Influence of Varying CO<sub>2</sub> and Orthophosphate Concentrations on Rates of Photosynthesis, and Synthesis of Glycolate and Dihydroxyacetone Phosphate by Wheat Chloroplasts

Usuda, Hideaki; Edwards, Gerald E.

doi:10.1104/pp.69.2.469

Cited by 36 publications

(16 citation statements)

References 16 publications

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“…The transition from 20%1o to 2% 02 in mannose-treated tissues is often accompanied (at leaf temperatures <23 C) by a series of dampening oscillations in the rate of CO, exchange which probably mirror similar oscillations in the RuBP pool size. All of the above is consistent with the existence of adenylate-dependent regulatory mechanisms which influence the RuBP supply and/or the kinetics of RuBP carboxylase oxygenase (1,3,8,15,17,20 (18,20). However, under conditions which favor Pglycolate synthesis, Pi deficiency might be offset by internal recycling of Pi released in the P-glycolate phosphatase reaction (18).…”

Section: Discussionsupporting

confidence: 56%

“…All of the above is consistent with the existence of adenylate-dependent regulatory mechanisms which influence the RuBP supply and/or the kinetics of RuBP carboxylase oxygenase (1,3,8,15,17,20 (18,20). However, under conditions which favor Pglycolate synthesis, Pi deficiency might be offset by internal recycling of Pi released in the P-glycolate phosphatase reaction (18). However, it should be noted that the significance of this photorespiratory recycling of Pi is dependent on a fraction of the glycerate either acting as an end product or being phosphorylated in the cytoplasm (2,18 …”

Section: Discussionsupporting

confidence: 56%

“…However, under conditions which favor Pglycolate synthesis, Pi deficiency might be offset by internal recycling of Pi released in the P-glycolate phosphatase reaction (18). However, it should be noted that the significance of this photorespiratory recycling of Pi is dependent on a fraction of the glycerate either acting as an end product or being phosphorylated in the cytoplasm (2,18 …”

Section: Discussionmentioning

confidence: 99%

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Effects of Mannose on Photosynthetic Gas Exchange in Spinach Leaf Discs

Harris¹,

Cheesbrough²,

Walker³

1983

Plant Physiol.

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When mannose is provided in the transpiration stream to spinach (Spinacia oleracea) leaf discs, a series of specific and nonspecific changes occur in CO2 and H20 vapor exchange as a function of feeding time. The initial increases in apparent photosynthesis and transpiration are nonspecific effects due to osmotic changes leading to passive stomatal opening. The mannose-specific effects are: (a) time-dependent changes in the CO2 concentration required for saturation; (b) complex kinetics of the inhibition of CO2 assimilation dependent on CO2 and 02 concentrations and the duration of feeding (high C02 and low 02 lead to rapid inhibitions of photosynthesis); (c) elimination of the capacity of 2% 02 to stimulate photosynthesis; and (d) oscillations in the CO2 exchange rate following transitions from 20% to 2% 02. The mannose-specific effects are reversible by orthophosphate. The mannose-dependent changes in gas exchange are attributed to altered IATPI/IADPI ratios.Previous work has established that when mannose is exogenously supplied to leaf discs it can lead to a progressive decline in the photosynthetic capacity of the tissue. This decline and the accompanying metabolic disturbances (10) have been attributed to the capacity of mannose to sequester Pi (4,11,12). In an effort to ascertain the early kinetics of the mannose-induced photosynthetic decline, and also the nature of the changes in the capacity of the leaf to respond to environmental parameters (02, C02), the photosynthetic gas exchange of spinach leaf discs was monitored during mannose feeding. MATERIALS AND METHODSMeasurements of CO2 and H20 vapor exchange were as reported previously (7). RESULTSWhen mannose was supplied to the transpiration stream of spinach leaf discs at mm concentrations (20-100 mM), several characteristic changes in the H20 vapor and CO2 exchange occurred. Leaf temperature dropped and transpiration and apparent photosynthesis increased within minutes of the start of feeding (Fig. 1) limits of the transpiration rate had not already been approached (data not shown). Following these initial nonspecific effects, a series of secondary changes occurred; these were only brought about by sugars which are known to sequester Pi (e.g. mannose and 2-deoxyglucose).When spinach leaf discs were enclosed within the Plexiglas chamber utilized in these experiments, they retained the characteristic C3 photosynthetic responses to changes in external partial pressures of 02 (2, 7). In saturating light at 25°C and with atmospheric concentrations of C02, the change from 20% 02 to 2% 02 increased apparent photosynthesis by 45% and lowered the mesophyll resistance (rm) from 3.8 to 2.2 s/cm (7). The kinetics of the transition to the higher rate under 2% 02 were without evident oscillations in the rate of CO2 exchange, and a new steady rate was generally reached in 2 to 5 min (Fig. 2).Following feeding with either deoxyglucose or mannose, there was progressive decline in the capacity of 2% 02 to stimulate photosynthesis, leading ultimately to a conditio...

