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1.
Schenk U.; Manderscheid R.; Hugen J.; Weigel H.J. 《Journal of experimental botany》1995,46(8):987-993
Seedlings of perennial ryegrass (Lolium perenne L. cv. Parcour)and white clover (Trifolium repens L. cv. Karina) grown at fivedifferent plant densities were exposed to ambient (390 ppm)and elevated (690 ppm) CO2 concentrations. After 43 d the effectsof CO2 enrichment and plant density on growth of shoot and root,nitrogen concentration of tissue, and microbial biomass carbon(Cmic) in soil were determined. CO2 enrichment of Lolium perenneincreased shoot growth on average by 17% independent of plantdensity, while effects on root biomass ranged between -4% and+ 107% due to an interaction with plant density. Since tilernumber per plant was unaffected by elevated CO2, the small responseof shoot growth to CO2 enrichment was atributed to low sinkstrength. A significant correlation between nitrogen concentrationof total plant biomass and root fraction of total plant drymatter, which was not changed by CO2 enrichment, indicates thatnitrogen status of the plant controls biomass partitioning andthe effect of CO2 enrichment on root growth. Effects of elevatedCO2 and plant density on shoot and root growth of Trifoliumrepens were not significantly interacting and mean CO2-relatedincrease amounted to 29% and 66%, respectively. However, growthenhancement due to elevated CO2 was strongest when leaf areaindex was lowest. Total amounts of nitrogen in shoots and rootswere bigger at 690 ppm than at 390 ppm CO2. There was a significantincrease in Cmic in experiments with both species whereas plantdensity had no substantial effect. Key words: CO2 enrichment, intraspecific competition, biomass partitioning, Lolium perenne, Trifolium repens, grassland 相似文献
2.
The responses of two genotypes of Arabidopsis thaliana, whichdiffer in their sensitivities to nutrients to present and predictedfuture CO2 concentration were determined under rich vs. poornutrient regimes on the basis of both single traits and thewhole plant. Based on individual traits, the two genotypes respondedsimilarly to CO2 enrichment for all the traits measured exceptfor rate of increase in crown diameter, for which a decreasewas observed in the less nutrient-sensitive genotype grown atincreased CO2. Based on the overall response of the whole plant,by analysing groups of plant traits using multivariate analysis,the two genotypes differed substantially from one another andboth responded more strongly to nutrient availability than toCO2 concentration, especially for traits measured at harvestthat related to reproductive fitness. The less nutrient-sensitivegenotype also showed a weaker overall response to CO2, and thepattern of the overall response was strikingly similar at differentnutrient supply. In contrast, the more nutrient-sensitive genotyperesponded more strongly to CO2 than the less nutrient-sensitivegenotype, and responded differently to CO2 at low vs. high nutrientavailability.Copyright 1995, 1999 Academic Press Plasticity, CO2 enrichment, nutrient status, nutrient x CO2 interaction, Arabidopsis thaliana, canonical analysis 相似文献
3.
We used a modified functional balance (FB) model to predictgrowth response of Helianthus annuus L. to elevated CO2. Modelpredictions were evaluated against measurements obtained twiceduring the experiment. There was a good agreement between modelpredictions of relative growth rate (RGR) responses to elevatedCO2and observations, particularly at the second harvest. Themodel was then used to compare the relative effects of biomassallocation to roots, nitrogen (N) uptake and photosyntheticN-use efficiency (PNUE) in determining plant growth responseto elevated CO2. The model predicted that a rather substantialincrease in biomass allocation to root growth had little effecton whole plant growth response to elevated CO2, suggesting thatplasticity in root allocation is relatively unimportant in determininggrowth response. Average N uptake rate at elevated comparedto ambient CO2was decreased by 2129%. In contrast, elevatedCO2increased PNUE by approx. 50% due to a corresponding risein the CO2-saturation factor for carboxylation at elevated CO2.The model predicted that the decreased N uptake rate at elevatedCO2lowered RGR modestly, but this effect was counterbalancedby an increase in PNUE resulting in a positive CO2effect ongrowth. Increased PNUE may also explain why in many experimentselevated CO2enhances biomass accumulation despite a significantdrop in tissue nitrogen concentration. The formulation of theFB model as presented here successfully predicted plant growthresponses to elevated CO2. It also proved effective in resolvingwhich plant properties had the greatest leverage on such responses.Copyright 2000 Annals of Botany Company Elevated CO2, functional balance model, Helianthus annuus L., N uptake, photosynthetic nitrogen use efficiency, root:shoot ratio 相似文献
4.
