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PubMed1966

Effect of oxygen on photosynthesis, photorespiration and respiration in detached leaves. I. Soybean.

The effect of O(2) on the CO(2) exchange of detached soybean leaves was measured with a Clark oxygen electrode and infrared carbon dioxide analysers in both open and closed systems.The rate of apparent photosynthesis was inhibited by O(2) while the steady rate of respiration after a few minutes in the dark was not affected. Part of the inhibition of apparent photosynthesis was shown to be a result of increased photorespiration. This stimulation of photorespiration by O(2) was manifested by an increase in the CO(2) compensation point.The differential effects of O(2) on dark respiration (no effect) and photorespiration (stimulation) indicated that these were 2 different processes.Moreover the extrapolation of the CO(2) compensation point to zero at zero O(2) indicated that dark respiration was suppressed in the light at least at zero O(2) concentration.

Journal Article↗
PubMed1966

Prediction of growth rate at different light levels from measured photosynthesis and respiration rates.

Light integrators with a linear response are not suitable for measuring the light climates of plants because plants are not linear integrators. It should be possible to make a quantitative allowance for this nonlinearity by using the CO(2) uptake curve of the plant. To test this, we have subjected white clover plants to different levels of constant light, comparing the rate of increase of total dry matter with the net rate of uptake of CO(2) per day. Temperature, humidity, daylength and nutrient supply were kept constant. The growth rate calculated from CO(2) uptake agreed well with the observed rate over the light levels tested (3.7-88 w.m(-2), 0.4-0.7 micron: 1 w.m(-2) = 10(3) erg . sec(-1) cm(-2)). All plants put on weight over the few days of the experiment, even those placed at light levels below their compensation point. The plants adapted their respiration rates to be a constant proportion of their growth rates. Most of the adaptation occurred within 24 hours of the light change. The adaptation of respiration has implications for models of light/growth relations in plant communities, almost all of which assume that respiration is proportional to leaf area and independent of growth rate or light level. The only model which does not is that of de Wit, and this gave good agreement with our results.

Journal Article↗
PubMed1967

Studies on the biochemistry and fine structure of silica shell formation in diatoms. Photosynthesis and respiration in silicon-starvation synchrony of Navicula pelliculosa.

Rates of photosynthesis, measured by oxygen electrode or by (14)CO(2) fixation, dark respiration and (32)P-phosphate incorporation are reported for the silicon-starvation synchrony of the fresh water diatom Navicula pelliculosa. During late exponential growth the rates were consistent with increase in carbon mass. During silicon starvation, rates of carbon dioxide fixation, oxygen evolution and (32)P incorporation fell, and the saturating light intensity decreased from 27,000 lux to 5000 lux. Reintroduction of silicon led to immediate transients in all parameters studied, followed by a prolonged increase in rate of dark respiration and a gradual increase in apparent photosynthesis. During release of daughter cells, the rates of dark respiration decreased as photosynthesis and (32)P incorporation increased. These results are discussed in relation to effects of silicon on the energy metabolism of the diatom.

Carbon Dioxide↗
PubMed1967

Growth and respiration patterns of snap bean fruits.

The relationship of respiration and growth of seed, pericarp tissue and whole fruit of snap beans (Phaseolus vulgaris L.) was studied. The whole fruit exhibited an apparent climacteric type of respiration pattern. This pattern resulted from an increase in CO(2) production by the enlarging seed followed by a rapid decrease in CO(2) evolution by the pericarp tissue, and the pattern was not associated with any concomitant increase in ethylene production. Therefore, the apparent climacteric respiration pattern of a developing bean fruit is not comparable to the phenomenon that occurs in other ripening fruits.

Journal Article↗
PubMed1968

Rapid starch synthesis associated with increased respiration in germinating lily pollen.

In vitro studies of germinating Lilium longiflorum pollen showed that starch increased more rapidly during the first 30 minutes of incubation than during the next several hours. The period of rapid starch formation coincided with the first period of high respiration. An estimate was made of the extra ATP utilized to form extra starch during the first 30 minutes, and this estimate indicates that starch synthesis accounts for a significant portion of the initial high rate of respiration. This pattern of respiration and starch synthesis was not altered when pollen germinated in a pentaerythritol medium that could not be metabolized instead of the standard sucrose medium.Sucrose was the predominant sugar in mature lily pollen. This sugar decreased 50% during several hours incubation in pentaerythritol culture medium. Reducing sugars remained low during incubation which may indicate that sucrose breakdown is regulated by the rate of utilization of hexose units.

Journal Article↗
PubMed1968

Influence of light intensity at different temperatures on rate of respiration of douglas-fir seedlings.

