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1.
HANSEN ALEXANDER P.; YONEYAMA TADAKATSU; KOUCHI HIROSHI 《Journal of experimental botany》1992,43(1):1-7
A comparison between two hydroponically-grown soybean genotypes(Glycine max [L.] Merr.) cv. Bragg and the supernodulating mutantnts 1007 was made in terms of dry matter accumulation, carbon,nitrogen, and mineral element distribution, 15N natural abundanceand the effect of short-term treatment with 4·0 mol m3KNO3 on nitrogenase activity and respiration. Differences weremost pronounced in nodule dry weight and plant nitrogen content,both of which were recorded to be substantially elevated inthe mutant. Mineral element concentrations in different plantparts proved to be rather similar with the exception of Ca,found to be lower in leaves of the mutant, and Mn concentrationswhich were twice as high in roots of nts 1007. The values of15N natural abundance showed that both genotypes were equallydependent on nitrogen fixation when nitrate was absent. Theresults of the acetylene reduction assays indicated similarspecific nodule activity, while on a per plant basis nitrogenaseactivity of the mutant proved to be more than twice the amountof Bragg. This effect was also reflected in higher nodule respirationwhile root respiration remained below that of Bragg. Nitrate induced a substantial reduction in nitrogenase activitynot only in Bragg, but also in nts 1007. Nodule respiratoryactivity of Bragg was reduced by nitrate from 1·27 to0·34 mg C h1 plant1. In nts 1007 correspondingvalues were 2·70 to 1·52 mg C h1 plant1.Starch concentration in nodules was decreased in both genotypes,but nevertheless remained higher in nts 1007. Values for solublesugars in nodules even increased in the mutant in response tonitrate while the same treatment caused a reduction in Bragg.The data indicate that nitrogenase activities of Bragg and nts1007 are equally sensitive to short-term application of nitrate. Key words: Glycine max, C and N distribution, nitrate, root respiration, 15N natural abundance 相似文献
2.
The specific respiration rates of nodulated root systems, ofnodules and of roots were determined during active nitrogenfixation in soya bean, navy bean, pea, lucerne, red clover andwhite clover, by measurements on whole plants before and afterthe removal of nodule populations. Similar measurements weremade on comparable populations of the six legumes, lacking nodulesbut receiving abundant nitrate-nitrogen, to determine the specificrespiration of their roots. All plants were grown in a controlled-environmentclimate which fostered rapid growth. The specific respiration rates of nodulated root systems ofthe three grain and three forage legumes during a 714-dayperiod of vegetative growth varied between 10 and 17 mg CO2g1 (dry weight) h1. This mean value consistedof two components: a specific root respiration rate of 69mg CO2 g1 h1 and a specific nodule respirationrate of 2246 mg CO2 g1 h1. Nodule respirationaccounted for 4270 per cent of nodulated root respiration;nodule weight accounted for 1240 per cent of nodulatedroot weight. The specific respiration rates of roots lackingnodules and utilizing nitrate nitrogen were generally 2030per cent greater than the equivalent rates of roots from nodulatedplants. The measured respiratory effluxes are discussed in thecontext of nitrogen nitrogen fixation, nitrate assimilation. Glycine max, Phaseolus vulgaris, Pisum sativum, Medicago sativa, Trifolium pratense, Trifolium repens, soya bean, navy bean, pea, lucerne, red clover, white clover, nodule respiration, root respiration, fixation, nitrate assimilation 相似文献
3.
HANSEN ALEXANDER P.; PEOPLES MARK B.; GRESSHOFF PETER M.; ATKINS CRAIG A.; PATE JOHN S.; CARROLL BERNARD J. 《Journal of experimental botany》1989,40(7):715-724
Growth and symbiotic performance of soybean (Glycine max (L.)Merrill) cv. Bragg and three of its induced nodulation mutants(nod49, non-nodulating; ntsl 116, intermediate supernodulator;nts1007, extreme supernodulator) were compared throughout developmentunder different nitrogen regimes (0, 2, 5 and 10 mol nitratem3). Nitrogen fixation was assessed using 15N-isotopedilution and xylem sap analysis for ureide content. Both techniquesconfirmed a complete lack of N2 fixation activity in nod49.Plant reliance on nitrogen fixation by the other genotypes wasdependent on the nitrate regime and the developmental stage.The ntsl007 and ntsl 116 mutants fixed more nitrogen than theparent cultivar in the presence of 10 mol m3 nitratein the nutrient solution, but higher input of symbioticallyderived nitrogen was still insufficient to offset the amountof nitrogen removed in the harvested seed. However, the mutantsutilized less nitrate for growth than Bragg. Comparison of estimatesof N2 fixation derived from the 15N-dilution technique withthose based on relative ureide content of xylem sap indicatedthat the latter offered a simple and reliable procedure forevaluating the symbiotic performance of supernodulating plants. Key words: 15N-isotope dilution, supernodulation, ureides 相似文献
4.
