共查询到20条相似文献,搜索用时 31 毫秒
1.
Overcoming Incompatibility in Brassica campestris L. by Carbon Dioxide, and Dark Fixation of the Gas by Self- and Cross-pollinated Pistils 总被引:1,自引:0,他引:1
Supplementing pollen suspension cultures with CO2 (35per cent) caused a marked increase in germination and tube growthin vitro in Brassica campestris L. cv. toria. A weakening ofself-incompatibility by increased CO2 levels from 35per cent was observed. The percentage of pollen tubes whichpenetrated the cuticle layer of stigmatic papilla cells in self-pollinatedpistils was high when CO2 level was 5 per cent. Phosphoenolpyruvate (PEP) carboxylase activity was greater in the pollengerminated in 4 per cent CO2 as compared to air (0.03 per cent).A possible role of CO2 for self-recognition and control of pollentube growth is proposed, proposed. Brassica campestris L., carbon dioxide, self-incompatibility, phosphoenol pyruvate carboxylase 相似文献
2.
The distribution of radioactivity in Chlorella during dark 14CO2fixation was investigated either (a) in normal cells with andwithout added ammonium chloride, or (b) in nitrogen-starvedcells supplied with intermediates of the Krebs-Henseleit ureacycle. In the control experiments almost all the activity was presentin compounds of or associated with, the tricarboxylic acid cycle. The amino-acids citrulline and arginine became radioactive onlyin the presence of ammonia or ornithine where initially theycomprised 4060 per cent. of the total activity, reactionsof the KrebsHenseleit urea cycle being implicated intheir formation. No evidence could be found for a complete ureacycle. Unidentified compounds deriving their radioactivity fromthe C4 carbon of citrulline and/or arginine were detected andformed up to 40 per cent. of the total 14CO2 incorporated after25 min. 相似文献
3.
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
4.
HEGARTY P. K.; SMART N. J.; SCRAGG A. H.; FOWLER M. W. 《Journal of experimental botany》1986,37(12):1911-1920
An investigation was carried out to examine the effect of aerationon the growth of Catharanthus roseus suspension cultures inairlift bioreactors. A high aeration rate (0·86 v.v.m.)was found to inhibit the growth of cultures. Venting culturesat a high rate with low oxygen content gas mixtures was equallyinhibitory to culture growth, showing that high aeration wasnot inhibitory as a result of oxygen toxicity. The dissolvedcarbon dioxide tension was found to be lower in cultures operatedat high aeration than those operated at low aeration. Supplyingexogenous CO2 to cultures at high aeration restored the CO2tension to values normally encountered at a low aeration rate,and was found to alleviate the inhibitory effects at high aeration.However, further increasing the CO2 supply to cultures was foundto be severely inhibitory to growth. Therefore, the growth ofC. roseus cultures is very sensitive to dissolved CO2 concentration,growth being inhibited at values either higher or lower thanan optimum. Key words: Aeration, carbon dioxide, Catharanthus roseus suspension culture 相似文献
5.
An understanding of volatilization of nitrogen (N) from leavesof crop and weed species may be important to the improvementof crop production. Foliar N loss (both reduced and oxidizedforms), net CO2 uptake, and transpiration rates were measuredconcomitantly at 30°C on soyabean (Glycine max (L.) Merr.)and sorghum (Sorghum bicolor (L.) Moench) leaves at low (1 percent), ambient (20 per cent), and high (40 per cent) levelsof oxygen. In soyabeans, maximum reduced and total N losseswere found at the highest O2 concentration, and the lowest Nlosses were measured at the lowest O2 level. Net CO2 assimilationwas significantly reduced with increasing O2 during two of threesamplings. Quantities of oxidized N lost were not altered. Sorghumshowed no significant effects from O2 on N loss or net CO2 assimilation.The increased ammonia released from soyabean foliage in thepresence of higher concentration of O2 probably affects metabolicpathways that contribute to the total reduced N volatilization. Glycine max, Sorghum bicolor, CO2 assimilation, nitrogen loss 相似文献
6.
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
7.
