Dark Respiration of Winter Wheat Crops in Relation to Temperature and Simulated Photosynthesis

The dark respiration of shoots (measured between March and anthesisin mid-June) and of ears (measured between anthesis and maturityat end of July) of winter wheat crops, grown in 1982 and 1985under different nitrogen application and irrigation conditions,was determined in the field. The respiration rate of 126 averagesof four samples was measured hourly for a 12–14-h darkperiod including the night. Respiration (expressed per unitdry mass) generally declined through the season for both shootsand ears. The average rate of respiration obtained on the samenight was greater for fertilized and irrigated crops, comparedwith unfertilized and droughted crops. The relationship betweenthe measured respiration and photosynthesis, simulated usinga modified version of the model developed by Spitters (1986),was analysed. This revealed that: (a) Shoot respiration was less well correlated with photosynthesisfrom the day preceding measurement than with the average ofthe photosynthesis from the two days preceding measurement. (b) The constants relating shoot respiration to total crop photosynthesisper unit crop mass and ear respiration to total crop photosynthesisper unit ear mass had similar values. This suggests that allgrowth respiration takes place in the ears at the end of theseason. (c) Crop growth respiration consumes about 35% of assimilatebefore anthesis, and that growth respiration of the ear consumesabout 40% of assimilate at the end of the season. (d) No significant effect of treatment on the relationship betweenrespiration and photosynthesis was detected, suggesting thatthe observed effect of treatment on respiration is due entirelyto differences in photosynthesis. Triticwn aestivum var. Avalon, winter wheat, dark respiration, growth coefficient, photosynthesis model, nitrogen nutrition, irrigation     

Dark Respiration during Photosynthesis in Wheat Leaf Slices

The metabolism of [¹⁴C]succinate and acetate was examined in leaf slices of winter wheat (Triticum aestivum L. cv Frederick) in the dark and in the light (1000 micromoles per second per square meter photosynthetically active radiation). In the dark [1,4-¹⁴C]succinate was rapidly taken up and metabolized into other organic acids, amino acids, and CO₂. An accumulation of radioactivity in the tricarboxylic acid cycle intermediates after ¹⁴CO₂ production became constant indicates that organic acid pools outside of the mitochondria were involved in the buildup of radioactivity. The continuous production of ¹⁴CO₂ over 2 hours indicates that, in the dark, the tricarboxylic acid cycle was the major route for succinate metabolism with CO₂ as the chief end product. In the light, under conditions that supported photorespiration, succinate uptake was 80% of the dark rate and large amounts of the label entered the organic and amino acids. While carbon dioxide contained much less radioactivity than in the dark, other products such as sugars, starch, glycerate, glycine, and serine were much more heavily labeled than in darkness. The fact that the same tricarboxylic acid cycle intermediates became labeled in the light in addition to other products which can acquire label by carboxylation reactions indicates that the tricarboxylic acid cycle operated in the light and that CO₂ was being released from the mitochondria and efficiently refixed. The amount of radioactivity accumulating in carboxylation products in the light was about 80% of the ¹⁴CO₂ release in the dark. This indicates that under these conditions, the tricarboxylic acid cycle in wheat leaf slices operates in the light at 80% of the rate occurring in the dark.     

