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1.
Phosphorus Deficiency Impairs Early Nodule Functioning and Enhances Proton Release in Roots of Medicago truncatula L. 总被引:10,自引:0,他引:10
The effect of phosphorus supply (115 µM) on protonrelease and the role of P in symbiotic nitrogen fixation inmedic (Medicago truncatula L. Jemalong) was investigated.As P concentration in the nutrient solution increased, shootand root growth increased by 19 and 15%, respectively by day35, with maximal growth at 4 µM P. A P concentration of15 µM appeared to be toxic to plants. Phosphorus supplyhad no influence on nodule formation by day 12 but increasednodule number by day 35. Nitrogenase activity was estimatedby in situ measurement of acetylene reduction activity (ARA)in an open-flow system. During the assay, a C2H2-induced declineof ARA was observed under all P concentrations except 4 µM.Specific ARA (per unit nodule weight) doubled when P supplywas increased from 1 to 8 µM. This effect of P was muchgreater than the effects of P on nodulation and host plant growth.Concentrations of excess cations in plants decreased with increasingP concentration in the nutrient solution. Phosphorus deficiencystimulated uptake of excess cations over anions by the plantsand hence enhanced proton release. The results suggest thatP plays a direct role in nodule functioning in medic and thatP deficiency increases acidification which may facilitate Pacquisition. Copyright 2001 Annals of Botany Company Medicago truncatula L. (medic), P deficiency, C2H2-ID, nitrogenase activity, proton release, cation-anion balance, open-flow system 相似文献
2.
MUSCHINEK GYORGYI; ALSCHER RUTH; ANDERSON LOUISE E. 《Journal of experimental botany》1987,38(6):1069-1075
Muschinek, G., Alscher, R. and Anderson, L. E. 1987. The sensitivityof light modulation of enzyme activity to arsenite and sulphiteand of photosynthetic induction to arsenite is determined bya cytoplasmic geneJ. exp. Bot. 38: 10691075. The membrane component of the light modulation system was moresensitive to arsenite and to sulphite in the Pisum cultivarNugget than in the cultivar Progress No.9. Likewise, the induction phase of CO2 fixation wasmore arsenite sensitive in chloroplasts isolated from Nuggetplants. Sensitivity was controlled by a cytoplasmic gene. Key words: Induction, light modulation, arsenite sensitivity 相似文献
3.
《Journal of experimental botany》1960,11(2):150
On page 235, Table I: Equation (1) for Node 4 should read A/Ac=0·840+0·0006Ac;Equation (2) for Node 4 should read A=0·89Acand Equation (2) for Node 510 should read A=0·813Ac. 相似文献
4.
SINGH N; SINGH S N; SRIVASTAVA K; YUNUS M; AHMAD K. J; SHARMA S C.; SHARGA A N 《Annals of botany》1990,65(1):41-44
Five Gladiolus cultivars, namely Aldebaran, BrightEye, Illusion, Manisha andManmohan, were exposed to 1 and 2 µg l1sulphur dioxide to test their relative-sensitivity toleranceto the pollutant Plants were fumigated experimentally for 2h daily Foliar injury symptoms were observed first in Manishafollowed by Aldebaran and Illusionat the higher dose Photosynthetic pigments and leaf extractpH were significantly decreased, particularly in Manishaand Illusion Overall disturbances in the plantmetabolism due to SO2 treatment led to retarded growth of plants,as evident from decreased shoot length and phytomass valuesThe order of sensitivity of the five Gladiolus cultivars toSO2 was as follows, with the greatest first Manisha, Illusion,Aldebaran, Bright Eye, Manmohan Cultivars, Gladiolus, sensitivity, sulphur dioxide, tolerance 相似文献
5.
《Journal of experimental botany》1977,28(6):1247
Effects of coupled solute and water flow in plant roots withspecial reference to Brouwer's experiment. Edwin L. Fiscus. p. 71 Abstract: Line 3 delete interval insertinternal. p. 73 Materials and Methods: line 6: delete diversion insert division line 9 equation should read Jv=Lp PRT(C0C1). 74 Last line of figure legend: 101 should read 1011. 75 Line 11: delete seems insert seem. le 1 column heading106 should read 1011. 77 delete ...membrane in series of... insert membranein series or... Delete final paragraph. 相似文献
6.
