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1.
To study the influence of elevated CO2 and nitrogen (N) fertilization on wood properties and energy, Populus × euramericana trees were exposed to ambient CO2 (about 370 μmol mol−1 CO2 ) or elevated CO2 (about 550 μmol mol−1 CO2 ) using Free Air CO2 Enrichment (FACE) technology in combination with two N levels. Elevated CO2 was maintained for 5 years. After three growing seasons, the plantation was coppiced, one half of each experimental plot was fertilized and secondary sprouts were harvested after two growing seasons. Fourier transform infrared (FT-IR) spectra of wood revealed significant effects of both elevated CO2 and N fertilization on wood chemistry, in particular, significant increases in lignin and decreases in N content. These results were corroborated by chemical analysis. Neither elevated CO2 nor N fertilization affected the calorific value of wood, which was 19.3 MJ kg−1 . N fertilization enhanced the energy production per land area by 16–69% because of higher aboveground woody biomass production than on nonfertilized land. Estimates indicate that high yielding poplar short rotation cultivation may significantly contribute as an alternative feedstock for energy production. 相似文献
2.
KAY-MAY MIYAGI TOSHIHIKO KINUGASA KOUKI HIKOSAKA TADAKI HIROSE 《Global Change Biology》2007,13(10):2161-2170
Elevated atmospheric CO2 concentration ([CO2 ]) stimulates seed mass production in many species, but the extent of stimulation shows large variation among species. We examined (1) whether seed production is enhanced more in species with lower seed nitrogen concentrations, and (2) whether seed production is enhanced by elevated [CO2 ] when the plant uses more N for seed production. We grew 11 annuals in open top chambers that have different [CO2 ] conditions (ambient: 370 μmol mol−1 , elevated: 700 μmol mol−1 ). Elevated [CO2 ] significantly increased seed production in six out of 11 species with a large interspecific variation (0.84–2.12, elevated/ambient [CO2 ]). Seed nitrogen concentration was not correlated with the enhancement of seed production by elevated [CO2 ]. The enhancement of seed production was strongly correlated with the enhancement of seed nitrogen per plant caused by increased N acquisition during the reproductive period. In particular, legume species tended to acquire more N and produced more seeds at elevated [CO2 ] than non-nitrogen fixing species. Elevated [CO2 ] little affected seed [N] in all species. We conclude that seed production is limited primarily by nitrogen availability and will be enhanced by elevated [CO2 ] only when the plant is able to increase nitrogen acquisition. 相似文献
3.
Elevated CO2 appears to be a significant factor in global warming, which will likely lead to drought conditions in many areas. Few studies have considered the interactive effects of higher CO2 , temperature and drought on plant growth and physiology. We grew canola ( Brassica napus cv. 45H72) plants under lower (22/18°C) and higher (28/24°C) temperature regimes in controlled-environment chambers at ambient (370 μmol mol−1 ) and elevated (740 μmol mol−1 ) CO2 levels. One half of the plants were watered to field capacity and the other half at wilting point. In three separate experiments, we determined growth, various physiological parameters and content of abscisic acid (ABA), indole-3-acetic acid and ethylene. Drought-stressed plants grown under higher temperature at ambient CO2 had decreased stem height and diameter, leaf number and area, dry matter, leaf area ratio, shoot/root weight ratio, net CO2 assimilation and chlorophyll fluorescence. However, these plants had increased specific leaf weight, leaf weight ratio and chlorophyll concentration. Elevated CO2 generally had the opposite effect, and partially reversed the inhibitory effects of higher temperature and drought on leaf dry weight accumulation. This study showed that higher temperature and drought inhibit many processes but elevated CO2 partially mitigate some adverse effects. As expected, drought stress increased ABA but higher temperature inhibited the ability of plants to produce ABA in response to drought. 相似文献
4.
