The Plant Acids

Ranson, S. L.

doi:10.1016/b978-1-4832-3243-0.50024-1

Cited by 35 publications

(14 citation statements)

References 55 publications

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“…For malonic acid, one of the carboxyl groups may come from oxidation in the production of acetyl CoA while the other comes directly from inorganic C, using acetyl CoA carboxylase. However, an alternative route to malonate (Ranson, 1965) involves a peroxidative decarboxylation of oxaloacetate, retaining the carboxyl group introduced by (C3 + C1) carboxylation and replacing that derived from, e.g. photosynthetic phosphoglycerate by oxidation of the adjacent oxo-group.…”

Section: Introductionmentioning

confidence: 99%

“…The ^^^C of carboxyl groups in malonate of legumes is not, apparently, known. As well as not knowing whether the acetyl CoA carboxylase pathway is the predominant pathway of malonic acid synthesis (see Section II), even the highest quoted malonate content of plants (Ranson, 1965) only requires 0-003 of total plant C to be fixed by acetyl CoA carboxylase if all malonate is synthesized by this pathway. Accordingly, this enzyme is ignored from now on.…”

Section: Introductionmentioning

confidence: 99%

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The influence of N metabolism and organic acid synthesis on the natural abundance of isotopes of carbon in plants

1990

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SUMMARY This paper relates the 13C/12C ratio of C3 plant material relative to that of source CO2 to the N source for growth, the organic N content of the plant, and the extent of organic acid synthesis. The 13C/12C ratio is quantified as Δ, defined as (δ13C substrate –δ13C product)/(1+δ13C product), where δ13C values of substrate or product (i.e. the samples) are defined as [13C/12C]sample]/[(13C/12C)standard]−1. The computation is performed by relating differences in plant composition as a function of N nutrition and acid synthesis to the fraction of plant C which is acquired via Rubisco and via other carboxylases. The fractional contribution of the different carboxylases to C gain is then related, using the known isotopic fractionations exhibited by these carboxylases, in a model to predict the final Δ of the plant (relative to atmospheric CO2). Application of this approach to a ‘typical’ C3 land plant yields predictions of the decrease of Δ relative to a hypothetical case in which all C is fixed via Rubisco. The predicted decreases range from 0–24 %, for NH4+ assimilation (which always occurs in the roots) to 2–80%, for NO3− assimilation in shoots with the organic acid salt which results from acid‐base balance, plus any additional organic acid salts plus free acids for a plant with a basal C:N molar ratio in organic material of 15. Intermediate values are predicted for symbiotic growth with N2, or where NO3− assimilation in root or shoot is accompanied by some acid‐base regulation via OH‐ loss to the root medium. Comparison with published data on the difference in Δ of Ricinus communis cultured with NH4+ or NO3− shows that the measured influence of nitrogen source is in the right direction (NO3− grown plants with a smaller Δ, i.e. a larger deviation from the value predicted for the absence of non‐Rubisco carboxylations) to be explained by the observed difference in composition and hence fractional C contribution by the various carboxylases. However, the effect of N source on Δ is greater than that predicted by the model, i.e. a 2.1 % decrease as opposed to a 0.10 % decrease. It is likely that the major cause of the difference in δ13C of the plants grown on the two N sources is a change in the ratio of transport and biochemical conductances of leaf photosynthesis. Such a change is quantitatively consistent with the lower water use efficiency of NH4+ ‐grown plants. The predicted, and observed, changes in Δ as a function of N source are of the same magnitude as those found for C3 terrestrial species grown at different temperatures or photon flux densities, or in environments yielding different water use efficiencies by changing root water supply relative to shoot evaporation potential. Variations in N source should be added to the factors which might alter δ of plants growing in the field.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The influence of N metabolism and organic acid synthesis on the natural abundance of isotopes of carbon in plants

1990

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“…In 0. oregana, conversion occurred equally well in the presence or absenice of light. This relationship between L-ascorbic acid metabolisnm and oxalic acid formation must be given careful consideration in attempts to explain oxalic accumulation in plants.Oxalic acid accumulates in certain species of plants such as spinach, woodsorrel, and begonia (6,10,12,23,24,26 Recently, Wagner and Loewus (27) described the conversion of L-ascorbic acid-1-'4C to labeled oxalic acid in detached vegetative apices of the lemon geranium (Pelargonium crispum). This observation has been extended by the present study to oxalateaccumulating plants.…”

mentioning

confidence: 99%

“…Oxalic acid accumulates in certain species of plants such as spinach, woodsorrel, and begonia (6,10,12,23,24,26). Its formation has been attributed variously to carbohydrate metabolism, interconversions of components in the tricarboxylic acid cycle, glycolate metabolism, and pyruvate metabolism (23).…”

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confidence: 99%

Metabolic Conversion of l-Ascorbic Acid to Oxalic Acid in Oxalate-accumulating Plants

Yang

Loewus²

1975

Plant Physiol.