KOUCHI HIROSHI; NAKAJI KIYOKAZU; YONEYAMA TADAKATSU; ISHIZUKA JUNJI 《Annals of botany》1985,56(3):333-346
Well-nodulated soya bean (Glycine max L.) plants were allowedto assimilate 13CO2 for 10 h in the light, under steady-stateconditions in which CO2 concentration and 13C abundance wereboth strictly controlled at constant levels. The respiratoryevolution of 13CO2 from roots and nodules and 13C incorporationinto various metabolic fractions were measured during the 13CO2feeding and subsequent 48 h chase period. CO2 respired from nodules was much more rapidly labelled with13C than that from roots. The level of labelling (percentageof carbon currently assimilated during the 13COM2 feeding period)of CO2 respired from nodules reached a maximum of about 87 percent after 4 h of steady-state l3CO2 assimilation and thereafterremained fairly constant. The absolute amount of labelled carbonevolved by the respiration of the nodules during the 10 h 13CO2feeding period was 1·5-fold that of root respiration.These results demonstrated that the currently assimilated (labelled)carbon was preferentially used to support nodule respiration,while root respiration relied considerably on earlier (non-labelled)carbon reserved in the roots. Sucrose pools were mostly composed of currently assimilatedcarbon in all tissues of the plants, since the levels of labellingaccounted for 8691 per cent at the end of the 13CO2 feeding.In the nodules, the kinetics and levels of sucrose labellingwere in fairly good agreement with those of respired CO2, whilein the roots, the level of labelling of respired CO2 was significantlylower than that of sucrose. Succinate and malate were highly labelled in both roots andnodules but they were labelled much more slowly than sucroseand respired CO2. The kinetics and levels of labelling of theseKrebs cycle intermediates resembled those of major amino acidswhich are derived directly from Krebs cycle intermediates. Itis suggested that large fractions of organic acids in noduleswere physically separate from the respiration site. Glycine max L., Soya bean, 13CO2 assimilation, respiratory evolution of 13CO2, carbon metabolism in root nodules 相似文献
5.
RYLE G. J. A.; ARNOTT R. A.; POWELL C. E.; GORDON A. J. 《Journal of experimental botany》1984,35(8):1156-1165
The respiratory effluxes of nodules and of roots of FiskebyV soyabean (Glycine max (L.) Merr.), grown in a controlled environment,were measured at intervals in air and 3% O2 from shortly afterthe onset of N2 fixation until plant senescence. The respiratoryburdens linked with nitrogenase plus ammonia metabolism, andnodule growth and maintenance, were calculated from gas exchangedata and related to the concurrent rates of N2 fixation. The specific respiration rates of nodules increased to a maximumof 21 mg CO2 g1 h1 at the time pods began development:the equivalent maximum for roots was c. 4.5 mg CO2 g1h1. Maximum nodule and root respiration rates per plantwere attained about 25 d later at the time N2 fixation peakedat 15 mg N d1 plant1. The relationship between nodule respiration and N2 fixationindicated an average respiratory cost of 13.2 mg CO2 mg1N until the last few days of plant development Separation ofnodule respiration into the two components: nitrogenase (+ NH3metabolism) respiration and nodule growth and maintenance respiration,indicated that the latter efflux accounted for c. 20% of nodulerespiration while N2 fixation was increasing and new noduletissue was being formed. When nodule growth ceased and N2 fixationdeclined, this component of respiration also declined. The respiratorycost of nitrogenase activity plus the associated metabolismof NH3 varied between 11 mg CO2 mg1 N during vegetativeand early reproductive growth, to 12.5 mg CO2 mg1 N duringthe later stages of pod development. Key words: N2 fixation, Respiration, Nodules, Nitrogenase 相似文献
6.