Effects of elevated carbon dioxide on three montane grass species: I. Growth and dry matter partitioning 总被引:4,自引:0,他引:4
Baxter R.; Ashenden T.W.; Sparks T.H.; Farrar J.F. 《Journal of experimental botany》1994,45(3):305-315
Upland grasslands are a major component of natural vegetationwithin the UK. Such grasslands support slow growing relativelystable plant communities. The response of native montane grassspecies to elevated atmospheric carbon dioxide concentrationshas received little attention to date. Of such studies, mosthave only focused on short-term (days to weeks) responses, oftenunder favourable controlled environment conditions. In thisstudy Agrostis caplllaris L.5, Festuca vivipara L. and Poa alpinaL. were grown under semi-natural conditions in outdoor open-topchambers at either ambient (340µmol mol1) or elevated(680µmol mol1) concentrations of atmospheric carbondioxide (CO2 for periods from 79 to 189 d, with a nutrient availabilitysimilar to that of montane Agrostis-Fescue grassland in Snowdonia,N. Wales. Whole plant dry weight was increased for A. capillarisand P. alpina, but decreased for F. vivipara, at elevated CO2.Major components of relative growth rate (RGR) contributingto this change at elevated CO2 were transient changes in specificleaf area (SLA) and leaf area ratio (LAR). Despite changes ingrowth rate at 680 µmol mol1 CO2, partitioningof dry weight between shoot and root in plants of A. capillarisand P. alpina was unaltered. There was a significant decreasein shoot relative to root growth at elevated CO2 in F. viviparawhich also showed marked discoloration of the leaves and increasedsenescence of the foliage. Key words: Allometry, growth analysis, elevated CO2, grasses 相似文献
5.
Unlike most plant species, Oryza sativa L. cv. S-201 and Echinochloaphyllopogon (Stev.) Koss germinate and grow under anaerobicconditions. In both species, the radicle or shoot emerged byday 3 when the seeds were germinated in air or N2. Under eithercondition, shoot and/or root dry weight (d. wt) increased linearlyfrom day 3 to day 7, with a corresponding decrease in seed d.wt. In anaerobically grown O. sativa, d. wt accumulation wasreduced to 7% of that in air whereas d. wt lost from the seedwas reduced to only 37%. No root growth occurred during anaerobicgermination and shoot d. wt accumulation accounted for 10% ofthe d. wt lost from the seed. In E. phyllopogon, d. wt accumulationduring anoxia was 25% of that in air, but loss of d. wt fromthe seed was 44% of the aerobic rate. In air, 48% of the d.wt lost from the seed was converted to shoot or root d. wt.Like O. sativa, E. phyllopogon does not produce a root underN2, but shoot growth accounted for 27% of the d. wt lost fromthe seed. Thus, either in air or N2, E. phyllopogon was moreefficient at converting seed reserves to shoot/root structuraldry matter than O. sativa . Based on changes in metabolite pools,O. sativa appeared to shift exclusively to fermentation duringanaerobic growth. In E. phyllopogon, however, fermentation alonecannot satisfy the energy requirement for growth without O2.Rather, fermentation, coupled with limited tricarboxylic acid(TCA) cycle operation could supply sufficient ATP for growthunder anaerobic conditions. An active oxidative pentose phosphatepathway and lipid synthesis were discussed as important mechanismsfor converting NADH to NAD, a necessary cofactor for fermentationand TCA cycle activity.Copyright 1994, 1999 Academic Press Anaerobiosis, Echinochloa phyllopogon, energetics model, fermentation, mitochondrial activity, Oryza sativa, rice, tricarboxylic acid cycle, watergrass 相似文献
6.