Responses of Plant Dark Respiration to Doubled CO2 Concentration

Ten species of plants were grown at ambient (350μmol CO2·mol-1 air) and doubled (700 μmol CO2·mol-1 air) CO2 concentrations at ambient temperature and illumination in order to examine changes of dark respiration of whole seedlings or detached leaves. Effects of CO2 on dark respiration were determined by brief exposure ( ≤ 5 min) to corresponding CO2 concentration and temperatures ( 15,20,25,30 and 35 ℃ ) with infrared CO2 analyzer. The reductions in dark respiration on a weight base for leaves of East-Liaoning oak (Quercus liaotungensis Koidz. ) at 15,20 and 25 ℃ and of soybean ( Glycine max L. ) at 20,25,30 and 35 ℃ and for whole seedlings of three- tcoloured amaranth (Amaranthus tricolor L. ) at 15 and 20 ℃ and cucumber ( Cucumis sativus L. ) at 15 cE measured at elevated concentration relative to the ambient CO2 concentration were observed. No significant difference in respiration responded was observed to elevated or ambient CO2 concentrations at 15 ℃ in maize (Zea mays L. ) seedlings and alfalfa (Medicago sativa L. ) leaves, at 35 ℃ in East-Liaoning oak leaves and at 20,25 and 30 ℃ in three-coloured amaranth seedlings. However CO2 efflux in leaves of weeping willow (Salix babylonica L. ), simon poplar (Populus simonii Carr. ) and eucommia (Eucommia ulmoides Oliv. ) at 15,20,25,30 and 35 ℃, alfalfa at 20,25,30 and 35 ℃, East-Liaoning oak at 30 ℃, maize at 15 ℃, seedlings of common buckwheat (Fagotrytum esculentum Moench) at 15,20,25,30 and 35 ℃, cucumber and maize at 20,25,30 and 35 ℃ and three-coloured amaranth at 35 ℃ showed an increase at elevated in contrast to ambient CO2 concentration. In general, at lower temperatures (i. e. 15, 20 ℃ ) there was no significant difference between elevated and ambient CO2 concentration for dark respiration, while at higher temperatures (i. e. 30,35 ℃ ) elevated CO2 concentration positively stimulate clark respiretion. It has not yet been described that double CO2 concentration could enhance plant dark respiration at 30 and 35 ℃. Impacts of the characteristics in dark respiration on the future changes of vegetation and its mechanism were discussed.     

Growth Responses of Two Solanum Species to Contrasting Temperatures and Irradiance Levels: Relations to Photosynthesis, Dark Respiration and Chlorophyll Fluorescence

Potato production in the tropical lowlands during the rainyseason is constrained by high temperature and low irradiance.This study examined the effect of these two variables on drymatter production and allocation, using plant growth, leaf anatomy,gas exchange and chlorophyll fluorescence measurements. Plantsof two clones, Solanum goniocalyx cv. Garhuash Huayro (GH) andDTO-33, a heat tolerant clone of S. tuberosum x S. phureja,were grown in growth chambers at 33/25 °C or 20/10 °Cday/night temperature. At each temperature, plants were grownin either 12 h high irradiance (430–450 µmol m^–2s^–1 PAR) or 12 h low irradiance (250–280 µmolm^–2 s^–1) both with a 6–h photoperiod extensionof 6 µmol m^–2 s^–1. Plants were harvested after10 d (initial harvest) and after 20 d (final harvest). By theend of the study DTO-33 had produced more dry matter and hadtuberized, whereas GH had a greater leaf area ratio (LAR) andspecific leaf area (SLA). The highest relative growth rate (RGR)was at low temperature and low irradiance, possibly due to acombination of thin leaves with a large surface area. At thehigh temperature, low irradiance had the opposite effect, producingthe lowest net assimilation rate (NAR) and lowest RGR. Bothtuber number and weight were markedly reduced by high temperature.Low irradiance, in combination with high temperature, producedvirtually no tubers. Stomatal density, which was greater onGH than in DTO-33, was increased at high temperature. When measuredat 30 °C both clones, especially DTO-33, showed heat-adaptationin terms of ability to maintain a high rate of net photosynthesisat 30 °C. Plants grown at high irr-adiance and low temperaturehad the lowest net photosynthetic rate at 30 °C. Concurrentmeasurements of chlorophyll fluorescence indicated that onlythe initial (O) fluorescence parameter was affected. The dataconfirm the field observation that reduction in potato growthat high temperature can be aggravated by lower irradiance. Thisreduction is associated with a reduced leaf area and NAR. Growth analysis, heat adaptation, light     

Acclimation of Leaf Dark Respiration to Temperature in Alpine and Lowland Plant Species

Acclimation to temperature in terms of dark respiration by leavesis a missing link in current efforts to predict the effectsof global warming on plant communities. We studied the acclimationof plants from alpine or lowland areas and asked two questions:(1) do plants acclimate to a change in temperature and doesacclimation depend on the plants' origin; and (2) have alpineplants adapted to low temperatures by respiring faster thanlowland plants at any given temperature? Nineteen alpine andcorresponding lowland species, collected in Switzerland, weregrown at 10 and 20°C for 5 weeks. Night-time leaf dark respirationrates were measured at the growth temperature of each plant.Acclimation patterns ranged from full to no acclimation. Fullacclimation to temperature, defined as the equality betweenrespiration measured at 20°C of plants grown at 20°Cand respiration measured at 10°C of plants grown at 10°C,occurred in only three out of 19 species. Dark respiration ofleaves was stimulated by a 10 K warming, but on average, byabout 50% less than predicted by the instantaneous temperatureresponse, i.e. Q₁₀. Acclimation did not depend on the alpineor lowland origin of the plant, but rather on its genus. Prostratealpine plants displayed the lowest acclimation potential. Weconclude that predictions at the community level cannot be madebased on single species because of the variety observed in therespiration responses.Copyright 1995, 1999 Academic Press Acclimation, alpine and lowland, climate warming, comparative ecology, dark respiration, grassland, Q₁₀, temperature     