Elevated concentrations of atmospheric
CO2 protect against and compensate for
O3 damage to photosynthetic tissues of
field-grown wheat 总被引:2,自引:0,他引:2
I. F. McKEE B. J. MULHOLLAND J. CRAIGON C. R. BLACK & S. P. LONG 《The New phytologist》2000,146(3):427-435
The effects of elevated concentrations of atmospheric carbon dioxide and ozone on diurnal patterns of photosynthesis have been investigated in field-grown spring wheat ( Triticum aestivum ). Plants cultivated under realistic agronomic conditions, in open-top chambers, were exposed from emergence to harvest to reciprocal combinations of two carbon dioxide and two ozone treatments: [CO2 ] at ambient (380 μmol mol−1 , seasonal mean) or elevated (692 μmol mol−1 ) levels, [O3 ] at ambient (27 nmol mol−1 , 7 hr seasonal mean) or elevated (61 nmol mol−1 ) levels. After anthesis, diurnal measurements were made of flag-leaf gas-exchange and in vitro Rubisco activity and content. Elevated [CO2 ] resulted in an increase in photoassimilation rate and a loss of excess Rubisco activity. Elevated [O3 ] caused a loss of Rubisco and a decline in photoassimilation rate late in flag-leaf development. Elevated [CO2 ] ameliorated O3 damage. The mechanisms of amelioration included a protective stomatal restriction of O3 flux to the mesophyll, and a compensatory effect of increased substrate on photoassimilation and photosynthetic control. However, the degree of protection and compensation appeared to be affected by the natural seasonal and diurnal variations in light, temperature and water status. 相似文献
5.
Monoterpene levels in current year needles of Douglas fir ( Pseudotsuga menziesii (Mirb.) Franco) seedlings were measured at the end of 4 years of exposure to ambient or elevated CO2 (+179 µmol mol−1 ), and ambient or elevated temperature (+0.3.5^C). Eleven monoterpenes were identified and quantified using gas chromatography/flame ionization detector/mass spectroscopy, with eight of these compounds regularly occurring in all trees examined. Elevated CO2 exposure significantly reduced the levels for four of the eight main compounds in needles. Total monoterpene production was reduced by 52% ( P < 0.05). Elevated temperature also reduced monoterpene levels ( P < 0.07). The combination of elevated temperature and elevated CO2 resulted in a 64% reduction in total monoterpenes compared with needles on ambient temperature trees. Two-way anova showed no significant temperature-CO2 interaction. It is hypothesized that seasonal reductions in needle monoterpene pools under elevated CO2 and temperature conditions may be due to a combination of competing carbon sinks, including increased carbon flux through the roots. 相似文献
6.
Lewis H. Ziska 《Physiologia plantarum》2003,119(1):105-112
A recognized invasive weed, Canada thistle ( Cirsium arvense L. Scop.) was grown at ambient and pre-ambient concentrations of atmospheric carbon dioxide [CO2 ] (373 and 287 μmol mol−1 , respectively) at three levels of supplemental nitrogen (N) (3, 6 and 14.5 m M ) from seeding until flowering [77 days after sowing (DAS)]. The primary objective of the study was to determine if N supply limited the potential photosynthetic and growth response of this species to the increase in atmospheric [CO2 ] which occurred during the 20th century (i.e. approximately 290 to 370 μmol mol−1 CO2 ). Leaf photosynthesis increased both as a function of growth [CO2 ] and N supply during the first 46 DAS. Although by 46 DAS photosynthetic acclimation was observed relative to a common measurement CO2 concentration, there was no interaction with N supply. Both [CO2 ] and N increased biomass, relative growth rates and leaf area whereas root : shoot ratio was increased by CO2 and decreased by increasing N; however, N supply did not effect the relative response to [CO2 ] for any measured vegetative parameter up to 77 DAS. Due to the relative stimulation of shoot biomass, total above-ground N increased at elevated [CO2 ] for all levels of supplemental N, but nitrogen use efficiency (NUE) did not differ as a function of [CO2 ]. Overall, these data suggest that any potential response to increased atmospheric [CO2 ] in recent decades for this noxious weedy species was probably not limited by nitrogen supply. 相似文献
7.
