled CO2 and O3 concentrations in open-top chambers. Leaf apoplastic extracts were analysed for peroxidase and oxidase activities in vitro, using different substrates. Partial loads in vivo were deduced using measured kinetic constants and substituted-enzyme catalysis approaches. Ascorbate use in O3 scavenging was calculated using measured stomatal conductances and ASC concentrations. Under elevated O3, stomatal conductance and O3 uptake were higher. O3 fluxes to the plasmalemma were levelled off by higher apoplastic ASC concentrations. The effect of CO2 enrichment on ASC concentrations under elevated O3 was minor. Under ambient O3, the ascending hierarchy of ASC users was: peroxidases, O3 scavenging, oxidases, coniferyl alcohol re-reduction. Under elevated O3, ASC use in O3 scavenging was higher than by oxidases. The redox state of ASC was not depressed by O3; there was no leaf injury. The cell wall/plasmalemma/cytosol system in birch had sufficient capacity to maintain ASC redox status in the apoplast, without necessity to restrict O3 uptake by stomatal closure. 相似文献