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1.
Photosynthetic acclimation of maize to growth under elevated levels of carbon dioxide 总被引:4,自引:0,他引:4
The effects of elevated CO2 concentrations on the photochemistry, biochemistry and physiology of C4 photosynthesis were studied in maize (Zea mays L.). Plants were grown at ambient (350 μL L−1) or ca. 3 times ambient (1100 μL L−1) CO2 levels under high light conditions in a greenhouse for 30 d. Relative to plants grown at ambient CO2 levels, plants grown under elevated CO2 accumulated ca. 20% more biomass and 23% more leaf area. When measured at the CO2 concentration of growth, mature leaves of high-CO2-grown plants had higher light-saturated rates of photosynthesis (ca. 15%), lower stomatal conductance (71%), higher water-use
efficiency (225%) and higher dark respiration rates (100%). High-CO2-grown plants had lower carboxylation efficiencies (23%), measured under limiting CO2, and lower leaf protein contents (22%). Activities of a number of C3 and C4 cycle enzymes decreased on a leaf-area basis in the high-CO2-grown plants by 5–30%, with NADP-malate dehydrogenase exhibiting the greatest decrease. In contrast, activities of fructose
1,6-bisphosphatase and ADP-glucose pyrophosphorylase increased significantly under elevated CO2 condition (8% and 36%, respectively). These data show that the C4 plant maize may benefit from elevated CO2 through acclimation in the capacities of certain photosynthetic enzymes. The increased capacity to synthesize sucrose and
starch, and to utilize these end-products of photosynthesis to produce extra energy by respiration, may contribute to the
enhanced growth of maize under elevated CO2.
Received: 30 April 1999 / Accepted: 17 June 1999 相似文献
2.
Response of plant roots to elevated atmospheric carbon dioxide 总被引:10,自引:0,他引:10
H. H. ROGERS C. M. PETERSON J. N. McCRIMMON J. D. CURE 《Plant, cell & environment》1992,15(6):749-752
Plant root response to atmospheric CO2 enrichment can be great. Results from this controlled environment investigation demonstrate substantial effects on root system architecture, micromorphology and physiology. The most pronounced effects were an increase in root length (110%) and root dry weight (143%). Root diameter, stele diameter, cortex width, root/shoot and root weight ratios all increased; root numbers did not increase. The long-term implications for belowground processes could be enormous. 相似文献
3.
Photosynthetic inhibition after long-term exposure to elevated levels of atmospheric carbon dioxide 总被引:38,自引:0,他引:38
The effect of long-term exposure to elevated levels of CO2 on biomass partitioning, net photosynthesis and starch metabolism was examined in cotton. Plants were grown under controlled conditions at 350, 675 and 1000 l l-1 CO2. Plants grown at 675 and 1000 l l-1 had 72% and 115% more dry weight respectively than plants grown at 350 l l-1. Increases in weight were partially due to corresponding increases in leaf starch. CO2 enrichment also caused a decrease in chlorophyll concentration and a change in the chlorophyll a/b ratio. High CO2 grown plants had lower photosynthetic capacity than 350 l l-1 grown plants when measured at each CO2 concentration. Reduced photosynthetic rates were correlated with high internal (non-stomatal) resistances and higher starch levels. It is suggested that carbohydrate accumulation causes a decline in photosynthesis by feedback inhibition and/or physical damage at the chloroplast level.Abbreviations Ci
internal CO2 concentration
- Chl
chlorophyll
- DMSO
dimethylsulfoxide
- HSD
honestly significant difference (procedure)
- MCW
methanolchloroform-water
- Pi
inorganic phosphate
- S.E.M.
standard error of mean 相似文献
4.
