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1.
KENDALL A. C.; TURNER J. C.; THOMAS S. M.; KEYS A. J. 《Journal of experimental botany》1985,36(2):261-273
Spring wheat plants were grown in a cage with a glass roof untilthree days after anthesis and then subjected to treatments inconstant environment rooms with any one of all combinationsof four irradiances and two concentrations of carbon dioxide.The photoperiod was 16 h and day/night temperatures 19?C/14?C.Growth and yield of grain were saturated at the two brightestirradiances. Carbon dioxide enrichment from 350 to 1200 mm3dm3 increased shoot dry weight and grain yield at finalharvest at all irradiances, by averages of 10.5 (not significant)and 23.5 (significant) percent respectively. However, increasingthe irradiance from 150 to 613 µE m2 s1caused much larger yield increases (approximately 3-fold). Increasedgrain production by increased light was caused by both increasesin dry weight per grain and by increases in grain number perspikelet. The increase caused by CO2 enrichment was mainly becauseof increased dry weight per grain. Increase in ear dry weightcaused by CO2 enrichment took place between 30 and 60 d afteranthesis. The increase in shoot dry weight took place immediatelyafter exposure to increased CO2 from 3 to 15 d after anthesis.Net photosynthesis by flag leaves on the main shoots was almostdoubled 16 d after anthesis by the CO2 enrichment even thoughstomatal resistance was also doubled. However, this increasewas not reflected by a proportional increase in yield, probablybecause increased mutual shading by bigger stems and late tillersreduced total assimilation and because of increased respirationby the shoots. The increase in photosynthesis was not due toa decrease in photorespiration but to an increase in gross photosynthesis. Key words: CO2enrichment, Photosynthesis, Photorespiration 相似文献
2.
Wheeler T.R.; Hong T.D.; Ellis R.H.; Batts G.R.; Morison J.I.L.; Hadley P. 《Journal of experimental botany》1996,47(5):623-630
Winter wheat (Triticum aestivum L. cv. Hereward) was grown inthe field inside polyethylene-covered tunnels at a range oftemperatures at either 380 or 684 µmol mol1 CO2.Serial harvests were taken from anthesis until harvest maturity.Grain yield was reduced by warmer temperatures, but increasedby CO2 enrichment at all temperatures. During grain-filling,individual grain dry weight was a linear function of time fromanthesis until mass maturity (attainment of maximum grain dryweight) within each plot. The rate of progress to mass maturity(the reciprocal of time to mass maturity) was a positive linearfunction of mean temperature, but was not affected by CO2 concentration.The rate of increase in grain dry weight per ear was 2.0 mgd1 greater per 1 C rise, and was 8.0 mg d1 greaterat 684 compared with 380 µmol mol1 CO2 at a giventemperature. The rate of increase in harvest index was 1.0%d1 in most plots at 380 µmol mol1 CO2 andin open field plots, compared with 1.18% d1 in all plotsat 684 µmol mol1 CO2. Thus, the increased rateof grain growth observed at an elevated CO2 concentration couldbe attributed partly to a change in the partitioning of assimilatesto the grain. In contrast, the primary effect of warmer temperatureswas to shorten the duration of grain-filling. The rate of graingrowth at a given temperature and the rate of increase in harvestindex were only independent of the number of grains per earabove a critical grain number of 2324 grains per ear({small tilde}20 000 grains m2). Key words: Winter wheat, grain growth, temperature, CO2, harvest index, critical grain number 相似文献
3.
Barley (Hordeum vulgare L. cv. Digger) was grown for 22 d inenclosed chambers with a CO2 enrichment of 35, 155, 400 or 675µmol CO2 mol1. CO2 enrichment increased photosyntheticcapacity in the plants grown at either of the two highest levelsof pCO2. A CO2 enrichment of 675µmol CO2 caused a significantincrement of shoot dry weight, whereas no changes were observedin fresh weight, chlorophyll or protein levels. At a light intensityof 860µmol m2s1 CO2 enrichment caused photosyntheticcapacity to increase by 250%, whereas no effect was observedat 80 µmol m2 s1. Over time, photosynthesisdecreased by 70% independent of CO2. A time-dependent increasein the level of extractable fructose was observed whereas totalextractable carbohydrate only changed slightly. Key words: Carbohydrates, CO2 enrichment, Hordeum vulgare, photosynthesis, respiration 相似文献
4.