Interactions between Photosynthesis and Respiration in the Green Alga Chlamydomonas reinhardtii (Characterization of Light-Enhanced Dark Respiration)

The rate of respiratory O2 consumption by Chlamydomonas reinhardtii cell suspensions was greater after a period of photosynthesis than in the preceding dark period. This "light-enhanced dark respiration" (LEDR) was a function of both the duration of illumination and the photon fluence rate. Mass spectrometric measurements of gas exchange indicated that the rate of gross respiratory O2 consumption increased during photosynthesis, whereas gross respiratory CO2 production decreased in a photon fluence rate-dependent manner. The rate of postillumination O2 consumption provided a good measure of the O2 consumption rate in the light. LEDR was substantially decreased by the presence of 3-(3,4-dichlorophenyl)-1,1-dimethylurea or glycolaldehyde, suggesting that LEDR was photosynthesis-dependent. The onset of photosynthesis resulted in an increase in the cellular levels of phosphoglycerate, malate, and phosphoenolpyruvate, and a decrease in whole-cell ATP and citrate levels; all of these changes were rapidly reversed upon darkening. These results are consistent with a decrease in the rate of respiratory carbon flow during photosynthesis, whereas the increase in respiratory O2 consumption during photosynthesis may be mediated by the export of photogenerated reductant from the chloroplast. We suggest that photosynthesis interacts with respiration at more than one level, simultaneously decreasing the rate of respiratory carbon flow while increasing the rate of respiratory O2 consumption.     

Photosynthesis and Dark Respiration in Leaves of Different Ages of Partly Flooded Maize Seedlings

Maize seedlings were flooded for periods from 1 to 15 days, and the leaves of different ages were then taken to examine photosynthesis, dark respiration, transpiration, chlorophyll content, and some morphometric parameters. The responses of leaves to root submergence essentially depended on the leaf layer and the treatment duration. A short-term flooding (1–24 h) induced primary stress responses in the first leaf. Photosynthesis and respiration in this leaf oscillated around the control levels with amplitudes of ±15–25% and ±40–60%, respectively. After a longer flooding, the CO₂ exchange in the second leaf was suppressed, while oxygen uptake was stimulated. In the third leaf, which was formed during submergence, the photosynthetic rate increased and the respiratory activity decreased. The transpiration rate did not change in these leaves for 15 days of flooding. The hypoxic treatment, at its early stages, retarded growth and disturbed the source–sink relations. At later stages the plants adapted to hypoxic environment: the seedling growth was restored, which elevated the demand for assimilates and stimulated photosynthesis. It is concluded that plants overcome negative impact of the root hypoxia at the systemic level.     

Effects of Variations in Daylength and Temperature on Net Rates of Photosynthesis, Dark Respiration, and Excretion by Isochrysis galbana Parke

The effects of variable daylength and temperature on net rates of photosynthesis, dark respiration, and excretion of a unicellular marine haptophyte, Isochrysis galbana Parke, were examined and related to division rates. Six combinations of daylength (18:6, 12:12, 6:18 light:dark, LD) and temperature (20, 25 C) were used. Daily rates of net photosynthesis were closely correlated to division rates, suggesting a direct relationship, and were maximal when cells were grown at 12:12 LD at both temperatures and 18:6 LD at 20 C. A daylength of 6 hours decreased daily rates by decreasing the time for carbon uptake. Further, cells grown with this daylength had maximal chlorophyll a contents, suggesting a physiological adaptation by photosynthetic units to short light periods. A photoperiod of 18:6 LD at 25 C decreased daily rates of net photosynthesis by reducing the hourly rate of net photosynthesis via an unidentified mechanism. The importance of rates of net dark respiration in controlling daily net photosynthesis was small, with carbon lost during dark periods varying between 4 and 14% of that gained during light periods. Also, the influence of net excretion was small, varying between 1.0 and 5.5% of daily net photosynthesis.     

