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1.
Central to the CHanging climate and potential Impacts on Potato yield and quality project (CHIP) was the consideration of the potential impacts of ozone and CO 2 on growth and yield of future European Potato crops. Potato crops, cv. Bintje, were exposed to ambient or elevated ozone; targeted daily average, 60 nl l −1 for 8 h, and ambient or elevated CO 2; targeted 680 μl l −1 averaged over the full growing season, in open top chambers (OTCs) at six European sites in 1998 and 1999, or to elevated CO 2 (550 μl l −1) in Free Air Carbon dioxide Enrichment facilities (FACE) at two sites in both years. Some OTC experiments included 550 μl l −1. Above and below ground biomass were measured at two destructive harvests; at maximum leaf area (MLA) and at final-harvest. Final-harvest fresh weight yields of marketable-size tubers, >35 mm diameter, from ambient conditions ranged from 1 to 12 kg m −2. There was no consistent ( P>0.1) CO 2×O 3 interaction for growth or yield variables at either harvest. No consistent effects of ozone were detected at the maximum-leaf-area harvest. However, at final harvest, ozone had reduced both above-ground biomass and tuber dry weight ( P<0.05), particularly of the largest (>50 mm) size class. These yield losses showed linear relationships both with accumulated ozone exposure; AOT40 expressed as nl l −1 h over 40 nl l −1, and with yields from chambered ambient-ozone treatments ( P<0.05) but, because of partial confounding between the treatment AOT40s and the ambient-ozone yields in the data, the two relationships were not completely independent. Yields from ambient-ozone treatments, however, explained a significant ( P<0.01) amount of the residual variation in ozone effects unexplained by AOT40. When averaged over all experiments, mean dry weights and tuber numbers from both harvests were increased by elevated CO 2. Only green leaf number at the MLA harvest was reduced. The CO 2 responses varied between sites and years. For marketable-size tubers, this variation was unrelated to variation in ambient-CO 2 treatment yields. Yield increases resulting from the 680 μl l −1 and 550 μl l −1 treatments were similar. Thus elevating [CO 2] from 550 to 680 μl l −1 was less effective than elevating [CO 2] from ambient to 550 μl l −1. On average, CO 2 elevation to 680 μl l −1 increased the dry weight of marketable-size tubers by about 17%, which far exceeded the average ozone-induced yield loss of about 5%. The net effect of raising CO 2 and O 3 concentrations on the European potato crop would be an increase marketable yield. 相似文献
2.
The physiological effects of elevated CO 2 and/or O 3 on Solanum tuberosum cv. Bintje were examined in Open-Top Chambers during 1998 and 1999 at experimental sites across Europe as part of the EU ‘Changing Climate and Potential Impacts on Potato Yield and Quality’ programme (CHIP). At tuber initiation (≈20 days after emergence, DAE) elevated CO 2 (680 μl l −1) induced a 40% increase in the light saturated photosynthetic rate ( Asat) of fully expanded leaves in the upper canopy. This was 16% less than expected from short-term exposures of plants grown under ambient CO 2 (360 μl l −1) to elevated CO 2, indicating that photosynthetic acclimation began at an early stage of crop growth. This effect resulted from a combination of a 12% reduction in stomatal conductance ( gs) and a decline in photosynthetic capacity, as indicated by the significant reductions in the maximum carboxylation rate of Rubisco ( Vc max) and light-saturated rate of electron transport ( Jmax) under elevated CO 2. The seasonal decline in the promotion of photosynthesis by elevated CO 2 reflected the concurrent decrease in gs. Vc max and Jmax were both reduced in plants grown under elevated CO 2 until shortly after maximum leaf area (MLA) was attained. Although non-photorespiratory mitochondrial respiration in the light ( Rd) increased during the later stages of the season, net photosynthesis was consistently increased by elevated CO 2 during the main part of the season. Photosynthetic rate declined more rapidly in response to elevated O 3 under ambient CO 2, and the detrimental impact of O 3 was most obvious after MLA was attained (DAE 40–50). Several exposure indices were compared, with the objective of determining the critical ozone level required to induce physiological effects. The critical O 3 exposure above which a 5% reduction in light saturated photosynthetic rate may be expected (expressed in terms of cumulative exposure above 0 nl l −1 O 3 between emergence and specific dates during the season (AOT0-cum)) was 11 μl l −1 h; however this value should only be extrapolated beyond the CHIP dataset with caution. The interaction between O 3 and stomatal behaviour was more complex, as it was influenced by both long-term and daily exposure levels. Elevated CO 2 counteracted the adverse effect of O 3 on photosynthesis, perhaps because the observed reduction in stomatal conductance decreased O 3 fluxes into the leaves. The results are discussed in the context of nitrogen deficiency, carbohydrate accumulation and yield. 相似文献
3.