Nine amounts of nitrogen fertilizer, ranging from 0 to 200 kgN ha1, were applied to spring wheat cv. Kleiber in the3 years 1972-1974. In 1972 grain dry weight with 125 kg N ha1or more was 100 g m2 (23 per cent) greater than withoutnitrogen. Grain yield was unaffected by nitrogen in the otheryears. Leaf area at and after anthesis was increased throughoutthe range of nitrogen tested, most in 1972 and least in 1973.Consequently, the addition of 200 kg N ha1 decreasedthe amount of grain produced per unit of leaf area by approximately25 per cent in all years. The dry weight of leaves and stems at anthesis and maturitywas increased by nitrogen in all years, similarly to leaf area.However, the change in stem dry weight between anthesis andmaturity was not affected by nitrogen; stems increased in dryweight for about 20 days after anthesis and then decreased tovalues similar to those at anthesis. The uptake of CO2 per unit area of flag leaf or second leaf(leaf below the flag leaf) was slightly decreased by nitrogenwhen the increase in leaf area caused by nitrogen appreciablydecreased the light intensity at the surface of these leaves.In spite of such decreases the CO2 absorbed by flag and secondleaves per unit area of land was always increased by nitrogen,and relatively more than was grain yield. It is suggested that increases in respiratory loss of CO2 withincreasing nitrogen fertilizer may explain why nitrogen increasedvegetative growth and leaf area relatively more than grain yield. 相似文献
5.
Temperature Effects on Rice at Elevated CO2 Concentration 总被引:1,自引:0,他引:1
The continuing increase in atmospheric carbon dioxide concentration([CO2]) and projections of possible future increases in globalairtemperatures have stimulated interest in the effects of theseclimate variables on agriculturally important food crops. Thisstudywas conducted to determine the effects of [CO2] and temperatureon rice (Oryza sativa L., cv. IR30). Rice plants weregrownseason-long in outdoor, naturally sunlit, controlled-environment,plant growth chambers in temperature regimes ranging from 25/18/21°Cto 37/30/34°C (daytime dry bulb air temperature/night-timedry bulb air temperature/paddy water temperature)and [CO2] of660 µmol CO2 mol1 air. An ambient chamber was maintainedat a [CO2] of 330 µmol mol1 and temperature regimesof 28/21/25°C. Carbon dioxide enrichment at 28/21/25°Cincreased both biomass accumulation and tillering and increasedgrain yield by 60%. In the 660 µmol mol1 [CO2]treatment, grain yield decreased from 10.4 to 1.0 Mg ha1with increasing temperature from 28/21/25°C to the 37/30/34°Ctemperature treatment. Across this temperature range, the numberof panicles plant1 nearly doubled while the number ofseeds panicle1 declined sharply. These results indicatethat while future increases in atmospheric [CO2] are likelyto be beneficial to rice growth and yield, potentially largenegative effects on rice yield are possible if air temperaturesalso rise. Key words: Oryza sativa, CO2, temperature, growth, yield 相似文献
6.
