Growth responses to elevated CO2 in NADP-ME, NAD-ME and PCK C4 grasses and a C3 grass from South Africa

2001 ◽  
Vol 28 (1) ◽  
pp. 13 ◽  
Author(s):  
Stephanie J. E. Wand ◽  
Guy F. Midgley ◽  
William D. Stock
Keyword(s):  
Gas Exchange ◽  
Elevated Co2 ◽  
Nicotinamide Adenine Dinucleotide ◽  
Malic Enzyme ◽  
Leaf Growth ◽  
Growth Potential ◽  
Nicotinamide Adenine ◽  
Individual Species ◽  
C4 Grasses ◽  
Growth Responses

The potential use of C4 biochemical subtypes [nicotinamide adenine dinucleotide phosphate-malic enzyme (NADP-ME), nicotinamide adenine dinucleotide-malic enzyme (NAD-ME) and phosphoenolpyruvate carboxykinase (PCK)] as delimiters of plant functional types (PFTs) with distinct responses to rising atmospheric CO2 concentrations was investigated in South African grass species. Gas exchange and above-ground growth in ambient and elevated CO2 (360 and 660 µmol mol–1 , respectively) were determined in three NADP-ME species, two NAD-ME species, two PCK species and one C3 species, all excavated from the same field site. Plants were grown in open-top chambers in a greenhouse for 178 d. Net CO2 assimilation rates were only significantly increased in one NAD-ME species, but stomatal conductances decreased (in six out of eight species, by a mean of 46%) and instantaneous leaf water-use efficiency increased (in all species, by a mean of 89%) in elevated CO2. These responses did not differ between photosynthetic pathways. Parameters derived from photosynthetic CO2 and light response curves were also not differentially influenced by CO2 treatment between pathways. Gas exchange responses were generally poorly related to CO2 responsiveness. Significant increases in leaf growth and canopy leaf area in elevated CO2 were found in two NADP-ME species, whereas increases in non-leaf above-ground growth were measured in three species representing all three C4 subtypes. Growth responses in elevated CO2 were apparently not simply correlated with biochemical subtype characteristics, although the most significant responses (particularly at the leaf level) were found for the NADP-ME pathway. This result was more likely attributable to the significant positive correlation found between CO2 responsiveness of leaf growth and relative leaf regrowth potential of individual species, the latter being higher in the two responsive NADP-ME species. Therefore, categorisation of PFTs according to relative growth potential may be more appropriate for predictions of CO2 responsiveness in C4 grasses.

High vapour pressure deficit and low soil water availability enhance shoot growth responses of a C4 grass (Panicum coloratum cv. Bambatsi) to CO2 enrichment

1998 ◽  
Vol 25 (3) ◽  
pp. 287 ◽  
Author(s):  
Saman P. Seneweera ◽  
Oula Ghannoum ◽  
Jann Conroy
Keyword(s):  
Soil Water ◽  
Elevated Co2 ◽  
Vapour Pressure ◽  
Shoot Growth ◽  
Vapour Pressure Deficit ◽  
C4 Grasses ◽  
Growth Responses ◽  
High Co2 ◽  
C4 Grass ◽  
Shoot Mass

The hypothesis that shoot growth responses of C4 grasses to elevated CO2 are dependent on shoot water relations was tested using a C4 grass, Panicum coloratum (NAD-ME subtype). Plants were grown for 35 days at CO2 concentrations of 350 or 1000 µL CO2 L-1. Shoot water relations were altered by growing plants in soil which was brought daily to 65, 80 or 100% field capacity (FC) and by maintaining the vapour pressure deficit (VPD) at 0.9 or 2.1 kPa. At 350 µL CO2 L-1, high VPD and lower soil water content depressed shoot dry mass, which declined in parallel at each VPD with decreasing soil water content. The growth depression at high VPD was associated with increased shoot transpiration, whereas at low soil water, leaf water potential was reduced. Elevated CO2 ameliorated the impact of both stresses by decreasing transpiration rates and raising leaf water potential. Consequently, high CO2 approximately doubled shoot mass and leaf length at a VPD of 2.1 kPa and soil water contents of 65 and 80% FC but had no effect on unstressed plants. Water use efficiency was enhanced by elevated CO2 under conditions of stress but this was primarily due to increases in shoot mass. High CO2 had a greater effect on leaf growth parameters than on stem mass. Elevated CO2 increased specific leaf area and leaf area ratio, the latter at high VPD only. We conclude that high CO2 increases shoot growth of C4 grasses by ameliorating the effects of stress induced by either high VPD or low soil moisture. Since these factors limit growth of field-grown C4 grasses, it is likely that their biomass will be enhanced by rising atmospheric CO2 concentrations.

scholarly journals Effects of glucose on the cytosolic ration of reduced/oxidized nicotinamide-adenine dinucleotide phosphate in rat islets of Langerhans

1979 ◽  
Vol 184 (3) ◽  
pp. 697-700 ◽  
Author(s):  
S J H Ashcroft ◽  
M R Christie
Keyword(s):  
Islets Of Langerhans ◽  
Nicotinamide Adenine Dinucleotide ◽  
Malic Enzyme ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Nicotinamide Adenine ◽  
Rat Islets ◽  
Equilibrium Reaction ◽  
Rat Islets Of Langerhans

The maximal extractable activity of “malic” enzyme (EC 1.1.1.40) in rat islets of Langerhans was similar to that reported for liver. Thus “malic” enzyme may catalyse a near-equilibrium reaction in the cytosol of islets of Langerhans. Measurements of islet content of malate and pyruvate, the metabolite substrate and product of “malic” enzyme, were therefore used to calculate the cytosolic ration of [NADPH]/[NADP+]. This ratio was higher in islets incubated with 20 mM-glucose than in islets incubated with 2 mM-glucose.