Potato cv. Bintje was grown in open-top-chambers and free-air-CO 2-enrichment systems at 7 sites across Europe for 2 years (1998–99). The effect of different treatments (CO 2 enrichment and O 3 fumigation) on the chlorophyll content of fully expanded upper and lower canopy leaves was investigated collecting Minolta SPAD-502 meter readings. In both CO 2 treated and O 3 fumigated plants, leaves had lower chlorophyll content than those in ambient air controls; season-long chlorophyll averages were 9.3% lower in the ‘CO 2’ treatments, 9.1% lower in ‘O 3’ treatments and 12.3% lower in ‘CO 2+O 3’ treatments. The analysis of chlorophyll content in three different growth phases (Emergence–Tuber Initiation; Tuber Initiation–Maximum Leaf Area; Maximum Leaf Area–Harvest) showed that in the early growth period, i.e. before tuber initiation there was a slight indication for an higher chlorophyll content at elevated CO 2 (+3.8%) or O 3 (+1.7%). However, from tuber initiation onwards the leaves of plants grown under elevated CO 2 or O 3 showed a progressively lower chlorophyll content (−4.8% for CO 2 treatments and −2.6% for O 3 treatments) indicating a faster senescence of leaves that increased during the late growth period (−12.8% for CO 2 treatments and −12.7% for O 3 treatments) and that was enhanced by CO 2–O 3 interaction (−17.8%). 相似文献
4.
Potato ( Solanum tuberosum L cv. Bintje) was exposed to ambient and elevated carbon dioxide (CO 2), to ambient and elevated ozone (O 3) and to elevated levels of both gases during two growing seasons, 1998 and 1999. Experiments in open-top chambers (OTC) were carried out in Finland, Sweden, Ireland, United Kingdom, Germany and Belgium and a FACE (Free Air Carbon dioxide Enrichment) experiment was carried out in Italy. In OTCs the plants were grown under ambient CO 2 concentrations or with 550 and 680 μl l −1 CO 2 alone or in combination with ambient or elevated O 3 concentrations (target seasonal mean of 60 nl l −1 8 h per day). In the FACE systems the plants were exposed to ambient or 550 μl l −1 CO 2. In the OTC experiments the reducing sugar content of potato tubers decreased significantly with increased concentration of O 3. The starch content of potato tubers decreased, with negative impact on tuber quality, but the ascorbic acid concentration increased as a function of the AOT40 (The sum of the differences between hourly ozone concentration and 40 nl l −1 for each hour when the concentration exceeds 40 nl l −1 during a relevant growing season). However, simultaneous exposure to elevated CO 2 counteracted the ozone effect. With increase in the CO 2 exposure, glycoalkaloid and nitrate concentrations decreased yielding improved quality, while the citric acid concentration decreased causing a higher risk for discoloration after cooking. The amount of dry matter and starch increased significantly in the FACE experiment. 相似文献
5.
Spring wheat cv. Minaret crop stands were grown under ambient and elevated CO 2 concentrations at seven sites in Germany, Ireland, the UK, Belgium and the Netherlands. Six of the sites used open-top chambers and one used a controlled environment mimicking field conditions. The effect of elevated CO 2 for a range of N application regimes, O 3 concentrations, and growth temperatures on flag leaf photosynthesis was studied. Before anthesis, flag leaf photosynthesis was stimulated about 50% by 650 compared with 350 μmol mol −1 CO 2 at all sites, regardless of other treatments. Furthermore, there was no evidence of a decrease in photosynthetic capacity of flag leaves due to growth at elevated CO 2 before anthesis, even for low N treatments. However, photosynthetic capacity, particularly carboxylation capacity, of flag leaves was usually decreased by growth at elevated CO 2 after anthesis, especially in low N treatments. Acclimation of photosynthesis to elevated CO 2 therefore appears to occur only slowly, consistent with a response to changes in sink–source relationships, rather than a direct response. Effect of elevated CO 2 on stomatal conductance was much more variable between sites and treatments, but on average was decreased by ˜10% at 650 compared with 350 μmol mol −1 CO 2. Carboxylation capacity of flag leaves was decreased by growth at elevated O 3 both before and after anthesis, regardless of CO 2 concentration. 相似文献
6.