CLOUX H. C. DU; ANDRE M.; DAGUENET A.; MASSIMINO J. 《Journal of experimental botany》1987,38(9):1421-1431
Du Cloux, H. C, André, M., Daguenet, A. and Massinuno,J. 1987. Wheat response to CO2 enrichment: Growth and CO2 exchangesat two plant densities.J. exp. Bot. 38: 14211431. The vegetative growth of wheat (Triticum aestivum L., var. Capitole)was followed for almost 40 d after germination in controlledconditions. Four different treatments were carried out by combiningtwo air concentrations of CO2, either normal (330 mm3 dm 3)or doubled (660 mm3 dm 3) with two plant densities, either 200plants m 2 or 40 plants m 2. Throughout the experiment the CO2gas exchanges of each canopy were measured 24 h d1. These provideda continuous growth curve for each treatment, which were comparedwith dry weights. After a small stimulation at the start (first13 d), no further effect of CO2 enrichment was observed on relativegrowth rate (RGR). However, RGR was stimulated throughout theexperiment when plotted as a function of biomass. The finalstimulation ol dry weight at 660 mm3 dm 3 CO2 was a factor of1·45 at high density and 1·50 at low density,contrary to other studies, no diminution of this CO2 effecton dry weight was observed over time. Nevertheless, at low density,a transient additional enhancement of biomass (up to 1·70)was obtained at a leaf area index (LAI) below 1. This effectwas attributed to a different build up of the gain of carbonin the case of an isolated plant or a closed canopy. In theformer, the stimulation of leaf area and the net assimilationrate are both involved; in the latter the enhancement becomesindependent of the effect on leaf area because the canopy photosynthesisper unit ground area as a function of LAI reaches a plateau. Key words: Triticum aestuum, L. var. Capitole, Vegetative growth, Canopy 相似文献
7.
Dark Respiration of Several Varieties of Winter Wheat Given Different Amounts of Nitrogen Fertilizer 总被引:1,自引:1,他引:0
Carbon dioxide production in the dark by ears and by the restof the shoot of winter wheat grown in the field was measuredin 2 years during grain growth. The respiration rate per g d.wt of the ears was increased by nitrogen fertilizer. Ears ofthe semi-dwarf varieties Maris Fundin and Hobbit respired moreslowly than ears of Maris Huntsman and Cappelle-Desprez. Respirationrates of the rest of the shoot were unaffected by nitrogen orvariety. The amount of carbohydrate required to provide the CO2 respiredduring the whole period of grain growth varied from 163 to 443g m2, or 42 to 76 per cent of the dry weight of the grain.More than half the CO2 lost was respired by the ear. The additionof 180 kg N ha1, which increased grain yield by 78 percent in 1975, almost trebled the amount of CO2 lost by the ears.The semi-dwarf varieties lost less CO2 from ears and shootsthan did the taller ones, and had larger yields of grain. Respiration was also estimated from the difference between the14C contents of shoots sampled immediately after a 30 s exposureto 14CO2 and at maturity. When 14C was supplied 10 days afteranthesis, the loss by maturity amounted to 1628 per centof that initially absorbed by flag leaves and 40 per cent ofthat absorbed by the leaf below the flag leaf. Most of the lossoccurred in the first day. The loss of 14C by maturity was significantlyincreased by nitrogen fertilizer in 1975. Triticum aestivum L., wheat, respiration, nitrogen supply, fertilizer treatment 相似文献
8.
Intraspecific variation in the response of rice (Oryza sativa L.) to increased CO2 and temperature: growth and yield response of 17 cultivars 总被引:4,自引:0,他引:4
Ziska Lewis H.; Manalo Paz A.; Ordonez Raymond A. 《Journal of experimental botany》1996,47(9):1353-1359
Seventeen rice (Oryza sativa L.) cultivars of contrasting ecosystemsand origins were exposed to two CO2 concentrations (373 [ambient]and 664 µl l1 CO2 [elevated]) at two differentday/night temperatures (29/21 C and 37/29 C) in glasshousesat the International Rice Research Institute phytotron duringthe dry seasons of 1994 and 1995. Growth at elevated CO2 (asdetermined by total plant biomass at maturity) increased byan average of 70% and 22%, respectively, for all cultivars forgrowth temperatures of 29/21 C and 37/29 C relative to theambient CO2 treatment. At the 29/21 C optimal growth temperature,grain yield increased on average c. 50% with enriched CO2. Incontrast, at the higher growth temperature (37/29 C), grainyield was almost zero, presumably due, in part, to temperature-inducedinfertility (i.e. the percentage of filled spikelets was <1%).Among cultivars, lAC 165, a tropical japonica from Brazil, showedthe largest relative increase in both biomass and grain yield.While the range of responses to increased CO2 and/or temperaturewere quite large (e.g. 10250%) and may not be applicableto field conditions, data indicate that lines are availablewhich could maximize productivity as CO2 concentration increases.Additional work, however, would be needed to identify cultivarswhich would maintain maximum yields in a high CO2, high temperatureenvironment. Key words: Plant growth analysis, experimental design, computational methods, relative growth rate, net assimilation rate 相似文献
9.
