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1.
Peter Roberntz 《Trees - Structure and Function》1999,13(4):188-198
Branches of 30-year-old Norway spruce [Picea abies (L.) Karst.] trees were enclosed in ventilated, transparent plastic bags and flushed with air containing ambient (A≈370 μmol
CO2 mol–1) or ambient plus 340 μmol CO2 mol–1 (EL). Light-saturated photosynthesis was on average 56% higher in EL compared to A. Branch phenology and morphology were
strongly related to nitrogen concentration (mg g–1 dry mass) in the foliage and to elevated temperatures in the bags, but no direct effect of EL was found. In 1995, budbreak
occurred on average 4 days earlier in the bags compared to the control branches, which was partly explained by the temperature
elevation in the bags. No nutrient or EL effect on budbreak was found. Increases in temperature and nitrogen supply increased
shoot growth: together they explained 76% of the variation in the extension rate, 63% of the variation in extension duration
and 65% of the variation in final length of leading shoots. Shoot morphology was altered both by increased nitrogen availability
and by the enclosure induced environmental changes inside the bags, leading to reduced mutual shading between needles. Specific
needle area (SNA) was lower in EL, but this was related to lower nitrogen concentrations. Total dry mass of the branches was
unaffected by EL. It is concluded that treating individual branches of Norway spruce with elevated CO2 does not increase branch growth. The nutrient status of the branch and climate determine its growth, i.e. its sink strength
for carbon. Increased export of carbohydrates to the rest of the tree is probable in EL treated branches.
Received: 20 July 1998 / Accepted 8 October 1998 相似文献
2.
The effect of elevated CO2 concentration and nutrient supply on carbon-based plant secondary metabolites in Pinus sylvestris L. 总被引:3,自引:0,他引:3
This study investigated changes in carbon-based plant secondary metabolite concentrations in the needles of Pinus sylvestris saplings, in response to long-term elevation of atmospheric CO2, at two rates of nutrient supply. Experimental trees were grown for 3 years in eight open-top chambers (OTCs), four of which
were maintained at ambient (∼350 μmol mol−1) and four at elevated (700 μmol mol−1) CO2 concentrations, plus four open air control plots. Within each of these treatments, plants received either high (7.0 g N m−2 year−1 added) or low (no nutrients added) rates of nutrient supply for two years. Needles from lateral branches were analysed chemically
for concentrations of condensed tannins and monoterpenes. Biochemical determinations of cellulase digestibility and protein
precipitating capacity of their phenolic extracts were made because of their potential of importance in ecological interactions
between pine and other organisms including herbivores and decomposers. Elevated CO2 concentration caused an increase (P<0.05) in dry mass per needle, tree height and the concentration of the monoterpene α-pinene, but there were no direct effects
of CO2 concentration on any of the other chemical measurements made. High nutrient availability increased cellulase digestibility
of pine needles. There was a significant negative effect of the OTCs on protein precipitating capacity of the needle extracts
in comparison to the open-air controls. Results suggest that predicted changes in atmospheric CO2 concentration will be insufficient to produce large changes in the concentration of condensed tannins and monoterpenes in
Scots pine. Processes which are influenced by these compounds, such as decomposition and herbivore food selection, along with
their effects on ecosystem functioning, are therefore unlikely to be directly affected through changes in these secondary
metabolites.
Received: 20 October 1997 / Accepted: 28 February 1998 相似文献
3.