The Effect of Subjecting Peas to Air Enriched with Carbon Dioxide: II. RESPIRATION AND THE METABOLISM OF THE MAJOR ACIDS 总被引:1,自引:0,他引:1
Whole peas at about 75 per cent of their maximum fresh weightwere subjected to 530 per cent CO2 in air for periodsof from 16 d, then returned to air for a further 1 d.Samples were withdrawn at intervals and organic acids, TCO2and ethanol estimated as well as the rate of respiration. Slicesof cotyledons suspended in water were also subjected to highconcentrations of CO2 in air for 3 h. The rate of respiration was inhibited progressively by increasein CO2 content of the tissue. The high internal CO2 contentof the intact pea causes an inhibition of its rate of respirationby about 25 per cent. Alcohol production commenced at between10 and 15 per cent CO2 in the ambient gas and slowly increasedin rate up to 37 per cent. The CO2-air mixtures reduced the content of malate, pyruvateand -oxoglutarate, increased that of succinate and left citrateunaffected. On return to air malate rose rapidly and succinatefell slowly to their original concentrations. During the sameperiod the concentration of PEP fell sharply and after about1 h rose again, whereas oxalacetate showed a reverse response.It is argued that the rapid re-synthesis of malate was by carboxylationof PEP to oxalacetate and that this reaction was stimulatedby a change in pH rather than by the direct effect of the changein concentration of CO2. In one experiment 14CO2 was supplied for 2 h before return toair and the movement of 14C followed for 6 h. The results supportthe method of re-synthesis of malate proposed. 相似文献
8.
Dwarf french beans (Phaseolus vulgaris var. Canadian Wonder)were grown in chambers at 25?C with the roots aerated at 20per cent oxygen and tops variously maintained at: T1 O2 0.21;CO2 270?106: T2; O2 0.05, CO2, CO2 270?106: T3;O2 0.21; CO2 550?106. Experiment 1 (T1 and T2) lasted2 weeks: Experiment 2 (T1 T2 and T3) only one week. Hourly estimatesof CO2 uptake were made by gas analysis and weekly estimatesof fresh weight, dry matter in tops and roots, and leaf area,by sampling. Light intensity was 80 W m2 of photosyntheticallyactive radiation. An attempt was made to explain the results in terms of a simplelight absorption model such that
where dV/dt is the rate of CO2 uptake per plant, ßis the photosynthetic efficiency, I0 is the incident light intensity,f is the fraction of incident light absorbed by unit leaf layerand L is the leaf area index. The analysis showed that ß(T2)was at least double ß(T1), whilst f(T2) was smallerthan f(T1) at a given leaf area. The results also required thatthroughout the period of the experiment, fL(T1)=fL(T2) at anygiven time, i.e. the treatment with the larger leaf area (T2)has the smaller value of f, and therefore intercepts less lightper unit leaf area. This could be advantageous for plant growth,but requires further experiments. The photosynthetic rates per unit leaf are about 40 per centgreater in T2 than T1. Over the relatively short period of the experiment the resultsare adequately described by U=btn, where U is the accumulatedcarbon dioxide uptake, b is related to the photosynthetic efficiency(different for the differing treatments), and n is a constant(similar for all treatments). This relationship with time isbelieved to be a relationship with accumulated radiation, forthe light was constant throughout the experiments. Comparisons of carbon fixed (measured gas uptake) and dry matteraccumulation (sampling) show great scatter with an average valueof 0.43. The first week's results were generally smaller thanthis value and the second week's greater. Energy fixation as a fraction of photosynthetically active radiationon the ground area covered by the plants ranged from 3.5 to10 per cent. The results from treatment T3 were similar to T2 suggestingthat increasing CO2 concentration decreases the growth inhibitionat 21 per cent O2. 相似文献
9.