Spring wheat cv. Minaret was grown in open-top chambers at four sites across Europe. The effect of different treatments (CO 2 enrichment, O 3 fumigation, drought stress and temperature) on the chlorophyll content of the flag leaf was investigated using the MINOLTA SPAD-502 meter. Under optimum growth conditions the maximum chlorophyll content, which was reached at anthesis, was consistent among the sites ranging from 460 to 500 mg chlorophyll m −2. No significant effect of elevated CO 2 or O 3 was observed at anthesis. Leaf senescence, indicated by the chlorophyll breakdown after anthesis, was relatively constant in the control chambers. Under control conditions, thermal time until 50% chlorophyll loss was reached was 600°C day. Elevated CO 2 caused a faster decline in chlorophyll content (thermal time until 50% chlorophyll loss was reduced to 500–580°C day) indicating a faster rate of plant development at two experimental sites. The effect of ozone on chlorophyll content depended on the time and dose of O 3 exposure. During grain filling, high O 3 concentrations induced premature senescence of the flag leaves (up to −130°C day). This deleterious effect was mitigated by elevated CO 2. Drought stress led to faster chlorophyll breakdown irrespective of CO 2 treatment. 相似文献
7.
In the ESPACE-Wheat programme, 25 open-top chamber experiments were carried out in 1994, 1995 and 1996, on nine locations, divided over eight European countries. In most experiments, spring wheat cv. Minaret was subjected to two levels of atmospheric CO 2 and two levels of ozone. Grain yields in the control treatments (ambient levels of CO 2 and O 3) varied strongly between sites. Also, yield response to elevated CO 2 and O 3 showed great variation. The present study was conducted to determine whether climatic differences between sites could account for the observed variation. Two simulation models were used for the analysis: AFRCWHEAT2-O3 and LINTULCC. AFRCWHEAT2-O3 simulates phenology, canopy development and photosynthesis in greater detail than LINTULCC. Both models account for the effects of radiation and temperature on crop growth. New algorithms were developed to simulate the effects of CO2 and O3. Weather data that were measured in the experiments were used as input, and simulated growth responses to CO2 and O3 were compared with measurements. No attempt was made to merge the two models. Thus two independent tools for analysis of data related to climate change were developed and applied. The average measured grain yield in the control treatment, across all 25 experiments, was 5.9 tons per hectare (t ha−1), with a standard deviation (SD) of 1.9 t ha−1. The models predicted similar average yields (5.5 and 5.8 t ha−1 for AFRCWHEAT2-O3 and LINTULCC, respectively), but smaller variation (SD for both models: 1.2 t ha−1). Average measured yield increase due to CO2-doubling was 30% (SD 22%). AFRCWHEAT2-O3 expected a slightly lower value (24%, SD 9%), whereas LINTULCC overestimated the response (42%, SD 11%). The average measured yield decrease due to nearly-doubled O3 levels was 9% (SD 11%). Both models showed similar results, albeit at lower variation (7% yield decrease at SDs of 6 and 4%). Simulations accounted well for the observation that, at elevated CO2, the percentage yield loss due to O3 was lower than at ambient CO2. The models predicted lower variation among sites and years than was measured. Yield response to CO2 and O3 was predicted to depend on the climate, with a predominant effect of temperature on the response to CO2. In the measurements, these climatic effects were indeed observed, but a greater part of the variation was not related to light intensity, temperature, CO2, or O3. This unexplained variability in the measured dataset was probably caused by factors not accounted for in the models, possibly related to soil characteristics. We therefore conclude that even perfect information on the climate variables examined in ESPACE-Wheat, i.e. light intensity and temperature, by itself would be insufficient for accurate prediction of the response of spring wheat to future elevated levels of CO2 and O3. 相似文献
8.
