Reduced Sink Activity in Growing Shoot Tissues of Maize under Salt Stress of the First Phase may be Compensated by Increased PEP-Carboxylase Activity

2016 ◽  
Vol 202 (5) ◽  
pp. 384-393 ◽  
Author(s):  
B. W. Hütsch ◽  
T. Osthushenrich ◽  
F. Faust ◽  
A. Kumar ◽  
S. Schubert
Keyword(s):  
Salt Stress ◽  
Carboxylase Activity ◽  
Pep Carboxylase ◽  
Sink Activity ◽  
Growing Shoot

PEP-Carboxylase Activity: A Comparison of its Role in a C4 and a C3 Species Under Salt Stress

2009 ◽  
Vol 196 (3) ◽  
pp. 185-192 ◽  
Author(s):  
S. Hatzig ◽  
A. Kumar ◽  
A. Neubert ◽  
S. Schubert
Keyword(s):  
Salt Stress ◽  
Carboxylase Activity ◽  
Pep Carboxylase ◽  
C3 Species

Diurnal expression of five protein phosphatase type 2C genes in the common ice plant, Mesembryanthemum crystallinum

2007 ◽  
Vol 34 (7) ◽  
pp. 581 ◽  
Author(s):  
Ko Sato ◽  
Hiroaki Ohsato ◽  
Shunsuke Izumi ◽  
Saori Miyazaki ◽  
Hans J. Bohnert ◽  
...  
Keyword(s):  
Salt Stress ◽  
Protein Phosphatase ◽  
Continuous Light ◽  
Mesembryanthemum Crystallinum ◽  
Diurnal Fluctuation ◽  
Mrna Levels ◽  
Ice Plant ◽  
Carboxylase Activity ◽  
The Common ◽  
Protein Phosphatase Type

The common ice plant, Mesembryanthemum crystallinum L., is a eu-halophytic model species with an environmental stress-initiated switch from C3 photosynthesis to crassulacean acid metabolism (CAM). Phosphoenolpyruvate carboxylase activity in 6-week-old plants exposed to salt stress for 5 days was ~15-fold higher than before stress, indicating the salinity-dependent induction of the C3 to CAM transition. Five plant protein phosphatase type 2C (PP2C) genes were cloned, representative of five of the 10 plant PP2C sub-families. We measured mRNA levels of these PP2Cs and of myo-inositol 1-phosphate synthase (Inps1) in 6-week-old plants before (C3) and after (CAM) salt stress. Remarkably, four PP2C genes and Inps1 were expressed with a diurnal fluctuation in plants in C3 mode. After salt-induced CAM induction, the six genes were expressed with more prominent fluctuations than before stress, suggesting that these PP2C genes may be involved in the diurnal regulation of protein phosphorylation in CAM. Under continuous light treatment the expression of two PP2C genes continued to fluctuate, indicating that their expression is controlled by circadian rhythm.

Photosynthetic Enzyme Activities in the C3-C4 Intermediate Neurachne minor S. T . Blake (Poaceae)

1986 ◽  
Vol 13 (3) ◽  
pp. 399 ◽  
Author(s):  
PW Hattersley ◽  
NE Stone
Keyword(s):  
Malic Enzyme ◽  
Acid Decarboxylase ◽  
Decarboxylase Activity ◽  
Carboxylase Activity ◽  
Pep Carboxylase ◽  
C3 Plant ◽  
Bisphosphate Carboxylase ◽  
C3 Species ◽  
Species Activity ◽  
Pep Carboxykinase