Elevated CO2 increases the leaf temperature of two glasshouse-grown C4 grasses

2002 ◽  
Vol 29 (12) ◽  
pp. 1377 ◽  
Author(s):  
Katharina Siebke ◽  
Oula Ghannoum ◽  
Jann P. Conroy ◽  
Susanne von Caemmerer
Keyword(s):  
Gas Exchange ◽  
Elevated Co2 ◽  
Leaf Gas Exchange ◽  
Stomatal Closure ◽  
Co2 Assimilation ◽  
High Irradiance ◽  
Leaf Temperature ◽  
C4 Grasses ◽  
Co2 Partial Pressure ◽  
The Difference

This study investigates the effect of elevated CO2 partial pressure (pCO2)-induced stomatal closure on leaf temperature and gas exchange of C4 grasses. Two native Australian C4 grasses, Astrebla lappacea (Lindl.) Domin and Bothriochloa bladhii Kuntze, were grown at three different pCO2 (35, 70 and 120 Pa) in three matched, temperature-controlled glasshouse compartments. The difference between leaf and air temperature (ΔT) was monitored diurnally with thermocouples. ΔT increased with both step-increases of ambient pCO2. Average noon leaf temperature increased by 0.4 and 0.3°C for A. lappacea with the 35–70 and 70–120 Pa steps of pCO2 elevation, respectively. For B. bladhii, the increases were 0.5°C for both pCO2 steps. ΔT was strongly dependent on irradiance, pCO2 and air humidity. Leaf gas exchange was measured at constant temperature and high irradiance at the three growth pCO2. Under these conditions, CO2 assimilation saturated at 70 Pa, while stomatal conductance decreased by the same extent (0.58-fold) with both step-increases in pCO2, suggesting that whole-plant water use efficiency of C4 grasses would increase beyond a doubling of ambient pCO2. The ratio of intercellular to ambient pCO2 was not affected by short- or long-term doubling or near-tripling of pCO2, in either C4 species when measured under standard conditions.

scholarly journals Interactions of nicotinamide-adenine dinucleotide phosphate analogues and fragments with pigeon liver malic enzyme. Synergistic effect between the nicotinamide and adenine moieties

1987 ◽  
Vol 245 (2) ◽  
pp. 407-414 ◽  
Author(s):  
H J Lee ◽  
G G Chang
Keyword(s):  
Synergistic Effect ◽  
Nicotinamide Adenine Dinucleotide ◽  
Malic Enzyme ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Nucleotide Binding ◽  
Phosphate Group ◽  
Nicotinamide Adenine ◽  
Oxidative Decarboxylation ◽  
Wide Range ◽  
Pigeon Liver

The structural requirements of the NADP+ molecule as a coenzyme in the oxidative decarboxylation reaction catalysed by pigeon liver malic enzyme were studied by kinetic and fluorimetric analyses with various NADP+ analogues and fragments. The substrate L-malate had little effect on the nucleotide binding. Etheno-NADP+, 3-acetylpyridine-adenine dinucleotide phosphate, and nicotinamide-hypoxanthine dinucleotide phosphate act as alternative coenzymes for the enzyme. Their kinetic parameters were similar to that of NADP+. Thionicotinamide-adenine dinucleotide phosphate, 3-aminopyridine-adenine dinucleotide phosphate, 5′-adenylyl imidodiphosphate, nicotinamide-adenine dinucleotide 3′-phosphate and NAD+ act as inhibitors for the enzyme. The first two were competitive with respect to NADP+ and non-competitive with respect to L-malate; the other inhibitors were non-competitive with NADP+. All NADP+ fragments were inhibitory to the enzyme, with a wide range of affinity, depending on the presence or absence of a 2′-phosphate group. Compounds with this group bind to the enzyme 2-3 orders of magnitude more tightly than those without this group. Only compounds with this group were competitive inhibitors with respect to NADP+. We conclude that the 2′-phosphate group is crucial for the nucleotide binding of this enzyme, whereas the carboxyamide carbonyl group of the nicotinamide moiety is important for the coenzyme activity. There is a strong synergistic effect between the binding of the nicotinamide and adenosine moieties of the nucleotide molecule.

Crystal Structure of the Malic Enzyme fromAscaris suumComplexed with Nicotinamide Adenine Dinucleotide at 2.3 Å Resolution†,‡

Biochemistry ◽  
2002 ◽  
Vol 41 (22) ◽  
pp. 6928-6938 ◽  
Author(s):  
David E. Coleman ◽  
G. S. Jagannatha Rao ◽  
E. J. Goldsmith ◽  
Paul F. Cook ◽  
Ben G. Harris
Keyword(s):  
Crystal Structure ◽  
Nicotinamide Adenine Dinucleotide ◽  
Malic Enzyme ◽  
Nicotinamide Adenine
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