R. Ceulemans M. E. Jach R. Van De Velde† J. X. Lin‡ M. Stevens† 《Global Change Biology》2002,8(2):153-162
Scots pine ( Pinus sylvestris L.) trees were grown in open top chambers for three years under ambient and elevated CO2 concentrations. The trees were aged 3 y at the beginning of the CO2 exposure, and the effects of the treatment on total stem volume, stem wood biomass, wood quality and wood anatomy were examined at the end of the exposure. The elevated CO2 treatment lead to a 49% and 38% increase in stem biomass and stem wood volume, respectively. However, no significant effects of the elevated CO2 treatment on wood density were observed, neither when green wood density was estimated from stem biomass and stem volume, nor when oven-dry wood density was measured on small wood samples. Under elevated CO2 significantly wider growth rings were observed. The effect of elevated CO2 on growth ring width was primarily the result of an increase in earlywood width. Wood compression strength decreased under elevated CO2 conditions, which could be explained by significantly larger tracheids and the increased earlywood band, that has thinner walls and larger cavities. A significant decrease of the number of resin canals in the third growth ring was observed under the elevated treatment; this might indicate that trees produced and contained less resin, which has implications for disease and pest resistance. So, although wood volume yield in Scots pine increased significantly with elevated CO2 after three years of treatment, wood density remained unchanged, while wood strength decreased. Whilst wood volume and stem biomass production may increase in this major boreal forest tree species, wood quality and resin production might decrease under future elevated CO2 conditions. 相似文献
8.
Interactive effects of elevated [CO2 ] and drought on cherry (Prunus avium) seedlings I. Growth, whole-plant water use efficiency and water loss 总被引:1,自引:0,他引:1
Seeds of cherry ( Prunus avium ) were germinated and grown for two growing seasons in ambient (∼350 μmol mol−1 ) or elevated (ambient+∼350 μmol mol−1 ) CO2 mole fractions in six open-top chambers. The seedlings were fertilized once a week, following Ingestad principles in order to supply mineral nutrients at free-access rates. In the first growing season gradual drought was imposed on rapidly growing cherry seedlings by withholding water for a 6-wk drying cycle. In the second growing season, the rapid onset of drought was imposed at the height of the growing season on the seedlings which had already experienced drought in the first growing season. Elevated [CO2 ] significantly increased total dry-mass production in both water regimes, but did not ameliorate the growth response to drought of the cherry seedlings subjected to two sequential drying cycles. Water loss did not differ in either well watered or droughted seedlings between elevated and ambient [CO2 ]; consequently whole-plant water- use efficiency (the ratio of total dry mass produced to total water consumption) was significantly increased. Similar patterns of carbon allocation between shoot and root were found in elevated and ambient [CO2 ] when the seedlings were the same size. Thus, elevated [CO2 ] did not improve drought tolerance, but it accelerated ontogenetic development irrespective of water status. 相似文献
9.
Usue Pérez-López Anabel Robredo Maite Lacuesta Cristina Sgherri Alberto Muñoz-Rueda Flavia Navari-Izzo Amaia Mena-Petite 《Physiologia plantarum》2009,135(1):29-42
Changes in antioxidant metabolism because of the effect of salinity stress (0, 80, 160 or 240 m M NaCl) on protective enzyme activities under ambient (350 μmol mol−1 ) and elevated (700 μmol mol−1 ) CO2 concentrations were investigated in two barley cultivars ( Hordeum vulgare L., cvs Alpha and Iranis). Electrolyte leakage, peroxidation, antioxidant enzyme activities [superoxide dismutase (SOD), EC 1.15.1.1; ascorbate peroxidase (APX), EC 1.11.1.11; catalase (CAT), EC 1.11.1.6; dehydroascorbate reductase (DHAR), EC 1.8.5.1; monodehydroascorbate reductase (MDHAR), EC 1.6.5.4; glutathione reductase (GR), EC 1.6.4.2] and their isoenzymatic profiles were determined. Under salinity and ambient CO2 , upregulation of antioxidant enzymes such as SOD, APX, CAT, DHAR and GR occurred. However, this upregulation was not enough to counteract all ROS formation as both ion leakage and lipid peroxidation came into play. The higher constitutive SOD and CAT activities together with a higher contribution of Cu,Zn-SOD 1 detected in Iranis might possibly contribute and make this cultivar more salt-tolerant than Alpha. Elevated CO2 alone had no effect on the constitutive levels of antioxidant enzymes in Iranis, whereas in Alpha it induced an increase in SOD, CAT and MDHAR together with a decrease of DHAR and GR. Under combined conditions of elevated CO2 and salinity the oxidative damage recorded was lower, above all in Alpha, together with a lower upregulation of the antioxidant system. So it can be concluded that elevated CO2 mitigates the oxidative stress caused by salinity, involving lower ROS generation and a better maintenance of redox homeostasis as a consequence of higher assimilation rates and lower photorespiration, being the response dependent on the cultivar analysed. 相似文献
10.
