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Effects of Light and Darkness on Gaseous Exchange of Bean Leaves

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rate of respiration of chlorophyllose tissue in the light. The results of these experiments have varied with the experimental technique employed and the process, CO2 evolution or 02 consumption, being measured. Early work by Brown and associates (2,19) indicated that respiratory rates of Chlorella and several vascular plants were identical in light and darkness. Decker (5) has questioned the interpretation of these results, and in his own work with tobacco (Nicotiana lacngsdorfii and N. sanderae) has reported CO2 production in the light to be greater than in the dark (4). Subsequently Brown and Weis (3) and Weis and Brown (23) derived equations for correcting respiratory rates of algae measured in the gaseous phase of Warburg vessels to make them correspond to rates which prevail in the liquid phase. These equations are based primarily on the relative diffusion barrier to 02 and CO2 presented by the gas-liquid interface. Use of these equations resulted in substantially lower values for respiration rates. Values for CO2 evolu

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... If, at times, carboxylating enzyme activities are rate limiting, it follows that [C02]e would not be zero, even at saturating light. I t is therefore not possible to specify that mesophyll resistance calcu Photorespiratory measurement with isotopic CO2.-When 14C02 or 13COz is supplied to an illiminated leaf, the net inward flux of the labeled species is usually greater than that of 1 2 COZ' The extent to which the net influx of 1 2 COZ is less than that of the nonabundant species is presumed to be a minimal es timate of photorespiration (16,17,126,138,160,168,170,208,264,265,271,280). Assuming that each CO2 species diffuses independently according to its own concentration gradient, there would be, immediately prior to the intro-duction of the labeled species, a net influx of 1 2 C02(F.;, Figure 1) which is lower than the optimal influx, Fic, because of the contribution of Fm'i, Fmi, and Fpi to [1 2 C02];. ...
... Tamiya & Huzisige (239) noted that the inhibition was moderated as the CO2 concentration increased and suggested that O2 caused inactivation of enzymes associated with the dark phase of CO2 reduction. Franck (84) advanced the alternative postulate that O2 may act as a Hill oxidant, thereby competing with CO2 for light generated reducing power (29,33,113,208). It was observed (186) that the light-generated capacity to reduce CO2 in a subsequent dark phase was dis sipated more rapidly in air than in N2• Moreover, Mehler (175,176) showed that O2 could participate as a Hill oxidant in isolated chloroplasts. ...
... In Anacystis, stimulation continued nearly to light saturation (132,133) . Insofar as we know, stimulation by 0.3 light saturation is a characteristic feature of both algae (29,132,133,272) and leaves (139,196,197,(208)(209)(210) , including corn (140) . Elimination of stimulation with DCMU when photo system I light was used (101,132,201) points to the necessity of photo system II as the ultimate electron source for the photostimulated O2 uptake. ...
... Such differences have been demonstrated by many workers using diverse methods and organisms. Isotopic CO and 0 exchange 2 2 were studied by Semenenko (1964), Ozbun, Volk and Jackson (1964) and Goldsworthy (1966). Rates of uptake and exchange transients of CO have been analysed by 2 Decker (1957Decker ( , 1959 , Tregunna. ...
... inhibited by low intensity light, and accelerated at medium and high light intensities in two species of unicellular algae, Scenedesmus and Anacystis. These effects had different wavelength dependences.Ozbun, Volk and Jackson (1964) measured O2 and C02 exchange simultaneously (at timed intervals) with almass spectro- ...
... A variety of methods have been developed in leaves and phytoplankton to measure net O 2 production (NOP; Kok, 1948;Cornic et al., 1989;Laisk et al., 1992;Laisk and Oja, 1998). GOP has been measured directly using an 18 O tracer and mass spectrometry (Mehler and Brown 1952;Hoch et al., 1963;Ozbun et al., 1964;Radmer and Ollinger, 1980;Ruuska et al., 2000). Two general approaches have been used to measure GOP: ...
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A fundamental challenge in plant physiology is independently determining the rates of gross O2 production by photosynthesis and O2 consumption by respiration, photorespiration, and other processes. Previous studies on isolated chloroplasts or leaves have separately constrained net and gross O2 production (NOP and GOP, respectively) by labeling ambient O2 with 18O while leaf water was unlabeled. Here, we describe a method to accurately measure GOP and NOP of whole detached leaves in a cuvette as a routine gas exchange measurement. The petiole is immersed in water enriched to a δ18O of ~9,000‰, and leaf water is labeled through the transpiration stream. Photosynthesis transfers 18O from H2O to O2. GOP is calculated from the increase in δ18O of O2 as air passes through the cuvette. NOP is determined from the increase in O2/N2. Both terms are measured by isotope ratio mass spectrometry. CO2 assimilation and other standard gas exchange parameters are also measured. Reproducible measurements are made on a single leaf for more than 15 hours. We used this method to measure the light response curve of NOP and GOP in Phaseolus vulgaris at 21% and 2% O2. We then used these data to examine the O2/CO2 ratio of net photosynthesis, the light response curve of mesophyll conductance, and the apparent inhibition of respiration in the light (Kok effect) at both oxygen levels. The results are discussed in the context of evaluating the technique as a tool to study and understand leaf physiological traits.