Nitrogen Partitioning During Early Development of Supernodulating Soybean (Glycine max [L.] Merrill) Mutants and their Wild-Type Parent 总被引:2,自引:0,他引:2
HANSEN ALEXANDER P.; PEOPLES MARK B.; BROWN PATRICK H.; CARROLL BERNARD J.; GRESSHOFF PETER M. 《Journal of experimental botany》1990,41(10):1239-1244
The relative importance of fixed N2, cotyledonary N, and nitratefor growth of seedlings of soybean cv. Bragg and two of itsnitrate tolerant supernodulating (nts) mutants (intermediatents 1116 and extreme nts1007) was investigated during symbioticdevelopment in the presence of nitrate (3.0 mol m3) using15N techniques. Newly-fixed N2 and nitrate were both major sourcesof N for nodule development and nitrate principally supportedearly shoot and root growth in Bragg. In the nts mutants, however,all plant parts and nodules in particular, relied more on Nstored in the cotyledons. This resulted in later nodule maturityand a period of prolonged N-starvation for the seedlings ofthe extreme supernodulator, and could be responsible for theirsubsequently lowered biomass accumulation compared to the parentcultivar. Key words: Nodules, N partitioning, supernodulating soybeans 相似文献
7.
KOUCHI HIROSHI; AKAO SHOICHIRO; YONEYAMA TADAKATSU 《Journal of experimental botany》1986,37(7):985-993
Kouchi, H., Akao, S. and Yoneyama, T. 1986. Respiratory utilizationof 13C-labelled photosynthate in nodulated root systems of soybeanplants.J. exp. Bot. 37: 985993. An improved method for the measurement of respiratory utilizationof current photosynthate in the nodulated root system of water-culturedsoybean (Glycine max L.) plants was developed using a steady-state13CO2 labelling technique. Well-nodulated plants at the latevegetative stage were allowed to assimilate 13CO2 for 10 h incontinuous light at a constant CO2 concentration with a constant13C abundance. The respiratory evolution of 13CO2 from rootsand nodules was measured continuously throughout the periodof 13CO2 assimilation and during a subsequent 36 h chase periodby using a differential infrared 13CO2 analyser. The plantswere grown with nitrogen-free or (15 mmol dm3)-containing culture solution for 3 d before13CO2 assimilation. In plants grown without , nodule respiration averaged 69% of the total respiration of the undergroundparts over the full experimental period and the CO2 respiredreached an apparent isotopic equilibrium at 8085% labellingafter initiating 13CO2 assimilation. By contrast, the CO2 respiredfrom the roots did not reach an isotopic equilibrium and labellingwas only 56% at the end of exposure to 13CO2 These findingsdemonstrated that nodule respiration is strongly dependent onrecently assimilated carbon compared with root respiration. Plants supplied with in the culture solution showed a decreased rate of nodule respirationand a slightly increased rate of root respiration. The extentsand time courses of labelling of respired CO2 from both theroots and nodules were similar in the presence and absence of except that the maximum level of labelling of CO2 derived from nodule respiration in plantswith was significantly higher (about 91%) than for plants growing without . Key words: Soybean (Glycine max L.), nodule respiration, 13CO2, assimilation, carbon partitioning 相似文献
8.
Kouchi, H. and Higuchi, T. 1988. Carbon flow from nodulatedroots to the shoots of soybean {Glycine max L. Merr.) plants:An estimation of the contribution of current photosynthate toureides in the xylem stream.J. exp. Bot. 39: 10151023. Well-nodulated, water-cultured soybean plants were allowed toassimilate 13CO2 at a constant specific activity for 10 h andthe 13C-labelling of total carbon and ureides in xylem sap wasinvestigated. Labelled carbon appeared very rapidly in the xylem stream. Percentageof labelled carbon (relative specific activity, RSA) in xylemsap was 18% at 2 h after the start of 13CO2 assimilation andreached 53% at the end of the 10 h assimilation. The amountof labelled carbon exported from nodulated roots to the shootsvia the xylem during the 10 h labelling period accounted for33% of total labelled carbon imported into the nodulated roots.Ureides (allantoin and allantoic acid) in xylem sap were stronglydependent on currently assimilated carbon. The RSA of ureidesin xylem sap had reached 83% at the end of the assimilationperiod. Labelled carbon in ureides accounted for 51% of totallabelled carbon returned from nodulated roots to the shootsvia the xylem during the 10 h assimilation period. A treatmentwith 20 mol m3 nitrate in the culture medium for 2 ddecreased the ureide concentration in the xylem sap slightly,but greatly decreased the RSA of ureides. By comparing the data with the results of analysis of the xylemsap of nodule-detached plants, it was concluded that the majorityof labelled carbon exported to the xylem stream from noduleswas in ureide form. A considerable amount of carbon was alsoreturned from roots to shoots via the xylem stream but it wasmore dependent on (non-labelled) carbon reserved in the roottissues. Key words: Soybean(Glycine max L.), root nodule, carbon partitoning, 13CO2 assimilation, xylem 相似文献
9.