Rumex obtusifolius plants were grown for several months in daylitenvironment chambers (Solardomes) force-ventilated with aircontaining 350 or 600 µ;mol mol1 C02. ElevatedCO2 was found to accelerate the natural ontogenic decline inphotosynthesis, but did not reduce leaf duration. In both CO2treatments photosynthetic rates declined progressively withincreasing leaf age, the decline being greater for plants grownin elevated C02 such that rates became lower than in ambientCO2. The degree of CO2-induced photosynthetic down-regulationas determined by A/C1 analysis was found to be dependent onleaf age. The major contribution to the decline in photosynthesiswas likely to be a reduction in Rubisco activity as changesin stomataland mesophyll limitations were small. Instantaneouswater use efficiency (WUE1) was greater for plants in elevatedCO2, but these values declined rapidly with leaf age, whereasin ambient CO2 values were always lower, but were maintainedfor longer. Growth analysis indicated an increased root:-shootratio for plants grown in elevated CO2, this occurring almostentirely as a result of increased root growth. Greater rootproliferation and increased WUE1, are characteristics whichshould give this persistent and troublesome weed an increasedcompetitive advantage under projected conditions of climatechange Key words: tusifoliu, elevated CO2, gas exchange, leaf age, senescence 相似文献
7.
Effects of elevated carbon dioxide on three grass species from montane pasture II. Nutrient uptake, allocation and efficiency of use 总被引:5,自引:0,他引:5
Baxter R.; Gantley M.; Ashenden T.W.; Farrar J.F. 《Journal of experimental botany》1994,45(9):1267-1278
Agrostis capillaris L.4 Festuca vivipara L. and Poa alpinaL.were grown in outdoor open-top chambers at either ambient (340µmol mol1) or elevated (680 µmol1)CO2 for periods from 79 to 189 d. Under these conditions thereis increased growth of A. caplllarls and P. alpina, but reducedgrowth of F. vivipara. Nutrient use efficiency, nutrient productivity(total plant dry weight gain per unit of nutrient) and nutrientallocation of all three grass species were measured in an attemptto understand their individual growth responses further andto determine whether altered nutrient-use efficiencies and productivitiesenable plants exposed to an elevated atmospheric CO2 environmentto overcome potential limitations to growth imposed by soilfertility. Total uptake of nutrients was, in general, greater in plantsof A. capillaris and P. alpina (with the exception of N andK in the latter) when grown at 680 µmol mol1 CO2.In F. vivipara, however, uptake was considerably reduced inplants grown at the higher CO2 concentration. Overall, a doubling of atmospheric CO2 concentration had littleeffect on the nutrient use efficiency or productivity of A.capillaris. Reductions in tissue nutrient content resulted fromincreased plant growth and not altered nutrient use efficiency.In P. alpina, potassium, magnesium and calcium productivitieswere significantly reduced and photosynthetic nitrogen and phosphorususe efficiencies were doubled at elevated CO2 with respect toplants grown at ambient CO2 F. vivipara grown for 189 d showedthe most marked changes in nutrient use efficiency and nutrientproductivity (on an extracted dry weight basis) when grown atelevated CO2, F. vivipara grown at elevated CO2 however, showedlarge increases in the ratio of non-structural carbohydrateto nitrogen content of leaves and reproductive tissues, indicatinga substantial imbalance between the production and utilizationof assimilate. Key words: Nutrient, allocation, nutrient use efficiency, grasses, nutrient productivity, elevated CO2, cliniate change 相似文献
8.