The activities of eight key photosynthetic enzymes were measured in leaf blade extracts of the C3-C4 intermediate Neurachne minor S. T. Blake, its C3 and C4 relatives, C3-C4 Panicum milioides Nees ex Trin., and controls (all Poaceae). Phosphoenolpyruvate (PEP) carboxylase (PEPC) activity in N. minor (5.46 �mol mg Chl-1 min-1) is higher than previously reported for any other C3-C3 plant, and the ratio of ribulose-1,5-bisphosphate carboxylase activity to PEPC activity is lower than for P. milioides or C3 species. Activity of pyruvate,PI dikinase (up to 0.88 �mol mg Chl-1 min-1) is 3-5 times higher than in P. milioides. Assays of NADP-malic enzyme (NADP-ME), NAD-malic enzyme (NAD-ME) and PEP carboxykinase (PCK) show Paraneurachne muelleri (Hack.) S. T. Blake and Neurachne munroi (F. Muell.) F. Muell., N. minor's two close C4 relatives, to be NADP-ME type, as predicted from leaf anatomy. Aspartate and alanine aminotransferase activities in these species are higher than expected, however. N. minor (C3-C4) exhibits higher C4 acid decarboxylase activity than C3 species or P. milioides, for NADP-ME only (up to 1.07 �mol mg Chl-1 min-1). Our results suggest that N. minor possesses a limited C4 acid cycle, and that it is the most C4-like C3-C4 intermediate grass currently identified, comparable with some of the known C3-C4 Flaveria (Asteraceae) species.

The influence of pH on kinetic parameters of coleoptile phosphoenolpyruvate carboxylase. Relationship to auxin-stimulated dark fixation

1979 ◽  
Vol 57 (5) ◽  
pp. 543-547 ◽  
Author(s):  
Ceredwyn Smith ◽  
Ahmed Doo ◽  
Alan W. Bown
Keyword(s):  
Binding Affinity ◽  
Catalytic Efficiency ◽  
Enzymic Activity ◽  
Carboxylase Activity ◽  
Pep Carboxylase ◽  
Ph Values ◽  
Dark Fixation ◽  
Rate Limiting ◽  
Cytosol Ph

In vitro phosphoenolpyruvate (PEP) carboxylase activity from Avena coleoptile tissue was investigated over a range of pH values which include cytosol pH values. Increasing the pH from 7.0 to 7.5 increased optimal PEP carboxylase activity (Vmax) by over 100%. In the presence of rate-limiting 0.07 mM PEP, noncompetitive inhibition by 0.1 mM malate decreased from 80% at pH 7.1 to 50% at pH 7.5. The Km for PEP was not influenced by malate, but as the pH was increased from 7.1 to 7.5, the Km decreased from 0.16 to 0.08 mM. Over the same pH rise, the KI for malate inhibition increased from 0.04 mM to 0.09 mM. Fusicoccin had no detectable influence on enzymic activity. These results are discussed in relation to the stimulation of H+ excretion and dark CO2 fixation by indoleacetic acid and fusicoccin. The data indicate that any increase in cytosol pH, resulting from H+ excretion, would stimulate PEP carboxylase activity by promoting catalytic efficiency and binding affinity for PEP and by reducing the binding affinity for the inhibitor malate.

Phosphoenolpyruvate carboxylase activity from Avena coleoptile tissue. Regulation by H+ and malate

1978 ◽  
Vol 56 (4) ◽  
pp. 404-407 ◽  
Author(s):  
B. C. Hill ◽  
A. W. Bown
Keyword(s):  
Phosphoenolpyruvate Carboxylase ◽  
Enzyme System ◽  
Mass Action ◽  
Direct Inhibition ◽  
Carboxylase Activity ◽  
Pep Carboxylase ◽  
Action Effect ◽  
Avena Coleoptile ◽  
Oxaloacetic Acid ◽  
Regulatory Properties