Photosynthetic acclimation to long-term exposure to elevated CO2 concentration in Pinus radiata D. Don. is related to age of needles 总被引:3,自引:2,他引:1
M. H. Turnbull D. T. Tissue K. L. Griffin G. N. D. Rogers & D. Whitehead 《Plant, cell & environment》1998,21(10):1019-1028
The effects of CO2 enrichment on photosynthesis and ribulose-1,5-bisphosphate carboxylase/ oxygenase (Rubisco) in current year and 1-year-old needles on the same branch were studied on Pinus radiata D. Don. trees growing for 4 years in large, open-top chambers at ambient (36 Pa) and elevated (65 Pa) CO2 partial pressures. At this age trees were 3·5–4 m tall. Measurements made late in the growing cycle (March) showed that photosynthetic rates at the growth CO2 concentration [(pCO2)a] were lower in 1-year-old needles of trees grown at elevated CO2 concentrations than in those of trees grown at ambient (pCO2)a. At elevated CO2 concentrations Vcmax (maximum carboxylation rate) was reduced by 13% and Jmax (RuBP regeneration capacity mediated by maximum electron transport rate) by 17%. This corresponded with photosynthetic rates at the growth (pCO2)a of 4·68 ± 0·41 μmol m–2 s–1 and 6·15 ± 0·46 μmol m–2 s–1 at 36 and 65 Pa, respectively (an enhancement of 31%). In current year needles photosynthetic rates at the growth (pCO2)a were 6·2 ± 0·72 μmol m–2 s–1 at 36 Pa and 10·15 ± 0·64 μmol m–2 s–1 at 65 Pa (an enhancement of 63%). The smaller enhancement of photosynthesis in 1-year-old needles at 65 Pa was accompanied by a reduction in Rubisco activity (39%) and content (40%) compared with that at 36 Pa. Starch and sugar concentrations in 1-year-old needles were not significantly different in the CO2 treatments. There was no evidence in biochemical parameters for down-regulation at elevated (pCO2)a in fully fexpanded needles of the current year cohort. These data show that enhancement of photosynthesis continues to occur in needles after 4 years’ exposure to elevated CO2 concentrations. Photosynthetic acclimation reduces the degree of this enhancement, but only in needles after 1 year of growth. Thus, responses to elevated CO2 concentration change during the lifetime of needles, and acclimation may not be apparent in current year needles. This transitory effect is most probably attributable to the effects of developmental stage and proximity to actively growing shoots on sink strength for carbohydrates. The implications of such age-dependent responses are that older trees, in which the contribution of older needles to the photosynthetic biomass is greater than in younger trees, may become progressively more acclimated to elevated CO2 concentration. 相似文献
5.
6.
With rising level of CO2 in the atmosphere plants are expected to be exposed to higher concentration of CO2. Since, CO2 is a substrate limiting photosynthesis particularly in C3 plants in the present atmosphere, the impact of elevated CO2 would depend mainly on how photosynthesis acclimates or adjusts to the long term elevated level of CO2. Photosynthetic acclimation is a change in photosynthetic efficiency of leaves due to long term exposure to elevated CO2. This change in photosynthetic efficiency could be a biochemical adjustment that may improve the overall performance of a plant in a high CO2 environment or it could be due to metabolic compulsions as a result of physiological dysfunction. Acclimation has generally become synonymous with the word response, if long term exposure to elevated CO2 decreases the photosynthesis rate (Pn) at a given CO2 level, it is called negative acclimation, if it stimulates Pn at a given CO2 level, it is called positive acclimation. Photosynthetic acclimation is clearly revealed by comparing Pn of ambient and elevated CO2 grown plants at same level of CO2. Species level differences in acclimation to elevated CO2 have been reported. The physiological basis of differential photosynthetic acclimation to elevated CO2 is discussed in relation to the regulation of photosynthesis and photosynthetic carbon partitioning at cellular level. 相似文献
7.
Shoots, roots and ectomycorrhiza formation of pine seedlings at elevated atmospheric carbon dioxide 总被引:4,自引:0,他引:4
The effect of elevated atmospheric CO2 concentration on the growth of shoots, roots, mycorrhizas and extraradical mycorrhizal mycelia of pine (Pinus silvestris L.) was examined. Two and a half-month-old seedlings were inoculated axenically with the mycorrhizal fungus Pisolithus tincto-rius (Pers.) by a method allowing rapid mycorrhiza formation in Petri dishes. The plants were then cultivated for 3 months in growth chambers with daily concentrations of 350 and 600 μmol mol?1 CO2 during the day. Whereas plants harvested after 1 and 2 months did not differ appreciably between ambient and increased CO2 concentrations, after 3 months they developed a considerably higher root biomass (%57%) at elevated CO2, but did not increase significantly in root length. The mycorrhizal fungus Pisolithus tinctorius, which depended entirely on the plant assimilates in the model system, grew much faster at increased CO2: 3 times more mycorrhizal root clusters were formed and the extraradical mycelium produced had twice the biomass at elevated as at ambient CO2. No difference in shoot biomass was found between the two treatments after 91 d. However, since the total water consumption of seedlings was similar in the two treatments, the water use efficiency was appreciably higher for the seedlings at increased CO2 because of the higher below-ground biomass. 相似文献
8.