The present study was conducted to investigate the possible interactive effects of rising atmospheric CO 2 concentration [CO 2] and drought stress on water use of wheat. Spring wheat ( Triticum aestivum cv. “Minaret”) was grown either in 1 m diameter lysimeters with 0.4 m soil depth (1998) or in the field (1999) in open-top chambers under two CO 2-concentrations (ambient, ambient + 280 ppm) and two watering regimes (well-watered = WW with a plant available water content PAW > 40 mm and drought stressed = DS, 10 mm < PAW < 30 mm) beginning after first node stage. Canopy evapotranspiration ( EC) was measured continuously from first the node stage until the beginning of flag leaf senescence using four open-system canopy chambers (0.78 m 3). Seasonal changes of the absorption of photosynthetically active radiation (APAR) of the canopy and root growth (1999) were also measured. In both growing seasons leaf area index increased in response to elevated [CO2] in both water treatments. The related effects of [CO2] on canopy radiation absorption (APAR) were, however, smaller. EC was linearily related to APAR in both growing seasons. While elevated [CO2] reduced the slope of this relation under WW conditions by ca. 20% in both growing seasons, it was not reduced (1998) and even increased (1999) under drought. Canopy conductance (GC) calculated as EC divided by vapour pressure deficit of air, showed a non-linear relationship to APAR that was best explained by saturation curves. Under WW conditions, elevated [CO2] reduced the initial slope of GC versus APAR as well as GC at saturating light conditions (ca. −30%), while under DS conditions no effect of elevated [CO2] could be detected. Under high light conditions (PAR > 400 μmol m−2 s−1) a critical “threshold value” of PAW (TPAW, ca. 40 mm) could be identified above which GC did not respond to PAW. While in 1998 GC did not respond to elevated [CO2] at PAW < TPAW, it was slightly increased at low PAW values in the field experiments of 1999. The reduction of TPAW by elevated [CO2] may be explained by enhanced root growth (1999) that would have given the plants better access to soil water resources. The present results suggest that below a critical soil water content elevated [CO2] will not reduce canopy water loss of wheat or may even enhance it. 相似文献
9.
A major objective of the ESPACE—wheat programme was to perform by means of open-top chambers (OTCs) ‘standardised’ experimental investigations of spring wheat responses to increased atmospheric CO 2 and O 3 concentrations and to other environmental stresses at different locations in Europe, representing a broad range of different climatic conditions. From 1994 to 1996 a total number of 25 OTC experiments were carried out. In addition, four growth chamber experiments focusing on key physiological processes of wheat growth in CO 2-enriched air were performed. According to the specific needs for subsequent modelling purposes, environmental data were collected during experiments, i.e. air temperature, global radiation, humidity and trace gas concentrations. In the present paper results of these measurements are summarised. It was shown, that the OTC-experiments covered a considerable range of growing season mean-air-temperatures (13.0–23.4°C) and global irradiances (10.8–18.1 MJ m −2 d −1), the most important driving variables for crop growth simulation models. Mean concentrations of CO 2 and O 3 in ambient air and in different treatments illustrated the observed variability of trace gas exposures between different experiments. Implications for subsequent analyses of biological response data are discussed. 相似文献
10.
The response of crop growth and yield to CO 2 and ozone is known to depend on climatic conditions and is difficult to quantify due to the complexity of the processes involved. Two modified mechanistic crop simulation models (AFRCWHEAT2-O3 and LINTULCC), which differ in the levels of mechanistic detail, were used to simulate the effects of CO 2 (ambient, ambient ×2) and ozone (ambient, ambient ×1.5) on growth and developmental processes of spring wheat in response to climatic conditions. Simulations were analysed using data from the ESPACE-wheat project in which spring wheat cv. Minaret was grown in open-top chambers at nine sites throughout Europe and for up to 3 years at each site. Both models closely predicted phenological development and the average measured biomass at maturity. However, intermediate growth variables such as biomass and leaf area index (LAI) at anthesis, seasonal accumulated photosynthetically active radiation intercepted by the crop (ΣIPAR), the average seasonal light use efficiency (LUE) and the light saturated rate of flag leaf photosynthesis (Asat) were predicted differently and less accurately by the two models. The effect of CO2 on the final biomass was underestimated by AFRCWHEAT2-O3 due to its poor simulation of the effect of CO2 on tillering, and LAI.LINTULCC overestimated the response of biomass production to changes in CO2 level due to an overprediction of the effect of CO2 on LUE. The measured effect of ozone exposure on final biomass was predicted closely by the two models. The models also simulated the observed interactive effect of CO2 and ozone on biomass production. However, the effects of ozone on LAI, ΣIPAR and Asat were simulated differently by the models and less accurately with LINTULCC for the ozone effects on LAI and ΣIPAR. Predictions of the variation between sites and years of growth and development parameters and of their responses to CO2 and ozone were poor for both AFRCWHEAT2-O3 and LINTULCC. It was concluded that other factors than those considered in the models such as chamber design and soil properties may have affected the growth and development of cv. Minaret. An analysis of the relationships between growth parameters calculated from the simulations supported this conclusion. In order to apply models for global change impact assessment studies, the difficulties in simulating biomass production in response to CO2 need to be considered. We suggest that the simulation of leaf area dynamics deserves particular attention in this regard. 相似文献
11.
