Enzymatic Regulation Of Photosynthetic Co2 Fixation In C3 Plants

Woodrow, Ian E.

doi:10.1146/annurev.arplant.39.1.533

Cited by 151 publications

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“…Leaf temperature was 25 °C, and the ambient relative humidity was 50%. The concentration of Rubisco active sites was calculated from A max using the equations of Woodrow and Berry (1988), and expressed on a dry weight basis using the overall leaf mass per area (LMA) for the plant.…”

Section: Plant Harvesting and Gas Exchangementioning

confidence: 99%

“…Similar to the growth responses, A max was reduced by some 24% in shade at high nitrogen (P<0.05), but there was no shade effect at low nitrogen. We also estimated the concentration of Rubisco active sites using the A max data, the measured intercellular CO 2 concentrations and respiration rates, and the assumption that Rubisco was 90% active under light saturation (Woodrow and Berry 1988; Table 2). The active site concentrations were approximately proportional to the A max values, indicating a reduction in Rubisco concentration of some 32% in shade under high nitrogen.…”

Section: Growth Biomass Allocation and Photosynthesismentioning

confidence: 99%

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Light alters the allocation of nitrogen to cyanogenic glycosides in Eucalyptus cladocalyx

2002

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Abstract. The effect of light on the partitioning of resources between photosynthesis and chemical defence was studied in Eucalyptus cladocalyx F. Muell. This species allocates up to 15% of leaf nitrogen to the constitutive cyanogenic glycoside, prunasin, making it an ideal system for studying resource allocation. By controlling the level of leaf nitrogen we were able to test the hypothesis that light limitation would result in the effective reallocation of nitrogen from the defensive to the photosynthetic apparatus. Seedlings were grown in full light or shade and supplied with 1.5 mM or 6 mM nitrogen in a 2 2 factorial design. We found that shading effected a decrease in the concentration of the cyanogenic glycoside, prunasin, and little if any change in the concentration of carbon-based secondary metabolites (total phenolics and condensed tannins). There was also significantly less prunasin, relative to total leaf nitrogen, chlorophyll concentration and carbon assimilation rates, when grown plants were grown in shade, particularly when there was an ample supply of nitrogen. This pattern is likely to be the result of relative changes in the energetic and resource costs of photosynthesis and defensive compounds at different photon flux densities.

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Section: Plant Harvesting and Gas Exchangementioning

confidence: 99%

Section: Growth Biomass Allocation and Photosynthesismentioning

confidence: 99%

Light alters the allocation of nitrogen to cyanogenic glycosides in Eucalyptus cladocalyx

2002

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“…In C 3 plants, gas exchange is a good indicator of in vivo Rubisco activity (von Caemmerer and Farquhar, 1981;Woodrow and Berry, 1988), with enzyme activity modulated in response to environmental stimuli (Woodrow and Berry, 1988;Sage et al, 1990). Rubisco activity in C 3 and C 4 plants is modulated by carbamylation of active sites and, in many cases, by the binding of specific inhibitors to carbamylated sites (Portis, 1992(Portis, , 1995.…”

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confidence: 99%

Modulation of Rubisco Activity during the Diurnal Phases of the Crassulacean Acid Metabolism Plant Kalanchoëdaigremontiana

Maxwell¹,

Borland²,

Haslam³

et al. 1999

Plant Physiology

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The regulation of Rubisco activity was investigated under high, constant photosynthetic photon flux density during the diurnal phases of Crassulacean acid metabolism in Kalanchoëdaigremontiana Hamet et Perr. During phase I, a significant period of nocturnal, C4-mediated CO2 fixation was observed, with the generated malic acid being decarboxylated the following day (phase III). Two periods of daytime atmospheric CO2 fixation occurred at the beginning (phase II, C4–C3 carboxylation) and end (phase IV, C3–C4 carboxylation) of the day. During the 1st h of the photoperiod, when phosphoenolpyruvate carboxylase was still active, the highest rates of atmospheric CO2 uptake were observed, coincident with the lowest rates of electron transport and minimal Rubisco activity. Over the next 1 to 2 h of phase II, carbamylation increased rapidly during an initial period of decarboxylation. Maximal carbamylation (70%–80%) was reached 2 h into phase III and was maintained under conditions of elevated CO2 resulting from malic acid decarboxylation. Initial and total Rubisco activity increased throughout phase III, with maximal activity achieved 9 h into the photoperiod at the beginning of phase IV, as atmospheric CO2 uptake recommenced. We suggest that the increased enzyme activity supports assimilation under CO2-limited conditions at the start of phase IV. The data indicate that Rubisco activity is modulated in-line with intracellular CO2 supply during the daytime phases of Crassulacean acid metabolism.