The Sensitivity of Net Photosynthesis in Several Plant Species to Short-term Fumigation with Sulphur Dioxide 总被引:4,自引:0,他引:4
The effects of exposure of up to 2 h with sulphur dioxide ona range of plant species was observed by measuring changes inthe rate of net photosynthesis under closely controlled environmentalconditions. Ryegrass, Lolium perenne S23 was thespecies most sensitive to SO2; significant inhibition was detectedat 200 nl l1. Fumigations at 300 nl l1 also inhibitedphotosynthesis in field bean (Vicia faba cv. Three FoldWhite and Blaze) and in barley (Hordeumvulgare cv. Sonja). No effect was detected inwheat (Triticum aestivum cv. Virtue) at concentrationsup to 600 nl l1 SO2, or in oil-seed rape (Brassica napuscv. Rafal) except at 800 nl l1 SO2). Recoverycommenced immediately after the fumigation was terminated andwas complete within 2 h when inhibition had not exceeded 20%during the SO2 treatment. Key words: Sulphur dioxide, short-term fumigation, photosynthesis 相似文献
7.
Developmental control of xylem hydraulic resistances and vulnerability to embolism in Fraxinus excelsior L.: impacts on water relations 总被引:3,自引:0,他引:3
Welbaum G.E.; Bian D.; Hill D.R.; Grayson R.L.; Gunatilaka M.K. 《Journal of experimental botany》1997,48(3):655-663
The freezing tolerance of many plants, such as pea (Pisum sativum),is increased by exposure to low temperature or abscisic acidtreatment, although the physiological basis of this phenomenonis poorly understood. The freezing tolerance of pea shoot tips,root tips, and epicotyl tissue was tested after cold acclimationat 2C, dehydration/rehydration, applications of 104M abscisic acid (ABA), and deacclimation at 25C. Tests wereconducted using the cultivar Alaska, an ABA-deficientmutant wil, and its wildtype. Freezinginjury was determined graphically as the temperature that caused50% injury (T50) from electrical conductivity. Endogenous ABAwas measured using an indirect enzyme-linked immunosorbant assay,and novel proteins were detected using 2-dimensional polyacrylamidegel electrophoresis. The maximum decrease in T50 for root tissuewas 1C for all genotypes, regardless of treatment. For Alaskashoot tips and epicotyl tissue, exogenous ABA increased thefreezing tolerance by 1.5 to 4.0C, while coldtreatment increased the freezing tolerance by 7.5 to14.8C. Cold treatment increased the freezing toleranceof shoot tips by 9 and 15C for wiland wild-type, respectively. Cold acclimationincreased endogenous ABA concentrations in Alaskashoot tips and epicotyls 3- to 4-fold. Immunogold labeling increasednoticeably in the nucleus and cytoplasm of the epicotyl after7 d at 2C and was greatest after 30 d at the time of maximumfreezing tolerance and soluble ABA concentration. Cold treatmentinduced the production of seven, three, and two proteins inshoot, epicotyl, and root tissue of Alaska, respectively.In Alaska shoot tissue, five out of seven novelproteins accumulated in response to both ABA and cold treatment.However, only a 24 kDa protein was produced in wiland wild-type shoot and epicotyl tissues aftercold treatment. Abscisic acid and cold treatment additivelyincreased the freezing tolerance of pea epicotyl and shoot tissuesthrough apparently independent mechanisms that both resultedin the production of a 24 kDa protein. Key words: Pisum sativum, cold acclimation, immuno-localization 相似文献
8.