A long-term, steady-state 13CO2 assimilation system at a constantCO2 concentration with a constant 13C abundance was designedand applied to quantitative investigations on the allocationof photoassimilated carbon in nodulated soya bean (Glycine maxL.) plants. The CO2 concentration in the assimilation chamberand its 13C abundance were maintained constant with relativevariances of less than ±0.5 per cent during an 8-h assimilationperiod. At the termination of 8-h 13CO2 assimilation by plantsat early flowering stage, the currently assimilated carbon relativeto total tissue carbon (measured by the degree of isotopic saturation)were for young leaves (including flower buds), 13.9 per cent;mature leaves, 15.7 per cent; stems+petioles, 5.9 per cent;roots, 5.4 per cent and nodules, 6.9 per cent, 48 h after theend of the 13CO2 assimilation period, they were 12.3, 7.5, 7.4,6.8 and 6.1 per cent, respectively. The treatment with a highconcentration of nitrate in the nutrient media significantlydecreased the allocation of 13C into nodules. Experiments on13CO2 assimilation by plants at the pod-filling stage were alsoconducted. Labelling by 13C was weaker than at the early floweringstage, but an intense accumulation of 13C into reproductiveorgans was observed. Glycine max L., nodulated soya bean plants, 13CO2 assimilation, carbon dynamics 相似文献
10.
Effects of blue light on respiration and carbon dioxide fixation in colorless Chlorella mutant cells
A colorless mutant of Chlorella vulgaris (Mutant #125) starvedin darkness, showed suppressed rates of respiration and darkCO2 fixation, which were significantly recovered by illuminationwith blue light. The main CO2 fixation product under blue lightwas aspartate. Such enhancements did not take place in cellsactively growing in the glucose medium. Both enhancing effectsof blue light (456 nm) were saturated at light intensities aslow as 400800 erg.cm-2.sec-1. The action spectra forthese enhancing effects were similar to each other; both showedpeaks at 460 nm and 380 nm, which correspond to the absorptionmaxima of flavin. All these findings indicate that the samemechanism underlies the observed effects of blue light on CO2fixation and respiration. The role of blue light which bringsabout the enhancements in CO2 fixation and respiration is discussed. (Received June 1, 1974; ) 相似文献
11.
Defoliation in White Clover: Nodule Metabolism, Nodule Growth and Maintenance, and Nitrogenase Functioning During Growth and Regrowth 总被引:1,自引:0,他引:1
In two experiments, the functioning and metabolism of nodulesof white clover, following a defoliation which removed abouthalf the shoot tissue, were compared with those of undefoliatedplants. In one experiment, the specific respiration rates of nodulesfrom undefoliated plants varied between 1160 and 1830 µmolCO2 g1h1, of which nodule growth and maintenanceaccounted for 22 ± 2 per cent, or 27 ± 3.6 percent, according to method of calculation. Defoliation reducedspecific nodule respiration and nodule growth and maintenancerespiration by 6070 per cent, and rate of N2 fixationby a similar proportion. The original rate of nodule metabolismwas re-established after about 5 d of regrowth; during regrowthnodule respiration was quantitatively related to rate of N2,fixation: 9.1 µmol CO2 µmol1N2. With the possible exception of nodules examined 24 h after defoliation,the efficiency of energy utilization in nitrogenase functioningin both experiments was the same in defoliated and undefoliatedplants: 2.0±0.1 µmol CO2 µmol1 C2H4;similarly, there was no change in the efficiency of nitrogenasefunctioning as rate of N2 fixation increased with plant growthfrom 1 to 22 µmol N2 per plant h1. Exposure of nodulated white clover root systems to a 10 percent acetylene gas mixture resulted in a sharp peak in rateof ethylene production after 1.52.5 min; subsequently,rate of ethylene production declined rapidly before stabilisingafter 0.51 h at a rate about 50 per cent of that initiallyobserved. Regression of peak rate of ethyleneproduction on rate of N2 fixation indicated a value of 2.9 µmolC2H4 µmol1 N2, for rates of N2 fixation between1 and 22 µmol N2 per plant h1. The relationshipsbetween nitrogenase respiration, acetylene reduction rates andN2 fixation rates are discussed. Trifolium repens, white clover, defoliation, nodule respiration, N2, fixation, nitrogenase 相似文献
12.