We examined how anticipated changes in CO2 concentration and temperature interacted to alter plant growth, harvest characteristics and photosynthesis in two cold-adapted herbaceous perennials, alfalfa ( Medicago sativa L. cv. Arc) and orchard grass ( Dactylis glomerata L. cv. Potomac). Plants were grown at two CO2 concentrations (362 [ambient] and 717 [elevated] μmol mol−1 CO2 ) and four constant day/night temperatures of 15, 20, 25 and 30°C in controlled environmental chambers. Elevated CO2 significantly increased total plant biomass and protein over a wide range of temperatures in both species. Stimulation of photosynthetic rate, however, was eliminated at the highest growth temperature in M. sativa and relative stimulation of plant biomass and protein at high CO2 declined as temperature increased in both species. Lack of a synergistic effect between temperature and CO2 was unexpected since elevated CO2 reduces the amount of carbon lost via photorespiration and photorespiration increases with temperature. Differences between anticipated stimulatory effects of CO2 and temperature and whole plant single and leaf measurements are discussed. Data from this study suggest that stimulatory effects of atmospheric CO2 on growth and photosynthesis may decline with anticipated increases in global temperature, limiting the degree of carbon storage in these two perennial species. 相似文献
11.
Iker Aranjuelo Pilar Pérez Libia Hernández Juan José Irigoyen Gloria Zita Rafael Martínez-Carrasco Manuel Sánchez-Díaz 《Physiologia plantarum》2005,123(3):348-358
Plants grown in an environment of elevated CO2 and temperature often show reduced CO2 assimilation capacity, providing evidence of photosynthetic downregulation. The aim of this study was to analyse the downregulation of photosynthesis in elevated CO2 (700 µmol mol−1 ) in nodulated alfalfa plants grown at different temperatures (ambient and ambient + 4°C) and water availability regimes in temperature gradient tunnels. When the measurements were taken in growth conditions, a combination of elevated CO2 and temperature enhanced the photosynthetic rate; however, when they were carried out at the same CO2 concentration (350 and 700 µmol mol−1 ), elevated CO2 induced photosynthetic downregulation, regardless of temperature and drought. Intercellular CO2 concentration measurements revealed that photosynthetic acclimation could not be accounted for by stomatal limitations. Downregulation of plants grown in elevated CO2 was a consequence of decreased carboxylation efficiency as a result of reduced rubisco activity and protein content; in plants grown at ambient temperature, downregulation was also induced by decreased quantum efficiency. The decrease in rubisco activity was associated with carbohydrate accumulation and depleted nitrogen availability. The root nodules were not sufficiently effective to balance the source–sink relation in elevated CO2 treatments and to provide the required nitrogen to counteract photosynthetic acclimation. 相似文献
12.