Welbaum G.E.; Bian D.; Hill D.R.; Grayson R.L.; Gunatilaka M.K. 《Journal of experimental botany》1997,48(3):643-654
The freezing tolerance of many plants, such as pea (Pisum sativum),is increased by exposure to low temperature or abscisic acidtreatment, although the physiological basis of this phenomenonis poorly understood. The freezing tolerance of pea shoot tips,root tips, and epicotyl tissue was tested after cold acclimationat 2C, dehydration/rehydration, applications of 104M abscisic acid (ABA), and deacclimation at 25C. Tests wereconducted using the cultivar Alaska, an ABA-deficientmutant wil, and its wildtype. Freezinginjury was determined graphically as the temperature that caused50% injury (T50) from electrical conductivity. Endogenous ABAwas measured using an indirect enzyme-linked immunosorbant assay,and novel proteins were detected using 2-dimensional polyacrylamidegel electrophoresis. The maximum decrease in T50 for root tissuewas 1C for all genotypes, regardless of treatment. For Alaskashoot tips and epicotyl tissue, exogenous ABA increased thefreezing tolerance by 1.5 to 4.0C, while coldtreatment increased the freezing tolerance by 7.5 to14.8C. Cold treatment increased the freezing toleranceof shoot tips by 9 and 15C for wiland wild-type, respectively. Cold acclimationincreased endogenous ABA concentrations in Alaskashoot tips and epicotyls 3- to 4-fold. Immunogold labeling increasednoticeably in the nucleus and cytoplasm of the epicotyl after7 d at 2C and was greatest after 30 d at the time of maximumfreezing tolerance and soluble ABA concentration. Cold treatmentinduced the production of seven, three, and two proteins inshoot, epicotyl, and root tissue of Alaska, respectively.In Alaska shoot tissue, five out of seven novelproteins accumulated in response to both ABA and cold treatment.However, only a 24 kDa protein was produced in wiland wild-type shoot and epicotyl tissues aftercold treatment. Abscisic acid and cold treatment additivelyincreased the freezing tolerance of pea epicotyl and shoot tissuesthrough apparently independent mechanisms that both resultedin the production of a 24 kDa protein. Key words: Pisum sativum, cold acclimation, immuno-localization 相似文献
9.
Influence of Flooding on Net CO2Assimilation, Growth and Stem Anatomy of Annona Species 总被引:1,自引:0,他引:1
NUNEZ-ELISEA ROBERTO; SCHAFFER BRUCE; FISHER JACK B.; COLLS ANGEL M.; CRANE JONATHAN H. 《Annals of botany》1999,84(6):771-780
A series of experiments was conducted to assess net CO2assimilationand growth responses to waterlogging of grafted and seedlingtrees in the genus Annona. Seedlings of A. glabra, A. muricataandA. squamosa L., and scions of Gefner atemoya(A. squamosaxA. cherimola Mill.), 49-11 (GefneratemoyaxA. reticulata L.), 4-5 (PriestleyatemoyaxA. reticulata), A. reticulata grafted onto either A.glabra, A. reticulata orA. squamosa rootstocks were floodedfor up to 60 d. Soil anaerobiosis occurred on the third dayof flooding. Seedlings ofA. glabra and A. muricata, and thescions 49-11, Gefner atemoya, andA. reticulata grafted onto A. glabra rootstock were consideredflood tolerant based on their ability to survive and grow inflooded conditions. Scions of the normally flood-sensitive A.reticulata, Gefner atemoya, and 49-11tolerated root waterlogging when grafted onto the flood-tolerantspecies, A. glabra. In contrast, flooding of A. squamosa seedlingsand rootstocks, and A. reticulata rootstocks greatly reducedgrowth and net CO2assimilation rates, and resulted in 2080%tree mortality. Stem anatomical responses to long-term flooding(12 continuous months) were assessed in seedlings of A. glabraand A. muricata, and trees of 49-11 grafted ontoA. glabra. Flooded trees developed hypertrophied stem lenticels,particularly in A. glabra, and enlarged xylem cells resultingin thicker stems with reduced xylem density. Flooding did notincrease air spaces in pre-existing xylem near the pith or inxylem tissue that was formed during flooding. Thus, flood tolerancedid not involve aerenchyma formation in the stem. Copyright1999 Annals of Botany Company Flood tolerance, net CO2assimilation, photosynthesis, stem anatomy, shoot growth, anaerobiosis, Annonaceae. 相似文献
10.