Scots pine (Pinus sylvestris L.) seedlings were grown for 3years in the ground in open top chambers and exposed to twoconcentrations of atmospheric CO2(ambient or ambient + 400 µmol mol-1) without addition of nutrients and water. Biomassproduction (above-ground and below-ground) and allocation, aswell as canopy structure and tissue nitrogen concentrationsand contents, were examined by destructive harvest after 3 years.Elevated CO2increased total biomass production by 55%, reducedneedle area and needle mass as indicated, respectively, by lowerleaf area ratio and leaf mass ratio. A relatively smaller totalneedle area was produced in relation to fine roots under elevatedCO2. The proportion of dry matter in roots was increased byelevated CO2, as indicated by increased root-to-shoot ratioand root mass ratio. Within the root system, there was a significantshift in the allocation towards fine roots. Root litter constituteda much higher fraction of fine roots in trees grown in the elevatedCO2than in those grown in ambient CO2. Growth at elevated CO2causeda significant decline in nitrogen concentration only in theneedles, while nitrogen content significantly increased in branchesand fine roots (with diameter less than 1 mm). There were nochanges in crown structure (branch number and needle area distribution).Based upon measurements of growth made throughout the 3 years,the greatest increase in biomass under elevated CO2took placemainly at the beginning of the experiment, when trees grownin elevated CO2had higher relative growth rates than those grownunder ambient CO2; these differences disappeared with time.Symptoms of acclimation of trees to growth in the elevated CO2treatmentwere observed and are discussed. Copyright 2000 Annals of BotanyCompany Elevated CO2, Pinus sylvestris, biomass production, allocation, fine roots, root litter, crown structure, nitrogen, C/N ratio 相似文献
9.
A novel photorespiratory mutant of Arabidopsis thaliana, designatedgld2, was isolated based on a growth requirement for abnormallyhigh levels of atmospheric CO2. Photosynthetic CO2 fixationwas inhibited in the mutant following illumination in air butnot in atmosphere containing 2% O2. Photosynthetic assimilationof 14CO2 in an atmosphere containing 50% O2 resulted in accumulationof 48% of the soluble label in glycine in the mutant comparedto 9% in the wild type. The rate of glycine decarboxylationby isolated mitochondria from the mutant was reduced to 6% ofthe wild type rate. In genetic crosses, the mutant complementedtwo previously described photorespiratory mutants of A. thalianathat accumulate glycine during photosynthesis in air due todefects in glycine decarboxylase (glyD, now designated gld1)and serine transhydroxymethylase (stm). Because glycine decarboxylaseis a complex of four enzymes, these results are consistent witha mutation in a glycine decarboxylase subunit other than thataffected in the gld1 mutant. The two gld loci were mapped tochromosomes 2 and 5, respectively.
3Present address: Department of Crop and Soil Sciences, MichiganState University, East Lansing, MI 48824, U.S.A.
4Present address: Department of Applied Bioscience, Facultyof Agriculture, Hokkaido University, Kita-Ku, Sapporo, 060 Japan
5Present address: Department of Biology, Carnegie Institutionof Washington, 290 Panama Street, Standford, CA 94305, U.S.A. 相似文献
10.
Effects of Elevated Carbon Dioxide on Plant Biomass Production and Competition in a Simulated Neutral Grassland Community 总被引:3,自引:0,他引:3
Using open-top chambers, four prominent species (Lolium perenne,Cynosurus cristatus, Holcus lanatusandAgrostis capillaris) ofIrish neutral grasslands were grown at ambient and elevated(700 µmol mol-1) atmospheric CO2for a period of 8 months.The effects of interspecific competition on plant responsesto CO2enrichment were investigated by growing the species ina four-species mixture. The results indicate that the speciesdiffer in their ability to respond to elevated CO2. CO2-enrichmenthad the largest effect on the biomass production ofH. lanatus,but substantial stimulations in biomass production were alsofound for the other three species. The CO2-stimulation of biomassproduction forH. lanatuswas accompanied by increased tillering.In addition, reductions in specific leaf area were found forall species. Exposure to elevated CO2increased the communitybiomass of the four-species mixture. This increase can be mainlyattributed to a significant increase in the biomass ofH. lanatusatelevated CO2. No statistically-significant changes in speciescomposition of community biomass were found. However,H. lanatusdidincrease its share of community biomass at each of the harvests,with the other three species, mainlyL. perenne, suffering lossesin their shares at elevated CO2. The results show that: (1)the species varied in their response to elevated CO2; and (2)species composition in natural plant communities is likely tochange at elevated CO2, but these changes may occur rather slowly.Much longer periods of exposure to elevated atmospheric CO2maybe required to permit detection of significant changes in speciescomposition.Copyright 1998 Annals of Botany Company Carbon dioxide (CO2) enrichment, competition, Lolium perenne,Cynosurus cristatus, Holcus lanatus, Agrostis capillaris, biomass, specific leaf area, tillering. 相似文献
11.