J. Oleksyn Mark G. Tjoelker Gabriela Lorenc-Plucińska Agata Konwińska Roma Żytkowiak Piotr Karolewski Peter B. Reich 《Trees - Structure and Function》1997,12(2):82-89
Pinus heldreichii Christ is a long-lived, slow-growing Tertiary relict from the Balkans. In this study we evaluated the physiological characteristics
of eight needle-age classes of P. heldreichii grown at the Arboretum of the Institute of Dendrology in Kórnik, Poland. At the end of the growing season, current-year foliage
had the highest rates of mass-based light-saturated net photosynthesis (Asat) of 33.5 nmol CO2· g–1· s–1. Asat decreased with needle age, but older needle classes retained from approximately 62 to 26% of the current needles’ rate. The
relationship between leaf N and chlorophyll a concentration among all needle-age classes was highly significant (r = 0.96, P = 0.0006). The variation in Asat of 1- to 7-year-old needles was linearly related to needle N concentration (r = 0.98, P = 0.0001). Needle dark respiration rates among these needle age classes ranged from 0.8 to 2.2 nmol · g–1· s–1 and decreased with needle age and nitrogen concentration. Total phenols and glucose concentrations increased linearly with
needle age. A similar pattern was observed in acid buffering capacity and the pH of tissue homogenates. The water content
ranged from 62% for the current needles to 51% for the 6-year-old needles. Greater investment in leaf structural tissue and
increased chemical defense is associated with higher structural cost of older needles and may reduce their photosynthetic
activity. Significant declines in water and nitrogen content with needle age and an increase in content of phenolics is most
likely a defense adaptation of P. heldreichii related to the species’ long-lived leaves.
Received: 8 January 1997 / Accepted: 4 March 1997 相似文献
4.
This study examined the effects of season-long exposure of Chinese pine (Pinus tabulaeformis) to elevated carbon dioxide (CO2) and/or ozone (O3) on indole-3-acetic acid (IAA) content, activities of IAA oxidase (IAAO) and peroxidase (POD) in needles. Trees grown in
open-top chambers (OTC) were exposed to control (ambient O3, 55 nmol mol−1 + ambient CO2, 350 μmol mol−1, CK), elevated CO2 (ambient O3 + high CO2, 700 μmol mol−1, EC) and elevated O3 (high O3, 80 ± 8 nmol mol−1 + ambient CO2, EO) OTCs from 1 June to 30 September. Plants grown in elevated CO2 OTC had a growth increase of axial shoot and needle length, compared to control, by 20% and 10% respectively, while the growth
in elevated O3 OTC was 43% and 7% less respectively, than control. An increase in IAA content and POD activity and decrease in IAAO activity
were observed in trees exposed to elevated CO2 concentration compared with control. Elevated O3 decreased IAA content and had no significant effect on IAAO activity, but significantly increased POD activity. When trees
pre-exposed to elevated CO2 were transferred to elevated O3 (EC–EO) or trees pre-exposed to elevated O3 were transferred to elevated CO2 (EO–EC), IAA content was lower while IAAO activity was higher than that transferred to CK (EC–CK or EO–CK), the change in
IAA content was also related to IAAO activity. The results indicated that IAAO and POD activities in Chinese pine needles
may be affected by the changes in the atmospheric environment, resulting in the change of IAA metabolism which in turn may
cause changes in Chinese pine’s growth.
An erratum to this article can be found at 相似文献
5.
Opposing effects of elevated CO2 and N deposition on Lymantria monacha larvae feeding on spruce trees 总被引:4,自引:0,他引:4
The effects of elevated atmospheric CO2 and increased wet N deposition on leaf quality and insect herbivory were evaluated in nine model ecosystems composed of 7-year-old
spruce trees (Picea abies) and three understorey species established on natural forest soil. Each model ecosystem was grown in a simulated montane
climate, and was exposed to one of three CO2 concentrations (280, 420, and 560 μl l−1), and to one of three levels of N deposition (0, 30, and 90 kg ha−1 year−1) for 3 years. In the 3rd year of the experiment second to third instars of the nun moth (Lymantria monacha) were allowed to feed directly on current-year needles of top canopy branches of each tree for 12 days. Specific leaf area
(SLA), water content, and N concentration decreased in needles exposed to elevated CO2, whereas the concentrations of starch, condensed tannins, and total phenolics increased. Increased N deposition had no significant
effect on SLA, and water content, but the concentrations of starch, condensed tannins, and total phenolics decreased, and
sugar and N concentrations increased. Despite higher relative consumption rates (RCRs) larvae consumed 33% less N per unit
larval biomass and per day at the two high CO2 treatments, compared to those feeding on 280 μl l−1-needles, but they maintained similar N accumulation rates due to increased N utilization efficiencies (NUE). However, over
the 12-day experimental period larvae gained less N overall and reached a 35% lower biomass in the two high-CO2 treatments compared to those at 280 μl l−1. The effects of increased N deposition on needle quality and insect performance were generally opposite to those of CO2 enrichment, but were lower in magnitude. We conclude that altered needle quality in response to elevated CO2 will impair the growth and development of L. monacha larvae. Increasing N deposition may mitigate these effects, which could lead to altered insect herbivore distributions depending
on regional patterns of N deposition.