Phenological development, leaf emergence, tillering and leaf area index (LAI), and duration (LAD) of spring wheat cv. Minaret, grown in open-top chambers at different sites throughout Europe for up to 3 years at each site, were investigated in response to elevated CO 2 (ambient CO 2×2) and ozone (ambient ozone ×1.5) concentrations. Phenological development varied among experiments and was partly explained by differences in temperature among sites and years. There was a weak positive relationship between the thermal rate of development and the mean daylength for the period from emergence to anthesis. Main stems produced on average 7.7 leaves with little variation among experiments. Variation was higher for the thermal rate of leaf emergence, which was partly explained by differences in the rate of change of daylength at plant emergence among seasons. Phenological development, rate of leaf emergence and final leaf number were not affected by CO2 and ozone exposure. Responses of tillering and LAI to CO2 and ozone exposure were significant only in some experiments. However, the direction of responses was consistent for most experiments. The number of tillers and ears per plant, respectively, was increased as a result of CO2 enrichment by about 13% at the beginning of stem elongation (DC31), at anthesis and at maturity. Exposure to ozone had no effect on tillering. LAI was increased as a result of CO2 elevation by about 11% at DC31 and by about 14% at anthesis. Ozone exposure reduced LAI at anthesis by about 9%. No such effect was observed at DC31. There were very few interactive effects of CO2 and ozone on tillering and LAI. Variations in tillering and LAI, and their responses to CO2 and ozone exposure, were partly explained by single linear relationships considering differences in plant density, tiller density and the duration of developmental phases among experiments. Consideration of temperature and incident photosynthetically active radiation in this analysis did not reduce the unexplained variation. There was a negative effect of ozone exposure on leaf area duration at most sites. Direct effects of elevated CO2 concentration on leaf senescence, both positive and negative, were observed in some experiments. There was evidence in several experiments that elevated CO2 concentration ameliorated the negative effect of ozone on leaf area duration. It was concluded from these results that an analysis of the interactive effects of climate, CO2 and ozone on canopy development requires reference to the physiological processes involved. 相似文献
12.
综述了臭氧（O 3）浓度升高、太阳辐射减弱、UV-B辐射、CO 2浓度升高及其与O 3复合作用对植物形态特征、光合作用、干物质累积及作物产量等生理生化机制的影响。交互作用的试验条件可以更好地模拟自然环境条件。O 3和UV-B辐射对植物几乎没有积极作用。太阳辐射减弱、CO 2浓度升高都会促进植物营养生长。但太阳辐射减弱降低干物质累积和产量,CO 2浓度升高对其有促进作用。CO 2浓度升高在与O 3复合条件下,可部分缓解太阳辐射减弱对植物造成的伤害。而UV-B辐射与O 3复合对植物造成的伤害更大。 相似文献
13.