Knight, S. L. and Mitchell, C. A. 1988. Effects of CO2 and photosyntheticphoton flux on yield, gas exchange and growth rate of Lactucasativa L. Waldmanns Green'.J. exp. Bot.39: 317328. Enrichment of CO2 to 46 mmol m3 (1 000 mm3 dm3)at a moderate photosynthetic photon flux (PPF) of 450 µmolm2 s1 stimulated fresh and dry weight gain oflettuce leaves 39% to 75% relative to plants at 16 mmol m3CO2 (350 mm3 dm3). Relative growth rate (RGR) was stimulatedonly during the first several days of exponential growth. ElevatingCO2 above 46 mmol m3 at moderate PPF had no further benefit.However, high PPF of 880900 µmol m2 s1gave further, substantial increases in growth, RGR, net assimilationrate (NAR) and photosynthetic rate (Pn), but a decrease in leafarea ratio (LAR), at 46 or 69 mmol m3 (1000 or 1500 mm3dm3) CO2, the differences being greater at the higherCO2 level. Enrichment of CO2 to a supraoptimal level of 92 mmolm3 (2000 mm3 dm3) at high PPF increased leaf areaand LAR, decreased specific leaf weight, NAR and Pn and hadno effect on leaf, stem and root dry weight or RGR relativeto plants grown at 69 mmol m3 CO2 after 8 d of treatment.The results of the study indicate that leaf lettuce growth ismost responsive to a combination of high PPF and CO2 enrichmentto 69 mmol m3 for several days at the onset of exponentialgrowth, after which optimizing resources might be conserved. Key words: Photosynthesis, relative growth rate, CO2 enrichment 相似文献
10.
Photosynthesis of Ears and Flag Leaves of Wheat and Barley 总被引:3,自引:0,他引:3
Immediately after anthesis ears of spring wheat absorbed lessthan 0.5 mg CO2, per hour in daylight and later evolved CO2,in the light and in the dark. The rate of apparent photosynthesisof the combined flag-leaf lamina and sheath and peduncle (collectivelycalled flag leaf) of two spring wheat varieties, Atle and JufyI, was 34 mg per hour; the rates of the flag leaf andthe ear of two spring barleys, Plumage Archer and Proctor, wereeach about 1 mg per hour. The gas exchange of ears and flag leaves between ear emergenceand maturity accounted for most of the final grain dry weight.The CO2, fixed by the wheat ear was equivalent to between 17and 30 per cent of the grain weight, but more than this waslost by respiration, so assimilation in the flag leaf was equivalentto 11020 per cent of the final grain weight. In barley,photosynthesis in the flag leaf and the net CO2 uptake by theear each provided about half of the carbohydrate in the grain. Barley ears photosynthesized more than wheat ears because oftheir greater surface, and flag leaves of wheat photosynthesizedmore than those of barley because they had more surface anda slightly greater rate of photosynthesis per dm2. 相似文献
11.