Soil CO2 efflux in a boreal pine forest under atmospheric CO2 enrichment and air warming 总被引:3,自引:0,他引:3
The response of forest soil CO2 efflux to the elevation of two climatic factors, the atmospheric concentration of CO2 (↑CO2 of 700 μmol mol−1 ) and air temperature (↑ T with average annual increase of 5°C), and their combination (↑CO2 +↑ T ) was investigated in a 4-year, full-factorial field experiment consisting of closed chambers built around 20-year-old Scots pines ( Pinus sylvestris L.) in the boreal zone of Finland. Mean soil CO2 efflux in May–October increased with elevated CO2 by 23–37%, with elevated temperature by 27–43%, and with the combined treatment by 35–59%. Temperature elevation was a significant factor in the combined 4-year efflux data, whereas the effect of elevated CO2 was not as evident. Elevated temperature had the most pronounced impact early and late in the season, while the influence of elevated CO2 alone was especially notable late in the season. Needle area was found to be a significant predictor of soil CO2 efflux, particularly in August, a month of high root growth, thus supporting the assumption of a close link between whole-tree physiology and soil CO2 emissions. The decrease in the temperature sensitivity of soil CO2 efflux observed in the elevated temperature treatments in the second year nevertheless suggests the existence of soil response mechanisms that may be independent of the assimilating component of the forest ecosystem. In conclusion, elevated atmospheric CO2 and air temperature consistently increased forest soil CO2 efflux over the 4-year period, their combined effect being additive, with no apparent interaction. 相似文献
13.
The temperature dependence of C3 photosynthesis may be altered by the growth environment. The effects of long-term growth in elevated CO2 on photosynthesis temperature response have been investigated in wheat ( Triticum aestivum L.) grown in controlled chambers with 370 or 700 μmol mol−1 CO2 from sowing through to anthesis. Gas exchange was measured in flag leaves at ear emergence, and the parameters of a biochemical photosynthesis model were determined along with their temperature responses. Elevated CO2 slightly decreased the CO2 compensation point and increased the rate of respiration in the light and ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) Vcmax , although the latter effect was reversed at 15°C. With elevated CO2 , Jmax decreased in the 15–25°C temperature range and increased at 30 and 35°C. The temperature response (activation energy) of Vcmax and Jmax increased with growth in elevated CO2 . CO2 enrichment decreased the ribulose 1,5-bisphosphate (RuBP)-limited photosynthesis rates at lower temperatures and increased Rubisco- and RuBP-limited rates at higher temperatures. The results show that the photosynthesis temperature response is enhanced by growth in elevated CO2 . We conclude that if temperature acclimation and factors such as nutrients or water availability do not modify or negate this enhancement, the effects of future increases in air CO2 on photosynthetic electron transport and Rubisco kinetics may improve the photosynthetic response of wheat to global warming. 相似文献
14.
The responses of individual stomata to CO2 concentrations ranging from 0 to 900 μmol mol−1 air were analysed in Ipomoea pes-caprae L. Sweet (Convolvulaceae). The stomata were directly observed using a measurement system that permitted continuous observation of stomatal movement under controlled light and CO2 conditions. A CO2 concentration of 350 μmol mol−1 or higher induced stomatal closure, whereas concentrations below 350 μmol mol−1 did not. The time lag before stomatal closure decreased with increasing CO2 concentration, as did the steady-state aperture of the stomata after a change in CO2 concentration. However, the rate of stomatal closure increased with increasing CO2 concentration. Therefore, not only the stomatal closure rate but also the time from the CO2 concentration change to the beginning of stomatal closure changed with increasing CO2 concentration. These results suggest that atmospheric CO2 may be the stimulus for the closure of guard cells. No significant differences were observed between adaxial and abaxial stomata in terms of their responses to CO2 . However, heterogeneous responses were detected between neighbouring stomata on each leaf surface. 相似文献
15.
The interaction of high temperature and elevated CO2 on photosynthetic acclimation of single leaves of rice in situ 总被引:1,自引:0,他引:1
Rice ( Oryza sativa L. cv. IR72) was grown at three different CO2 concentrations (ambient, ambient + 200 μmol mol−1 , ambient + 300 μmol mol−1 ) at two different growth temperatures (ambient, ambient + 4°C) from sowing to maturity to determine longterm photosynthetic acclimation to elevated CO2 with and without increasing temperature. Single leaves of rice showed a cooperative enhancement of photosynthetic rate with elevated CO2 and temperature during tillering, relative to the elevated CO2 condition alone. However, after flowering, the degree of photosynthetic stimulation by elevated CO2 was reduced for the ambient + 4°C treatment. This increasing insensitivity to CO2 appeared to be accompanied by a reduction in ribulose-1.5-bisphosphate carboxylase/oxygenase (Rubisco) activity and/or concentration as evidenced by the reduction in the assimilation (A) to internal CO2 (C1 ) response curve. The reproductive response (e.g. percent filled grains, panicle weight) was reduced at the higher growth temperature and presumably reflects a greater increase in floral sterility. Results indicate that while CO2 and temperature could act synergistically at the biochemical level, the direct effect of temperature on floral development with a subsequent reduction in carbon utilization may change sink strength so as to limit photosynthetic stimulation by elevated CO2 concentration. 相似文献
16.