The rate of photorespiration of Douglas-fir seedlings was measured under different light intensities by: (1) extrapolating the curve for CO(2) uptake in relation to atmospheric CO(2) content to zero CO(2) content, and (2) measuring CO(2) evolution of the plants into a CO(2)-free airstream. Different results, obtained from these techniques, were believed to be caused by a severe restriction of the photosynthetic activity when the latter was used. With the first method, CO(2) evolution was lower than the dark respiration rate at low light intensity. For all temperatures studied (6 degrees , 20 degrees , 28 degrees ) a further increase in light intensity raised the CO(2) evolution above dark respiration before it leveled off. The rate of CO(2) evolution was stimulated by increase in temperature at all light intensities. With the CO(2)-free air method, CO(2) evolution in the light was less than dark respiration at all light intensities.

Journal Article↗
PubMed1970

Glycolytic control of respiration during aging of carrot root tissue.

Changes in respiration in aging carrot slices are correlated with a characteristic sequence of activation of the irreversible reactions of the glycolytic pathway. The induced "wound" respiration increases in two stages; these appear to correspond to a period of active synthesis, when ADP, produced in the cytoplasm from synthetic reactions, activates pyruvate kinase, and a period of readjustment when ATP, no longer reacting in synthetic reactions, activates phosphofructokinase. Although ATP is cited frequently as a negative effector of phosphofructokinase, unless the concentration of ATP at the site of phosphofructokinase is 50-fold higher than the concentration expressed per unit fresh weight of the tissue, it cannot act in this way in carrot slices. The activation of the oxidative pentose phosphate pathway observed by ap Rees and Beevers is restricted to the first stage of the induced respiration.

Adenine Nucleotides↗
PubMed1970

Changes in Respiration and Cyanide Sensitivity of the Barley Floret during Development and Maturation.

The 6-week period of development and maturation of the barley (Hordeum vulgare L.) floret from anthesis to harvest is characterized by two phases: an early phase of rapid increase in respiration rate and dry weight, and a late phase during which respiration decreased rapidly whereas dry weight remained unchanged. Consumption of O(2) by the embryo changed little during the entire developmental period, whereas O(2) uptake by the endosperm and the lemma and palea decreased significantly during the late phase.Maximal inhibition of O(2) uptake by cyanide in whole florets and floret parts coincided with maximal respiration and growth rates. Differences in sensitivity of embryo and endosperm to cyanide, as the floret matured, appeared to be related to developmental differences between these two tissues. Electron micrographs of embryo and endosperm cells are presented to illustrate some of their ultrastructural features, both at early and late stages of development. Increases in O(2) uptake and cyanide sensitivity of the caryopsis after the lemma and palea were removed suggested that the lemma, palea, and pericarp contributed partly to the increased resistance of the mature floret to cyanide by acting as barriers to gas exchange, thus restricting the movement of both cyanide and oxygen into the caryopsis.

Journal Article↗
PubMed1973

Changes in respiration, photosynthesis, adenosine 5'-triphosphate, and total adenylate content of ozonated pinto bean foliage as they relate to symptom expression.

The effect of 0.25 to 0.30 microliter per liter ozone on photosynthesis and respiration and on the ATP and total adenylate content of the primary leaves of pinto beans (Phaseolus vulgaris L.) was examined. Changes in these parameters over a 72-hour time period were correlated with the development of symptoms of ozone toxicity. Toxicity symptoms normally appeared within 24 hours. The content of ATP and total adenylates increased immediately following a 3-hour exposure to ozone. Photosynthesis was depressed initially, but returned to normal within 24 hours. Respiration was not always altered initially, but it was significantly stimulated within 24 hours. We interpret the results to mean that the changes in adenylate content and photosynthesis are early events in the initiation of ozone damage and that the change in respiration is a consequence rather than a cause of cellular injury.

Journal Article↗
PubMed1978

Confounding of alternate respiration by lipoxygenase activity.

The initial burst of respiratory activity (Q(o) (2)) of imbibing soybean (Glycine max [L.] Merr. var. Wayne) seed tissue is cyanide-insensitive, and sensitive to salicylhydroxamate: presumptive evidence for the presence of alternate respiration. The initial O(2) consumption is also highly sensitive to propyl gallate. Soybean lipoxygenase exhibits similar characteristics of insensitivity to cyanide and sensitivity to salicylhydroxamate and to propyl gallate. The initial burst of respiration is enhanced by the addition of linoleic acid, a lipoxygenase substrate. These results indicate that the conventional tests for alternate respiration in plant tissues can be confounded by lipoxygenase; they also suggest that propyl gallate can be used to assess the possible participation of lipoxygenase in the O(2) uptake by plant tissues.