Sanhewe A. J.; Ellis R. H.; Hong T. D.; Wheeler T. R.; Batts G. R.; Hadley P.; Morison J. I. L. 《Journal of experimental botany》1996,47(5):631-637
Winter wheat (Triticum aestivum L.) cv. Hereward was grown inthe field in two double-walled polyethylene-covered tunnelswithin each of which a temperature gradient was superimposedon diurnal and seasonal fluctuations in temperature. The meantemperature between anthesis and harvest maturity varied from14.3 to 18.4C among plots within these tunnels. The CO2 concentrationwas controlled at different values in each tunnel; seasonalmean concentrations were 380 and 684 µmol CO2 mol1air. Crops were also grown outside the tunnels at ambient temperaturesand CO2. Samples of seeds were harvested sequentially from eachplot between anthesis and harvest maturity. Seed germinationand seed survival during subsequent air-dry storage were determinedfor each sample. The onset of both ability to germinate anddesiccation tolerance (ability to germinate after rapid desiccationto 1015% moisture content and subsequent rehydration)coincided in all environments. Full germination capacity (>97%, determined at 10C) was reached 418 d before theend of the seed-filling phase (mass maturity) in most cases.There was little or no decline in germination capacity duringsubsequent seed development and maturation. Differences in seedquality were evident, however, throughout seed development andmaturation when seed survival curves during subsequent storagewere compared. Potential longevity in air-dry storage (assessedby the value K1 of the seed viability equation) improved consistentlyboth before and after mass maturity. There was a significantpositive relation between the rate of increase in potentiallongevity (dK1Idt) and temperature (the minimum temperaturefor seed quality development was 4.8 C), but neither CO2 concentrationnor production within the polyethylene tunnels affected thisrelation. Key words: Wheat, Triticum aestivum L., seed development, seed longevity, carbon dioxide, temperature 相似文献
12.
The photosynthetic response to CO2 concentration, light intensityand temperature was investigated in water hyacinth plants (Eichhorniacrassipes (Mart.) Solms) grown in summer at ambient CO2 or at10000 µmol(CO2) mol1 and in winter at 6000 µmol(CO2)mol1 Plants grown and measured at ambient CO2 had highphotosynthetic rate (35 µmo1(CO2) m2 s1),high saturating photon flux density (15002000) µmolm2 s1 and low sensitivity to temperature in therange 2040 °C. Maximum photosynthetic rate (63 µmol(CO2)m2 s1) was reached at an internal CO2 concentrationof 800 µmol mol1. Plants grown at high CO2 in summerhad photosynthetic capacities at ambient CO2 which were 15%less than for plants grown at ambient CO2, but maximum photosyntheticrates were similar. Photosynthesis by plants grown at high CO2and high light intensity had typical response curves to internalCO2 concentration with saturation at high CO2, but for plantsgrown under high CO2 and low light and plants grown under lowCO2 and high light intensity photosynthetic rates decreasedsharply at internal CO2 concentrations above 1000 µmol1. Key words: Photosynthesis, CO2, enrichment, Eichhornia crassipes 相似文献
13.
A study was made of the incorporation of 14C by intact leavesof Coffea arabica (cultivars Mundo Novo, Catuai, 113013,and H 65862) and Coffea canephora (cultivar Guarini)supplied with gas mixtures containing 14CO2 under controlledconditions. Samples of the leaves were combusted and the 14Cin the CO2 produced measured using a liquid scintillation counter.The results were used to estimate photosynthetic rates. Theeffects of changing the partial pressures of O2 and CO2 on thephotosynthetic rate were studied and estimates made of the CO2compensation point and photorespiration. The data obtained show differences between the mean net photosyntheticrates of the C. arabica cultivars (6·14 mg CO2 dm2h1) and the mean rate for the C. canephora cultivar (3·96mg CO2 dm2 h1). The cultivar of the latter speciesphotorespired more rapidly than the cultivar Catuai of C. arabica.Rates of photosynthesis in coffee measured using the 14CO2 methodwere similar to rates obtained by others using an infrared gasanalyser. The 14CO2 method proved to be reliable for photosyntheticmeasurements and the apparatus is suitable for use in fieldconditions. 相似文献
14.