Gorka Erice Juan J. Irigoyen Pilar Pérez Rafael Martínez-Carrasco Manuel Sánchez-Díaz 《Physiologia plantarum》2006,126(3):458-468
Rising atmospheric CO2 may increase potential net leaf photosynthesis under short-term exposure, but this response decreases under long-term exposure because plants acclimate to elevated CO2 concentrations through a process known as downregulation. One of the main factors that may influence this phenomenon is the balance between sources and sinks in the plant. The usual method of managing a forage legume like alfalfa requires the cutting of shoots and subsequent regrowth, which alters the source/sink ratio and thus photosynthetic behaviour. The aim of this study was to determine the effect of CO2 (ambient, around 350 vs. 700 µmol mol−1 ), temperature (ambient vs. ambient + 4° C) and water availability (well-irrigated vs. partially irrigated) on photosynthetic behaviour in nodulated alfalfa before defoliation and after 1 month of regrowth. At the end of vegetative normal growth, plants grown under conditions of elevated CO2 showed photosynthetic acclimation with lower photosynthetic rates, Vcmax and ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco) activity. This decay was probably a consequence of a specific rubisco protein reduction and/or inactivation. In contrast, high CO2 during regrowth did not change net photosynthetic rates or yield differences in Vcmax or rubisco total activity. This absence of photosynthetic acclimation was directly associated with the new source-sink status of the plants during regrowth. After cutting, the higher root/shoot ratio in plants and remaining respiration can function as a strong sink for photosynthates, avoiding leaf sugar accumulation, the negative feed-back control of photosynthesis, and as a consequence, photosynthetic downregulation. 相似文献
17.
OULA GHANNOUM NATHAN G. PHILLIPS JANN P. CONROY RENEE A. SMITH RENEE D. ATTARD ROSLYN WOODFIELD BARRY A. LOGAN§ JAMES D. LEWIS¶ DAVID T. TISSUE 《Global Change Biology》2010,16(1):303-319
To investigate if Eucalyptus species have responded to industrial-age climate change, and how they may respond to a future climate, we measured growth and physiology of fast- ( E. saligna ) and slow-growing ( E. sideroxylon ) seedlings exposed to preindustrial (290), current (400) or projected (650 μL L−1 ) CO2 concentration ([CO2 ]) and to current or projected (current +4 °C) temperature. To evaluate maximum potential treatment responses, plants were grown with nonlimiting soil moisture. We found that: (1) E. sideroxylon responded more strongly to elevated [CO2 ] than to elevated temperature, while E. saligna responded similarly to elevated [CO2 ] and elevated temperature; (2) the transition from preindustrial to current [CO2 ] did not enhance eucalypt plant growth under ambient temperature, despite enhancing photosynthesis; (3) the transition from current to future [CO2 ] stimulated both photosynthesis and growth of eucalypts, independent of temperature; and (4) warming enhanced eucalypt growth, independent of future [CO2 ], despite not affecting photosynthesis. These results suggest large potential carbon sequestration by eucalypts in a future world, and highlight the need to evaluate how future water availability may affect such responses. 相似文献
18.