Journal Article↗
PubMed1978

Effect of ethylene and carbon dioxide on potato metabolism: stimulation of tuber and mitochondrial respiration, and inducement of the alternative path.

The respiration of potato tubers (Solanum tuberosum var. Russet Burbank) which have been kept at room temperature for 10 days is stimulated upon subsequent treatment with C(2)H(4) (10 microliters per liter) and O(2). The respiratory rise reaches a peak in 24 to 30 hours and thereafter declines. Coincident with the rise in tuber respiration is an increase in the respiratory rates of fresh slices and isolated mitochondria. Slices and mitochondria from C(2)H(4)- and O(2)-treated tubers also display substantial resistance to CN, and the resistant respiration is inhibited by hydroxamates.The longer the tubers are stored after harvest, the less effective is C(2)H(4) in causing CN resistance in slices and mitochondria from treated tubers. Addition of 10% CO(2) to the C(2)H(4)-O(2) mixture, however, causes extensive CN resistance to develop, even in slices and mitochondria from old tubers. The results show that C(2)H(4), O(2), and CO(2) act synergistically to induce alternative path development in potatoes.

Journal Article↗
PubMed1979

Factors Influencing the Development of Cyanide-resistant Respiration in Potato Tissue.

Ethylene, cyanide gas, and volatalized ethanol, acetaldehyde, and acetic acid were applied in a continuous flow to whole potato tubers. Freshly cut slices were obtained periodically during the treatment, and showed a progressive development of a cyanide-resistant respiration. The application of the employed volatiles in 100% O(2) accelerated the onset and the magnitude of the cyanide-resistant respiration.These results show that, similar to ethylene and cyanide, the application of ethanol, acetaldehyde, or acetic acid can also lead to the development of cyanide-resistant respiration in whole potato tubers, and that this type of respiration is retained in freshly cut slices.

Journal Article↗
PubMed1980

Wounding Stimulates Cyanide-sensitive Respiration in the Highly Cyanide-resistant Leaves of Bryophyllum tubiflorum Harv.

The rate of respiration in sectioned leaves of Bryophyllum tubiflorum Harv. increases with decreasing section thickness. The rates of uninhibited respiration in 2- and 8-millimeter-thick sections are 74 and 46 microliters of O(2) per gram fresh weight of unruptured tissue per hour at 20 C, whereas the rate in the presence of cyanide is 31 microliters of O(2) in each case. The rates are unaffected by salicylhydroxamic acid, but cyanide and salicylhydroxamic acid together completely eliminate O(2) uptake. The capacity of the alternative respiratory pathway is thus initially high (estimated at 84% of the uninhibited respiratory rate in whole leaves) and remains constant but probably unexpressed subsequent to the rapid induction of wound respiration.

Journal Article↗
PubMed1981

Inhibitory effects of 2,3,5-triiodobenzoic Acid on ion absorption, respiration, and carbon metabolism in excised barley roots.

The ability of 2,3,5-triiodobenzoic acid (TIBA) to alter ion absorption, respiration, carbon metabolism, and the permeability of the cell membranes of excised barley roots has been examined. Roots pretreated in either H(2)O, KCl, or TIBA followed by treatment in KCl, TIBA, or KCl and TIBA demonstrated that inhibition of ion uptake due to TIBA was reversible. These studies also suggest that ions already accumulated within the vacuole remain sequestered after the addition of TIBA, whereas cytoplasmic ions leak out into the external medium. A 20-minute lag period was present prior to the onset of inhibition of O(2) consumption by TIBA. A b-type cytochrome from corn that is apparently associated with the plasmalemma and possibly involved in respiration or ion uptake, or both, was unaffected by TIBA. The addition of TIBA to treatment solutions resulted in the synthesis and accumulation of ethanol. Analysis of organic acids showed that only the malate concentration was affected by treatment with TIBA. A reduction of 26% was noted for malate in the presence of 2 micromolar TIBA. These combined results suggest that the inhibitory action of TIBA in barley roots involves an alteration of mitochondrial respiration and not a direct depolarization of the plasmalemma.

Journal Article↗
PubMed1981

Effect of Temperature and BASF 13 338 on the Lipid Composition and Respiration of Wheat Roots.