Bunce JA 《Photosynthesis research》2001,68(3):237-245
Strawberry (Fragaria × ananassa) plants were grown in field plots at the current ambient [CO2], and at ambient + 300 and ambient + 600 μmol mol−1 [CO2]. Approximately weekly measurements were made of single leaf gas exchange of upper canopy leaves from early spring through
fall of two years, in order to determine the temperature dependence of the stimulation of photosynthesis by elevated [CO2], whether growth at elevated [CO2] resulted in acclimation of photosynthesis, and whether any photosynthetic acclimation was reduced when fruiting created
additional demand for the products of photosynthesis. Stimulation of photosynthetic CO2 assimilation by short-term increases in [CO2] increased strongly with measurement temperature. The stimulation exceeded that predicted from the kinetic characteristics
of ribulose-1,5-bisphosphate carboxylase at all temperatures. Acclimation of photosynthesis to growth at elevated [CO2] was evident from early spring through summer, including the fruiting period in early summer, with lower rates under standard
measurement conditions in plants grown at elevated [CO2]. The degree of acclimation increased with growth [CO2]. However, there were no significant differences between [CO2] treatments in total nitrogen per leaf area, and photosynthetic acclimation was reversed one day after switching the [CO2] treatments. Tests showed that acclimation did not result from a limitation of photosynthesis by triose phosphate utilization
rate at elevated [CO2]. Photosynthetic acclimation was not evident during dry periods in midsummer, when the elevated [CO2] treatments conserved soil water and photosynthesis declined more at ambient than at elevated [CO2]. Acclimation was also not evident during the fall, when plants were vegetative, despite wet conditions and continued higher
leaf starch content at elevated [CO2]. Stomatal conductance responded little to short-term changes in [CO2] except during drought, and changed in parallel with photosynthetic acclimation through the seasons in response to the long-term
[CO2] treatments. The data do not support the hypothesis that source-sink balance controls the seasonal occurrence of photosynthetic
acclimation to elevated [CO2] in this species.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
9.
The effects of elevated CO2 concentration upon the mycorrhizal relationships of Scots pine (Pinus sylvestris) seedlings were investigated. Plants were grown for 4 months with their shoots exposed to ambient (CAMB=360 μl l−1) or elevated (CELEV=700 μl l−1) CO2 environments while their root systems, either colonised by the mycorrhizal fungi Paxillus involutus or Suillus bovinus, or left in the non-mycorrhizal condition, were maintained in sealed dishes. In one series of these plants the effects of CELEV upon the extent of mycorrhizal development and upon their growth and nutrition were determined, while another series were transferred from the dishes after 1 month, to transparent observation chambers before being returned to the two CO2 environments. In these chambers, the effects of CELEV upon development of the external mycelial systems of the two mycorrhizal fungi was determined by measuring the advance of the hyphal fronts of the mycorrhizal fungi across non-sterile peat from the colonised plants. The dry mass and number of mycorrhizal tips were significantly higher in CELEV than in the CAMB condition in plants colonised by both fungi in the dishes. Yields of whole plants and of shoots were higher in the CELEV treatment whether or not they were grown in the mycorrhizal condition, but the greater yields were not associated in these sealed systems with enhanced nutrient gain. The dry mass of non-mycorrhizal plants was greater than that of those colonised by mycorrhizal fungi under elevated CO2. This is thought to be attributable to the energetic cost of production of the larger mycorrhizal systems in this treatment. The extent of development of the mycorrhizal mycelial systems of both fungi was greatly increased in CELEV relative to that in CAMB environments. It is hypothesised that increased allocation of carbon to mycorrhizal root systems and their associated mycelia would provide the potential for enhancement of nutrient acquisition in open systems of greater fertility. 相似文献
10.