Single clonal plants of white clover (Trifolium repens L) grownfrom explants in a Perlite rooting medium, and dependent fornitrogen on N2 fixation in root nodules, were grown for severalweeks in controlled environments which provided two regimesof CO2, and temperature 23/18 °C day/night temperaturesat 680 µmol mol1 CO2, (C680), and 20/15 °Cday/night temperatures at 340 µmol mol1 CO2 (C340)After 34 weeks of growth, when the plants were acclimatedto the environmental regimes, leaf and whole-plant photosynthesisand respiration were measured using conventional infra-red gasanalysis techniques Elevated CO2 and temperature increased ratesof photosynthesis of young, fully expanded leaves at the growthirradiance by 1729%, despite decreased stomatal conductancesand transpiration rates Water use efficiency (mol CO2 mol H2O1)was also significantly increased Plants acclimated to elevatedCO2, and temperature exhibited rates of leaf photosynthesisvery similar to those of C340 leaves instantaneouslyexposed to the C680 regime However, leaves developed in theC680 regime photosynthesised less rapidly than C340 leaves whenboth were exposed to a normal CO2, and temperature environmentIn measurements where irradiance was varied, the enhancementof photosynthesis in elevated CO2 at 23 °C increased graduallyfrom approx 10 % at 100 µmol m1 s1 to >27 % at 1170 µmol m2 s1 In parallel, wateruse efficiency increased by 2040 % at 315 µmolm2 s1 In parallel, water use efficiency increasedby 2040 % at 315 µmol m2 s1 In parallel,water use efficiency increased by 2040 % at 315 µmolm2 s1 In parallel, water use efficiency increasedby 2040 % at 315 µmol m2 s1 to approx100 % at the highest irradiance Elevated CO2, and temperatureincreased whole-plant photosynthesis by > 40 %, when expressedin terms of shoot surface area or shoot weight No effects ofelevated CO2 and temperature on rate of tissue respiration,either during growth or measurement, were established for singleleaves or for whole plants Dependence on N2, fixation in rootnodules appeared to have no detrimental effect on photosyntheticperformance in elevated CO2, and temperature Trifolium repens, white clover, photosynthesis, respiration, elevated CO2, elevated temperature, water use efficiency, N2 fixation 相似文献
15.
The stomatal response of seedlings grown in 360 or 720 µmolmol1 to irradiance and leaf-to-air vapour pressure deficit(VPD) at both 360 and 720 µmol mol1 to CO2 wasmeasured to determine how environmental factors interact withCO2 enrichment to affect stomatal conductance. Seedlings offour species with different conductances and life histories,Cercis canadensis (L.), Quercus rubra (L.), Populus deltoides(Bartr. ex Marsh.) P. nigra (L.), and Pinus taeda (L.), weremeasured in hopes of identifying general responses. Conductanceof seedlings grown at 360 and 720 µmol mol1 CO2were similar and responded in the same manner to measurementCO2 concentration, irradiance and VPD. Conductance was lowerfor all species when measured at 720 than when measured at 360µmol mol1 CO2 at both VPDs ({small tilde}1.5 and{small tilde}2.5 kPa) and all measured irradiances greater thanzero (100, 300, 600,>1600 µmol m2 S2)The average decrease in conductance due to measurement in elevatedCO2 concentration was 32% for Cercis, 29% for Quercus, 26% forPopulus, and 11% for Pinus. For alt species, the absolute decreasein conductance due to measurement in CO2 enrichment decreasedas irradiance decreased or VPD increased. The proportional decreasedue to measurement in CO2 enrichment decreased in three of eightcases: from 0.46 to 0.10 in Populus and from 0.18 to 0.07 inPinus as irradiance decreased from>1600 to 100 µmolm2 s1 and from 0.35 to 0.24 in Cercis as VPD increasedfrom 1.3 to 2.6 kPa. Key words: Stomatal conductance, CO2 enrichment, irradiance, vapour pressure deficit 相似文献
16.