为阐明大气CO 2浓度升高和不同氮素水平对湿地植物光合生理特性和生长的影响,本研究以三江平原湿地优势植物小叶章( Calamagrostis angustifolia)为研究对象,通过野外原位控制试验,利用开顶式气室(OTC)模拟环境大气CO 2浓度变化,设置E 0(380 ±20 µmol/mol)、E 1(550 ±20 μmol/mol)和E 2(700 ± 20 μmol/mol)3个CO 2浓度;在每个OTC内设置 N 0(0 g N/m 2)、N 1(4 g N/m 2)和N 2(8 g N/m 2)3个氮素水平。结果表明,N 0条件下,与E 0处理相比,E 1和E 2处理（72 天）后小叶章叶片净光合速率分别降低11%和12%( P<0.05),其叶片可溶性蛋白含量、氮素含量（CO 2熏蒸72 天）、小叶章株高（CO 2熏蒸86 天）均显著低于E 0处理( P<0.05);N 1条件下,与E 0处理相比,E 1和E 2处理（72 天）后小叶章叶片净光合速率降低5%( P>0.05)和10%( P<0.05),其叶片氮素含量( P<0.05)、小叶章株高均低于E 0处理;N 2条件下,E 1和E 2处理（72 天）小叶章净光合速率均呈稍增加的趋势( P>0.05),其叶片可溶性蛋白含量显著增加( P<0.05),氮素含量和小叶章株高无显著变化( P>0.05)。N 0、N 1和N 2条件下,CO 2浓度升高均显著增加了小叶章叶片可溶性糖含量。本研究表明长期CO 2浓度升高可能通过降低小叶章叶片光合酶活性,进而降低了其净光合速率,而施加高浓度的氮肥可以缓解长期高CO 2浓度对湿地植物光合及生长的负面影响。 相似文献
14.
Nutrient element concentrations and grain quality were assessed in spring wheat grown under elevated CO 2 concentrations and contrasting levels of tropospheric ozone at different nitrogen supply rates at several European sites. Carbon dioxide enrichment proved to affect nutrient concentrations in a complex manner. In green leaves, all elements (with exception of phosphorus and iron) decreased. In contrast, effects on the element composition of grains were restricted to reductions in nitrogen, calcium, sulphur and iron. Ozone exposure resulted in no significant effects on nutrient element concentrations in different tissues in the overall analysis. The nitrogen demand of green tissues was reduced due to CO 2 enrichment as shown by reductions in the critical leaf nitrogen concentration and also enhanced nitrogen use efficiency. Reductions in the content of ribulose-bisphosphate carboxylase/oxygenase and repression of the photorespiratory pathway and reduced nitrogen allocation to enzymes driving the photosynthetic carbon oxidation cycle were chiefly responsible for this effect. Thus, nitrogen acquisition by the crop did not match carbon acquisition under CO 2 enrichment. Since crop nitrogen uptake from the soil was already completed at anthesis, nitrogen allocated to the grain after anthesis originated from vegetative pools—causing grain nitrogen concentrations to decrease under CO 2 enrichment (on average by 15% when CO 2 concentrations increased from 360 to 680 μmol mol −1). Correspondingly, grain quality was reduced by CO 2 enrichment. The Zeleny value, Hagberg value and dry/wet gluten content decreased significantly with increasing [CO 2]. Despite the beneficial impact of CO 2 enrichment on growth and yield of C 3 cereal crops, declines in flour quality due to reduced nitrogen content are likely in a future, [CO 2]-rich world. 相似文献
15.
The increase of atmospheric concentration of carbon dioxide ([CO 2]) has substantially had a huge impact on agricultural production. As the sole substrate for photosynthesis, the increase of atmospheric [CO 2] stimulates the net photosynthetic rate, thus promoting the biomass accumulation and yield level in many crops. However, the ‘fertilization’ effect of the elevated atmospheric [CO 2] on crop production is less than theoretical expectation, and elevated [CO 2] increases the health risk due to the decline in grain quality. The relevant mechanism is still unclear. In this paper, we analyzed the effect of elevated [CO 2] on crop photosynthesis system, reviewed various responses of key photosynthesis indicators, such as the leaf net photosynthetic rate, the intercellular [CO 2] of leaves, maximum carboxylation rate of Rubisco ( Vc, max), and the capacity of Rubp-regeneration ( Jmax) in different crops, in response to the elevated atmospheric [CO 2]. Based on the C-N metabolism of the whole plant, we summarized two prevailing hypotheses about the acclimation of photosynthetic capacity under elevated atmospheric [CO 2], namely the source-sink regulation mechanism and N limitation mechanism, respectively. We summarized the influence of elevated [CO 2] on the nutritional quality of the grain, such as the change in the protein, oil, mineral elements, and vitamin concentrations. Furthermore, we also reviewed the potential interactive effect of the elevated atmospheric temperature and [CO 2] on crop growth. Finally, the main research directions of this field in the future are proposed. In summary, this review can provide theoretical reference for accurately assessing the changes in crop yield and quality under climate change conditions, maximizing the ‘fertilization’ effect of elevated [CO 2], and mitigating the adverse effects of climate change on crop production. 相似文献
16.