Seasonal patterns of growth, dehydrins and water-soluble carbohydrates in genotypes of Dactylis glomerata varying in summer dormancy 总被引:1,自引:0,他引:1
Background and Aims Summer dormancy in perennial grasseshas been studied inadequately, despite its potential to enhanceplant survival and persistence in Mediterranean areas. The aimof the present work was to characterize summer dormancy anddehydration tolerance in two cultivars of Dactylis glomerata(dormant Kasbah, non-dormant Oasis)and their hybrid using physiological indicators associated withthese traits. Methods Dehydration tolerance was assessed in a glasshouseexperiment, while seasonal metabolic changes which produce putativeprotectants for drought, such as carbohydrates and dehydrinsthat might be associated with summer dormancy, were analysedin the field. Key Results The genotypes differed in their ability tosurvive increasing soil water deficit: lethal soil water potential(s) was 3·4 MPa for Kasbah (althoughnon-dormant), 1·3 MPa for Oasis,and 1·6 MPa for their hybrid. In contrast, lethalwater content of apices was similar for all genotypes (approx.0·45 g H2O g d. wt1), and hence the greater survivalof Kasbah can be ascribed to better drought avoidancerather than dehydration tolerance. In autumn-sown plants, Kasbahhad greatest dormancy, the hybrid was intermediate and Oasishad none. The more dormant the genotype, the lower the metabolicactivity during summer, and the earlier the activity declinedin spring. Decreased monosaccharide content was an early indicatorof dormancy induction. Accumulation of dehydrins did not correlatewith stress tolerance, but dehydrin content was a function ofthe water status of the tissues, irrespective of the soil moisture.A protein of approx. 55 kDa occurred in leaf bases of the mostdormant cultivar even in winter. Conclusions Drought avoidance and summer dormancy arecorrelated but can be independently expressed. These traitsare heritable, allowing selection in breeding programmes. 相似文献
11.
A gene transfer system that ensured recovery of whole planttransformants was developed for safflower (Carthamus tinctoriusL.). Embryo axes of germinating seeds with one of the cotyledonsremoved were pricked with a sterile sewing needle at the cotyledonarynode and infected by gentle agitation for 10 min in a suspensionofAgrobacterium tumefaciens . Following a 24 h co-cultivationand decontamination with cefotaxime for 1 h, they were placedon soilrite moistened with water to allow germination to progress.Later, the seedlings were transferred to soil in pots wherethey grew into normal healthy plants in the greenhouse. Thehistochemical assay of an uid A gene that expresses only inplant tissues and PCR amplification of uid A and npt II markergenes were used for early determination of putative transformants,whereas Southern analysis of T0and T1plant DNA was used to confirmintegration of the transgenes. The combined results indicatedthat the frequency of transformation was 5.3% in safflower A-1and 1.3% in A-300. Four T0plants of A-1yielded transformed T1progeny. The strategy, in principle, shouldbe applicable to all cultivars and genotypes of safflower whichare susceptible to Agrobacterium tumefaciens infection. Thusfar, this is the only procedure available for safflower thatcould successfully be used to generate whole plant transformants.Copyright 2000 Annals of Botany Company Safflower (Carthamus tinctorius L.), transformation, non-tissue culture method, embryo axes,Agrobacterium , transgene expression 相似文献
12.
Nitrate provision has been found to regulate the capacity forChara corallina cells to take up nitrate. When nitrate was suppliedto N sufficient cells maximum nitrate uptake was reached after8 h. Prolonged treatment of the cells in the absence of N alsoresulted in the apparent ability of these cells to take up nitrate.Chlorate was found to substitute partially for nitrate in theinduction step. The effects on nitrate reductionwere separated from those on nitrate uptake by experiments usingtungstate. Tungstate pretreatment had no effect on NO3uptake induced by N starvation, but inhibitedNO3 uptake associated with NO3 pretreatment. Chloridepretreatment similarly had no effect on NO3 uptake inducedby N deprivation, but inhibited NO3 uptake followingNO3 pretreatment. The data suggest that there are atleast two mechanisms responsible for the inductionof nitrate uptake by Chara cells, one associated with NO3reduction and induced by CIO3 or NO3and one associated with N deprivation. Key words: Nitrate, Chlorate, Chara corallina, Induction 相似文献
13.
Plants of four isolines of soyabean [Glycine max(L.) Merrill]Clark, vizL71-920 (maturity genecomplemente1e2e3 ), L80-5914 (E1e2e3), Clark(e1E2E3), and L65-3366 (E1E2E3), were grown inshort (12.25 h d - 1natural light) and long days (12.25 h d- 1natural light supplemented with 2.75 h d - 1low-irradianceartificial light) from first flowering to maturity in a polythenetunnel maintained at 30/24°C (day/night). Whereas therewere few differences among the isolines grown in short days,in long days the dominant alleles increased crop duration, biomassand seed yield substantially. Increases in biological and economicyield were not solely a consequence of longer crop duration:the dominant alleles also increased crop growth rate and radiationuse efficiency in long days (from 1.3 g MJ - 1total radiationine1e2e3 to 2.8 g MJ - 1inE1E2E3 ). Greater radiation use efficiencyresulted from a relatively longer leaf area duration, betterdistribution and orientation of a larger mass of leaves withinthe canopy, and smaller partitioning of assimilates to reproductivestructures. The work reveals the substantial effects of thethree lociE1 / e1, E2/ e2and E3/e3 on the response of plantgrowth, as well as development, to environment. Their relevanceto crop adaptation is discussed. Copyright 2000 Annals of BotanyCompany Glycine max(L.) Merrill, soyabean, maturity genes, flowering, phenology, growth, yield 相似文献
14.
