Carbohydrate status and sucrose metabolism in mungbean roots and nodules

Chopra, Jyoti; Kaur, Narinder; Gupta, Anil Kumar

doi:10.1016/s0031-9422(98)00375-6

Cited by 13 publications

(8 citation statements)

References 29 publications

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“…Ethanol extracts of each sample were pooled and concentrated by evaporation at 50 °C under vacuum. Sucrose was determined by an enzymatic hydrolysis of the extract with acid invertase (Sigma I 4504) and then determining the glucose using glucose oxidase and peroxidase reaction (Chopra et al 1998). Quantity of glucose present before the invertase hydrolysis was also determined in the sugar extract.…”

Section: Quantification Of Assimilatesmentioning

confidence: 99%

Changes in the activities of carbon metabolizing enzymes with pod development in lentil (Lens culinaris L.)

2003

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carbon metabolism, sucrose metabolism, sucrose synthase, sucrose phosphate synthase, invertase, phosphoenol pyruvate carboxylase, malic enzyme, isocitrate dehydrogenase. AbstractActivities of some key enzymes of carbon metabolism sucrose synthase, acid and alkaline invertase, phosphoenol pyrnvate carboxylase, malic enzyme and isocitrate dehydrogenase were investigated in relation to the carbohydrate status in lentil pods. Sucrose remained the dominant soluble sugar in the pod wall and seed, with hexoses (glucose and fructose) present at significantly lower levels. Sucrose synthase is the predominant sucrolytic enzyme in the developing seeds of lentil (Lens culinaris L.). Acid invertase was associated with pod elongation and showed little activity in seeds. Sucrose breakdown was dominated by alkaline invertase during the development of podwall, while both the sucrose synthase and alkaline invertase were active in the branch of inflorescence. A substantial increase of sucrolytic enzymes was observed at the time of maximum seed filling stage (10-20 DAF) in lentil seed. The pattern of activity of sucrose synthase highly paralleled the phase of rapid seed filling and therefore, can be correlated with seed sink strength. It seems likely that the fruiting structures of lentil utilize phosphoenol pyruvate carboxylase for recapturing respired carbon dioxide. Higher activities of isocitrate dehydrogenase and malic enzyme in the seed at the time of rapid seed filling could be effectively linked to the deposition of protein reserves.

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Section: Quantification Of Assimilatesmentioning

confidence: 99%

Changes in the activities of carbon metabolizing enzymes with pod development in lentil (Lens culinaris L.)

2003

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“…Void volume was determined by eluting dextran blue from the sephadex G-25 column. For the extraction of acid and alkaline invertases, 20 mol.m -3 sodium phosphate buffer (pH 7.0) was used and the supernatant was made free from soluble sugars by passing it through sephadex G-25 column (Chopra et al 1998). …”

Section: Extraction Of Enzymesmentioning

confidence: 99%

Sink development, sucrose metabolising enzymes and carbohydrate status in turnip (Brassica rapa L.)

2001

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A b s t r a c tAccumulation of 60-70 % of biomass in turnip root takes place between 49-56 days after sowing. To understand the phenomenon of rapid sink filling, the activities of sucrose metabolising enzymes and carbohydrate composition in leaf blades, petiole and root of turnip from 42-66 days of growth were determined. An increase (2-3 folds) in glucose and fructose contents of roots accompanied by an increase in activities of acid and alkaline invertases was observed during rapid biomass accumulating phase of roots. The observed decrease in the activities of acid and alkaline invertases along with sucrose synthase (cleavage) in petiole during this period could facilitate unrestricted transport of sucrose from leaves to the roots. During active root filling period, a decrease in sucrose synthase (cleavage) and alkaline invertase activities was also observed in leaf blades. A rapid decline in the starch content of leaf blades was observed during the phase of rapid sink filling. These metabolic changes in the turnip plant led to increase in hexose content (35-37 %) of total dry biomass of roots at matnrity. High hexose content of the roots appears to be due to high acid invertase activity of the root.

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“…The enzymes involved in sucrose hydrolysis have been shown to be present in the plant fraction of mungbean nodules in an earlier study (Chopra et aL 1998). Pentose phosphate pathway, involving NADP-G6PD and NADP-6PGD, may operate in the bacteroids but in view of the low activities of these enzymes such a pathway is unlikely to play a quantitatively important role in the production of energy.…”

Section: Discussionmentioning

confidence: 96%

A comparative developmental pattern of enzymes of carbon metabolism and pentose phosphate pathway in mungbean and lentil nodules

2002

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The activities of enzymes of pentose phosphate pathway (PPP) viz. glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase and carbon metabolism viz. phosphoenol pyruvate carboxylase, NADP-isocitrate dehydrogenase and NADP-malic enzyme were measured in the plant and bacteroid fractions of mungbean (ureide exporter) and lentil (amide exporter) nodules along with the developing roots for comparison. The enzymes of pentose phosphate pathway in legume cytosol had higher activities at a stage of maximum nitrogenase activity and higher sucrose metabolism. However, bacteroids had only limited capacity for this pathway. The specific activities of these enzymes were greater in ureide than in anfide exporter. CO2 fixation via higher activity of phosphoenolpyruvate carboxylase in the plant part of the nodules in lentil might have been due to the greater synthesis of four carbon amino acids for amide export. The peak of NADP-isocitrate dehydrogenase in both legumes coincided with the pentose phosphate pathway enzymes at the time of high rates of sucrose metabolism and nitrogen fixation. Higher activities of NADP-malic enzyme were obtained in mungbean than in the lentil nodules. These findings are consistent with the role of these enzymes in providing reductant (NADPH) and substrates for energy yielding metabolism of bacteroids and carbon skeletons for ammonia assimilation.

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Carbohydrate status and sucrose metabolism in mungbean roots and nodules

Cited by 13 publications

References 29 publications

Changes in the activities of carbon metabolizing enzymes with pod development in lentil (Lens culinaris L.)

Changes in the activities of carbon metabolizing enzymes with pod development in lentil (Lens culinaris L.)

Sink development, sucrose metabolising enzymes and carbohydrate status in turnip (Brassica rapa L.)

A comparative developmental pattern of enzymes of carbon metabolism and pentose phosphate pathway in mungbean and lentil nodules

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