A Comparison of the Rate of Maintenance Respiration in Some Crop Legumes and Tobacco Determined by Three Methods 总被引:2,自引:0,他引:2
Carbon exchange was measured on whole plants of field bean,lucerne, chick pea, kidney bean, pea and tobacco. The maintenance respiration rate was measured in three ways:(i) by allowing the CO2 efflux to decay in prolonged darknessto an asymptotic value which was then taken to be the maintenancevalue (the dark decay method); (ii) by plotting the dark CO2efflux as a function of the net CO2 uptake over a range of irradiancesand taking maintenance as the dark CO2 efflux when the net CO2uptake was zero (the dynamic method); and (iii) by plottingthe total CO2 uptake as a function of the growth rate and takingmaintenance respiration as the CO2 efflux when the growth ratewas zero (the zero growth rate method). The range of valuesfor the maintenance coefficient over all species was from 1.6to 2.1 per cent of the dry weight per day, 1.8 to 2.1 per centand 2.7 to 2.9 per cent as determined by these three methodsrespectively. There was a linear relationship, common to allspecies, between the maintenance respiration rate (dark decaymethod) and dry weight, total nitrogen and the organic nitrogencontent. The growth coefficient (0.69±0.01) was the samefor field bean, chick pea and lucerne and was unaffected bythe method of estimation. It was concluded that the dark decay method provided the bestestimate of the minimal maintenance requirements in the plantsstudied. Vicia faba L., Medicago sativa L., Cicer arientinum L., Phaseolus vulgaris L., Pisum sativum L., Nicotiana tobacum L., field bean, lucerne, chick pea, kidney bean, pea, tobacco, respiration, maintenance, growth, nitrogen content 相似文献
10.
Etiolated Avena sativa L. coleoptile sections were used to determinethe influence of C2H4 on in vivo and in vitro rates of CO2 fixation,and to measure the influence of various permutations of C2H4,CO2, and malate on growth. Whereas 1 mM malate or 320 µI-1 CO2 stimulated growth by approximately 100 per cent, inhibitionof growth by 10-8 µ I-1 C2H4 was substantial only in thepresence of malate or CO2 The increase in growth rate in responseto these two agents was eliminated by the simultaneous applicationof C2H4. The in vivo rate of dark [14C]bicarbonate fixationand in vitro enzymic assays of fixation were not measurablyinhibited by C2H4. These results are discussed in the lightof evidence which indicates that CO2-stimulated growth is mediatedby dark fixation. The data do not support the view that C2H4inhibition of growth results from an inhibition of fixation,but suggests that C2H4 may inhibit some step in the processby which malate stimulates growth. 相似文献
11.
The results of experiments on the effect of high pressures ofoxygen on apples are outlined. It is shown that partial pressuresof the order of 500 per cent, oxygen are toxic to the tissuesand that there is no evidence of an initial increase in CO2,output over that in 1 atmosphere 100 per cent, oxygen. It isfurther shown that the actual pressure (up to 20 atmospheres)is not responsible for the disorganization of the cells butthat there is specific oxygen toxicity. 相似文献
12.
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
13.
The Heterotrophic Nutrition of Chlorella vulgaris (Brannon No. 1 Strain): With two Figures In the Text 总被引:1,自引:0,他引:1
A range of sugars, sugar alcohols, sugar phosphates, organicacids, and monohydric alcohols have been tested as carbon sourcesfor growth and as respiratory substrates using Chlorella vulgaris,Brannon I, grown in darkness. Much higher rates of growth and respiration were obtained withd-glucose than with any other substance tested. Ethanol (at0·005 M.) sustained both growth and respiration at c.50 per cent, of the level with glucose (0·028 M. or higher).Evidence was obtained that the organism can become adaptedto utilize d-galactose and sucrose as effective carbon sources.Sustained growth was not obtained with any of the other substancestested. The glucose monophosphates, methanol and certain organic acids(oxalacetate, -ketoglutarate, cis-aconitate, and pyruvate) clearlystimulated oxygen uptake but to a less extent than ethanol.The other substances tested were either inhibitory to respirationor inactive or of very low activity as substrates. The growth in darkness and in liquid culture of Chlorella whensupplied with d-glucose was insensitive to pH over the range4·5 to 7·0 and was markedly enhanced by a highlevel of aeration. Gains in cellular dry weight ranging from45 to 90 per cent, of the weight of d-glucose disappearing fromthe culture medium were recorded in growth experiments; measurementsof CO2 evolution in the Warburg indicated retention of up totwo-thirds of the glucose-C in cell material. 相似文献
14.