Responses of soil biota to elevated atmospheric carbon dioxide 总被引:16,自引:2,他引:14
Elizabeth G. O'Neill 《Plant and Soil》1994,165(1):55-65
Increasing concentrations of atmospheric CO2 could have dramatic effects upon terrestrial ecosystems including changes in ecosystem structure, nutrient cycling rates,
net primary production, C source-sink relationships and successional patterns. All of these potential changes will be constrained
to some degree by below ground processes and mediated by responses of soil biota to indirect effects of CO2 enrichment. A review of our current state of knowledge regarding responses of soil biota is presented, covering responses
of mycorrhizae, N-fixing bacteria and actinomycetes, soil microbiota, plant pathogens, and soil fauna. Emphasis will be placed
on consequences to biota of increasing C input through the rhizosphere and resulting feedbacks to above ground systems. Rising
CO2 may also result in altered nutrient concentrations of plant litter, potentially changing decomposition rates through indirect
effects upon decomposer communities. Thus, this review will also cover current information on decomposition of litter produced
at elevated CO2.
Summary Predictably, the responses of soil biota to CO2 enrichment and the degree of experimental emphasis on them increase with proximity to, and intimacy with, roots. Symbiotic
associations are all stimulated to some degree. Total plant mycorrhization increases with elevated CO2. VAM fungi increase proportionately with fine root length/mass increase. ECM fungi, however, exhibit greater colonization
per unit root length/mass at elevated CO2 than at current atmospheric levels. Total N-fixation per plant increases in all species examined, although the mechanisms
of increase, as well as the eventual benefit to the host relative to N uptake may vary. Microbial responses are unclear. The
assumption that changes in root exudation will drive increased mineralization and facilitate nutrient uptake should be examined
experimentally, in light of recent models. Microbial results to date suggest that metabolic activity (measured as changes
in process rates) is stimulated by root C input, rather than population size (measured by cell or colony counts). Insufficient
evidence exists to predict responses of either soil-borne plant pathogens or soil fauna (i.e., food web responses). These
are areas requiring attention, the first for its potential to limit ecosystem production through disease and the second because
of its importance to nutrient cycling processes. Preliminary data on foliar litter decomposition suggests that neither nutrient
ratios nor decomposition rates will be affected by rising CO2. This is another important area that may be better understood as the number of longer term studies with more realistic CO2 exposures increase. Evidence continues to mount that C fixation increases with CO2 enrichment and that the bulk of this C enters the belowground component of ecosystems. The global fate and effects of this
additional C may affect all hierarchical levels, from organisms to ecosystems, and will be largely determined by responses
of soil biota. 相似文献
11.
Elevated atmospheric carbon dioxide (eCO2) has been shown to have a variety of ecosystem‐level effects in terrestrial systems, but few studies have examined how eCO2 might affect aquatic habitats. This limits broad generalizations about the effects of a changing climate across biomes. To broaden this generalization, we used free air CO2 enrichment to compare effects of eCO2 (i.e., double ambient ~720 ppm) relative to ambient CO2 (aCO2~360 ppm) on several ecosystem properties and functions in large, outdoor, experimental mesocosms that mimicked shallow sand‐bottom prairie streams. In general, we showed that eCO2 had strong bottom‐up effects on stream autotrophs, which moved through the food web and indirectly affected consumer trophic levels. These general effects were likely mediated by differential CO2 limitation between the eCO2 and aCO2 treatments. For example, we found that eCO2 decreased water‐column pH and increased dissolved CO2 in the mesocosms, reducing CO2‐limitation at times of intense primary production (PP). At these times, PP of benthic algae was about two times greater in the eCO2 treatment than aCO2 treatment. Elevated PP enhanced the rate of carbon assimilation relative to nutrient uptake, which reduced algae quality in the eCO2 treatment. We predicted that reduced algae quality would negatively affect benthic invertebrates. However, density, biomass and average individual size of benthic invertebrates increased in the eCO2 treatment relative to aCO2 treatment. This suggested that total PP was a more important regulator of secondary production than food quality in our experiment. This study broadens generalizations about ecosystem‐level effects of a changing climate by providing some of the first evidence that the global increase in atmospheric CO2 might affect autotrophs and consumers in small stream ecosystems throughout the southern Great Plains and Gulf Coastal slope of North America. 相似文献
12.