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“…The use of transgenic plants with altered amounts of Rubisco revolutionized the analysis of photosynthesis and its interaction with the whole plant (Quick et al, 1991b;Stitt and Schulze, 1994). However, because Rubisco constitutes such a large proportion of the protein in a leaf (up to 40%; Woodrow and Berry, 1988), a decrease in amounts of Rubisco substantially disrupts the N balance of the plant, making it difficult to establish direct links between photosynthesis and growth and allocation than if there were a more specific alteration in the rate of photosynthesis. What is required is genetic modification of a photosynthetic enzyme that accounts for a fraction of the N content in the leaf.…”

mentioning

confidence: 99%

Decrease in Phosphoribulokinase Activity by Antisense RNA in Transgenic Tobacco. Relationship between Photosynthesis, Growth, and Allocation at Different Nitrogen Levels1

et al. 1999

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3 ). The activation state of PRK increased as the amount of enzyme was decreased genetically at both levels of N. At high N a 94% decrease in PRK activity had only a small effect (20%) on photosynthesis and growth. At low N a 94% decrease in PRK activity had a greater effect on leaf photosynthesis (decreased by up to 50%) and whole-plant photosynthesis (decreased by up to 35%) than at high N. These plants were up to 35% smaller than plants with higher PRK activities because they had less structural dry matter and less starch, which was decreased by 3-to 4-fold, but still accumulated to 24% to 31% of dry weight; young leaves contained more starch than older leaves in older plants. Leaves had a higher ion and water content, and specific leaf area was higher, but allocation between shoot and root was unaltered. In conclusion, low N in addition to a 94% decrease in PRK by antisense reduces the activity of PRK sufficient to diminish photosynthesis, which limits biomass production under conditions normally considered sink limited.The relationship between photosynthesis and growth is a complex one, with growth rate not being well correlated with the rate of photosynthesis on a leaf-area basis . This is because growth also depends on the investment of biomass in growing sinks and investment in leaf area (Chapin et al., 1990;). There have been many thorough investigations of the relationship between photosynthesis, growth, environment, and genotype, but they have not provided definitive information on the relationship between photosynthesis and growth. This is because of the complex interaction between factors, so it has not been easy to decide whether changes in sink growth result from changes in photosynthesis or vice versa. The elucidation of the relationship between photosynthesis and growth requires specific changes in photosynthesis or sink growth independent of other changes. Genetic manipulation of enzymes involved in photosynthesis and/or sink processes provides a means to achieve this. The use of transgenic plants with altered amounts of Rubisco revolutionized the analysis of photosynthesis and its interaction with the whole plant (Quick et al., 1991b;Stitt and Schulze, 1994). However, because Rubisco constitutes such a large proportion of the protein in a leaf (up to 40%;Woodrow and Berry, 1988), a decrease in amounts of Rubisco substantially disrupts the N balance of the plant, making it difficult to establish direct links between photosynthesis and growth and allocation than if there were a more specific alteration in the rate of photosynthesis. What is required is genetic modification of a photosynthetic enzyme that accounts for a fraction of the N content in the leaf.PRK is one such enzyme, accounting for less than 1% of the protein in a leaf (Evans, 1989). Tobacco (Nicotiana tabacum L.) plants were transformed with an inverted cDNA encoding tobacco PRK (Knight and Gray, 1994). First, it was determined that the effect of this modification on photosynthesis under standard growth-chamber conditions was minim...

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Enzymatic Regulation Of Photosynthetic Co2 Fixation In C3 Plants

Cited by 151 publications

References 0 publications

Light alters the allocation of nitrogen to cyanogenic glycosides in Eucalyptus cladocalyx

Light alters the allocation of nitrogen to cyanogenic glycosides in Eucalyptus cladocalyx

Modulation of Rubisco Activity during the Diurnal Phases of the Crassulacean Acid Metabolism Plant Kalanchoëdaigremontiana

Decrease in Phosphoribulokinase Activity by Antisense RNA in Transgenic Tobacco. Relationship between Photosynthesis, Growth, and Allocation at Different Nitrogen Levels1

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