The effects of increased atmospheric carbon dioxide (CO2) of700 µmol mol1 and increased air temperature of+ 4C were examined in Lolium perenne L. cv. Vigor, growingin semi-controlled greenhouses. Leaf growth, segmental elongationrates (SER), water relations, cell wall (tensiometric) extensibility(%P) and epidermal cell lengths (ECL) were measured in expandingleaves in spring and summer. In elevated CO2, shoot dry weight (SDW) increased in mid-summer.In both seasons, SDW decreased in elevated air temperatureswith this reduction being greater in summer as compared to spring.Specific leaf area (SLA) decreased in elevated CO2 and in CO2 temperature in both seasons. In spring, increased leaf extensionand SER in elevated CO2 were linked with increased ECL, %P andfinal leaf size whilst in summer all were reduced. In high temperature,leaf extension, SER, %P and final leaf size were reduced inboth seasons. In elevated CO2 temperature, leaf extension,SER, %P, and ECL increased in spring, but final leaf size remainedunaltered, whilst in summer all decreased. Mid-morning waterpotential did not differ with CO2 or temperature treatments.Leaf turgor pressure increased in elevated CO2 in spring andremained similar to the control in summer whilst solute potentialdecreased in spring and increased in summer. Contrasting seasonalgrowth responses of L. perenne in response to elevated CO2 andtemperature suggests pasture management may change in the future.The grazing season may be prolonged, but whole season productivitymay become more variable than today. Key words: Lolium perenne, ryegrass, CO2 and temperature, leaf extension, cell wall rheology 相似文献
17.
Photosynthesis by Flag Leaves of Wheat in Relation to Protein, Ribulose Bisphosphate Carboxylase Activity and Nitrogen Supply 总被引:11,自引:2,他引:9
The effects of nitrate supply on the composition (cell numbers,protein and chlorophyll contents) of flag leaves of winter wheatgrown with two amounts of N fertilizer and of spring wheat grownin the glasshouse under controlled nitrate supply are describedand related to photosynthesis. Nitrogen deficiency decreasedthe size of leaves, mainly by reducing cell number and, to asmaller extent, by decreasing cell volume. Protein content perunit leaf area, per cell and per unit cell volume was largerwith abundant N. Total soluble protein, ribulose bisphosphatecarboxylase-oxygenase (RuBPc-o) protein and chlorophyll changedin proportion irrespective of nitrogen supply and leaf age.Photosynthesis per unit area of flag leaf and carboxylationefficiency in both winter and spring wheat were proportionalto the amount of total soluble protein up to 7.0 g m2and to the amount of RuBPc-o protein up to 4.0 g m2.However, photosynthesis did not increase in proportion to theamount of total soluble or RuBPc-o protein above these amounts.In young leaves with a high protein content the measured ratesof photosynthesis were lower than expected from the amount andactivity of RuBPc-o. Carboxylation per unit of RuBPc-o protein,measured in vitro, was slightly greater in N-deficient leavesof winter wheat but not of spring wheat. RuBPc-o activity perunit of RuBPc-o protein was similar in winter and spring wheatleaves and remained approximately constant with age, but increasedin leaves showing advanced senescence. RuBPc-o protein fromN-deficient leaves migrated faster on polyacrylamide gels thanprotein from leaves with high N content. Regulation of the rateof photosynthesis in leaves and chloroplasts with a high proteincontent is discussed. The conductance of the cell to the fluxof CO2 from intercellular spaces to RuBPc-o active sites iscalculated, from cell surface areas and CO2 fluxes, to decreasethe CO2 partial pressure at the active site by less than 0.8Pa at an internal CO2 partial pressure of 34 Pa. Thus the decreasein partial pressure of CO2 is insufficient to account for theinefficiency of RuBPc-o in vivo at high protein contents. Otherlimitations to the rate of photosynthesis are considered. Key words: Wheat, photosynthesis, nitrogen, ribulose, bisphosphate carboxylase 相似文献
18.
Nutrient Dilution by Starch in CO2-enriched Chrysanthemum 总被引:1,自引:0,他引:1
KUEHNY JEFF S.; PEET MARY M.; NELSON PAUL V.; WILLITS DAN H. 《Journal of experimental botany》1991,42(6):711-716
Increasing growth irradiance and CO2 generally decreases foliarnutrient concentration on a dry weight basis and increases foliarstarch concentration. However, the extent to which starch concentrationsdilute foliar nutrient concentrations when thelatter are expressed on a dry weight basis is not known. Todetermine the importance of differential starch accumulationin calculating nutrient concentrations on a dry weight basis,leaf nutrient and starch concentrations were measured in Chrysanthemum? morifolium Fiesta (Ramat.) cuttings grown atthree irradiance levels and two CO2 levels for eight weeks inboth winter and spring. On a dry weight basis, foliar concentrationsof most nutrients were lower in both seasons as a result ofthe elevated CO2 and irradiance levels, and total dry weightswere higher. Per cent starch was greater at the high CO2 levelin both seasons but was only greater at higher irradiances inthe winter experiment. When starch was subtracted from the leafdry weights, the differences between CO2 and irradiance treatmentsdisappeared with respect to N, P, K, Ca, Mg, S, and B but notfor Fe, Mn, Zn, and Cu. Key words: CO2 enrichment, starch, nutrients, irradiance 相似文献
19.