Received: 8 June 1998 / Accepted: 27 October 1998 相似文献
6.
Respiration of 1-year-old needles of 30-year-old Norway spruce trees [Picea abies (L.) Karst.] was studied in a nutrient optimisation experiment in northern Sweden. Respiration rates of detached needles,
from ten control (C) and ten irrigated-fertilised (IL) trees, were measured on 16 occasions from June 1992 to June 1993. The
aim of the study was to determine the influence of temperature on the seasonal course of needle maintenance respiration, and
the effect of nitrogen concentration [N] and carbohydrate content on needle respiration in young Norway spruce trees subjected
to long-term fertilisation. The IL treatment significantly affected needle size, in terms of dry mass and length, but not
specific needle length (SNL). There was, however, a strong tree-specific effect on SNL (P<10–9, R
2 = 0.75). Needle starch content varied markedly with season (0–25% of total dry mass). This, unless accounted for, would cause
erroneous estimates of nutrient concentrations, and of rates of needle respiration, within and between treatments. There was
considerable seasonal variation in needle respiration, both in terms of maintenance respiration and temperature dependence
(Q10). Q10 had its highest value (2.8) during winter and its lowest (2.0) in the middle of summer. In early autumn (August, September),
respiration rate and needle [N] were significantly related (C: P = 0.001, IL: P<0.0005). There was no significant difference in the slope between the two regression lines, but a difference in intercept.
At the same needle [N], needles from IL-plots always had a lower respiration rate than needles from control plots. No obvious
explanation for the observed difference in intercept was found, but some plausible assumptions are put forward and discussed.
Received: 24 January 1997 / Accepted: 1 July 1997 相似文献
7.
Elevated [CO2], temperature increase and N supply effects on the turnover of below-ground carbon in a temperate grassland ecosystem 总被引:5,自引:0,他引:5
The effects of elevated [CO2] (700 μl l-1 CO2) and temperature increase (+3 °C) on carbon turnover in grassland soils were studied during 2.5 years at two N fertiliser
supplies (160 and 530 kg N ha-1 y-1) in an experiment with well-established ryegrass swards (Lolium perenne) supplied with the same amounts of irrigation water.
During the growing season, swards from the control climate (350 μl l-1 [CO2] at outdoor air temperature) were pulse labelled by the addition of 13CO2. The elevated [CO2] treatments were continuously labelled by the addition of fossil-fuel derived CO2 (13
C of -40 to -50 ‰). Prior to the start of the experimental treatments, the carbon accumulated in the plant parts and in the
soil macro-organic matter (‘old’ C) was at −32‰. During the experiment, the carbon fixed in the plant material (‘new’ C) was
at −14 and −54‰ in the ambient and elevated [CO2] treatments, respectively. During the experiment, the 13C isotopic mass balance method was used to calculate, for the top soil (0–15 cm), the carbon turnover in the stubble and roots
and in the soil macro-organic matter above 200 μ (MOM). Elevated [CO2] stimulated the turnover of organic carbon in the roots and stubble and in the MOM at N+, but not at N−. At the high N supply,
the mean replacement time of ‘old’ C by ‘new’ C declined in elevated, compared to ambient [CO2], from 18 to 7 months for the roots and stubble and from 25 to 17 months for the MOM. This resulted from increased rates
of ‘new’ C accumulation and of ‘old’ C decay. By contrast, at the low N supply, despite an increase in the rate of accumulation
of ‘new’ C, the soil C pools did not turnover faster in elevated [CO2], as the rate of ‘old’ C decomposition was reduced. A 3 °C temperature increase in elevated [CO2] decreased the input of fresh C to the roots and stubble and enhanced significantly the exponential rate for the ‘old’ C
decomposition in the roots and stubble. An increased fertiliser N supply reduced the carbon turnover in the roots and stubble
and in the MOM, in ambient but not in elevated [CO2]. The respective roles for carbon turnover in the coarse soil OM fractions, of the C:N ratio of the litter, of the inorganic
N availability and of a possible priming effect between C-substrates are discussed.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
8.