The main objective of the CHIP project was to perform ‘standardised’ investigations of potato ( Solanum tuberosum L. cv Bintje) responses to increased O 3 and CO 2 concentrations by means of open-top chambers (OTC) and free air carbon dioxide enrichment (FACE) systems. The experimental sites are located across Europe representing a broad range of different climatic conditions. In 1998 and 1999 a total number of 12 OTC experiments and four FACE experiments were conducted. According to the specific needs for subsequent modelling purposes, environmental data were collected during experiments, i.e. air temperature, global radiation, air humidity (vapour pressure deficit (VPD)), soil moisture and trace gas concentrations. In the present paper, the results of these measurements are summarised. It was shown that the experiments covered a considerable range of growing season mean air temperatures (13.8–19.9 °C) and global irradiances (12.0–21.3 MJ m −2 per day), the most important driving variables for crop growth simulation models. Analysis of the soils used during the experiments demonstrated that in most cases sufficient nutrient elements were available to guarantee an undisturbed growth. Mean concentrations of CO 2 and O 3 in ambient air and in different treatments illustrate the observed variability of trace gas exposures between different sites and experiments. However, the effects of these parameters on growth and yield are subject of separate papers. The general climatic conditions across Europe are also causing important growth and yield effects. Comparison of marketable tuber yields revealed an increase at higher latitudes. This result was associated with lower temperatures and VPD and longer day lengths at the higher latitudes, which in turn were associated with longer growing seasons. 相似文献
17.
One of the major goals of the European Stress Physiology and Climate Experiment (ESPACE-wheat) was to investigate the sensitivity of wheat growth and productivity to the combined effects of changes in CO 2 concentration, ozone and other physiological stresses. Experiments were performed at different sites throughout Europe, over three consecutive growing-seasons using open-top chambers. This paper summarizes the main experimental findings of the effects of CO 2 enrichment and other factors i.e. ozone (O 3), drought stress or nitrogen supply on the biomass and yield of spring wheat ( Triticum aestivum cv. Minaret). Final harvest data from different sites and seasons were statistically analysed: (1) to identify main effects and interactions between experimentally controlled factors; and (2) to evaluate quantitative relationships between environmental variables and biological responses. Generally, ‘Minaret’ wheat did not respond significantly to O 3, suggesting that this cultivar is relatively tolerant to the O 3 levels applied. The main effect of CO 2 was a significant enhancement of grain yield and above-ground biomass in almost all experiments. Significant interactions between CO 2 and other factors were not common, although modifications in different N- and water supplies also led to significant effects on grain yield and biomass. In addition, climatic factors (in particular: mean air temperature and global radiation) were identified as important co-variables affecting grain yield or biomass, repectively. On average, the yield increase as a result of a doubling of [CO 2] was 35% compared with that observed at ambient CO 2 concentrations. However, linear regressions of grain yield or above-ground biomass for individual experiments revealed a large variability in the quantitative responses of ‘Minaret’ wheat to CO 2 enrichment (yield increase ranging from 11 to 121%). Hence, CO 2 responsiveness was shown to differ considerably when the same cultivar of wheat was grown at different European locations. Multiple regression analyses perfomed to evaluate the relative importance of the measured environmental parameters on grain yield indicated that although yield was significantly related to five independent variables (24 h mean CO 2 concentration, 12 h mean O 3 concentration, temperature, radiation, and drought stress), a large proportion of the observed variability remained unexplained. 相似文献
18.