A field experiment consisting of 18 birch trees grown in opentop chambers in ambient and elevated CO2concentrations was setup with the aim of testing whether the positive growth responseobserved in many short-term studies is maintained after severalgrowing seasons. We present the results of growth and biomassafter 4.5 years of CO2exposure, one of the longest studies sofar on deciduous tree species. We found that elevated CO2ledto a 58% increase in biomass at the end of the experiment. However,estimation of stem mass during the growing season showed thatelevated CO2did not affect relative growth rate during the fourthgrowing season, and therefore, that the large accumulation ofbiomass was the result of an early effect on relative growthrate in previous years. Trees grown in elevated CO2investedmore carbon into fine roots and had relatively less leaf areathan trees grown in ambient CO2. In contrast with previous studies,acceleration of growth did not involve a significant declinein nutrient concentrations of any plant tissue. It is likelythat increased fine root density assisted the trees in meetingtheir nutrient demands. Changes in the species composition ofthe ectomycorrhizal fungi associated with the trees grown inelevated CO2in favour of late successional species supportsthe hypothesis of an acceleration of the ontogeny of the treesin elevated CO2.Copyright 1997 Annals of Botany Company Betula pendula; silver birch; elevated CO2; growth; biomass allocation; ectomycorrhizas; tissue composition; nutrients; leaf morphology; specific leaf area; stomatal density; shoot structure 相似文献
12.
Effect of Elevated CO2 on the Photosynthesis, Respiration and Growth of Perennial Ryegrass 总被引:1,自引:0,他引:1
Single, seed-grown plants of ryegrass (Lolium perenne L. cv.Melle) were grown for 49 d from the early seedling stage ingrowth cabinets at a day/night temperature of 20/15 C, witha 12 h photoperiod, and a CO2 concentration of either 340 or680µI 11 CO2. Following complete acclimation tothe environmental regimes, leaf and whole plant CO2 effluxesand influxes were measured using infra-red gas analysis techniques.Elevated CO2 increased rates of photosynthesis of young, fullyexpanded leaves by 3546% and of whole plants by morethan 50%. For both leaves and whole plants acclimation to 680µI1 CO2 reduced rates of photosynthesis in bothCO2 regimes, compared with plants acclimated to 340µll1. There was no significant effect of CO2 regime onrespiration rates of either leaves or whole plants, althoughleaves developed in elevated CO2 exhibited generally lower ratesthan those developed in 340µI I1 CO2. Initially the seedling plants in elevated CO2 grew faster thantheir counterparts in 340µI I1 CO2, but this effectquickly petered out and final plant weights differed by onlyc. 10%. Since the total area of expanded and unexpanded laminaewas unaffected by CO2 regime, specific leaf area was persistently1340% lower in elevated CO2 while, similarly, root/shootratio was also reduced throughout the experiment. Elevated CO2reduced tissue nitrogen contents of expanded leaves, but hadno effect on the nitrogen contents of unexpanded leaves, sheathsor roots. The lack of a pronounced effect of elevated CO2 on plant growthwas primarily due to the fact that CO2 concentration did notinfluence tiller (branch) numbers. In the absence of an effecton tiller numbers, any possible weight increment was restrictedto the c. 2.5 leaves of each tiller. The reason for the lackof an effect on tillering is not known. Key words: Lolium perenne, ryegrass, elevated CO2, photosynthesis, respiration, growth, development 相似文献
13.