The fatty acid composition of wheat seedling roots changed in response to temperature. As temperature declined, the level of linolenic acid increased and the level of linoleic acid decreased. The distribution of phospholipid classes was not influenced by temperature. Phosphatidyl choline and phosphatidyl ethanolamine were the predominant phospholipids isolated and comprised 85% of the total lipid phosphorus. Smaller quantities of phosphatidyl glycerol, phosphatidyl inositol, phosphatidic acid, and phosphatidyl serine were isolated. The fatty acid composition of phosphatidyl choline and phosphatidyl ethanolamine were the same and temperature affected the fatty acid composition of both phospholipids in the same manner.Growth in the presence of the substituted pyridazinone, BASF 13 338 (4-chloro-5-dimethylamino-2-phenyl-3(2H)pyridazinone), reduced the level of linolenic acid and increased the level of linoleic acid in the phosphatidyl choline, phosphatidyl ethanolamine, and total polar lipid fractions. BASF 13 338 did not affect the levels of palmitate, stearate, and oleate or the distribution of phospholipid classes.Respiration rates of wheat root tips were measured over a range of temperatures. The respiration rate declined as the temperature decreased. Neither the temperature at which the tissue was grown nor BASF 13 338 treatment influenced the ability of root tips to respire at any temperature from 4 to 30 C. The results indicated that the relative proportion of linolenic acid to linoleic acid did not influence the plants ability to grow and respire over the range of temperatures tested.

Journal Article↗
PubMed1981

Use of Tetraethylthiuram Disulfide to Discriminate between Alternative Respiration and Lipoxygenase.

Mitochondria from axes of Glycine max (L.) Merr. cv. Chippewa 64 seedlings purified on discontinuous Percoll gradients exhibited classical cyanide-resistant respiration. These mitochondria also possessed lipoxygenase activity, as determined by O(2) uptake in the presence of 0.8 millimolar linoleic acid. This activity is inhibited by most known inhibitors of alternative respiration (i.e. hydroxamates and propyl gallate). Tetraethylthiuram disulfide (disulfiram) at 50 micromolar inhibited cyanide-resistant succinate oxidation by 90 per cent, whereas concentrations as high as 100 micromolar had no effect on lipoxygenase activity. Use of tetraethylthiuram disulfide allows discrimination between alternative respiration and lipoxygenase activity in mitochondria.

Journal Article↗
PubMed1982

Potentiating effect of pure oxygen on the enhancement of respiration by ethylene in plant storage organs: a comparative study.

A number of fruits and bulky storage organs were studied with respect to the effect of pure O(2) on the extent and time-course of the respiratory rise induced by ethylene. In one group, of which potato (Solanum tuberosum var. Russet) and carrot (Daucus carota) are examples, the response to ethylene in O(2) is much greater than in air. In a second group, of which avocado (Persea americana Mill. var. Hass) and banana (Musa cavendishii Lambert var. Valery) are examples, air and O(2) are equally effective. When O(2)-responsive organs are peeled, air and O(2) synergize the ethylene response to the same extent in parsnip (Pastinaca sativa), whereas O(2) is more stimulatory than air in carrots. In the latter instance, carrot flesh is considered to contribute significantly to diffusion resistance. The release of CO(2), an ethylene antagonist, is recognized as another element in the response to peeling.The potentiating effect of O(2) is considered to be primarily on ethylene action in the development of the respiratory rise rather than on the respiration process per se. On the assumption that diffusion controls O(2) movement into bulky organs and the peel represents the major diffusion barrier, simple calculations indicate that the O(2) concentration in untreated organs in air readily sustains respiration. Furthermore, in ethylene-treated organs in pure O(2), the internal O(2) concentration is more than enough to maintain the high respiration rates. Skin conductivity to O(2) is the fundamental parameter differentiating O(2)-responsive from O(2)-nonresponsive fruits and bulky storage organs. The large preceding the earliest response to ethylene, as well as the magnitude of the ethylene-induced respiratory rise, is also controlled by permeability characteristics of the peel.

Journal Article↗
PubMed1983

Temperature dependence of vegetative growth and dark respiration: a mathematical model.

A mathematical model of the processes involved in carbon metabolism is described that predicts the influence of temperature on the growth of plants. The model assumes that the rate of production of dry matter depends both on the temperature and the level of nonstructural carbohydrate. The level of nonstructural carbohydrate is determined by the rates of photosynthesis, growth, and maintenance respiration. The model describes the rate of growth and dark respiration, and the levels of carbohydrate seen in vegetative growth of carnation and tomato. The model suggests that the growth of plants at low temperatures is limited by a shortage of respiratory energy, whereas at high temperatures growth is limited by the shortage of carbohydrate. Thermoperiodism, wherein a warm day and cool night results in faster growth than does constant temperature, is explained by the model as an increase in the level of nonstructural carbohydrate which promotes the rate of growth relative to the rate of maintenance respiration.

Journal Article↗