Effects of Elevated Carbon Dioxide Concentration in the Dark on the Growth of Soybean Seedlings 总被引:2,自引:2,他引:0
Previous work has shown that elevated carbon dioxide (CO2) concentrationsin the dark reversibly reduce the rate of CO2 efflux from soybeans.Experiments were performed exposing soybean plants continuallyto concentrations of 350 or 700 cm3 m-3 for 24 h d-1, or to350 during the day and 700 cm3 m-3 at night, in order to determinethe importance of the reduced rate of dark CO2 efflux for plantgrowth. High CO2 applied only at night conserved carbon andincreased dry mass during initial growth compared with the constant350 cm3 m-3 treatment. Long-term net assimilation rate was increasedby high CO2 in the dark, without any increase in daytime leafphotosynthesis. However, leaf area ratio was reduced by thedark CO2 treatment to values equal to those of plants continuallyexposed to the higher concentration. From days 14-21, leaf areawas less for the elevated night-time CO2 treatment than foreither the constant 350 or 700 cm3 m-3 treatments. For the days7-21-period, relative growth rate was significantly reducedby the high night CO2 treatment compared with the 350 cm3 m-3continuous treatment. The results indicate that some functionallysignificant component of respiration was reduced by the elevatedCO2 concentration in the dark.Copyright 1995, 1999 AcademicPress Glycine max L. (Merr.), carbon dioxide, plant growth, respiration 相似文献
13.
Imsande, J. 1986. Inhibition of nodule development in soybeanby nitrate or reduced nitrogen.J. exp. Bot. 37: 348355. Nodulation of hydroponically grown soybean plants [Glycine max(L.) Merr.] is inhibited by continuous growth in the presenceof 4· mol m3 KNO3 The presence of 4·0 molm3 starter nitrate for 3-6 d during noduledevelopment, however, subsequently stimulates nodule dry weightaccumulation and nitrogenase activity. These stimulations occureven though 4· mol m3 nitrate temporarily delaysnodule development, i.e. the late steps of nodule developmentare reversibly inhibited by a short-term exposure to 4·0mol m3 nitrate. On the other hand, treatment with 4·0mol m3 nitrate in excess of 14 d significantly reducesnodule dry weight Thus, extended growth in the presence of 4·0mol m3 KNO3 seems to block both early and late stepsof nodule development. Nodulation of hydroponically grown soybeansis also inhibited by continuous growth in the presence of 2·0mol m3 (NH4)2SO4 This inhibition is not caused by acidityof the growth medium. On the other hand, nodule development6 d after inoculation with Rhizoblum japonicum is not delayedby a 7-d exposure to 2·0 mol m3 (NH4)2SO4 butis partially inhibited by a prolonged exposure to (NH4)2SO4Because repression of nodulation by 4·0 mol m3KNO3 is more severe than that by 2·0 mol m3 (NH4)2SO4and because ammonium taken up by the soybean plant is not activelyoxidized to nitrate, it is suggested that there are at leasttwo mechanisms by which nitrate utilization represses noduleformation in soybean. Key words: Glycine max, nitrogen, nitrogen fixation, nodulation 相似文献
14.