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Publisher Summary This chapter discusses the methods used in the measurement of photorespiration. The photorespiration refers to the evolution of carbon dioxide (CO 2 ) from a green leaf in the light. The rate of photorespiration is determined from the amount of 14 CO 2 released by the leaf into a CO 2 -free gas stream after a period of photosynthesis in 14 CO 2 . In gas analysis systems, the components for measuring CO 2 and 14 CO 2 fluxes in leaves can be arranged to form several different types of gas circuits. The basic circuits can be used to estimate or measure CO 2 evolution from green leaves in the light. The compensated semi-closed or semi-open systems possess some advantages when used for the measurements of the rate of apparent photosynthesis however offer no advantage for the measurement of the rate of CO 2 evolution. The estimation of CO 2 evolution by extrapolation of the rate of apparent photosynthesis to a CO 2 concentration of zero is also described in the chapter.
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Differences among species in respiration rates in CO2-free air, in light and dark, were studied using the standard leaf chamber technique and the infrared carbon dioxide analyzer. Photosynthesis, transpiration and respiration were measured. In all species studied, rates of respiration were considerably higher in dark than in light. This effect was assumed to be due to reassimilation of the respiratory CO2. A resistance analogy model was derived to account for the apparent differences in internal recycling of CO2 among species; the differences were correlated with differences in maximum photosynthetic rates in normal air and optimal conditions (P310) and with internal resistances to CO2 diffusion (rk). Species with high P310 and low rk appear to reassimilate all the endogenous CO2, whereas other species with lower P310 and higher rk appear to reassimilate only a part of their respiratory CO2. Experiments with the photosynthetic inhibitor, 3-(3,4-dichlorophcnyl)-l,l-dimethyl urea (DCMU), indicated that species with zero respiration in CO2-free air and light release respiratory CO2 when photosynthesis is inhibited. It is concluded that the CO2 released in the presence of DCMU represents respiratory CO2 which recycles to photosynthesis under normal conditions.
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The relation between CO2-exchange in the pleurococcoid green alga Apatococcus lobatus and light, temperature and humidity was investigated, and the water-content in relation to vapour pressure was determined. The unwettable thalli achieve hydration equilibrium with the vapour pressure of the air, so that the measurement of physiological capabilities at defined water-potential is made possible. The relation between real CO2-uptake (“photosynthesis”) and water-potential at 10 and 20° C was determined. Fifty percent of the maximum capacity is reached at a water-potential of 142 bar (90% r.h.) and 10% is still reached at 370 bar (76% r.h.). The limit of measurable CO2-uptake is at about 520 bar (68% r.h.). When the algae are being dried “photosynthesis” and dark-respiration do not decrease proportionally; up to 25% (water-potential 252 bar, 83% r.h.) of the initial values the CO2-uptake is favoured, since respiration decreases first an increase of the apparent CO2-uptake is observed. The change in the ratio apparent CO2-uptake/dark-respiration, that is, the change in the CO2-balance in relation to temperature and hydration is discussed. The imbibition with liquid water has an unfavourable influence on the CO2-balance, and the relation between apparent CO2-uptake and dark-respiration of vapour-saturated thalli is almost optimal. At 20° C and 0,025 cal cm-2min-1 the most favourable CO2-balance corresponds to a water-potential of about 27–40 bar (97–98% r.h.) and to a saturation deficit of 35–43%. The CO2-exchange in these algae seems to be remarkably adapted to their aerophillic way of life.
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The rate of photorespiration in several grass species was shown to be highly variable and dependent on the species, genotype, and conditions under which the plants were grown. Photorespiration, measured as oxygen uptake, was negligible in Cenchrus ciliaris and Paspalum dilatatum but significant in Lolium spp. and Festuca arundinacea. There were significant differences in the rate of photorespiration among plants within a Lolium population of diverse origin and these differences were independent of the conditions under which the plants were grown. Among the temperate grasses there was a significant correlation between photorespiration and the CO2-compensation concentration and both parameters were very low in P. dilatatum. Plants grown in day/night temperatures of 15/10 °C compared with 25/20 °C had faster rates of dark respiration but slower rates of light respiration when measured at the same temperature. Photorespiration was faster than dark respiration although differences in respiration among plants in the light were not shown in the dark.