Preparations of phosphoenolpyruvate (PEP) carboxylase activity from Avenu sativa coleoptile tissue were assayed by measuring the incorporation of labelled bicarbonate into a derivative of oxaloacetic acid or by coupling oxaloacetic acid production to malate dehydrogenase activity and the oxidation of NADH. Malate inhibition of PEP carboxylase activity was found to be noncompetitive, was not due to a mass action effect on the coupled enzyme system or to chelation of Mg2+, and probably involved direct inhibition of the enzyme by malate. Maximal PEP carboxylase activity was exhibited around pH 8.0 and increased 125% between pH 7.0 and pH 7.6. Inhibition by 4 mML-malate was virtually complete at pH 7.0 and decreased to 10% inhibition at pH 8. This information is discussed in the light of data which demonstrates that in response to IAA. coleoptile tissue accumulates malate and secretes H+. The regulatory properties of PEP carboxylase are consistent with a role in malate production which could resist increases in intracellular pH resulting from an auxin-stimulated H+ efflux.

scholarly journals EFFECT OF SALT (NaCl) ON PHOTOSYNTHESIS AND CARBOHYDRATES IN LEAVES OF TWO RAGI (ELEUSINE CORACANA (L.) GAERTN) VARIETIES

2021 ◽  
Vol 21 (No 1) ◽  
Author(s):  
R. Desingh ◽  
G. Kanagaraj
Keyword(s):  
Salt Stress ◽  
Crop Production ◽  
Photochemical Efficiency ◽  
Sucrose Phosphate Synthase ◽  
Eleusine Coracana ◽  
Carboxylase Activity ◽  
Bisphosphate Carboxylase ◽  
Photosynthetic Rates ◽  
Sucrose Phosphate ◽  
Phosphate Synthase

Salinity is one of the most widespread environmental threats to global crop production, especially in arid and semi-arid regions. Photosynthesis and carbohydrates were determined in two ragi (Eleusine coracana (L.) Gaertn) varieties (CO13 and PAIYUR-1), subjected to salt stress of different concentrations (0, 40, 80 and 120mM). Salinity was given as a basal dose and sampling was done in leaves on 30th Days. After Treatment (DAT). There was a marked variation in the photosynthetic rates and ribulose-1, 5-bisphosphate carboxylase activity between the two ragi varieties subjected to salt stress. Photosystem II (PSII) and sucrose phosphate synthase activities were also significantly reduced as measured by salt stressed conditions. The quantity of glucose and sucrose decreased with increasing salt stress while starch showed a reverse trend under salt-stressed conditions. The results revealed that CO-13 exhibits higher photosynthetic rates and activities of ribulose-1,5-bisphosphate carboxylase, sucrose phosphate synthase with photochemical efficiency of PSII compared to PAIYUR-1

scholarly journals Diffusion of CO2 across the Mesophyll-Bundle Sheath Cell Interface in a C4 Plant with Genetically Reduced PEP Carboxylase Activity

2018 ◽  
Vol 178 (1) ◽  
pp. 72-81 ◽  
Author(s):  
Hugo Alonso-Cantabrana ◽  
Asaph B. Cousins ◽  
Florence Danila ◽  
Timothy Ryan ◽  
Robert E. Sharwood ◽  
...  
Keyword(s):  
Bundle Sheath ◽  
Sheath Cell ◽  
C4 Plant ◽  
Carboxylase Activity ◽  
Pep Carboxylase ◽  
Bundle Sheath Cell ◽  
Cell Interface

Pep‐carboxylase activity during ammonium‐assimilation in wheat plants

1989 ◽  
Vol 12 (1) ◽  
pp. 85-94 ◽  
Author(s):  
P.A. Arnozis ◽  
A.J. Barneix
Keyword(s):  
Ammonium Assimilation ◽  
Carboxylase Activity ◽  
Pep Carboxylase

Effect of withdrawal of phosphorus on nitrate assimilation and PEP carboxylase activity in tomato

1993 ◽  
Vol 154 (1) ◽  
pp. 111-117 ◽  
Author(s):  
D. J. Pilbeam ◽  
I. Cakmak ◽  
H. Marschner ◽  
E. A. Kirkby
Keyword(s):  
Nitrate Assimilation ◽  
Carboxylase Activity ◽  
Pep Carboxylase
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