Photosynthesis, Dark Respiration and Bud Sugar Concentrations in Pepper Cultivars Differing in Susceptibility to Stress-induced Bud Abscission

Pepper (Capsicum annuum L.) cultivars differ in susceptibilityto stress-induced abscission. Previous research indicates thatthe stress susceptible cultivar 'Shamrock' undergoes a largerreduction in net assimilation rate (NAR) under low light stress,and partitions less dry matter (DM) to reproductive structuresand more to leaves than the more tolerant cultivar 'Ace'. Todetermine if photosynthetic rates under low light stress couldexplain NAR differences, photosynthesis was measured on 'Ace'and 'Shamrock'. Assimilate partitioning was compared throughmeasurement of leaf and bud respiration rates and analysis ofbud sugar concentrations. Photosynthetic rates per unit leafarea of leaves fully exposed to incident light revealed no cultivardifferences under low light conditions. Bud respiration ratesfell to a lower level in 'Shamrock' than 'Ace' in low light-stressedplants, while expanded leaves respired at higher rates in 'Shamrock'than 'Ace' under both full and low light. Bud sugar concentrationswere significantly lower in 'Shamrock' than 'Ace' after 3 dof low light stress. Susceptibility to low light stress-inducedabscission in 'Shamrock' appears to be associated with reducedassimilate partitioning to flower buds, which may be relatedto high assimilate consumption in maintenance of expanded leaves.Copyright1994, 1999 Academic Press Pepper (Capsicum annuum L.), abscission, low light stress, photosynthesis, respiration, sugars, assimilate partitioning, cultivar     

Effects of Low Concentrations of Sulphur Dioxide on Net Photosynthesis and Dark Respiration of Vicia faba

Rates of net photosynthesis, P_N, and dark respiration of Viciafaba plants were measured in the laboratory in clean air andin air containing up to 175 parts 10^–9 (500 µg m^–3)SO₂. At all SO₂ concentrations exceeding 35 parts 10^–9,P_N was inhibited compared with clean air. At light saturation,the magnitude of inhibition depended on SO₂ concentration butat low irradiances the inhibition was independent of concentration.Dark respiration rates increased substantially, independentof concentration. When exposures continued for up to 3 days,P_N returned to clean air values about 1 h after fumigation ceased:dark respiration recovered after one photoperiod. There wereno visible injuries. Reviewing possible mechanisms responsible for the inhibitionof P_N, it is suggested that SO₂ competes with CO₂ for bindingsites in RuBP carboxylase. Analysis of resistance analoguesdemonstrates that SO₂ altered both stomatal and internal (residual)resistances. A model of crop photosynthesis shows the implications of theobserved responses for the growth of field crops in which plantsare assumed to respond like laboratory plants. Photosynthesisof the crop would be less sensitive than that of individualplants to SO₂ concentration. Daily dry matter accumulation ofhypothetical ‘polluted crops’ would be substantiallyless than clean air values but would vary relatively littlewith SO₂ concentration. It is concluded that physiological basesexist to account for observed reductions in growth of plantsat very low SO₂ concentrations, and that thresholds for plantresponses to SO₂ require reassessment.     

Acclimation of Photosynthesis and Dark Respiration of a Submersed Angiosperm beneath Ice in a Temperate Lake

Ceratophyllum demersum L. remained physiologically active beneath ice of a southeastern Michigan lake. The effect of seasonally low photosynthetic photon flux density (PPFD) and cold but nonfreezing temperature on whole-plant physiology was studied. Net photosynthesis was measured at six temperatures and 12 PPFDs. Net photosynthesis, soluble protein concentration, ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) protein concentration, and Rubisco activity of winter plants were 32, 31, 33, and 70% lower, respectively, than those of plants collected in the summer. Optimum temperatures for net photosynthesis of winter and summer plants were 5 and 30[deg]C, respectively. Dark respiration of winter plants was up to 313% greater than that of summer plants. Reduced Rubisco activity and increased dark respiration interacted to reduce net photosynthesis. Interaction of reduced net photosynthesis and increased dark respiration increased CO2 and light compensation points and the light saturation point of winter plants. Growth of C. demersum was limited by the ambient phosphorus concentration of lake water during summer. Apical stem segments of winter-collected plants had 54 and 35% more phosphorus and nitrogen, respectively, than summer-collected plants. Physiologically active perennation beneath ice enabled C. demersum to accumulate phosphorus during the winter when it was most abundant. Partial uncoupling of phosphorus acquisition from utilization may reduce phosphorus limitation upon growth during the summer when phosphorus concentration is seasonally the lowest.     