X. Zhou Z. M. Ge S. Kellom?ki K. Y. Wang H. Peltola P. J. Martikainen M. Lemettinen A. Hassinen R. Ikonen 《Photosynthetica》2012,50(1):24-34
This paper describes the technical information and performance of a new multi-objective chamber system enabling the control
of environmental variables (e.g., temperature, CO2, air humidity, wind speed, and UV-B radiation) for understanding plant responses to climate change. Over a whole growing
season, four different climate scenarios were evenly programmed into the system’s 16 chambers as ambient environment (AMB),
elevated temperature (ET), elevated CO2 concentration (EC) and elevated temperature and CO2 concentration (ETC). Simultaneously, the chamber effects were assessed regarding the physiological responses and growth of
a boreal perennial grass (reed canary grass, Phalaris arundinacea L.). During the growing season, the chamber system provided a wide variety of climatic conditions for air temperature (T
a), relative humidity (RH) and CO2 concentration (C
a) in the AMB chambers following outside conditions. The target temperature (+3.5°C) was achieved to a good degree in the ET
and ETC chambers, being on average 3.3°C and 3.7°C higher than ambient conditions, respectively. The target concentration
of CO2 (700 ppm) was also well achieved in the EC and ETC chambers, being on average 704 ppm and 703 ppm, respectively. The stable
airflow condition inside all of the chambers provided a homogeneous distribution of gases and temperature. The decreases in
RH and increases in vapour pressure deficit (VPD) in the elevated temperature chambers were also maintained at a low level.
Chamber effects were observed, with some physiological and growth parameters of plants being significantly lower in the AMB
chambers, compared to outside conditions. The plant growth was negatively affected by the reduced radiation inside the chambers. 相似文献
9.
Yu-Mei Zhou Cun-Guo Wang Shi-Jie Han Xu-Bing Cheng Mai-He Li A-Nan Fan Xiu-Xiu Wang 《Trees - Structure and Function》2011,25(2):163-173
There is, so far, no common conclusion about photosynthetic responses of trees to long-term exposure to elevated CO2. Photosynthesis and specific leaf area (SLA) of 1-year-old and current-year needles in Pinus koraiensis and P. sylvestriformis grown in open-top chambers were measured monthly for consecutive two growing seasons (2006, 2007) after 8–9 years of CO2 enrichment in northeastern China, to better understand species-specific and needle age-related responses to elevated CO2 (500 μmol mol−1 CO2). The light-saturated photosynthetic rates (P
Nsat) increased in both species at elevated CO2, but the stimulation magnitude varied with species and needle age. Photosynthetic acclimation to elevated CO2, in terms of reduced V
cmax (maximum carboxylation rate) and J
max (maximum electron transport rate), was found in P. koraiensis but not in P. sylvestriformis. The photosynthetic parameters (V
cmax, J
max, P
Nsat) measured in different-aged needles within each species responded to elevated CO2 similarly, but elevated CO2 resulted in much pronounced variations of those parameters in current-year needles than in 1-year-old needles within each
species. This result indicated that needle age affects the magnitude but not the patterns of photosynthetic responses to long-term
CO2 enrichment. The present study indicated that different species associated with different physioecological properties responded
to elevated CO2 differently. As global change and CO2 enrichment is more or less a gradual rather than an abrupt process, long-term global change experiments with different plant
species are still needed to character and better predict the global change effects on terrestrial ecosystems. 相似文献
10.