Effects of Radiation and Temperature on Tiller Survival, Grain Number and Grain Yield in Winter Wheat 总被引:6,自引:0,他引:6
Effects of the environment on shoot survival were studied inwinter wheat cv. Avalon grown in microplots at a density of247 plants m2. The incident radiation and mean temperaturewere altered during one of three periods of between 14 and 29d duration, the first (P1) starting at the end of tiller productionand the last (P3) finishing near the end of the tiller deathphase, about three weeks before anthesis. Plants were giventemperature and radiation treatments in growth rooms in twoexperiments and extra light outdoors in a third experiment:they were at other times grown outdoors. Increasing radiation by between 60 and 100 per cent during P1had negligible effects on shoot number; during P2 it alwaysdelayed tiller death but increased final ear number in onlyone experiment; during P3 it consistently increased ear numberby up to 100 m2. Increased radiation always increasedcrop dry weight immediately after treatment but only sometimesdid this increase persist to maturity. Grain dry weight wasincreased by treatment during P3 of one experiment. Increasingthe temperature by 4 C decreased shoot number, usually onlytemporarily, by hastening death of some tillers. Warmer temperaturesdecreased crop growth after, but not during, treatment and decreasedgrain dry weight. Radiation and temperature rarely interacted. Variation in grain yield within and between experiments relatedwell to variation in number of grains m2, which in turnrelated to variation in ear dry weight at anthesis. Triticum aestivum L., wheat, radiation, temperature, tillers, grain yield, grain number 相似文献
20.
Temporal and Nutritional Influences on the Response to Elevated CO2 in Selected British Grasses 总被引:3,自引:0,他引:3
To investigate the duration of the CO2 response and its interactionwith mineral nutrition, CO2-enrichment experiments were performedon four British grasses of differing ecology and functionaltype: Arrhenatherum elatius (L.) Beauv., Festuca ovina L., Festucarubra L. and Poa annua L. Naturally-lit, glasshouse cabinetswere used, with a non-limiting water supply and a daytime meantemperature of 18 °C. Two CO2 treatments were maintainedat nominal concentrations of 350 and 700 vpm and were combinedfactorially with two levels of balanced mineral nutrition atconductivities of 0·1 and 1 mS cm-1. Harvests took placeat planting-out, and at 16, 37 and 58 d thereafter. Fitted curves were used to derive instantaneous values of totaldry weight, relative growth rate (RGR), shoot weight fraction(SWF) and unit shoot rate (USR) for all combinations of species,CO2 level, nutrient level and time of harvesting. At the higher nutrient level there was a reasonably close agreementwith previous estimates of the CO2 response in the four species.The response, if any, most often arose from an increase in USRbeing accompanied by a less than proportionate decline in SWF.Responses were sustained throughout the period studied. At thelower nutrient level, all species showed a CO2 response initially,but this declined at a rate which was inversely related to theCO2-responsiveness of the species at the higher nutrient level. The underlying ontogenetic drift appeared to be markedly towardsadjustment in SWF and away from that of USR. However, this driftwas retarded, suspended or even reversed by low-nutrient conditionsand/or by high CO2 responsiveness in the species itself.Copyright1995, 1999 Academic Press Climate change, CO2 enrichment, plant strategies, mineral nutrition, growth analysis, relative growth rate, shoot weight fraction, unit shoot rate, functional equilibria 相似文献