Measurements of stomatal conductance on field-grown potato ( Solanum tuberosum L.) cv. Bintje from the CHIP programme were combined to study the response to environmental factors. 3274 data points were used. Data were obtained from five sites: Jokioinen in Finland, Östad in Sweden, Giessen in Germany, Tervuren in Belgium and Sutton Bonnington in UK. Measurements were made in open-top chamber treatments with ozone and carbon dioxide exposure and in the ambient air. A typical light response curve was obtained with light saturation at approximately 400 μmol m −2 s −1 photosynthetically active radiation (PAR). The leaf temperature optimum for stomatal conductance was 29 °C. The stomatal conductance declined strongly at leaf-to-air vapour pressure differences >20 hPa. An elevated carbon dioxide concentration (680 μl l −1) reduced the stomatal conductance by up to approximately 20%. Elevated ozone reduced the stomatal conductance towards the end of the growth period, in addition to the negative effect by ordinary senescence on stomatal conductance. A multiplicative model, based on the boundary line technique, was used to estimate the relationship between stomatal conductance and the environmental variables. Test with the data sets from two sites providing sufficient data, Östad and Giessen, showed that the multiplicative model had R2-values of 0.60 and 0.42, respectively, for the relationship between calculated and observed conductance. Test of the model with an independent data set from an open-top chamber experiment with the potato cultivar Kardal showed an R2 of 0.59 between calculated and observed conductance. The conductance model was used to estimate the accumulated ozone uptake (CUO 3) by potato leaves from emergence to harvest. The relationship between CUO 3 and relative yield loss, using a threshold for the ozone uptake rate of 7 nmol m −2 s −1, provided a higher R2-value (0.45) than CUO 3 without any threshold and relationships based on the accumulated exposure over 40 nmol mol −1 (AOT40) or the sum of all hourly average ozone concentrations exceeding 60 nmol mol −1 (SUM06). All four relationships were however statistically significant. 相似文献
19.
In rape ( Brassica napus L., cv. Global) seed growth mainly depends on husk CO 2 assimilation. In irrigated plants, the net photosynthetic rate ( Amax) was 10–13 μmol CO 2 m −2 s −1 in non-maturing pods and correlated with nitrogen content. The stomatal conductance of water vapour ( gH2O) was 0.3 mol m −2 s −1 in non-maturing pods. The photosynthetic nitrogen use efficiency (NUE) was 8.3 μmol CO 2g −1 N s −1, about one-third of that in leaves. The photosynthetic water use efficiency (WUE; AmaxgH2O−1) was similar in pods and leaves. In severely droughted plants, the photosynthetic rate was reduced to 38%. The seed growth rate, however, was not influenced by intermittent periods of water stress, indicating translocation of assimilates to the seeds. The drought resistant character of the pods was due to low specific area, succulence, low stomatal conductance causing a small decrease of ΔΨ day −1 during soil drying and maintenance of high relative water content during severe drought. A mathematical formulation of the pod water release curve was undertaken. © (1997) Elsevier Science B.V. 相似文献
20.
以马铃薯品种中薯5号(早熟, 株型直立)和米拉(中晚熟, 株型扩散)单作为对照, 在大田条件下, 调查马铃薯/玉米套作模式中2个品种光合指标的变化、块茎形成期至块茎增长期不同叶位气体交换参数的变化, 分析光合指标对产量的影响。结果表明, 整个生育期马铃薯叶绿素含量(Chl a+Chl b)套作高于单作, 叶面积指数(LAI)、比叶重(SLW)和叶绿素a/b值(Chl a/b)套作低于单作。从块茎形成期至块茎增长期, 群体光合有效辐射(PAR)、水分利用效率(WUE)、气孔限制值(L s)呈下降趋势, 净光合速率(P n)、气孔导度(G s)、胞间二氧化碳浓度(C i)、蒸腾速率(T r)呈上升趋势。PAR、P n、G s、T r均随叶位的降低显著下降, 套作下降幅度低于单作。套作中、下层叶片P n的下降受气孔因素和非气孔因素限制。套作降低了马铃薯上层叶P n, 提高了中、下层叶P n。套作中薯5号的Chl a+Chl b生育前期高于米拉, 生育后期低于米拉, SLW则相反; LAI和Chl a/b整个生育期高于米拉。套作中薯5号上层叶PAR高于米拉, 中、下层叶PAR低于米拉; 套作中薯5号上层叶P n与米拉相近, 中、下层叶P n高于米拉; 各层叶WUE、L s高于米拉, G s、C i、T r低于米拉。总之, 套作改变了马铃薯的光合特性, 并显著降低了马铃薯块茎产量; 套作恶化了中薯5号/玉米复合群体的光环境, 改善了米拉/玉米复合群体的光环境, 米拉/玉米套作体系土地当量比(1.40)大于中薯5号/玉米体系(1.24), 显示了较强的套作优势, 宜在生产中优先推广。 相似文献
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