Tommi Räisänen Aija Ryyppö Riitta Julkunen-Tiitto Seppo Kellomäki 《Trees - Structure and Function》2008,22(1):121-135
The aim of this study was to evaluate the long-term effects of elevated CO2 concentration (doubling of ambient CO2 concentration) and temperature (2–6°C elevation) on the concentration and content of secondary compounds in the needles of
Scots pine (Pinus sylvestris L.) saplings grown in closed-top environmental chambers. The chamber treatments included (1) ambient temperature and CO2, (2) ambient temperature and elevated CO2, (3) elevated temperature and ambient CO2, and (4) elevated temperature and elevated CO2. The needle sampling and analyses of monoterpenes, HPLC-phenolics and condensed tannins in current- and 1-year-old needles
were made in two consecutive years. The results showed that the effects of elevation of CO2 and temperature were greatest on the monoterpene concentration in the needles while the concentration of HPLC-phenolics remained
almost unaffected by the changed growing conditions. Most of the observed decrease in monoterpene concentration was caused
by the CO2 enrichment while the effect of elevated temperature alone was not as significant. The accumulation of condensed tannins tended
to increase due to the elevation of CO2 alone compensating the reduced carbon allocation to monoterpenes. Overall, the responses of the concentrations of secondary
compounds to the elevation of CO2 and temperature are variable and depend strongly on the properties and characteristics of each compound as well as on the
interrelation between the production of these compounds and the primary production of trees. 相似文献
11.
Ecosystem-level experiments on the effects of atmospheric CO2 enrichment and N deposition on forest trees are urgently needed. Here we present data for nine model ecosystems of spruce
(Picea abies) on natural nutrient-poor montane forest soil (0.7 m2 of ground and 350 kg weight). Each system was composed of six 7-year-old (at harvest) trees each representing a different
genotype, and a herbaceous understory layer (three species). The model ecosystems were exposed to three different CO2 concentrations (280, 420, 560 μl l−1) and three different rates of wet N deposition (0, 30, 90 kg ha−1 year−1) in a simulated annual course of Swiss montane climate for 3 years. The total ecosystem biomass was not affected by CO2 concentration, but increased with increasing N deposition. However, biomass allocation to roots increased with increasing
CO2 leading to significantly lower leaf mass ratios (LMRs) and leaf area ratios (LARs) in trees grown at elevated CO2. In contrast to CO2 enrichment, N deposition increased biomass allocation to the aboveground plant parts, and thus LMR and LAR were higher with
increasing N deposition. We observed no CO2 × N interactions on growth, biomass production, or allocation, and there were also no genotype × treatment interactions.
The final leaf area index (LAI) of the spruce canopies was 19% smaller at 420 and 27% smaller at 560 than that measured at
280 μl CO2 l−1, but was not significantly altered by increasing N deposition. Lower LAIs at elevated CO2 largely resulted from shorter branches (less needles per individual tree) and partially from increased needle litterfall.
Independently of N deposition, total aboveground N content in the spruce communities declined with increasing CO2 (−18% at 420 and −31% at 560 compared to 280 μl CO2 l−1). N deposition had the opposite effect on total above ground N content (+18% at 30 and +52% at 90 compared to 0 kg N ha−1 year−1). Our results suggest that under competitive conditions on natural forest soil, atmospheric CO2 enrichment may not lead to higher ecosystem biomass production, but N deposition is likely to do so. The reduction in LAI
under elevated CO2 suggests allometric down-regulation of photosynthetic carbon uptake at the canopy level. The strong decline in the tree nitrogen
mass per unit ground area in response to elevated CO2 may indicate CO2-induced reductions of soil N availability.
Received: 11 May 1997 / Accepted: 4 August 1997 相似文献
12.
13.
M. Lippert Karl Steiner Thomas Pfirrmann Hans-Dieter Payer 《Trees - Structure and Function》1997,11(5):306-315
Well-supplied and K-deficient 4-year-old clonal Norway spruce trees were exposed to combinations of two levels of ozone (20
and 80 nl l –
1 O3) and carbon dioxide (350 and 750 μl l –
1 CO2) to study the effects of possible future climate factors on gas exchange characteristics. The fumigation was performed in
environmental chambers for a complete growing season. After the exposure, plants were cultivated outdoors to investigate possible
recovery and delayed effects. During the exposure 1-year-old needles responded to the 80 nl l –
1 O3 treatment by a sharp but transient decrease of both apparent carboxylation efficiency (CE) and maximum photosynthetic capacity
(A2500). Elevated CO2 also reduced CE and A2500. The effect became stronger in the course of the exposure and was accompanied by decreases of N and P as well as chlorophyll
contents. In case of K deficiency, the acclimation response of current-year needles was even more pronounced reflecting lower
sink capacities for carbon metabolites. The joint application of elevated O3 and CO2 resulted in the lowest values of gas exchange parameters and chlorophyll contents. At the beginning of the growing season
after the exposure and under outdoor conditions, all these treatment effects disappeared in the needles which had developed
during the fumigation. In the course of the development of the new flush, however, the well-supplied 1-year-old needles which
had been treated with 80 nl l –
1 O3 and 350 μl l –
1 CO2 in the year before, exhibited a sharp decline of CE and A2500. Simultaneously, chlorotic mottle and bands developed. These delayed symptoms are discussed in the context of the previously
published “memory” effect for O3 (Sandermann et al. 1989). Additionally, evidence is presented that shoot development is altered in plants which had been
exposed to elevated O3.
