scholarly journals CO2 Assimilation and Activities of Photosynthetic Enzymes in High Chlorophyll Fluorescence Mutants of Maize Having Low Levels of Ribulose 1,5-Bisphosphate Carboxylase

1988 ◽  
Vol 86 (2) ◽  
pp. 533-539 ◽  
Author(s):  
Gerald E. Edwards ◽  
Colin L. D. Jenkins ◽  
John Andrews
Keyword(s):  
Chlorophyll Fluorescence ◽  
Co2 Assimilation ◽  
Bisphosphate Carboxylase ◽  
Photosynthetic Enzymes ◽  
Low Levels

Rates of Photosynthesis Relative to Activity of Photosynthetic Enzymes, Chlorophyll and Soluble Protein Content Among Ten C4 Species

1984 ◽  
Vol 11 (6) ◽  
pp. 509 ◽  
Author(s):  
H Usuda ◽  
MSB Ku ◽  
GE Edwards
Keyword(s):  
Leaf Area ◽  
Soluble Protein ◽  
High Light ◽  
Soluble Protein Content ◽  
Bisphosphate Carboxylase ◽  
Unit Leaf ◽  
C4 Species ◽  
Photosynthetic Enzymes ◽  
Rate Of Photosynthesis ◽  
High Degree

Among 10 C4 species having a wide range in photosynthetic activity, the rates of photosynthesis/leaf area under high light were examined and compared with the chlorophyll and soluble protein content and the activities of several photosynthetic enzymes. The species examined were Digitaria sanguinalis, Echinochloa crus-galli, Microstegium vimineum, Panicum capillare, Panicum miliaceum, Paspalum dilatatum, Paspalum notatum, Pennisetum purpureum, Setaria lutescens, and Zea mays. The photosynthetic rates per unit leaf area ranged from 10 to 38 �mol CO2 fixed m-2 s-1. Among the 10 species there was a high degree of correlation of rate of photosynthesis/leaf area with soluble protein (r = 0.88), ribulose 1,5-bisphosphate carboxylase (r = 0.88) and pyruvate,PI dikinase (r = 0.94), but a lower correlation of photosynthetic rate/leaf area with phosphoenolpyruvate carboxylase (r = 0.74) and no significant correlation of photosynthetic rate/leaf area with chlorophyll content (r = 0.56). Among eight species of the NADP-malic enzyme C4 subgroup, there was a good correlation of photosynthetic ratelleaf area with NADP-malate dehydrogenase (r = 0.88) and NADP- malic enzyme (r = 0.92). Extractable activities of both the ribulose 1,5-bisphosphate carboxylase and the dikinase were generally close to the rate of photosynthesis. When comparing the activity per unit leaf area of one enzyme with another, generally a high degree of correlation was found among the species. The results suggest that a given C4 species tends to maintain a balance in the activities of several photosynthetic enzymes and that there is potential to estimate capacity for C4 photosynthesis under high light through determining activity of certain photosynthetic enzymes.

scholarly journals CO2 Assimilation, Photosynthetic Enzymes, and Carbohydrates of `Concord' Grape Leaves in Response to Iron Supply

2004 ◽  
Vol 129 (5) ◽  
pp. 738-744 ◽  
Author(s):  
Li-Song Chen ◽  
Brandon R. Smith ◽  
Lailiang Cheng
Keyword(s):  
Sucrose Concentration ◽  
Calvin Cycle ◽  
Sucrose Phosphate Synthase ◽  
Nonstructural Carbohydrates ◽  
Bisphosphate Carboxylase ◽  
Chl A ◽  
Photosynthetic Enzymes ◽  
Fe Content ◽  
Significant Difference ◽  
Assimilation Capacity

Own-rooted 1-year-old `Concord' grapevines (Vitis labruscana Bailey) were fertigated twice weekly for 11 weeks with 1, 10, 20, 50, or 100 μm iron (Fe) from ferric ethylenediamine di (o-hydroxyphenylacetic) acid (Fe-EDDHA) in a complete nutrient solution. As Fe supply increased, leaf total Fe content did not show a significant change, whereas active Fe (extracted by 2,2′-dipyridyl) content increased curvilinearly. Chlorophyll (Chl) content increased as Fe supply increased, with a greater response at the lower Fe rates. Chl a: b ratio remained relatively constant over the range of Fe supply, except for a slight increase at the lowest Fe treatment. Both CO2 assimilation and stomatal conductance increased curvilinearly with increasing leaf active Fe, whereas intercellular CO2 concentrations decreased linearly. Activities of key enzymes in the Calvin cycle, ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), NADP-glyceraldehyde-3-phosphate dehydrogenase (GAPDH), phosphoribulokinase (PRK), stromal fructose-1,6-bisphosphatase (FBPase), and a key enzyme in sucrose synthesis, cytosolic FBPase, all increased linearly with increasing leaf active Fe. No significant difference was found in the activities of ADP-glucose pyrophosphorylase (AGPase) and sucrose phosphate synthase (SPS) of leaves between the lowest and the highest Fe treatments, whereas slightly lower activities of AGPase and SPS were observed in the other three Fe treatments. Content of 3-phosphoglycerate (PGA) increased curvilinearly with increasing leaf active Fe, whereas glucose-6-phosphate (G6P), fructose-6-phosphate (F6P), and the ratio of G6P: F6P remained unchanged over the range of Fe supply. Concentrations of glucose, fructose, sucrose, starch, and total nonstructural carbohydrates (TNC) at both dusk and predawn increased with increasing leaf active Fe. Concentrations of starch and TNC at any given leaf active Fe content were higher at dusk than at predawn, but both glucose and fructose showed the opposite trend. No difference in sucrose concentration was found at dusk or predawn. The export of carbon from starch breakdown during the night, calculated as the difference between dusk and predawn measurements, increased as leaf active Fe content increased. The ratio of starch to sucrose at both dusk and predawn also increased with increasing leaf active Fe. In conclusion, Fe limitation reduces the activities of Rubisco and other photosynthetic enzymes, and hence CO2 assimilation capacity. Fe-deficient grapevines have lower concentrations of nonstructural carbohydrates in source leaves and, therefore, are source limited.

