Comparative Responses of Carbon Dioxide Outburst and Uptake in Tobacco.

Decker, John P.

doi:10.1104/pp.34.2.100

Cited by 48 publications

(34 citation statements)

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“…Independent experiments have established that photorespiration is fairly constant between the range of "zero" CO2 and 300 ppm (normal concentration) in the ambient atmosphere (18,19). If a shorter time than 45 min is used for the period of 14CO2 fixation in the assay, the light to dark ratio (see beloWv) is little affected (17).…”

Section: Characteristics Of Photorespirationmentioning

confidence: 99%

Plant Productivity and the Control of Photorespiration

Zelitch

1973

Proc. Natl. Acad. Sci. U.S.A.

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The Green Revolution of the last decade has seen the yield of some food crops at least doubled by genetic alterations of plant stature and the ability of plants to respond to increased fertilizer. Since only 5-10% of the dry weight of plants comes from minerals and nitrogen in the soil, it is becoming more difficult to obtain further increases in productivity by this approach. Even scientists associated with the Green Revolution believe they have reached a plateau by these methods (1). Therefore, the next large increases in productivity must come from increasing the 90-95% of the dry weight that comes from the assimilation of airborne CO2 during photosynthesis.The productivity of plants (dry weight per unit of ground area) is determined by the gross CO2 assimilation during photosynthesis minus the CO2 released during respiration. The "dark" respiration processes of green plants, which probably also occur as well in the light, are biochemically similar to those found in animal tissues and many microorganisms, and are essential for the growth and maintenance of plant cells. It is not certain whether all of the dark respiration is essential, or whether some portion of it may sometimes be uncoupled from ATP production. This wasteful portion of respiration could cause diminished productivity (2). However, it is well documented that many plant species and varieties respire away large portions of their recently fixed CO2 during illumination by an entirely different biochemical process of respiration, known as photorespiration. Since photorespiration is often much faster in terms of CO2 production than dark respiration, photorespiration greatly lowers plant productivity where this occurs. Some biochemical and plant breeding experiments will be described that hold promise for retention of much of the photorespired C02, leading to large increases in crop yields.Relation of net photosynthesis to productivity among speciesCrop species vary greatly in their yields of dry weight. For example, from statistics of average market yield in the United States (Table 1), one can calculate that the crop growth rate for maize silage, sorghum silage, and sugarcane (cane) is at least double that for spinach, tobacco (leaf plus stalk), and hay grasses (3). The higher-yielding leafy species all have low fluxes of photorespiration compared with the less efficient species. Table 2 contains typical values of CO2 assimilation taken from the literature; it shows that much faster rates are usually found in the higher-yielding tropical grasses and in some weeds, as compared with many common crop plantsincluding spinach, tobacco, and orchard grass-that are lower yielding. A large part of the differences in net photosynthesis between the efficient and nonefficient species can be explained by the much slower rate of photorespiration that is encountered naturally only in the efficient plants. Characteristics of photorespirationSince photorespiration is such an important process, it is interesting to speculate on why its discovery was so long delayed....

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Section: Characteristics Of Photorespirationmentioning

confidence: 99%

Plant Productivity and the Control of Photorespiration

Zelitch

1973

Proc. Natl. Acad. Sci. U.S.A.

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“…It has been reported that the rates of CO2 evolution by green leaves in light are affected by both O, concentration (6, 9, 11, 14, 29) and light intensity (3,6,15, 17,18,27). Decker (3) has shown that the post-illumination CO., outburst from tobacco at 33.5' was 3 times as large as that at 17.50 and Zelitch (34) has also shown that CO., evolution in light increases with a temperature increase from 250 to 350.…”

Section: Introductionmentioning

confidence: 99%

“…Decker (3) has shown that the post-illumination CO., outburst from tobacco at 33.5' was 3 times as large as that at 17.50 and Zelitch (34) has also shown that CO., evolution in light increases with a temperature increase from 250 to 350. Further data on the effect of temperature on CO. evolutioni in light is scanity although the response of CO.2 evolution in darkness has been well documented (19).…”

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confidence: 99%

Effects of Temperature on Photosynthesis and CO₂ Evolution in Light and Darkness by Green Leaves

Hew¹,

Krotkov²,

Canvin³

1969

Plant Physiol.

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Abstract.Using an open and a closed system of gas analysis, it was found that CO., evolution in light and in darkness from plant leaves (sunflower, soybean, watermelon, eggplant, and jackbean) have a different response to temperature. While the rate of CO, evolution in light increased with incre-asing temperature from 17 to 350 and then declined, the rate of CO, evolution in darkness increased continuously up to 400. The rate of CO, evolution in light was affected by light intensity. At 1800 ft-c and below 350 the rate of CO2 evolution in light was greater than in darkness, but above 350 it beoame lower than in darkness. The Q10 for CO2 evolution in light was consistently lower than that in darkness.Apparent photosynthesis decreased with increasing temperature, from 20 to 400 and its rate was affected 'by both light intensity and oxygen concentration. In leaves of dicotyledonous plants studied 'the decrease in apparent photosynthesis between 20 to 300 at 21 % 02 was shown to be due primarily to an increase in CO. evolution in light with relatively little effect on photosynthesis.In corn which does not evolve CO2 during illumination there was little effect of increasing temperature on the rate of apparent photosynthesis.The different response to temperature of CO., evolution in light and in darkness support the earlier conclusion that these are 2 different processes.It has been reported that the rates of CO2 evolution by green leaves in light are affected by both O, concentration (6, 9, 11, 14, 29) and light intensity (3,6,15, 17,18,27). Decker (3) has shown that the post-illumination CO., outburst from tobacco at 33.5' was 3 times as large as that at 17.50 and Zelitch (34) has also shown that CO., evolution in light increases with a temperature increase from 250 to 350. Further data on the effect of temperature on CO. evolutioni in light is scanity although the response of CO.2 evolution in darkness has been well documented (19). Additional knowledge would be of interest since there is increasing evidence to in.dicate that in green 'leaves the processes leading to the evolution of CO., in light and in darkness mav be different (6,9,11, 17,23 35-day old watermelon and eggplants were used. The closed and the open systems of gas analysis were the same as described previously ( 15, 16). The closed system was used to study the magnitude of the post-illumination CO. outburst, the CO., compen'sation point, and the effect of CO) concen,tration on -the rate of apparent photosynthesis at various temperattures. The open system. was used to studv the effect of temperature on the steadv rates of apparent photosynthesis at 0.03 % CO2 in air anid CO., evolution into CO-free air in light and in darkness.The various leaf temperatures were obtained by circulating water (Hakke temperature controller) of the desired temperature around the leaf chamber.