Article
Hamil grass and Siratro were grown as single plants in pots in controlled environment cabinets at a temperature favouring high growth rates and with adequate water and mineral nutrients. Leaf areas and dry weights of plant parts were recorded in two experiments, to which some of the plants were common. In the first experiment, weekly samples until 4 weeks from sowing provided data for the calculation of relative growth rates, net assimilation rates, and leaf area ratios. The relative growth rate of Hamil grass was almost twice that of Siratro and appears to be the highest yet recorded for any plant. The higher growth rate for the grass resulted from a high net assimilation rate, although the leaf area ratio was lower. The second experiment used Watson and Hayashi's method, in which plants are kept in darkness for a varying number of days to separate net assimilation rate into photosynthetic and respiratory components. Data were collected at 2 and 4 weeks from sowing. The high net assimilation rate of the grass was shown to result from a higher photosynthetic rate, despite a much greater respiration rate than in the legume. The technique used for estimating photosynthesis and respiration is discussed in relation to some of the assumptions that it makes.
Article
This paper presents an effective method to analyze the transmission performance of linkages that have joint clearance. Joint clearance was treated as virtual link to simplify the study. Equivalent kinematical pairs were used to model the motion freedoms caused by the joint clearances. With joint clearance presented, the number of unknown joint parameters is greater than the number of loop closure equations obtained in position analysis. Under kine-static and dynamic analysis, a mechanism should be in equilibrium at any configuration. The joint transmission wrench should equilibrate all externally applied wrenches for each link member. An extra set of constraint equations can be obtained since the joint transmission wrench screw should be reciprocal to the joint twist screw of the member. Then the mechanism positions can be solved with the loop closure and reciprocal equations simultaneously.
Article
1. Extra O2 uptake following illumination with linear polarized blue light was studied in DCMU treated leaves of Climatium dendroides, Brachythecium selebrosum (mosses), Elodea canadensis and Lemna trisulca.
Article
Recalculations of soybeanphotorespiration indicate that meanrates arecloser to16.1than5.6milligrams ofCO2per squaredecimeter perhouraspreviously reported. Photorespi- ration ofsoybean thusamountstoatleast a30% carbonturn- over of light-saturated photosynthesis. Photorespiration showednosignificant relationship tonetphotosynthesis. Nega- tivecorrelations werefoundbetweenC02efflux andstomatal resistance aswellasbetweencorrected photorespiration and residual intracellular resistance oftheleaftoCO2uptake. studies (1O). Bytheprocess ofsummation andaveraging: dB~~~ L(ext)j *(Rco2) i E L(int)iE i-l i2=l rmij L int)' = _
Article
Recalculations of soybean photorespiration indicate that mean rates are closer to 16.1 than 5.6 milligrams of CO2 per square decimeter per hour as previously reported. Photorespiration of soybean thus amounts to at least a 30% carbon turnover of light-saturated photosynthesis. Photorespiration showed no significant relationship to net photosynthesis. Negative correlations were found between CO2 efflux and stomatal resistance as well as between corrected photorespiration and residual intracellular resistance of the leaf to CO2 uptake.
Article
The roles of some chemical factors influencing leaf expansion were investigated using disks cut from the primary leaves of young plants of Phaseolus grown in subdued light. Mineral nutrients, cobalt, sucrose, GA and IAA or NAA at suitable concentrations all caused increases in fresh and dry weights of such disks. When all these substances were applied together the increases in diameter and in fresh and dry weight and cell number were very large and comparable with the rates found in intact leaf tissue. The response of disks to sucrose was found to be light dependent, and a number of other significant interactions were noted. Disks cut from older leaves, in which cell division had ceased, did not show large increases in fresh weight in response to treatment with sucrose, and in this such disks differ from those cut from leaves in which cell divisions are continuing. The possible significance of this is discussed and the roles of light and the other chemical factors investigated are assessed in terms of influence on cell division and expansion in disk tissue.