The role of temperature in determining the stimulation of CO2 assimilation at elevated carbon dioxide concentration in soybean seedlings 总被引:1,自引:0,他引:1
Soybean ( Glycine max cv. Clark) was grown at both ambient (ca 350 μmol mol−1 ) and elevated (ca 700 μmol mol−1 ) CO2 concentration at 5 growth temperatures (constant day/night temperatures of 20, 25, 30, 35 and 40°C) for 17–22 days after sowing to determine the interaction between temperature and CO2 concentration on photosynthesis (measured as A, the rate of CO2 assimilation per unit leaf area) at both the single leaf and whole plant level. Single leaves of soybean demonstrated increasingly greater stimulation of A at elevated CO2 as temperature increased from 25 to 35°C (i.e. optimal growth rates). At 40°C, primary leaves failed to develop and plants eventually died. In contrast, for both whole plant A and total biomass production, increasing temperature resulted in less stimulation by elevated CO2 concentration. For whole plants, increased CO2 stimulated leaf area more as growth temperature increased. Differences between the response of A to elevated CO2 for single leaves and whole plants may be related to increased self-shading experienced by whole plants at elevated CO2 as temperature increased. Results from the present study suggest that self-shading could limit the response of CO2 assimilation rate and the growth response of soybean plants if temperature and CO2 increase concurrently, and illustrate that light may be an important consideration in predicting the relative stimulation of photosynthesis by elevated CO2 at the whole plant level. 相似文献
19.
Interaction of enriched CO2 and water stress on the physiology of and biomass production in sweet potato grown in open-top chambers 总被引:2,自引:2,他引:0
N. C. BHATTACHARYA D. R. HILEMAN P. P. GHOSH R. L. MUSSER S. BHATTACHARYA P. K. BISWAS 《Plant, cell & environment》1990,13(9):933-940
Abstract. The objective of this study was to investigate the effects of water stress in sweet potato ( Ipomoea batatas L. [Lam] 'Georgia Jet') on biomass production and plant-water relationships in an enriched CO2 atmosphere. Plants were grown in pots containing sandy loam soil (Typic Paleudult) at two concentrations of elevated CO2 and two water regimes in open-top field chambers. During the first 12 d of water stress, leaf xylem potentials were higher in plants grown in a CO2 concentration of 438 and 666 μmol mol−1 than in plants grown at 364 μmol mol−1 . The 364 μmol mol−1 CO2 grown plants had to be rewatered 2 d earlier than the high CO2 -grown plants in response to water stress. For plants grown under water stress, the yield of storage roots and root: shoot ratio were greater at high CO2 than at 364 μmol mol−1 ; the increase, however, was not linear with increasing CO2 concentrations. In well-watered plants, biomass production and storage root yield increased at elevated CO2 , and these were greater as compared to water-stressed plants grown at the same CO2 concentration. 相似文献
20.
Plant responses to elevated CO2 can be modified by many environmental factors, but very little attention has been paid to the interaction between CO2 and changes in vapour pressure deficit (VPD). Thirty-day-old alfalfa plants ( Medicago sativa L. cv. Aragón), which were inoculated with Sinorhizobium meliloti 102F78 strain, were grown for 1 month in controlled environment chambers at 25/15°C, 14 h photoperiod, and 600 µmol m−2 s−1 photosynthetic photon flux (PPF), using a factorial combination of CO2 concentration (400 µmol mol−1 or 700 µmol mol−1 ) and vapour pressure deficit (0.48 kPa or 1.74 kPa, which corresponded to relative humidities of 85% and 45% at 25°C, respectively). Elevated CO2 strongly stimulated plant growth under high VPD conditions, but this beneficial effect was not observed under low VPD. Under low VPD, elevated CO2 also did not enhance plant photosynthesis, and plant water stress was greatest for plants grown at elevated CO2 and low VPD. Moreover, plants grown under elevated CO2 and low VPD had a lower leaf soluble protein and photosynthetic activity (photosynthetic rate and carboxylation efficiency) than plants grown under elevated CO2 and high VPD. Elevated CO2 significantly increased leaf adaxial and abaxial temperatures. Because the effects of elevated CO2 were dependent on vapour pressure deficit, VPD needs to be controlled in experiments studying the effect of elevated CO2 as well as considered in the extrapolations of results to a warmer, high-CO2 world. 相似文献