Changes in net photosynthesis and growth of Pinus eldarica seedlings in response to atmospheric CO2 enrichment 总被引:3,自引:2,他引:1
Pinus eldarica L. trees, rooted in the natural soil of an agricultural field at Phoenix, Arizona, were grown from the seedling stage in clear-plastic-wall open-top enclosures maintained at four different atmospheric CO2 concentrations for 15 months. Light response functions were determined for one tree from each treatment by means of whole-tree net CO2 exchange measurements at the end of this period, after which rates of carbon assimilation of an ambient-treatment tree were measured across a range of atmospheric CO2 concentrations. The first of these data sets incorporates the consequences of both the CO2-induced enhancement of net photosynthesis per unit needle area and the CO2-induced enhancement of needle area itself (due primarily to the production of more needles), whereas the second data set reflects only the first of these effects. Hence the division of the normalized results of the first data set by the normalized results of the second set yields a representation of the increase in whole-tree net photosynthesis due to enhanced needle production caused by atmospheric CO2 enrichment. In the solitary trees we studied, the relative contribution of this effect increased rapidly with the CO2 concentration of the air to increase whole-tree net photosynthesis by nearly 50% at a CO2 concentration approximately 300 μmol mol−1 above ambient. 相似文献
13.
Canopy warming caused photosynthetic acclimation and reduced seed yield in maize grown at ambient and elevated [CO2]
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Ursula M. Ruiz‐Vera Matthew H. Siebers David W. Drag Donald R. Ort Carl J. Bernacchi 《Global Change Biology》2015,21(11):4237-4249
Rising atmospheric CO2 concentration ([CO2]) and attendant increases in growing season temperature are expected to be the most important global change factors impacting production agriculture. Although maize is the most highly produced crop worldwide, few studies have evaluated the interactive effects of elevated [CO2] and temperature on its photosynthetic physiology, agronomic traits or biomass, and seed yield under open field conditions. This study investigates the effects of rising [CO2] and warmer temperature, independently and in combination, on maize grown in the field throughout a full growing season. Free‐air CO2 enrichment (FACE) technology was used to target atmospheric [CO2] to 200 μmol mol?1 above ambient [CO2] and infrared heaters to target a plant canopy increase of 3.5 °C, with actual season mean heating of ~2.7 °C, mimicking conditions predicted by the second half of this century. Photosynthetic gas‐exchange parameters, leaf nitrogen and carbon content, leaf water potential components, and developmental measurements were collected throughout the season, and biomass and yield were measured at the end of the growing season. As predicted for a C4 plant, elevated [CO2] did not stimulate photosynthesis, biomass, or yield. Canopy warming caused a large shift in aboveground allocation by stimulating season‐long vegetative biomass and decreasing reproductive biomass accumulation at both CO2 concentrations, resulting in decreased harvest index. Warming caused a reduction in photosynthesis due to down‐regulation of photosynthetic biochemical parameters and the decrease in the electron transport rate. The reduction in seed yield with warming was driven by reduced photosynthetic capacity and by a shift in aboveground carbon allocation away from reproduction. This field study portends that future warming will reduce yield in maize, and this will not be mitigated by higher atmospheric [CO2] unless appropriate adaptation traits can be introduced into future cultivars. 相似文献
14.
We tested the main and interactive effects of elevated carbon dioxide concentration ([CO2]), nitrogen (N), and light availability on leaf photosynthesis, and plant growth and survival in understory seedlings grown in an N‐limited northern hardwood forest. For two growing seasons, we exposed six species of tree seedlings (Betula papyrifera, Populus tremuloides, Acer saccharum, Fagus grandifolia, Pinus strobus, and Prunus serotina) to a factorial combination of atmospheric CO2 (ambient, and elevated CO2 at 658 μmol CO2 mol−1) and N deposition (ambient and ambient +30 kg N ha−1 yr−1) in open‐top chambers placed in an understory light gradient. Elevated CO2 exposure significantly increased apparent quantum efficiency of electron transport by 41% (P<0.0001), light‐limited photosynthesis by 47% (P<0.0001), and light‐saturated photosynthesis by 60% (P<0.003) compared with seedlings grown in ambient [CO2]. Experimental N deposition significantly increased light‐limited photosynthesis as light availability increased (P<0.037). Species differed in the magnitude of light‐saturated photosynthetic response to elevated N and light treatments (P<0.016). Elevated CO2 exposure and high N availability did not affect seedling growth; however, growth increased slightly with light availability (R2=0.26, P<0.0001). Experimental N deposition significantly increased average survival of all species by 48% (P<0.012). However, seedling survival was greatest (85%) under conditions of both high [CO2] and N deposition (P<0.009). Path analysis determined that the greatest predictor for seedling survival in the understory was total biomass (R2=0.39, P<0.001), and that carboxylation capacity (Vcmax) was a better predictor for seedling growth and survival than maximum photosynthetic rate (Amax). Our results suggest that increasing [CO2] and N deposition from fossil fuel combustion could alter understory tree species recruitment dynamics through changes in seedling survival, and this has the potential to alter future forest species composition. 相似文献
15.