Influence of Daily Short-Term Temperature Drops on Respiration to Photosynthesis Ratio in Chilling-Sensitive Plants

Cucumber (Cucumis sativus L.), tomato (Solanum lycopersicum L.), and sweet pepper (Capsicum annuum L.) plants were subjected daily over 13 days to short-term (2 h) temperature drops to 12, 8, 4, and 1°C (DROP treatments) at the end of night periods, and effects of these chilling treatments on the ratio of dark respiration in leaves (R_d) to gross photosynthesis (A_g) were examined. The results showed that DROP treatments affected the R_d/A_g ratio in leaves: this ratio increased significantly in cucumber and tomato plants and was slightly affected in pepper plants. When the temperature drops to 12°C were applied, the increase in R_d/A_g ratio in cucumber and tomato plants was entirely due to the rise in R_d. In the case of temperature drops to 8°C and below, the increase in R_d/A_g was determined by both elevation of R_d and the concurrent decrease in Ag. In cucumber plants, the extent of Ag and R_d changes increased with the DROP severity, i.e., with lowering the temperature of DROP treatment. The inhibition of photosynthesis by DROP treatment in cucumber plants was accompanied by the diminished efficiency of light energy use for photosynthesis and by the increase in the light compensation point. The elevation in R_d/A_g ratio in cucumber plants was accompanied by the decline in growth characteristics, such as accumulation of aboveground biomass, plant height, and leaf area. It was concluded that the R/A ratio is an important indicator characterizing the adaptive potential of chilling-sensitive plant species and their response to daily short-term temperature drops.     

Dark Respiration Protects Photosynthesis Against Photoinhibition in Mesophyll Protoplasts of Pea (Pisum sativum)

The optimal light intensity required for photosynthesis by mesophyll protoplasts of pea (Pisum sativum) is about 1250 microeinsteins per square meter per second. On exposure to supra-optimal light intensity (2500 microeinsteins per square meter per second) for 10 min, the protoplasts lost 30 to 40% of their photosynthetic capacity. Illumination with normal light intensity (1250 microeinsteins per square meter per second) for 10 min enhanced the rate of dark respiration in protoplasts. On the other hand, when protoplasts were exposed to photoinhibitory light, their dark respiration also was markedly reduced along with photosynthesis. The extent of photoinhibition was increased when protoplasts were incubated with even low concentrations of classic respiratory inhibitors: 1 micromolar antimycin A, 1 micromolar sodium azide, and 1 microgram per milliliter oligomycin. At these concentrations, the test inhibitors had very little or no effect directly on the process of photosynthetic oxygen evolution. The promotion of photoinhibition by inhibitors of oxidative electron transport (antimycin A, sodium azide) and phosphorylation (oligomycin) was much more pronounced than that by inhibitors of glycolysis and tricarboxylic acid cycle (sodium fluoride and sodium malonate, respectively). We suggest that the oxidative electron transport and phosphorylation in mitochondria play an important role in protecting the protoplasts against photoinhibition of photosynthesis. Our results also demonstrate that protoplasts offer an additional experimental system for studies on photoinhibition.     

Responses of Respiration to Increases in Carbon Dioxide Concentration and Temperature in Three Soybean Cultivars