Guerrero et al (1994) promote Tauti's equation, rate = a exp(b temp), as simple to fit by log conversion (which may be formallyinappropriate), empirically adequate, and having appropriatebiological characteristics. No function is justifiablefrom reductionist theories, but Belehrádek's, rate =a (temp T0)b, with b fixed for the taxon of interest,fits equally well, and singularly distinguishes differencesattributable to temperature adaptation (T0, often misunderstoodas biological zero), and to size or other species-dependentproperties (a). 相似文献
15.
Effect of Inorganic Phosphate on the Biosynthesis of Purine and Pyrimidine Nucleotides in Suspension-Cultured Cells of Catharanthus roseus 总被引:1,自引:0,他引:1
The levels of purine and pyrimidine nucleotides in suspensioncultures of Catharanthus roseus were determined 24 h after stationary-phasecells were transferred to fresh complete (+Pi)or phosphate-deficient (Pi) Murashige-Skoogmedium. The levels of ATP, GTP, UTP and CTP were from approx.3 to 5-fold greater in the cells grown in +Pimedium than in the cells grown in Pi medium.The levels of almost all other nucleotides were slightly higherin the cells in +Pi medium. The rates of de novoand salvage biosynthesis of purine and pyrimidine nucleotideswere estimated from the rates of incorporation of radioactivityfrom [14C]formate, [214C]glycine, NaH14CO3, [614C]orotate,[814C]adenine, [814C]adenosine, [214C]uraciland [214C]uridine. The results indicated that the activityof both the de novo and the salvage pathway was higher in thecells in +Pi medium than in the cells in Pimedium. The rate of degradation estimated from the rate of releaseof 14CO2 from labelled purines and pyrimidines indicated thatdegradation of uridine was significantly reduced in the cellsin +Pi medium, but no significant difference wasfound in the degradation of adenine, adenosine and uracil. Thepossible role of Pi in the control of the biosynthesis of nucleotidesand in the degradation of uridine is discussed. Catharanthus roseus, Madagascar periwinkle, suspension culture, inorganic phosphate, nucleotides, purines, pyrimidines, biosynthesis, degradation 相似文献
16.
17.
KARGIOLAKI HARIKLIA; OSBORNE DAPHNE J.; THOMPSON FRANK B. 《Journal of experimental botany》1991,42(9):1189-1198
Differences in premature leaf abscission and in visible steminjury in genetic lines of poplar followed continuous fumigationswith air pollutant levels of SO2 (90100 nl l1)and O3 (7080 nl l1) either separately or together.The clones used were: Populus deltoides var. missiouriensisMarsh., P. nigra cv. italicd L., and the hybridsP. nigra cv. italica xP. deltoides (He-X/3) andP. nigra cv.italica x P. nigra cv. Serres(He-K/7). While most leaf abscission occurred within 20 d fromthe start of fumigation, stem lesions (intumescences), appearedonly after 72 d. Their anatomical characteristics include theformation of lysigenous aerenchyma in the lower parts of theintumescence, the sloughing of superficial cells from the injuredarea, and the development of crystalline formations on the surfaceof the lesions. P. deltoides exhibited the least morphologicalresponse to the gases. Ethylene released from fumigated leaves was determined at thesame gas concentration of SO2 (100 nl l1), O3 (75 nll1) and their mixture. Leaves of P. deltoides consistentlyshowed the lowest ethylene production after the gas treatments.P. italica production was higher but was littlealtered by the treatments. The two hybrids He-X/3 and He-K/7showed the greatest increases in ethylene evolution with time.With He-K/7 exposed to the gas mixture the production of ethylenedecreased after the initial sharp rise during days 12,and reflected the considerable leaf damage observed after day3. The results suggest that sensitivity to air pollution, (as shownby leaf abscission and the formation of stem intumescences)can be correlated with the level of pollutant-induced ethyleneevolution from leaves. Initially high levels could induce abscission,whilst prolonged production could be responsible for intumescenceinitiation. The discussion proposes a series of events fromSO2 and/or O3 entry into the leaf and the physiological reasonsfor the clonal differences. Key words: Sulphur dioxide, ozone, ethylene, poplar, leaf abscission, stem lesions 相似文献
18.