scholarly journals Effects of nitrogen form on growth, CO2 assimilation, chlorophyll fluorescence, and photosynthetic electron allocation in cucumber and rice plants

2011 ◽  
Vol 12 (2) ◽  
pp. 126-134 ◽  
Author(s):  
Yan-hong Zhou ◽  
Yi-li Zhang ◽  
Xue-min Wang ◽  
Jin-xia Cui ◽  
Xiao-jian Xia ◽  
...  
Keyword(s):  
Chlorophyll Fluorescence ◽  
Co2 Assimilation ◽  
Nitrogen Form ◽  
Rice Plants

Genetic Manipulation of Key Photosynthetic Enzymes in the C4 Plant Flaveria bidentis

1997 ◽  
Vol 24 (4) ◽  
pp. 477 ◽  
Author(s):  
Robert T. Furbank ◽  
Julie A. Chitty ◽  
Colin L.D. Jenkins ◽  
William C. Taylor ◽  
Stephen J. Trevanion ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Malate Dehydrogenase ◽  
Genetic Manipulation ◽  
Photosynthetic Performance ◽  
Covalent Modification ◽  
Wild Type ◽  
Bisphosphate Carboxylase ◽  
Photosynthetic Enzymes ◽  
Flaveria Bidentis

The NADP-malic enzyme type C4 dicot Flaveria bidentis (L.) Kuntze was transformed with antisense and cosense gene constructs that resulted in specific decreases in single photosynthetic enzymes. The enzymes targeted were ribulose-1,5-bisphosphate carboxylase/oxygenase [EC 4.1.1.39] (Rubisco), pyruvate, Pi dikinase [EC 2.7.9.1] (PPDK) and NADP malate dehydrogenase [EC 1.1.1.82] (NADP-MDH). These enzymes were chosen as targets because they have low activity compared to photosynthetic rates (Rubisco), are subject to complex covalent regulation (NADP-MDH), or both (PPDK). T1 progeny of a number of lines of these transformants were examined for the effects of these gene constructs on enzyme levels and photosynthetic performance. Rubisco antisense transformants expressing between 15 and 100% of wild-type enzyme activity were obtained. Pyruvate, Pi dikinase antisense lines were obtained with 40–100% wild-type levels. NADP malate dehydrogenase sense constructs caused a co-suppression of enzyme activity with some lines containing less than 2% of wild- type activity. Under saturating illumination, the control coefficients for these enzymes were determined to be up to 0.7 for Rubisco, 0.2–0.3 for PPDK and effectively zero for NADP-MDH. The implications of these observations for the regulation of photosynthetic flux and metabolism in C4 plants and the role of regulation by covalent modification are discussed.

scholarly journals CO2-assimilation and chlorophyll fluorescence as indirect selection criteria for host tolerance against Striga

Euphytica ◽  
2007 ◽  
Vol 160 (1) ◽  
pp. 75-87 ◽  
Author(s):  
Jonne Rodenburg ◽  
Lammert Bastiaans ◽  
Ad. H. C. M. Schapendonk ◽  
Peter E. L. van der Putten ◽  
Aad van Ast ◽  
...  
Keyword(s):  
Chlorophyll Fluorescence ◽  
Selection Criteria ◽  
Co2 Assimilation ◽  
Indirect Selection ◽  
Host Tolerance

A comparison of CO2 and O2 exchange patterns and the relationship with chlorophyll fluorescence during photosynthesis in C3 and CAM plants

1998 ◽  
Vol 25 (1) ◽  
pp. 45 ◽  
Author(s):  
Kate Maxwell ◽  
Murray R. Badger ◽  
C. Barry Osmond
Keyword(s):  
Chlorophyll Fluorescence ◽  
Tca Cycle ◽  
Co2 Assimilation ◽  
Phase Iii ◽  
O2 Evolution ◽  
Co2 Uptake ◽  
Cam Plants ◽  
Co2 Diffusion ◽  
Oxygenase Activity ◽  
C3 Species

Patterns of CO2 and O2 exchange coupled to chlorophyll fluorescence were examined in the CAM plants Kalanchoe daigremontiana Hamet et Perr. and Hoya carnosa (L.f.) R.Br., and compared with the C3 species Sonchus oleraceus L. Patterns of CO2 assimilation during phase IV of CAM were as predicted for Rubisco-mediated atmospheric CO2 uptake in both CAM plants. The high energetic demand during decarboxylation (phase III) was reflected in a high, CO2-insensitive rate of gross O2 evolution. Uptake of external CO2 was significant during phase III and was not saturated at 1.5% CO2. Gross oxygen uptake in the light was CO2 sensitive in H. carnosa during phases III and IV, which suggests Rubisco oxygenase activity. Oxygen consumption comprised around 33% linear electron transport in K. daigremontiana during phase III (7.5 µmol O2 m-2 s-1 at saturating CO2), but we cannot yet distinguish whether this involves the Mehler reaction or TCA cycle and oxidative phosphorylation during deacidification. CO2 assimilation was saturated at 0.2% CO2 when the epidermis was removed in K. daigremontiana, suggesting a large stomatal and mesophyll resistance to CO2 diffusion. A linear relationship was obtained between the quantum yield of gross O2 evolution and the quantum efficiency of PSII.

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