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L-Ascorbic acid-l-11C and its oxidation product, dehydro-L-ascorbic acid, produced labeled oxalic acid in oxalateaccumulating plants such as spinach seedlings (Spinacia oleracea) and the detached leaves of woodsorrel (Oxalis stricta and 0. oregana), shamrock (Oxalis adenopylla), and begonia (Begonia evansiana). In 0. oregana, conversion occurred equally well in the presence or absenice of light. This relationship between L-ascorbic acid metabolisnm and oxalic acid formation must be given careful consideration in attempts to explain oxalic accumulation in plants.Oxalic acid accumulates in certain species of plants such as spinach, woodsorrel, and begonia (6,10,12,23,24,26 Recently, Wagner and Loewus (27) described the conversion of L-ascorbic acid-1-'4C to labeled oxalic acid in detached vegetative apices of the lemon geranium (Pelargonium crispum). This observation has been extended by the present study to oxalateaccumulating plants. MATERIALS AND METHODSSpinach seedlings (Spinacia oleracea, var. Bloomsdale) were grown under greenhouse conditions in a vermiculite-pearlite mixture. Twelve-day-old seedlings were detached from their roots and placed in vials containing the radioactive solution as described in earlier studies (27)

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“…3,27,28,41). The nightly acidification of the leaves results primarily from an enzymatic carboxylation of PEP with atmospheric CO2 which yields oxalacetate and, through subsequent reduction, malate (37).…”

mentioning

confidence: 99%

The Relation between Photosynthesis, Respiration, and Crassulacean Acid Metabolism in Leaf Slices of Aloe arborescens Mill

Denius¹,

Homann²

1972

Plant Physiol.

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Leaves and leaf slices from Aloe arborescens Mill. were used to study the interrelations between Crassulacean acid metabolism, photosynthesis, and respiration. Oxygen exchange of leaf slices was measured polarographically. It was found that the photosynthetic utilization of stored malic acid resulted in a net evolution of oxygen. This oxygen produetion, and the decrease in acid content of the leaf tissue, were completely inhibited by amytal, although the rate of respiratory oxygen uptake was hardly affected by the presence of this inhibitor of mitochondrial electron transport. Other poisons of respiration (cyanide) and of the tricarboxylic acid cycle (trifluoroacetate, 2-diethyl malonate) also were effective in preventing aciddependent oxygen evolution. It is concluded that the mobilization of stored acids during light-dependent deacidification of the leaves depends on the operation of the tricarboxylic acid cycle and of the electron transport of the mitochondria.A mits a closure of the stomata during the hot daytime by making CO, available for photosynthesis from the endogenous acid pools (24).Many striking resemblances exist between the mechanism of CO. assimilation in CAM and that in the C-dicarboxylic acid pathway of CO, fixation which is characterized by the appearance of labeled dicarboxylic acids as first stable products of the photosynthetic assimilation of 'CO2. Many data and concepts have recently been published on the physiological differences which separate C-plants from plants with the "classical" Calvin-Benson pathway of CO2 fixation (C,-plants). Investigations on CAM, however, have been few. This situation is reflected in Hatch and Slack's (13) review on the mechanisms of CO2 assimilation. The photosynthetic use of CO2 from stored malate in chlorophyllous tissue with CAM should be reflected in a light-dependent net evolution of oxygen even in the absence of external CO,. It was the aim of this work to devise a rapid and reproducible method for the measurement of 02 exchange in such tissue under various conditions. This approach was hoped to permit an analysis of the physiological conditions regulating the storage and photosynthetic utilization of CO2 in plants with CAM.The use of intact leaves was not desirable because their gas exchange is influenced by the activity of the stomata and by the diffusion of gases through the bulky tissue. Sectioning of the leaf would lessen, or eliminate, such problems and facilitate the entry of added inhibitors and other substances. Bruinsma (6) had observed, however, that CAM was adversely affected when Bryophyllum leaves were sliced. This appeared to have been due to actions of leached tannins and other phenolic compounds. Therefore, we had to find a plant which was relatively free of such potentially inhibitory compounds. This criterium eliminated nearly all plants which had been used by other investigators in the past, e.g., from the genera Bryophyllum, Sedum, and Kalanchoe. Leaves from Aloe arborescens Mill. (Liliaceae), however, had a very low conten...

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The Plant Acids

Cited by 35 publications

References 55 publications

The influence of N metabolism and organic acid synthesis on the natural abundance of isotopes of carbon in plants

The influence of N metabolism and organic acid synthesis on the natural abundance of isotopes of carbon in plants

Metabolic Conversion of l-Ascorbic Acid to Oxalic Acid in Oxalate-accumulating Plants

The Relation between Photosynthesis, Respiration, and Crassulacean Acid Metabolism in Leaf Slices of Aloe arborescens Mill

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