Accepted: 5 August 1996 相似文献
14.
Leena Sallas Pirjo Kainulainen Jarkko Utriainen Toini Holopainen Jarmo K. Holopainen† 《Global Change Biology》2001,7(3):303-311
Terpene, resin acid and total phenolic concentrations in five‐year‐old Scots pine (Pinus sylvestris L.) seedlings were analysed after exposure to ambient and realistically elevated (2 × ambient) O3 and CO2 concentrations and their combination in open‐top chambers during two growing seasons. Under O3 exposure, limonene concentration in needles and isopimaric concentration in stems decreased significantly. As a response to elevated CO2, α‐pinene and total phenolic concentrations in needles increased significantly, while bornyl acetate concentration in needles and palustric + levopimaric and neoabietic acid concentrations in stems decreased significantly. Some terpenes and resin acids were found at lower concentrations in the combined O3 and CO2 treatment than in O3 exposure or elevated CO2. A negative chamber effect was found: seedlings growing inside the chambers with ambient air had significantly lower concentrations of some terpenes and resin acids than seedlings growing outside the chambers. There was a lot of between‐tree variation in terpene and resin acid concentrations, which is typical of open‐pollinated populations. The results of this study suggest that, at least in short‐term experiments, Scots pine secondary metabolites are relatively insensitive to climate change factors. Total phenolics in the needles were the most responsive group showing about 25% increase in elevated CO2, and O3 exposure did not mitigate this CO2 effect. Terpenes and resin acids were less responsive, although some individual compounds showed notable responses, e.g. α‐pinene in needles, which increased about 50% in response to elevated CO2. As a consequence, although there were only slight effects on total pools of needle secondary metabolites, considerable O3 and CO2 effects on certain individual compounds might have ecological significance via trophic amplification, e.g. in decomposing processes of needle litter. 相似文献
15.
Shi-Rong Liu Craig Barton Helen Lee Paul G. Jarvis Dave Durrant 《Plant biosystems》2013,147(2):189-198
ABSTRACT After a 3-year exposure to elevated CO2, young trees of Sitka spruce (Picea sitchensis (Bong.) Carr.) were planted in native, nutrient-deficient forest soil and grown for two more years with three CO2 treatments in open-top chambers, and with two nutrient treatments (with and without supplied N). Elevated CO2 resulted in larger fresh mass, dry mass, leaf area and leaf thickness in two-year old needles, but had no effect on one-year old and current needles. Tree height, basal diameter and biomass production also increased, regardless of N supply. In trees without added N, elevated CO2 resulted in higher root-to-shoot and absorbing roots-to-stump ratios. Regardless of N supply, trees grown in elevated CO2 had lower photosynthetic rates on a leaf area basis. Photosynthesis reduction was accompanied by a decline in Rubisco activity and leaf N concentration. Under elevated CO2, added N elevated photosynthesis and Rubisco activity, suggesting a dependence on N availability of the photosynthetic response to elevated CO2. Stomatal conductance of trees grown with added N decreased in response to elevated CO2. This may account for the larger reduction in intercellular CO2 concentration, and hence photosynthesis, in the trees supplied with N than in those without N supply. 相似文献
16.