Facility for studying the effects of elevated carbon dioxide concentration and increased temperature on crops 总被引:4,自引:3,他引:1
D. W. LAWLOR R. A. C. MITCHELL J. FRANKLIN V. J. MITCHELL S. P. DRISCOLL E. DELGADO 《Plant, cell & environment》1993,16(5):603-608
The requirements for the experimental study of the effects of global climate change conditions on plants are outlined. A semi-controlled plant growth facility is described which allows the study of elevated CO2 and temperature, and their interaction on the growth of plants under radiation and temperature conditions similar to the field. During an experiment on winter wheat (cv. Mercia), which ran from December 1990 through to August 1991, the facility maintained mean daytime CO2 concentrations of 363 and 692 cm3 m?3 for targets of 350 and 700 cm3 m?3 respectively. Temperatures were set to follow outside ambient or outside ambient +4°C, and hourly means were within 0.5°C of the target for 92% of the time for target temperatures greater than 6°C. Total photosynthetically active radiation incident on the crop (solar radiation supplemented by artifieal light with natural photoperiod) was 2% greater than the total measured outside over the same period. 相似文献
16.
Photosynthetic rates and photosynthate partitioning were studied in three-week-old soybean [Glycine max (L.) Merr. cv. Williams] plants exposed to either ambient (35 Pa) or elevated (70 Pa) CO2 in controlled environment chambers. Ambient CO2-grown plants also were given a single 24 h treatment with 70 Pa CO2 1 d prior to sampling. Photosynthetic rates of ambient CO2-grown plants initially increased 36% when the measurement CO2 was doubled from 35 to 70 Pa. Photosynthetic rates of the third trifoliolate leaf, both after 1 and 21 d of elevated CO2 treatment, were 30 to 45% below those of ambient CO2-grown plants when measured at 35 Pa CO2. These reduced photosynthetic rates were not due to increased stomatal resistance and were observed for 2 to 8 h after plants given 1 d of CO2 enrichment were returned to ambient CO2. Initial and total ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) activities, percent activation, Rubisco protein, soluble protein and leaf chlorophyll content were similar in all CO2 treatments. Quantum yields of photosynthesis, determined at limiting irradiances and at 35 Pa CO2, were 0.049±0.003 and 0.038±0.005 mol CO2 fixed per mol quanta for ambient and elevated CO2-grown plants, respectively (p<0.05). Leaf starch and sucrose levels were greater in plants grown at 70 than at 35 Pa CO2. Starch accumulation rates during the day were greater in ambient CO2-grown plants than in plants exposed to elevated CO2 for either 1 or 21 d. However, the percentage of C partitioned to starch relative to total C fixed was unaffected by 1 d of CO2 enrichment. The above results showed that both photosynthetic and starch accumulation rates of soybean leaflets measured at 35 Pa CO2 were temporarily reduced after 1 and 21 d of CO2 enrichment. The biochemical mechanism affecting these responses was not identified.Abbreviations SLW-
specific leaf weight (g m–2)
- Rubisco-
ribulose 1,5-bisphosphate carboxylase/oxygenase
- Rul-
5bisP, ribulose 1,5 bisphosphate
- DAP-
days after planting
- SAR-
starch accumulation rate
- Ci-
intercellular CO2 concentration 相似文献
17.