Inoculating Proctor barley leaves with Erysiphe graminis decreasedrates of photosynthesis, after an initial lag period, and increasedrespiration. Increasing the area inoculated progressively decreased ratesof photosynthesis, but the effects cannot be attributed to asimple loss of leaf area. When less than 30 per cent of a leafwas inoculated, decreases were equivalent to area losses greaterthan those inoculated; when more than 30 per cent was inoculatedthe photo-synthetic losses were equivalent to area losses lessthan those inoculated. Although the relative effects of E. graminis on photosynthesisand respiration were of the same order, the absolute effectson photosynthesis were greater than those on respiration. Inoculating30 per cent of a leaf decreased photosynthesis by 56mg CO2/dm2/hr from 12.9 in the uninoculated controls to 7.3.Respiration increased by 0.6 mg CO2/dm/hr, from 1.7 to 2.3- 相似文献
15.
The influence of salinity in the growing media on ribulose-1,5-bisphosphate (RuBP) carboxylase and on CO2 fixation by intactsugar beet (Beta vulgaris) leaves was investigated. RuBP carboxylase activity was mostly stimulated in young leavesafter exposure of plants for 1 week to 180 mM NaCl in the nutrientsolution. This stimulation was more effective at the higherNaHCO2 concentrations in the reaction medium. Salinity also enhanced CO2 fixation in intact leaves mostlyat rate-limiting light intensities. A 60 per cent stimulationin CO2 fixation rate was obtained by salinity under 450 µEm2 s1. At quantum flux densities of 150 µEm2 s1 (400700 nm) this stimulation was280 per cent. Under high light intensities no stimulation bysalinity was found. In contrast, water stress achieved by directleaf desiccation or by polyethylene glycol inhibited enzymeactivity up to fourfold at 1.2 MPa. Beta vulgaris, sugar beet, ribulose-1, 5-bisphosphate carboxylase, salt stress, water stress, carbon dixoide fixation, salinity 相似文献
16.
The Interdependence of Tillers in Lolium multiflorum Lam.--a Quantitative Assessment 总被引:5,自引:0,他引:5
Experiments were made to determine the extent of reciprocaltransfer of products (derived from the assimilation of 14CO2)between various parts of the young vegetative grass plant (Loliummultiflorum Lam.). When individual laminae on different tillerswere supplied with 14CO2, 4764 per cent of the fixedcarbon was exported after 24 h. The principal sinks were theroot system and the shoot or tiller to which the fed leaf wasattached. Other tillers also received significant quantitiesof radiocarbon. When whole tillers were supplied with 14CO2the percentage of fixed radiocarbon exported within 24 h rangedfrom 1431 per cent. Of this, 5074 per cent wasrecovered from the root system (except in the case of exportfrom the youngest tiller) but exchange of material between tillersalso occurred.A reciprocity diagram is presented and it is concludedthat despite the magnitude of the exchange no tiller showedan over-all net gain or loss. The main shoot and the tillersdiffered in the extent of their carbon exchange and in theirdegree of independence. The oldest daughter tiller of the mainshoot was the most independent and the main shoot most interdependent. 相似文献
17.
The Response of Phaseolus vulgaris L. to Root-zone Anaerobiosis, Waterlogging and High Sodium Chloride 总被引:1,自引:0,他引:1
Phaseolus vulgaris L. grown at a range of external concentrationsof NaCl (0 to 80 mM) responded differently to gaseous anaerobiosis(N2 gas) in nutrient solution or stagnant waterlogging of theroot-zone. With similar patterns of distribution of Na+ andCl- occurring in the plants with comparable NaCl treatments,and similar final concentrations of Na+ and Cl- in plants grownunder both root-zone conditions, rates of uptake of Na+ andCl- were much higher in plants with the stagnant waterloggedrootzones. After 72 h stagnant waterlogging, plant tops fromplants grown at 40 mM NaCl contained 1.42 per cent Na+ and 3.44per cent Cl- (d. wt basis) while after 9 days exposure to NaClwith gaseous anaerobiosis, leaf tissue contained 1.49 per centNa+ and 4.28 per cen Cl- (d. wt basis). Plants exposed to 40mM external NaCl were severely damaged within 72 h when grownwith stagnant waterlogged root-zones; those grown with N2 anaerobiosiscontinued growth and development over the 9 d period. Plantsgrown in nutrient solution showed changes in distribution andconcentration of Na+ and Cl- when oxygen concentration was reducedbelow 21 per cent O2 (full aeration). Phaseolus vulgaris. L., bean, mineral salt distribution, anaerobiosis, salinity, waterlogging 相似文献
18.