D.J. Beerling 《Acta Oecologica》1997,18(6):697
The Climate Change Experiment (CLIMEX) is a unique large scale facility in which an entire undisturbed catchment of boreal vegetation has been exposed to elevated CO2 (560 ppm) and temperature (+3°C summer, +5°C winter) for the past three years with all the soil-plant-atmosphere linkages intact. Here, carbon isotope composition and stomatal density have been analysed from sequential year classes of needles of mature Scots pine trees (Pinus sylvestris L.) to investigate the response of time-integrated water-use efficiency (UWE) and stomatal density to CO2 enrichment and climate change. Carbon isotope discrimination decreased and WUE increased in cohorts of needles developing under increased CO2 and temperature, compared to needles on the same trees developing in pretreatment years. Mid-season instantaneous gas exchange, measured on the same trees for the past four years, indicated that these responses resulted from higher needle photosynthetic rates and reduced stomatal conductance. Needles of P. sylvestris developing under increased CO2 and temperature had consistently lower stomatal densities than their ambient grown counterparts on the same trees. The stomatal density of P. sylvestris needles was inversely correlated with δ13C-derived WUE, implying some effect of this morphological response on leaf gas exchange. Future atmospheric CO2 and temperature increases are therefore likely to improve the water economy of P. sylvestris, at least at the scale of individual needles, by affecting stomatal density and gas exchange processes. 相似文献
17.
Carbon dioxide enrichment may increase the Al tolerance of trees by increasing root growth, root exudation and/or mycorrhizal
colonization. The effect of elevated CO2 on the response of mycorrhizal pitch pine (Pinus rigida Mill.) seedlings to Al was determined in two experiments with different levels of nutrients, 0.1- or 0.2-strength Clark solution.
During each experiment, seedlings inoculated with the ectomycorrhizal fungus Pisolithus tinctorius (Pers.) Coker & Couch were grown 13 weeks in sand irrigated with nutrient solution (pH 3.8) containing 0, 6.25, 12.5, or
25 mg/l Al (0, 232, 463, or 927 μM Al) in growth chambers fumigated with 350 (ambient) or 700 (elevated) μl/l CO2. At ambient CO2, in the absence of Al, mean total dry weights (DW) of seedlings at the high nutrient level were 164% higher than those at
the low level. Total DW at elevated CO2, in the absence of Al, was significantly greater than that in ambient CO2 at the low (+34%) and high (+16%) nutrient levels. Root and shoot DW at both nutrient levels decreased with increasing Al
concentrations with Al reducing root growth more than shoot growth. Although visible symptoms of Al toxicity in roots and
needles were reduced by CO2 enrichment, there were no significant CO2 × Al interactions for shoot or root DW. The percentage of seedling roots that became mycorrhizal was negatively related to
nutrient level and was greater at elevated than at ambient CO2 levels. Generally, elevated CO2 had little effect on concentration of mineral nutrients in roots and needles. Aluminum reduced concentrations of most nutrients
by inhibiting uptake.
Received: 18 June 1997 / Accepted: 8 December 1997 相似文献
18.
JohN. V. H. Constable Marcy E. Litvak James P. Greenberg† Russell K. Monson 《Global Change Biology》1999,5(3):252-267
It was hypothesized that high CO2 availability would increase monoterpene emission to the atmosphere. This hypothesis was based on resource allocation theory which predicts increased production of plant secondary compounds when carbon is in excess of that required for growth. Monoterpene emission rates were measured from needles of (a) Ponderosa pine grown at different CO2 concentrations and soil nitrogen levels, and (b) Douglas fir grown at different CO2 concentrations. Ponderosa pine grown at 700 μmol mol–1 CO2 exhibited increased photosynthetic rates and needle starch to nitrogen (N) ratios when compared to trees grown at 350 μmol mol–1 CO2. Nitrogen availability had no consistent effect on photosynthesis. Douglas fir grown at 550 μmol mol–1 CO2 exhibited increased photosynthetic rates as compared to growth at 350 μmol mol–1 CO2 in old, but not young needles, and there was no influence on the starch/N ratio. In neither species was there a significant effect of elevated growth CO2 on needle monoterpene concentration or emission rate. The influence of climate warming and leaf area index (LAI) on monoterpene emission were also investigated. Douglas fir grown at elevated CO2 plus a 4 °C increase in growth temperature exhibited no change in needle monoterpene concentration, despite a predicted 50% increase in emission rate. At elevated CO2 concentration the LAI increased in Ponderosa pine, but not Douglas fir. The combination of increased LAI and climate warming are predicted to cause an 80% increase in monoterpene emissions from Ponderosa pine forests and a 50% increase in emissions from Douglas fir forests. This study demonstrates that although growth at elevated CO2 may not affect the rate of monoterpene emission per unit biomass, the effect of elevated CO2 on LAI, and the effect of climate warming on monoterpene biosynthesis and volatilization, could increase canopy monoterpene emission rate. 相似文献
19.