This research determined constants for a viability equationto predict the longevity of groundnut seeds and to improve themanagement of seedlot storage throughout the trading period.Seeds of the Brazilian cultivar Tatu (Valenciabunch type) were tested. Nine moisture content levels (rangingfrom 2.4 to 12.8%) and three storage temperatures (40, 50 and65 °C) were used. Sub-samples for each moisture content-storagetemperature combination were sealed in laminated aluminium-foilpackets and stored in incubators until complete survival curveswere obtained. A reliable equation was obtained to predict groundnutseed longevity through the constantsKE=6.177,CW=3.426,CH=0.0304andCQ=0.000453.Copyright 1998 Annals of Botany Company Arachis hypogaeaL., seed longevity, seed storage, viability equation. 相似文献
19.
ROMERO-ARANDA R.; BONDADA B. R.; SYVERTSEN J. P.; GROSSER J. W. 《Annals of botany》1997,79(2):153-160
The effect of tetraploidy on leaf characteristics and net gasexchange was studied in diploid (2x ) and autotetraploid (4x) Valencia sweet orange (Citrus sinensis (L.)Osb.) and Femminello lemon (Citrus limon (L.)Burm. f.) leaves. Comparisons between ploidy levels were madeunder high irradiance (I) in a growth chamber or low total Iin a glasshouse. Tetraploids of both species had thicker leaves,larger mesophyll cell volume and lower light transmittance thandiploids regardless of growth I. Mesophyll surface area perunit leaf area of 2x leaves was 515% greater than on4x leaves. Leaf thickness and mesophyll cell volume were greaterin high I leaves than low I leaves. In high I, average leafarea was similar for 2x and 4x leaves, whereas in low I it was30% greater in 4x than in 2x leaves. Nitrogen and chlorophyllconcentration per cell increased with ploidy level in both growthconditions. The ratio of chlorophyll a:b was 25% greater in2x than in 4x leaves. When net CO2assimilation rate (ACO2) wasbased on leaf area, 4x orange leaves had 2435% lowerACO2than their diploids. There were no significant differencesin ACO2between 2x and 4x orange or lemon leaves when expressedon a per cell basis. Overall, lower ACO2per unit leaf area oftetraploids was related to increase in leaf thickness, largermesophyll cell volume, the decrease in mesophyll area exposedto internal air spaces, and the lower ratio between cell surfaceto cell volume. Such changes probably increased the resistanceto CO2diffusion to the site of carboyxlation in the chloroplasts. Cell volume; chlorophyll; irradiance; leaf thickness; nitrogen; photosynthesis; ploidy; Citrus limon ; C. sinensis ; Valencia sweet orange; Femminello lemon 相似文献
20.
Simulated swards of each of two selection lines of Lolium perennecv. S23 with fast and slow ratesof mature tissue respiration were establishedin growth rooms at 20/15 °C day/night temperatures and studiedover four successive regrowth periods of 46, 30, 26 and 53 daysduration. The slow line outyielded the fast,both in harvestable shoot (above a 5 cm cut) and in root andstubble. Its advantage increased over successive regrowth periodsto 23 per cent (total biomass). Gas analysis measurements onthe entire communities (including roots), during the final regrowthperiod, showed that the slow line had a 2234per cent lower rate of dark respiration per unit dry weight.This enabled it to maintain its greater mass of tissue for thesame cost in terms of CO2 efflux per unit ground area. Halfthe extra dry weight produced by the slow line,relative to the fast, could be attributed to itsmore economic use of carbon. The rest could be traced to a 25per cent greater tiller number which enabled the slowline to expand leaf area faster (though not at a greater rateper tiller), intercept more light and fix more carbon, earlyin the regrowth period. Lolium perenne L., ryegrass, respiration, maintenance respiration, tiller production, simulated swards, canopy photosynthesis, carbon economy 相似文献