Soil respiration of Alaskan tundra at elevated atmospheric carbon dioxide concentrations 总被引:3,自引:0,他引:3
Summary CO2 efflux from tussock tundra in Alaska that had been exposed to elevated CO2 for 2.5 growing seasons was measured to assess the effect of long- and short-term CO2 enrichment on soil respiration. Long-term treatments were: 348, 514, and 683 μll−1 CO2 and 680 μll−1 CO2+4°C above ambient. Measurements were made at 5 CO2 concentrations between 87 and 680 μll−1 CO2. Neither long- or short-term CO2 enrichment significantly affected soil CO2 efflux. Tundra developed at elevated temperature and 680 μll−1 CO2 had slightly higher, but not statistically different, mean respiration rates compared to untreated tundra and to tundra under
CO2 control alone. 相似文献
18.
19.
New insights into the cellular mechanisms of plant growth at elevated atmospheric carbon dioxide concentrations 总被引:2,自引:0,他引:2
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Dananjali Gamage Michael Thompson Mark Sutherland Naoki Hirotsu Amane Makino Saman Seneweera 《Plant, cell & environment》2018,41(6):1233-1246
Rising atmospheric carbon dioxide concentration ([CO2]) significantly influences plant growth, development, and biomass. Increased photosynthesis rate, together with lower stomatal conductance, has been identified as the key factors that stimulate plant growth at elevated [CO2] (e[CO2]). However, variations in photosynthesis and stomatal conductance alone cannot fully explain the dynamic changes in plant growth. Stimulation of photosynthesis at e[CO2] is always associated with post‐photosynthetic secondary metabolic processes that include carbon and nitrogen metabolism, cell cycle functions, and hormonal regulation. Most studies have focused on photosynthesis and stomatal conductance in response to e[CO2], despite the emerging evidence of e[CO2]'s role in moderating secondary metabolism in plants. In this review, we briefly discuss the effects of e[CO2] on photosynthesis and stomatal conductance and then focus on the changes in other cellular mechanisms and growth processes at e[CO2] in relation to plant growth and development. Finally, knowledge gaps in understanding plant growth responses to e[CO2] have been identified with the aim of improving crop productivity under a CO2 rich atmosphere. 相似文献
20.
MARK G. TJOELKER JACEK OLEKSYN†‡ PETER B. REICH† ROMA YTKOWIAK‡ 《Global Change Biology》2008,14(4):782-797
Patterns and mechanisms of short‐term temperature acclimation and long‐term climatic adaptation of respiration among intraspecific populations are poorly understood, but both are potentially important in constraining respiratory carbon flux to climate warming across large geographic scales, as well as influencing the metabolic fitness of populations. Herein we report on leaf dark respiration of 33‐year‐old trees of jack pine (Pinus banksiana Lamb.) grown in three contrasting North American common gardens (0.9, 4.6, and 7.9 °C, mean annual temperature) comprised of identical populations of wide‐ranging geographic origins. We tested whether respiration rates in this evergreen conifer acclimate to prevailing ambient air temperatures and differ among populations. At each of the common gardens, observed population differences in respiration rates measured at a standard temperature (20 °C) were comparatively small and largely unrelated to climate of seed‐source origin. In contrast, respiration in all populations exhibited seasonal acclimation at all sites. Specific respiration rates at 20 °C inversely tracked seasonal variation in ambient air temperature, increasing with cooler temperatures in fall and declining with warmer temperatures in spring and summer. Such responses were similar among populations and sites, thus providing a general predictive equation regarding temperature acclimation of respiration for the species. Temperature acclimation was associated with variation in nitrogen (N) and soluble carbohydrate concentrations, supporting a joint enzyme and substrate‐based model of respiratory acclimation. Regression analyses revealed convergent relationships between respiration and the combination of needle N and soluble carbohydrate concentrations and between N‐based respiration (RN, μmol mol N? 1 s? 1) and soluble carbohydrate concentrations, providing evidence for general predictive relationships across geographically diverse populations, seasons, and sites. Overall, these findings demonstrate that seasonal acclimation of respiration modulates rates of foliar respiratory carbon flux in a widely distributed evergreen species, and does so in a predictable way. Genetic differences in specific respiration rate appear less important than temperature acclimation in downregulating respiratory carbon fluxes with climate warming across wide‐ranging sites. 相似文献