Article
The effect of oxygen concentration on the rate of CO2-uptake in continuous and intermittent light was studied as well as the CO2-fixation during a short dark period after light was turned off. In addition the dark respiration and the CO2-compensation point of attached and detached corn leaves were determined. Leaves of 4 to 22-day old plants were used as experimental material. A closed circuit system of an infrared carbon dioxide analyzer was employed to measure the rate of CO2-exchange. It was found that in an atmosphere consisting of 100 % oxygen, there was about 50 per cent inhibition of the rate of CO2-uptake in continuous and intermittent light compared to that in an atmosphere consisting of 21% oxygen. The same was true of the rate of CO2-fixation in darkness during a short period after the light was turned off. Since the response to oxygen concentration of the CO2-uptake in light and of the CO2-fixation in darkness after the light was turned off were similar, it is concluded that the fixation of CO2 in the short dark period represents an over- shoot of photosynthesis. The rate of dark respiration was little affected by the oxygen concentration in the ranges used in the experiments. The carbon dioxide compensation point which has been observed in leaves of 4 to 14-day old plants was not influenced by either oxygen concentration or light intensity. Since the changes in the rate of CO2-uptake due to changes in the concentration of oxygen and light intensity had no effect on the CO2-compensation point, it is concluded that a reabsorption of respiratory CO2 by photosynthesis could not account for the low value of this point. These results are interpreted as a further corroboration of the statement that the leaves of corn lack the process of photorespiration and that dark respiration is inhibited in light.
Article
Efflux of carbon dioxide in light and darkness was measured at low ambient CO2 concentrations in leaves of Rumex acetosa. Light carbon dioxide production (photo-respiration) was found to depend on irradiance and to differ from dark production as to the response to temperature and ambient concentrations of O2 and CO2. These observations support previously made suggestions that photorespiration follows a different metabolic pathway to dark respiration.
Article
Instrumentation has been developed for measuring absolute simultaneous assimilation of carbon dioxide and evolution of oxygen by photosynthetic systems in anaerobic atmospheres under flow conditions. Time-dependent photosynthetic quotients (PSQ) have bccn obtained. A detailed description of the instrument, including how it was constructed, calibrated and uscd for photosynthesis measurements, is presented. An important factor in the measurements was a clear understanding of the response time of the instrument. As with any flow system, flow rate, forward void volume and relative position of the O2 and CO2 sensors in the gas train were crucial to performance. Response time was measured by step-function calibrations mimicking PSQ of unity. Oxygen was generated using an in-line electrolysis cell driven by a programmable constant current source. Carbon dioxide assimilation was mimicked with the use of a programmable electronic gas blending system. Simultaneous step functions of these two key photosynthetic parameters fully characterized the response time and sensitivity of the instrument. In this report, time-dependent PSQ for spinach leaf disks and the microalga Scenedesmus D3 are reported. It is explicitly demonstrated that the transient approach to steady state is different for the two systems. Whereas the time-dependent PSQ for spinach depended on illumination history and reached a steady-state value less than 1, this was not the case for Scenedesmus.
Article
Full-text available
Mesophyll chloroplasts of three C(4) sub types, Panicum miliaceum (NAD-malic enzyme), Panicum maximum (PCK), and Zea mays (NADP-malic enzyme), were prepared from protoplast extracts and used to study the photoreduction of O(2). The processes of O(2) uptake and evolution in these preparations, which lack ribulose 1,5-bisphosphate carboxylase/oxygenase, were studied simultaneously using stable isotopes of O(2) and mass spectrometry. The responses of O(2) uptake to O(2) tension and addition of various substrates (3-phosphoglycerate, pyruvate, and oxaloacetate) were studied in detail. The addition of photosynthetic substrates differing in ATP to NADPH demands indicated that photoreduction of O(2) in these chloroplast preparations is linked to ATP production and strongly regulated by NADP(+) levels. The results clearly indicate that photoreduction of O(2) could be of physiological relevance in balancing the ATP to NADPH requirements of C(4) mesophyll chloroplasts.
Article
Experiments were performed, using rice, barley and Hydrangea leaves, to examine the re-assimilation of respiratory ¹⁴CO2 while photosynthesis is going on in an open air flow system. It was found that the leaves which had assimilated ¹⁴CO2 beforehand evolved, when kept under photosynthesizing conditions, three to four tenths (variable according to plant species and external conditions) of the amount of ¹⁴CO2 to be produced in the dark. Such an incomplete re-utilization of ¹⁴CO2 was observed also in spinach leaf homogenate as well as in the leaves which had previously absorbed ¹⁴C-glucose. The ¹⁴CO2 output in rice leaves was found to be accelerated by the light of high intensity. A possibility of light stimulation on the respiration was suggested.
Article
Photosynthesis in tobacco and 8 other plant species was measured at varied illumination and CO2 concentration. Measurements were made with an infrared gas analyzer in a closed recycling system. Curves of apparent photosynthesis vs light intensity and of apparent photosynthesis vs CO2 concentration can be interpreted as demonstrating that CO2 production was greater during photosynthesis than in the dark.