Seed production and seedling recruitment were measured over 2 years under ambient (360 ppm) and elevated (475 ppm) atmospheric CO2 in a free air carbon dioxide enrichment (FACE) experiment, carried out in a sheep-grazed pasture on dry, sandy soil in New Zealand. In both years elevated CO2 led to more dispersed seeds of the grasses Anthoxanthum odoratum, Lolium perenne and Poa pratensis, the legumes Trifolium repens and T. subterraneum and the herbs Hypochaeris radicata and Leontodon saxatilis. The increased seed dispersal in A. odoratum, H. radicata, Leontodon saxatilis and T. repens reflected both more inflorescences per unit area and more seeds per inflorescence under elevated CO2. The increased seed dispersal in Lolium perenne, P. pratensis and T. subterraneum was due solely to more inflorescences per unit area. The number of seedlings that emerged and survived to at least 7 months of age was increased by elevated CO2 for H. radicata, Leontodon saxatilis, T. repens and T. subterraneum in both years and for A. odoratum and Lolium perenne in the first year. For species where increased seedling recruitment was noted, there was a significant positive correlation between seed production in summer and seedling emergence in the following autumn and winter, and sowing 200 extra seeds per species m-2 resulted in more seedlings compared to unsown controls. Elevated CO2 did not affect seedling survival in any species. There was no measurable effect of elevated CO2 on canopy and soil surface conditions or soil moisture at the time of seedling emergence. The results suggest the dominant effect of elevated CO2 on seedling recruitment in this pasture was an indirect one, reflecting effects on the number of seeds produced. The biomass of H. radicata, Leontodon saxatilis, T. repens and T. subterraneum in the above-ground vegetation was greater under elevated than ambient CO2. However, the size of individual seedlings and mature plants of these four species was unaffected by elevated CO2. The results indicate an important way elevated CO2 influenced plant species composition in this pasture was through changes in the pattern of seedling recruitment. 相似文献
14.
Simulating Growth and Root-shoot Partitioning in Prairie Grasses Under Elevated Atmospheric CO2and Water Stress 总被引:7,自引:0,他引:7
We constructed a model simulating growth, shoot-root partitioning,plant nitrogen (N) concentration and total non-structural carbohydratesin perennial grasses. Carbon (C) allocation was based on theconcept of a functional balance between root and shoot growth,which responded to variable plant C and N supplies. Interactionsbetween the plant and environment were made explicit by wayof variables for soil water and soil inorganic N. The modelwas fitted to data on the growth of two species of perennialgrass subjected to elevated atmospheric CO2and water stresstreatments. The model exhibited complex feedbacks between plantand environment, and the indirect effects of CO2and water treatmentson soil water and soil inorganic N supplies were important ininterpreting observed plant responses. Growth was surprisinglyinsensitive to shoot-root partitioning in the model, apparentlybecause of the limited soil N supply, which weakened the expectedpositive relationship between root growth and total N uptake.Alternative models for the regulation of allocation betweenshoots and roots were objectively compared by using optimizationto find the least squares fit of each model to the data. Regulationby various combinations of C and N uptake rates, C and N substrateconcentrations, and shoot and root biomass gave nearly equivalentfits to the data, apparently because these variables were correlatedwith each other. A partitioning function that maximized growthpredicted too high a root to shoot ratio, suggesting that partitioningdid not serve to maximize growth under the conditions of theexperiment.Copyright 1998 Annals of Botany Company plant growth model, optimization, nitrogen, non-structural carbohydrates, carbon partitioning, elevated CO2, water stress,Pascopyrum smithii,Bouteloua gracilis, photosynthetic pathway, maximal growth 相似文献
15.
Increased root growth in elevated CO2: a biophysical analysis of root cell elongation 总被引:2,自引:0,他引:2
A biophysical analysis of root expansion was conducted in fourchalk downland herbs (Sanguisorba minor Scop., Lotus corniculatusL., Anthyllis vul-neraria L. and Plantago media L.) exposedto either ambient or elevated CO2in controlled environment cabinets.Measurements of fine (F) and extra-fine (EF) root extensionrate (RER), water relations, and cell wall tensiometric extensibilityrevealed differences in the diurnal pattern of root growth betweenspecies. After 35 d of exposure to elevated CO2, RER of bothF and EF roots increased significantly in darkness and on illuminationfor S. minor, whilst for A. vulneraria (EF roots only) and L.corniculatus a significant increase occurred at night whereasfor P. media a significant increase occurred during the day.Cells measured in the zone of elongation were longer in allspecies exposed to elevated CO2. Water potential ( 相似文献
16.