Wall GW Adam NR Brooks TJ Kimball BA Pinter PJ Lamorte RL Adamsen FJ Hunsaker DJ Wechsung G Wechsung F Grossman-Clarke S Leavitt SW Matthias AD Webber AN 《Photosynthesis research》2000,66(1-2):79-95
Atmospheric CO2 concentration continues to rise. It is important, therefore, to determine what acclimatory changes will occur within the
photosynthetic apparatus of wheat (Triticum aestivum L. cv. Yecora Rojo) grown in a future high-CO2 world at ample and limited soil N contents. Wheat was grown in an open field exposed to the CO2 concentration of ambient air [370 μmol (CO2) mol−1; Control] and air enriched to ∼200 μmol (CO2) mol−1 above ambient using a Free-Air CO2 Enrichment (FACE) apparatus (main plot). A High (35 g m−2) or Low (7 and 1.5 g m−2 for 1996 and 1997, respectfully) level of N was applied to each half of the main CO2 treatment plots (split-plot). Under High-N, FACE reduced stomatal conductance (g
s) by 30% at mid-morning (2 h prior to solar noon), 36% at midday (solar noon) and 27% at mid-afternoon (2.5 h after solar
noon), whereas under Low-N, g
s was reduced by as much as 31% at mid-morning, 44% at midday and 28% at mid-afternoon compared with Control. But, no significant
CO2 × N interaction effects occurred. Across seasons and growth stages, daily accumulation of carbon (A′) was 27% greater in FACE than Control. High-N increased A′ by 18% compared with Low-N. In contrast to results for g
s, however, significant CO2 × N interaction effects occurred because FACE increased A′ by 30% at High-N, but by only 23% at Low-N. FACE enhanced the seasonal accumulation of carbon (A′′) by 29% during 1996 (moderate N-stress), but by only 21% during 1997 (severe N-stress). These results support the premise
that in a future high-CO2 world an acclimatory (down-regulation) response in the photosynthetic apparatus of field-grown wheat is anticipated. They also demonstrate, however, that the stimulatory
effect of a rise in atmospheric CO2 on carbon gain in wheat can be maintained if nutrients such as nitrogen are in ample supply.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
20.
L. M. van Heerwaarden S. Toet R. S. P. van Logtestijn R. Aerts 《Plant and Soil》2005,277(1-2):255-264
Nutrient resorption from senescing leaves is an important aspect of internal plant nutrient cycling. Global environmental
change very likely affects this process. In an 8-month experiment, we investigated the effect of increased nitrogen (N) availability
and CO2 concentration on the contribution of leaf N resorption to the internal nitrogen dynamics of the perennial deciduous graminoid
Molinia caerulea (L.) Moench. Plants were grown in a factorial combination of two levels of N (65 and 265 N ha−1 year−1) and CO2 (380 and 700 μL L−1) in a greenhouse. Both N and CO2 addition increased the total biomass and the total N pools of mature Molinia plants considerably, without a significant interaction. Nitrogen-resorption efficiency from senescing leaves (% of the mature
leaf N pool that is resorbed) was neither affected by the N- nor by the CO2 treatments. When averaged over the treatments, the N-resorption efficiency was 85% ± 1 (SE). The final N concentration in
the litter (N-resorption proficiency) was also not affected by the treatments and was on average 3.6 mg N g−1 ± 0.25 (SE). The contribution of resorbed N from senescing leaves to the late seasonal N requirements (seed and stem production
and storage of N for next year’s growth) of M. caerulea plants was (negatively) affected by the N treatment only, and no interaction effects with CO2 were found. Resorption from stems and/or direct reserve and seed formation during growth became relatively more important.
Thus, internal N cycling processes in Molinia caerulea are only affected when N availability is increased, but not under elevated CO2 concentrations. Under high N conditions, this species shifts from a N recycling strategy to reserve formation during growth. 相似文献