The purpose of this experiment was to determine how respirationof soybeans may respond to potential increases in atmosphericcarbon dioxide concentration and growth temperature. Three cultivarsof soybeans (Glycine max L. Merr.), from maturity groups 00,IV, and VIII, were grown at 370, 555 and 740cm³m^-3carbon dioxideconcentrations at 20/15, 25/20, and 31/26°C day/night temperatures.Rates of carbon dioxide efflux in the dark were measured forwhole plants several times during exponential growth. Thesemeasurements were made at the night temperature and the carbondioxide concentration at which the plants were grown. For thelowest and highest temperature treatments, the short term responseof respiration rate to measurement at the three growth carbondioxide concentrations was also determined. Elemental analysisof the tissue was used to estimate the growth conversion efficiency.This was combined with the observed relative growth rates toestimate growth respiration. Maintenance respiration was estimatedas the difference between growth respiration and total respiration.Respiration rates were generally sensitive to short term changesin the measurement carbon dioxide concentration for plants grownat the lowest, but not the highest carbon dioxide concentration.At all temperatures, growth at elevated carbon dioxide concentrationsdecreased total respiration measured at the growth concentration,with no significant differences among cultivars. Total respirationincreased very little with increasing growth temperature, despitean increase in relative growth rate. Growth respiration wasnot affected by carbon dioxide treatment at any temperature,but increased with temperature because of the increase in relativegrowth rate. Values calculated for maintenance respiration decreasedwith increasing carbon dioxide concentration and also decreasedwith increasing temperature. Calculated values of maintenancerespiration were sometimes zero or negative at the warmer temperatures.This suggests that respiration rates measured in the dark maynot have reflected average 24-h rates of energy use. The resultsindicate that increasing atmospheric carbon dioxide concentrationmay reduce respiration in soybeans, and respiration may be insensitiveto climate warming. Glycine max L. (Merr.); carbon dioxide; respiration; temperature; climate change     

The Effect of Cadmium on Net Photosynthesis, Transpiration, and Dark Respiration of Excised Silver Maple Leaves

Excised leaves of silver maple (Acer saccharinum L.) exposed to 0, 0.045, 0.090, or 0.180 mM Cd²⁴ exhibited reduced net photosynthesis and transpiration, and increased dark respiration. Rates of net photosynthesis and transpiration diminished with time and were strongly correlated with solution concentration and tissue content of Cd²⁴, Net photosynthesis and transpiration were reduced to 18 and 21%, respectively, of the untreated controls after 64 h. Dark respiration increased as much as 193% of the untreated controls but was poorly correlated with solution concentration or tissue content of Cd²⁴, Diffusive resistances of leaves to carbon dioxide and water vapor transfer increased with both increasing Cd²⁴ concentration and time. These findings are discussed in relation to stomatal function.     

不同强度的UV-B辐射对高山植物麻花艽光合作用及暗呼吸的影响

以人工种植的多年生高山植物麻花艽(Uentiana straminea)为材料,在3个不同强度的UV—B辐射处理下,定时测定处理和对照叶片的净光合速率、表观量子效率和暗呼吸的变化。结果显示：UV—B处理对麻花艽叶片的光合作用在短期内有一定的抑制作用,但随着处理时间的增加,该高山植物能很快地适应强UV—B辐射的处理。表明麻花艽这种青藏高原常见的高山植物在长期的自然选择过程中可能已经形成了适应UV—B辐射的特有生理机制。暗呼吸的实验结果亦表明：在3种强度的UV—B辐射处理下,麻花艽叶片的呼吸作用从一开始就未受到抑制;随着UV—B辐射时间的增加,UV—B辐射强度越高,呼吸强度越强;这可能是UV—B辐射并未引起麻花艽呼吸机构的破坏所致。     

Temperature Responses of Photosynthesis and Respiration of Maize (<Emphasis Type="Italic">Zea mays</Emphasis>) Plants to Experimental Warming

Understanding the key processes and mechanisms of photosynthetic and respiratory acclimation of maize (Zea mays L.) plants in response to experimental warming may further shed lights on the changes in the carbon exchange and Net Primary Production (NPP) of agricultural ecosystem in a warmer climate regime. In the current study, we examined the temperature responses and sensitivity of foliar photosynthesis and respiration for exploring the mechanisms of thermal acclimation associated with physiological and biochemical processes in the North China Plain (NCP) with a field manipulative warming experiment. We found that thermal acclimation of A_n as evidenced by the upward shift of A_n-T was determined by the maximum velocity of Rubisco carboxylation (V_cmax), the maximum rate of electron transport (J_max), and the stomatal- regulated CO₂ diffusion process (g_s), while the balance between respiration and photosynthesis (R_d/A_g), and/or regeneration of RuBP and the Rubisco carboxylation (J_max/V_cmax) barely affected the thermal acclimation of A_n. We also found that the temperature response and sensitivity of R_d was closely associated with the changes in foliar N concentration induced by warming. These results suggest that the leaf-level thermal acclimation of photosynthesis and respiration may mitigate or even offset the negative impacts on maize from future climate warming, which should be considered to improve the accuracy of process-based ecosystem models under future climate warming.