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“…The principle of this assay is attractive because it minimizes the problem of refixation of photorespiratory CO2 during photosynthesis, can be conducted over a wide range of CO2 and 02 concentrations, and is technically and conceptually straightforward. A serious limitation of closed systems for measuring the CO2 released was that photorespiration was based on an estimate of the tangent to the initial increase in CO2 concentration versus time in the recirculated gas (3,4). Even under ideal conditions, this approach would somewhat underestimate the rate.…”

mentioning

confidence: 99%

“…Also, both open and closed systems operate under nonsteady state conditions (14,16,19). The IRGA response model presented in the previous paper (16) (4,7,8,21). Increasing C02 concentrations appear to diminish the importance of photorespiration when compared to net photosynthesis (1,2,4,12,13).…”

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confidence: 99%

Estimation of Photorespiration Based on the Initial Rate of Postillumination CO₂ Release

Peterson¹

1983

Plant Physiol.

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An open system associated with an infrared gas analyzer was employed to study transients in CO2 exchange generated upon darkening preilluminated leaf discs of tobacco (Nicotiana tabacum vars John Williams Broadleaf and Havana Seed). An empirical formula presented previously enabled prediction of the analyzer response under nonsteady state conditions as a function of time and of the leaf CO2 exchange rate. A computer was used to evaluate parameters of the leaf CO2 release rate to provide an estimate of the initial rate of postillumination CO2 evolution and to produce maximal agreement between predicted aVnd observed analyzer responses. In 21% 02, the decline in rate of CO2 evolution upon darkening followed first order kinetics. Initial rates of CO2 evolution following darkening were relatively independent of the prior ambient CO2 concentrations. However, rates of photorespiration expressed as a fraction of net photosynthesis declined rapidly with increasing external CO2 concentration at 21% 02. Under normal atmospheric conditions, photorespiration was 45 to 50% of the net CO2 fixation rate at 320C and high irradiance. The rapid initial CO2 evolution observed upon darkening at 21% 02 was absent in 3% 02. Rates of photorespiration under normal atmospheric concentrations of CO2 and 02 as measured by the postillumination burst were highly dependent upon temperature (observed activation energy = 30.1 kilocalories per mole). The results are discussed with respect to previously published estimates of photorespiration in C3 leaf tissue.in a closed system, immediately after darkening (the PIB'). This rate of CO2 evolution declined rapidly with time. In spite of considerable effort aimed at elucidating the physiology, identity of metabolic intermediates, and regulation of photorespiration over the past 20 years, much uncertainty remains concerning the magnitude of this important process in C3 leaves. Existing assays are indirect and those which are conducted in light certainly underestimate photorespiration due to refixation of the released CO2 before it can escape the leaf and be detected (24). Although of comparative value, some methods such as CO2 evolution into C02-free air are conducted under nonphysiological conditions. Other assays, such as the CO2 compensation point as an indicator of photorespiration, are ambiguous or insensitive (8). Inhibition of net CO2 uptake by 21% 02 versus 3% 02 has been used, and the results are largely due to increased photorespiration but also include other inhibitory effects of high 02 concentrations (7).Decker (3, 4) reported that preilluminated leaves of C3 plants displayed vigorous CO2 evolution, detectable by IR gas analysis MATERIALS AND METHODS These are described in the companion paper (16). Unless stated otherwise, all correlation coefficients reported here are significant at P < 0.01. RESULTSInitial attempts to measure the PIB using the model described previously (16) indicated that net CO2 uptake continues for a short period immediately after darkening the samples. Thi...

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Comparative Responses of Carbon Dioxide Outburst and Uptake in Tobacco.

Cited by 48 publications

References 3 publications

Plant Productivity and the Control of Photorespiration

Plant Productivity and the Control of Photorespiration

Effects of Temperature on Photosynthesis and CO₂ Evolution in Light and Darkness by Green Leaves

Estimation of Photorespiration Based on the Initial Rate of Postillumination CO₂ Release

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Comparative Responses of Carbon Dioxide Outburst and Uptake in Tobacco.

Cited by 48 publications

References 3 publications

Plant Productivity and the Control of Photorespiration

Plant Productivity and the Control of Photorespiration

Effects of Temperature on Photosynthesis and CO2 Evolution in Light and Darkness by Green Leaves

Estimation of Photorespiration Based on the Initial Rate of Postillumination CO2 Release

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Product

Resources

About

Effects of Temperature on Photosynthesis and CO₂ Evolution in Light and Darkness by Green Leaves

Estimation of Photorespiration Based on the Initial Rate of Postillumination CO₂ Release