Chloroplasts were isolated using aqueous and nonaqueous procedures.Aqueous chloroplasts lost approximately 50 per cent, of theirsoluble proteins during isolation. Nonaqueous chloroplasts retainedall their soluble enzymes, but lost their ability to performthe light reactions of photosynthesis. It was possible to reconstitutea chloroplast system of higher activity by adding soluble enzymesfrom nonaqueous chloroplasts to protein-deficient aqueous chloroplasts.The properties of the reconstituted chloroplast system wereas follows: 1. The CO2 fixation rate of the reconstituted chloroplast system( 4 µM./. chlorophyll/hr.) was 34 times that ofthe aqueous chloroplasts ( I µM./. chlorophyll/hr.). Thefixation of aqueous chloroplasts isapparently limited in partby lack of soluble enzymes. 2. During light-fixation, the reconstituted chloroplast systemaccumulated PGA. This indicates that the reduction of PGA totriosephosphate is a rate-limiting step in this system. 3. It was possible to increase the CO2 fixation to 12 µM.CO2/mg. chlorophyll/ hr. by addition of ATP and TPNH to thesystem, but the reduction of PGA was still rate-limiting. 4. Further increase in the fixation rate was obtained by concentratingthe reaction mixture. Part of the striking differences of theCO2-fixing capabilities of chloroplasts in vivo and in vitrois caused by dilution effects. Extrapolation of the dilutioneffect to the protein concentration which exists in chloroplastsyields a CO2 fixation rate of approximately 30 µM./mg.chlorophyll/hr. 5. Inhibitors which are located in vivo outside the chloroplastsaffect the CO2 fixation in vitro. 6. Under consideration of the examined factors which influencethe CO2 fixation of isolated chloroplasts, it is possible toraise the fixation from approximately 1 per cent, to at least15 per cent, of the fixation in vivo. 相似文献
19.
Respiration rates of Lemna gibba fronds and Orobanche aegyptiacaand Lactuca sativa seedlings, were measured with a Clark typeoxygen electrode in the presence or absence of a carbon-dioxideabsorber (KOH) in the gas phase. Measured respiration ratesin the presence of KOH were 17-34% higher than in its absence.The suppression of respiration by high CO2 concentrations, [CO2],was confirmed by parallel studies of CO2 efflux, made by infraredgas spectrometry. These results are consistent with other reportsof reduced rates of respiration at high [CO2]. Measurements of respiration quotients of Lemna and Lactuca weremade at 0 and 100 Pa [CO2]. Results did not support the possibilityof induced dark fixation of CO2 at the ambient atmospheric [CO2]predicted for the next century (35-100 Pa). It is concluded that the numerous reports of respiration measurementsmade with O2 electrodes, in the absence of a CO2 absorber, maycontain a significant errorCopyright 1993, 1999 Academic Press Lemna gibba, Lactuca sativa, Orobanche aegyptiaca, CO2 accumulation, O2 electrode, respiration, dark CO2 fixation, respiration quotient, atmospheric CO2 相似文献
20.
BECCARI E.; D'AGNOLO G.; MORPURGO G.; POCCHIARI F. 《Journal of experimental botany》1969,20(1):110-112
In Daucus carota cells cultivated in vitro, the ammonium ionstimulates the incorporation of radioactivity from labelledglucose and labelled pyruvate into CO2 and into the residueinsoluble in 60 per cent (v/v) ethanol. There is a higher 14CO2production from [6-14C2] glucose than from [6-14C] glucose.These results suggest a possible stimulation of glycolysis bythe ammonium ion. 相似文献