Effect of water stress on some enzymes of nitrogen metabolism in pigeonpea

Sheoran, I. S.; Luthra, Y. P.; Kuhad, M. S.; Singh, Randhir

doi:10.1016/0031-9422(81)85265-x

Cited by 27 publications

(8 citation statements)

References 23 publications

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“…Soluble sugars, free amino acids and ureides were analysed in nodules differing in P to assess their potential role in regulating intercellular water and P. Nodule soluble sugars ranged from 77 to 103 /u,mol gfw"' (Table 1), and nodule ureides ranged from 1-6 to 4.4/jLmol gfw~' (Table 1). Reported values for the concentrations of nodule soluble sugars and ureides are highly variable and dependent upon both plant (Fellows et al 1987;Khanna-Chopra, Koundal & Sinha 1984;Sheoran et al 1981;Walsh et al 1987Walsh et al , 1989) and environmental (Finn & Brun 1982;Swaraj, Sheoran & Garg 1988;Walsh et al 1987;Williams, Dejong & Phillips 1982) factors. The concentrations of nodule soluble sugars and ureides from experiments in this report (Table 1) were within the range for control treatments in the studies cited previously.…”

Section: Resultsmentioning

confidence: 99%

An osmotic hypothesis for the regulation of oxygen permeability in soybean nodules

Purcell

Sinclair

1994

Plant Cell & Environment

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Nodule permeability (F) controls the amount of O2 entering the nodule, and thereby the rates of both nodule respiration and N2 fixation. P may be regulated by changes in the effective thickness of a water-filled diffusion barrier in the nodule cortex. Regulation of diffusion barrier thickness was hypothesized to result from changes in the water content of intercellular spaces. Modulation of intercellular water would be a response to osmotic potential gradients in the tissue. To test this hypothesis, preliminary experiments examined three classes of solutes (soluble sugars, free amino acids, and ureides) in nodules of intact plants exposed to 10 or 21 kPa O2 for 24 h. Neither soluble sugars nor free amino acids in nodules were responsive to O2 treatments. However, nodule ureides accumulated after exposure to lOkPa O2 for 24h. A symplastic increase in nodule ureides under the lOkPa O2 treatment compared to the 21kPa O2 treatment may have removed water from intercellular spaces in the nodule cortex and increased P. In addition, the nodule cortex of intact plants was infiltrated with water, polyethylene glycol (PEG), KCI, or Na-succinate solutions to determine the effect of intercellular water and osmoticants on dinitrogenase activity and P. Results from infiltrating the apoplast of the nodule cortex with osmotic solutions indicated that both increases in intercellular water and decreases in the apoplastic water potential decrease dinitrogenase activity and P. Furthermore, the inability to recover dinitrogenase activity and P following the infiltration of the cortex with PEG compared to either KCI or Na-succinate treatments may indicate that recovery was dependent upon removal of the solute from the apoplast.

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Section: Resultsmentioning

confidence: 99%

An osmotic hypothesis for the regulation of oxygen permeability in soybean nodules

Purcell

Sinclair

1994

Plant Cell & Environment

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“…Plants were grown in sand culture as described previously [25]. Seventy days after sowing, plants were subjected to water stress by withholding irrigation.…”

Section: Methodsmentioning

confidence: 99%

Effect of water stress on photosynthesis and in vitro activities of the PCR cycle enzymes in pigeonpea (Cajanus cajan L.)

1985

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Leaf water potential was decreased by withholding irrigation to provide three levels of stress described as mild ({ie69-1}) moderate ({ie69-2}) and severe ({ie69-3}). The specific activity of NADP linked glyceraldehyde-3-phosphate dehydrogenase, phosphoglycerate kinase, aldolase, phosphogluco-isomerase and RuBP carboxylase decreased under mild stress, but the activity of phosphoglucomutase showed an increase whilst ribulose-5-phosphate kinase was least affected. With further decrease in water potential, the activity of NADP linked glyceraldehyde-3-phosphate dehydrogenase and aldolase showed a decrease, whereas, the activities of fructose-1,6-bisphosphatase, phosphoglycerate kinase, phosphogulcomutase and RuBP carboxylase increased. Net CO2 fixation decreased sharply with stress, whereas, respiration and photorespiration increased in moderate stress, but decreased under severe stress. Stomatal resistance also increased with decrease in water potential. It seems that in vitro enzyme activities of PCR cycle are not responsible for decreased photosynthesis in pigeonpea under short term water stress.

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“…1). This was explained by the findings that ammonium assimilation remains appreciably active under water stress conditions; that '•''NH-, incorporation into glutamic acid and glutamine was not impaired in stressed barley leaves (Hanson and Tully 1979); that '"NH, level remained low in stressed bean shoots supplied with "NH4+ (Frota and Tucker 1978b); that glutamine synthetase and glutamate synthase are active (Sheoran et al 1981); and that glutamate con-version to proline is stimulated under water stress conditions (Barnett and Naylor 1966, Morris et al 1969, Boggess et al 1976, Stewart 1978. Consequently, the possibility that the enhanced synthesis of proline may play a supplemental role for amide asparagine in ammonium detoxification and conservation of nitrogen, in the younger green leaves, cannot be excluded.…”

Section: Protein Metabolism and Proline Accumulationmentioning

confidence: 99%

Sources of proline‐nitrogen in water‐stressed soybean (Glycine max). II. Fate of ¹⁵N‐labelled protein

Fukutoku

Yamada

1984

Physiologia Plantarum

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The absorption of nitrate, protein metabolism and the source of nitrogen for proline synthesis were studied in soybean (Glycine max L. cv. Akisengoku) with 15N tracer technique under water stress conditions. The absorption of nitrate was sensitive to water stress and the flow of nitrate into the leaves completely ceased under severe stress conditions. Net protein loss from the water‐stressed leaves was attributable to both a decrease in synthetic activity and a stimulation of protein degradation. Proline and asparagine accumulated extensively in the severely water‐stressed plant tissues, especially in the younger green leaves. Fifty four % of the loss of leaf protein‐15N during the stress period was balanced by a gain in 15N in the free amino acids, 41% being found in proline and asparagine. The increase in 15N content of the free proline was 3 times greater than the decrease in 15N content of the protein‐bound proline in the leaf. The results indicate that the accumulation of proline in response to water stress was caused by enhanced synthesis and that the nitrogen source for this proline is the leaf protein. The possible association of these findings with stress tolerance is discussed.

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Effect of water stress on some enzymes of nitrogen metabolism in pigeonpea

Cited by 27 publications

References 23 publications

An osmotic hypothesis for the regulation of oxygen permeability in soybean nodules

An osmotic hypothesis for the regulation of oxygen permeability in soybean nodules

Effect of water stress on photosynthesis and in vitro activities of the PCR cycle enzymes in pigeonpea (Cajanus cajan L.)

Sources of proline‐nitrogen in water‐stressed soybean (Glycine max). II. Fate of ¹⁵N‐labelled protein

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Effect of water stress on some enzymes of nitrogen metabolism in pigeonpea

Cited by 27 publications

References 23 publications

An osmotic hypothesis for the regulation of oxygen permeability in soybean nodules

An osmotic hypothesis for the regulation of oxygen permeability in soybean nodules

Effect of water stress on photosynthesis and in vitro activities of the PCR cycle enzymes in pigeonpea (Cajanus cajan L.)

Sources of proline‐nitrogen in water‐stressed soybean (Glycine max). II. Fate of 15N‐labelled protein

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Sources of proline‐nitrogen in water‐stressed soybean (Glycine max). II. Fate of ¹⁵N‐labelled protein