The Effects of CO2 Enrichment and Nutrient Supply on Growth Morphology and Anatomy of Phaseolus vulgaris L. Seedlings 总被引:2,自引:0,他引:2
Plants of Phaseolus vulgaris were grown from seed in open-topgrowth chambers at the present (P, 350 µmol mol1)atmospheric CO2 concentration and at an elevated (E, 700 µmolmol1) CO2 concentration, and at low (L, without additionalnutrient solution) and high (H, with additional nutrient solution)nutrient supply for 28 d The effects of CO2 and nutrient availabilitywere examined on growth, morphological and biochemical characteristics Leaf area and dry mass were significantly increased by CO2 enrichmentand by high nutrient supply Stomatal density, stomatal indexand epidermal cell density were not affected by elevated CO2concentration or by nutrient supply Leaf thickness respondedpositively to CO2 increasing particularly in mesophyll areaas a result of cell enlargement Intercellular air spaces inthe mesophyll decreased slightly in plants grown in elevatedCO2 Leaf chlorophyll content per unit area or dry mass was significantlylower in elevated CO2 grown plants and increased significantlywith increasing nutrient availability The content of reducingcarbohydrates of leaves, stem, and roots was not affected byCO2 but was significantly increased by nutrient addition inall plant parts Starch content in leaves and stem was significantlyincreased by elevated CO2 concentration and by high nutrientsupply Phaseolus vulgaris, elevated atmospheric CO2, CO2-nutrient interaction, stomatal density, leaf anatomy, chlorophyll, carbohydrates, starch 相似文献
17.
Contrasting effects on the stomatal index (SI), stomatal density,epidermal cell size and number were observed in four chalk grasslandherbs (Sanguisorba minor Scop., Lotus corniculatus L., Anthyllisvulneraria L. and Plantago media L.) following exposure to elevatedcarbon dioxide concentrations (CO2) in controlled environmentgrowth cabinets. SI of S. minor increased for both leaf surfaces,whilst in A. vulneraria and P. media SI decreased on one surfaceonly. In L. corniculatus , no differences in SI were observedas epidermal cell density changed in parallel with stomataldensity. In L. corniculatus and S. minor stomatal density increasedon both surfaces, whereas in P. media it decreased; in A. vulnerariastomatal density decreased on the abaxial leaf surface alonefollowing exposure to elevated CO2. In the latter three species,SI changed because stomatal density did not change in parallelwith epidermal cell density. The results suggest elevated CO2is either directly or indirectly affecting cell differentiationand thus stomatal initiation in the meristem. In S. minor and P. media leaf growth increased in elevated CO2,because of increased cell expansion of epidermal cells, whereasin L. corniculatus, epidermal cell size decreased and greaterleaf growth was because of an increase in epidermal cell divisions.In A. vulneraria, leaf size did not change, but increased cellexpansion on the adaxial surface suggests CO2 affects leaf surfacesdifferently, either directly or indirectly at the cell differentiationstage or as the leaf grows. These results suggest component species of a plant communitymay differ in their response to elevated CO2. Predicting theeffect of environmental change is therefore difficult.Copyright1994, 1999 Academic Press Elevated CO2, Sanguisorba minor (salad burnet), Lotus corniculatus (birdsfoot trefoil), Anthyllis vulneraria (kidney vetch), Plantago media (hoary plantain), stomatal index, stomatal density, epidermal cell size 相似文献
18.