Article
In the course of some kinetic studies on photosynthesis of barley seedlings, it has been found that plants utilize C{sup 12}O{sub 2} faster than C{sup 14}O{sub 2}. The plants were placed in a closed system containing an infra-red absorption-cell for the analysis of total CO{sub 2} and an ionization chamber for the determination of C{sup 14}O{sub 2} in the gas phase, both instruments recording continuously. Carbon dioxide, containing about 2% C{sup 14}O{sub 2}, was introduced in the dark and the specific activity at this point taken as unity. After a short dark period, the lights were turned on and photosynthesis was allowed to take place. A figure shows the result of a typical experiment. During the initial dark period the specific activity fell because of dilution by inactive respired CO{sub 2}. However, as photosynthesis proceeded, the specific activity of the residual CO{sub 2} rose until, when only 1/6 of it remained, the specific activity reached a peak some 20% higher than it had been at the start of photosynthesis. At this point the steady respiratory dilution became an appreciable fraction of the total remaining CO{sub 2}, and the specific activity dropped rapidly.
Article
Whole spinach chloroplast fixed C14O2 for 1–10 min. in the light into products of the photosynthetic carbon cycle and into small amounts of glycolate-C14. During a subsequent 30 sec. period of filtration on a celite pad with saline solution, about 50% of the fixed C14 was converted to phosphoglycolate and glycolate and a small amount of glycine, all of which appeared in the supernatant fluid. No other C14-labeled product of photosynthesis was excreted by the chloroplasts.Added glycolate-C14 would not reenter the chloroplasts, but glyoxylate-C14 readily moved into the plastids where it was reduced to glycolate in the light. The results suggest that phosphoglycolate is actively excreted and then hydrolyzed to glycolate by a specific phosphoglycolic acid phosphatase. After oxidation of glycolate to glyoxylate by cytoplasmic glycolic acid oxidase, the two carbon moiety as glyoxylate may reenter the plastids and be reduced to glycolate by glyoxylic acid reductase with photosynthetic assimilatory power. These data suggest the possibility of a cyclic process for transport of carbon products and assimilatory power of photosynthesis between the plastids and the cytoplasm.
Article
A mass spectrometer inlet system has been devised which permits continuous sampling of gases dissolved in liquid phases. The principle is that of a semipermeable membrane which allows the dissolved gases, but not the liquid phases, to enter the mass spectrometer. The instrument permits rapid time response and high sensitivity. The application of this system to the study of reaction kinetics is described.
Article
The effect of light on oxygen uptake and production by algae has been studied. Illumination was found to influence oxygen uptake by two mechanisms. Oxygen uptake was found to be inhibited at low light intensities and accelerated at medium to high intensities. The inhibition of uptake was mainly sensitized by chlorophyll a. The effects of starvation, glucose supplementation, and DCMU inhibition on the oxygen uptake rates in the light are described.
The interrelation of photosynthesis and respiration in plants. A. N. Bakh Biochemical Institute
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DOMAN, N. G. 1958. The interrelation of photosynthesis and respiration in plants. A. N. Bakh Biochemical Institute, Academy of Science, USSR, Moscow p 15-20.
Absorption of 02 by green leaves in relation to the intensity and spectral composition of the light
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VASKRESENSKAYA, N. P. AND G. S. GRISHINA. 1960. Absorption of 02 by green leaves in relation to the intensity and spectral composition of the light. Fizol. Rast. 7: 497-506. (Soviet Plant Physiol. 7: 415-21).
Studies on photosynthetic processes I. The effect of light intensity on TPNH reduction, ATP forma-tion and CO2 assimilation in spinach chloroplasts
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TURNER, J. F., C. C. BLACK, AND M. GIBBS. 1962. Studies on photosynthetic processes I. The effect of light intensity on TPNH reduction, ATP forma-tion and CO2 assimilation in spinach chloroplasts. J. Biol. Chem. 237: 577-79.
Secretion of glycolic acid by chloroplasts. The photochemical apparatus, its structure and function
TOLBERT, N. E. 1958. Secretion of glycolic acid by chloroplasts. The photochemical apparatus, its structure and function. Brookhaven Symp. Biol. 11: 271-75.
The effects of light on respiration using isotopically enriched oxygen: An objection and alternate interpretation
DECKER, J. P. 1958. The effects of light on respiration using isotopically enriched oxygen: An objection and alternate interpretation. Plant. Sci. Bull. 4: 3-4.
The interrelation of photosynthesis and respiration in plants
DOMAN, N. G. 1958. The interrelation of photosynthesis and respiration in plants. A. N. Bakh Biochemical Institute, Academy of Science, USSR, Moscow p 15-20.