GORDON A J.; MACDUFF J H.; RYLE G. J. A.; POWELL C E. 《Journal of experimental botany》1989,40(5):527-534
Established, nodulated white clover plants were transferredto eight tanks of a flowing culture apparatus with solutiontemperatures of 5, 11, 17, and 25 ?C (two tanks per temperature).Shoot temperature and light environment were common to all plants.After 7 d, (10 mmol m3) was continuouslysupplied to one tank at each temperature while in the remainingfour tanks (one at each temperature) the plants were completelydependent on nodule N2-fixation. Plants were randomly selected at intervals during the following14 d period in order to measure root and nodule respirationand acetylene reduction activity (ARA) in a flow-through systemset at the adapted root temperature. Additional plants wereassayed for in vitro nitrate reductase activity in leaves, roots,and nodules. Apparent nitrogenase activity (ARA) and respiration associatedwith it were each markedly affected by temperature in two ways;(1) Activity per unit weight of nodule was reduced at lowertemperatures; (2) Development of the plant, and thus also nodulemass, was restricted at lower temperatures which, in turn, restrictedtotal nodule activity per plant. The presence of nitrate significantly reduced ARA of nodules,particularly at higher temperatures. However, significant discrepancieswere found when N2-fixation rates, estimated from the acetylenereduction assay, were compared with N2-fixation rates calculatedfrom curves fitted to N accumulation data (minus the rate of uptake in the case of nitrate-treated plants). Carbon use efficiency (CO2 respired per C2H4 produced) was notsignificantly affected by temperature or the presence of nitrate. Nitrate reductase activity (NRA) developed in all plant partsat the three highest temperatures, but not at 5 ?C. We calculatethat leaf NRA may account for 82, 75, and 68% of total nitratereduction at 11, 17, and 25 ?C respectively. Key words: Trifolium repens, white clover, N2 fixation, root temperature, acetylene reduction assay, nitrate, nitrate reductase 相似文献
15.
Diurnal temperature fluctuations induced change in soya bean-pod[Glycine max (L.) Merr.] carbon exchange rate (CER, where positiveCER represents CO2 evolution). CER appeared to depend linearlyon temperature. Linear regressions of CER on temperature interceptedthe temperature axis at 5°C (i.e. zero CER at 5°C).Slopes of these regressions (i.e. temperature sensitivity) changedover the season. The CER-temperature sensitivity coefficient,K, (calculated from observed values of CER. pod temperatureand temperature intercept) rose from less than 0·02 mgCO2 h1 pod1 °C1 during early pod-flll,peaked at over 0·04 mg CO2 h1 pod1 °C1at mid pod-fill, and then declined during late pod-fill andmaturation. Glycine max (L.) Merr., Soya bean, carbon exchange rate, temperature 相似文献
16.
Effects of Prolonged Darkness on the Sensitivity of Leaf Respiration to Carbon Dioxide Concentration in C3and C4Species 总被引:3,自引:1,他引:2
Predicting responses of plant and global carbon balance to theincreasing concentration of carbon dioxide in the atmosphererequires an understanding of the response of plant respirationto carbon dioxide concentration ([CO2]). Direct effects of thecarbon dioxide concentration at which rates of respiration ofplant tissue are measured are quite variable and their effectsremain controversial. One possible source of variation in responsivenessis the energy status of the tissue, which could influence thecontrol coefficients of enzymes, such as cytochrome-c oxidase,whose activity is sensitive to [CO2]. In this study we comparedresponses of respiration rate to [CO2] over the range of 60to 1000 µmol mol-1in fully expanded leaves of four C3andfour C4herbaceous species. Responses were measured near themiddle of the normal 10 h dark period, and also after another24 h of darkness. On average, rates of respiration were reducedabout 70% by the prolonged dark period, and leaf dry mass perunit area decreased about 30%. In all species studied, the relativedecrease in respiration rate with increasing [CO2] was largerafter prolonged darkness. In the C3species, rates measured at1000 µmol mol-1CO2averaged 0.89 of those measured at 60µmol mol-1in the middle of the normal dark period, and0.70-times when measured after prolonged darkness. In the C4species,rates measured at 1000 µmol mol-1CO2averaged 0.79 of thoseat 60 µmol mol-1CO2in the middle of the normal dark period,and 0.51-times when measured after prolonged darkness. In threeof the C3species and one of the C4species, the decrease in theabsolute respiration rate between 60 and 1000 µmol mol-1CO2wasessentially the same in the middle of the normal night periodand after prolonged darkness. In the other species, the decreasein the absolute rate of respiration with increase in [CO2] wassubstantially less after prolonged darkness than in the middleof the normal night period. These results indicated that increasingthe [CO2] at the time of measurement decreased respiration inall species examined, and that this effect was relatively largerin tissues in which the respiration rate was substrate-limited.The larger relative effect of [CO2] on respiration in tissuesafter prolonged darkness is evidence against a controlling roleof cytochrome-c oxidase in the direct effects of [CO2] on respiration.Copyright 2001 Annals of Botany Company Carbon dioxide, respiration, Abutilon theophrasti(L.), Amaranthus retroflexus(L.),Amaranthus hypochondriacus (L.), Datura stramonium(L.), Helianthus annuus(L.), Solanum melongena(L.), Sorghum bicolor(L. Moench), Zea mays 相似文献
17.