Sediment CO2, entering via the roots, contributes a significantportion of the total carbon uptake for isoetids (small, evergreen,submersed, vascular plants). Laboratory studies of inorganiccarbon uptake via the roots and shoots by five isoetids wereused to model the use of root-zone CO2. Simple first-order linearmodels accounted for at least 75 per cent of the variation inthe data for Gratiola aurea, Isoetes macrospora, Littorellauniflora and Lobelia dortmanna. For Eriocaulon septangulare,which relies almost exclusively on root-zone CO2, models couldaccount for only about 62 per cent of the variation in root-zoneCO2 use. For each species, we present the best fitting regressionof root-zone CO2 use as a function of root- and shoot-zone CO2concentrations. For the species studied, carbon uptake was not saturated atfield concentrations of root and shoot-zone CO2. Maximum ratesof carbon uptake were lower for species that naturally occurredat greater depths, compared with species more common in shallowwater. At equal external CO2 concentrations carbon entry perunit root surface area was several times more rapid than entryper unit shoot surface area for L. dortmanna. The entry ratesper unit root and shoot surface area were about equal for G.aurea and E. septangulare. Shoots were equally or more permeablethan the roots of L. uniflora and I. macrospora, a fact thatmay be related to the functioning of crassulacean acid metabolismin these plants. Carbon, CO2, photosynthesis, isoetid, Eriocaulon septangulare, Gratiola aurea, Isoetes macrospora, Littorella uniflora, Lobelia dortmanna 相似文献
19.
Belén Márquez‐García Gloria Comadira Nieves Fernandez‐Garcia Enrique Olmos Daniel Schnaubelt Karl J. Kunert Christine H. Foyer 《Plant biotechnology journal》2014,12(7):903-913
Ectopic cystatin expression has long been used in plant pest management, but the cysteine protease, targets of these inhibitors, might also have important functions in the control of plant lifespan and stress tolerance that remain poorly characterized. We therefore characterized the effects of expression of the rice cystatin, oryzacystatin‐I (OCI), on the growth, development and stress tolerance of crop (soybean) and model (Arabidopsis thaliana) plants. Ectopic OCI expression in soybean enhanced shoot branching and leaf chlorophyll accumulation at later stages of vegetative development and enhanced seed protein contents and decreased the abundance of mRNAs encoding strigolactone synthesis enzymes. The OCI‐expressing A. thaliana showed a slow‐growth phenotype, with increased leaf numbers and enhanced shoot branching at flowering. The OCI‐dependent inhibition of cysteine proteases enhanced drought tolerance in soybean and A. thaliana, photosynthetic CO2 assimilation being much less sensitive to drought‐induced inhibition in the OCI‐expressing soybean lines. Ectopic OCI expression or treatment with the cysteine protease inhibitor E64 increased lateral root densities in A. thaliana. E64 treatment also increased lateral root densities in the max2‐1 mutants that are defective in strigolactone signalling, but not in the max3‐9 mutants that are defective in strigolactone synthesis. Taken together, these data provide evidence that OCI‐inhibited cysteine proteases participate in the control of growth and stress tolerance through effects on strigolactones. We conclude that cysteine proteases are important targets for manipulation of plant growth, development and stress tolerance, and also seed quality traits. 相似文献
20.
Nectar Production and Floral Characteristics of Tropaeolum majus L. Grown in Ambient and Elevated Carbon Dioxide 总被引:2,自引:0,他引:2
Tropaeolum majus (nasturtiums) were grown from seed in growthcabinets, under 380 and 750 ppmv CO2. Elevated CO2significantlyincreased nectar secretion rate, both in flowers milked of nectardaily and in once sampled, 3-d-old flowers. Elevated CO2didnot affect time to flowering, total number of flowers produced,pollen to ovule ratio, or the total or individual concentrationsof nectar amino acids. The dry weight and longevity of individualflowers was also unchanged. Nectar sugar content was unchangedby elevated CO2in a subset of flowers used to assess the 3-d-oldnectar volume. This subset did not show the same increase innectar volume under elevated CO2as the full set, resulting inthe concentration of sugars remaining unchanged. Overall, thequantity rather than the quality of the nectar changed underelevated CO2while flower characteristics remained constant,implying that the identity of pollinators may remain the samewhile foraging behaviour (e.g. number of visits per plant, distancetravelled) may change in the future. Copyright 1999 Annals ofBotany Company Tropaeolum majus, nasturtiums, elevated CO2, nectar, phenology, floral characteristics, amino acids, pollinator-plant interactions. 相似文献