In vivo net CO2 exchange characteristics of attached Brassicapods were studied during the entire period of their growth anddevelopment after anthesis. 14CO2 was fed both from the externalatmosphere and internally through the pod cavity, and the anatomyof the pod-wall was examined microscopically. Stomata were observedin the outer epidermal layer of the pod wall. Net in vivo CO2fixation by the pods was observed throughout the period of theirdevelopment and was maximum on day 42 after anthesis (DAA).Compared to the internal feeding experiments, 14CO2 fixationfrom the external environment was very high. Apparent translocationof fixed carbon from the pod wall to seeds was rapid. Pod photosynthesiscontributed substantially to seed growth. pods, Brassica campestris L., CO2 fixation, stomata 相似文献
18.
In vivo net CO2 exchange characteristics of attached Brassicapods were studied during the entire period of their growth anddevelopment after anthesis. 14CO2 was fed both from the externalatmosphere and internally through the pod cavity, and the anatomyof the pod-wall was examined microscopically. Stomata were observedin the outer epidermal layer of the pod wall. Net in vivo CO2fixation by the pods was observed throughout the period of theirdevelopment and was maximum on day 42 after anthesis (DAA).Compared to the internal feeding experiments, 14CO2 fixationfrom the external environment was very high. Apparent translocationof fixed carbon from the pod wall to seeds was rapid. Pod photosynthesiscontributed substantially to seed growth. pods, Brassica campestris L, CO2 fixation, stomata 相似文献
19.
Effects of nitrogen on Pinus palustris foliar respiratory responses to elevated atmospheric CO2 concentration 总被引:2,自引:0,他引:2
Mitchell R.J.; Runion G.B.; Prior S.A.; Rogers H.H.; Amthor J.S.; Henning F.P. 《Journal of experimental botany》1995,46(10):1561-1567
Indirect effects of atmospheric CO2 concentration [CO2], onlongleaf pine (Pinus palustris Mill.) foliage respiration werestudied by growing trees in a factorial arrangement of low andhigh [CO2] (369 and 729µmol CO2 mol1) and low andhigh N (40 and 400 kg ha1 yr1). Direct effectsof [CO2] on leaf respiration were tested by measuring respirationrates of foliage from all treatments at two CO2 levels (360and 720µmol CO2mol1) at the time of measurement.Elevated CO2 did not directly or indirectly affect leaf respirationwhen expressed on a leaf area or mass basis, but a significantincrease in respiration per unit leaf N was observed in treesgrown in elevated [CO2] (indirect response to elevated [CO2]).The lack of a [CO2] effect on respiration, when analysed onan area or mass basis, may have resulted from combined effectsof [CO2] on factors that increase respiration (e.g. greateravailability of non-structural carbohydrates stimulating growthand carbon export from leaves) and on factors that decreaserespiration (e.g. lower N concentration leading to lower constructioncosts and maintenance requirements). Thus, [CO2] affected factorsthat influence respiration, but in opposing ways. Key words: Pinus palustris, elevated CO2, nitrogen, foliar, respiration 相似文献
20.
Commercially available cell wall-degrading enzymes frequentlyused for protoplast isolation inhibited CO2 fixation and photosyntheticO2 evolution, and stimulated dark respiration by leaf tissueand isolated mesophyll protoplasts of Nicotiana tabacum L. andAntirrhinum majus L. They also depolarized the membrane potentialof cells of leaf tissue, inhibited uptake of 86Rb by tobaccoleaf tissue and isolated mesophyll protoplasts, and stimulated36CI uptake by tobacco leaf tissue. Where studied, these effectswere found to be reversible. The depolarization effect on Antirrhinumleaf cells occurred even when the enzyme preparations had beendenatured, dialysed, or desalted, and the effect was greatestin those fractions of the enzyme preparation which showed thehighest cellulase activity. Plasmolysis of tobacco leaf tissue inhibited photosyntheticO2 evolution, CO2 fixation, and 86Rb uptake to levels belowthose exhibited by isolated protoplasts in media of the samecomposition and osmolarity. The implications of these resultsfor work with leaf tissue and isolated protoplasts are discussed. 相似文献