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Section: Discussionsupporting

confidence: 56%

Section: Discussionsupporting

confidence: 56%

Section: Discussionmentioning

confidence: 99%

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Effects of Mannose on Photosynthetic Gas Exchange in Spinach Leaf Discs

Harris¹,

Cheesbrough²,

Walker³

1983

Plant Physiol.

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“…9). A similar desensitivity of CO2 (10), and Usuda and Edwards (19) have discussed the sparing effect of RuBP oxgenation on phosphate deficiency in experiments with isolated chloroplasts. It is possible that the rate of photosynthesis becomes insensitive to the ratio of carboxyation to oxygenation when phosphate is sequestered in the cytoplasm by mannose (10) or by the accumulation of carbohydrates in the leaf cells, because under these conditions the rate of CO2 assimilation may be controlled by the rate of release of phosphate in the cytosol (6,10,11).…”

Section: Effect Of Prior Photosynthesis On Subsequent Rate Of Net Co2mentioning

confidence: 79%

Inhibition of Photosynthesis by Carbohydrates in Wheat Leaves

1983

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The rate of net CO2 assimilation of mature wheat (Triticum aestivum L.) leaves in ambient air (21% 02. 340 microbars C02) declined with time of illumination at temperatures lower than 25°C, but not at higher temperatures, and the rate of decline increased when maintained in air with higher CO2 concentration (700425 microbars). In this latter case, the decline in the rate of net CO2 assimilation also occurred at high temperatures. Stomatal conductance also declined with time in some cases and stomata became more sensitive to C02, but this was not the primary cause of the decrease in CO2 assimilation because internal partial MATERIALS AND METHODSPlant Material. Triticum aestivum L. (cv Gabo) plants were grown from seed in a controlled environment cabinet in pots of soil. They were watered twice a day, and were fertilized every other day with nitrate-type Hewitt's solution containing: KNO3, 4 mM; Ca(NO3)2, 4 mM; MgSO4, 1.5 mM; NaH2PO4, 1.33 mM; EDTA FeNa, 60 gM; MnSO4, 10 uM; ZnSO4,1 ,uM; CuSO4,1 ALM; H3BO3, 50 uM; Na2MoO4, 0.5 jiM; NaCl, 0.1 mM; Co(NO3)2, 0.2 uM. The pH of the solution was 6.5. PPFD2 was about 600 to 700 gE _m 2 -s-'. The day/night temperature regime was 25/ 20°C with a daylength of 13 h. RH was between 60 and 80%.Gas Exchange Techniques. Wheat plants were selected from the growth cabinet near the end ofthe night period (10 AM). One or two attached recently mature leaves were enclosed in a photosynthetic chamber, which received an incident PPFD of 1000 iE -m2 -s-'. The rest of the plant, which was kept intact, was also illuminated. CO2 and water exchanges were measured in leaves using an open system gas analysis apparatus (2). Calculations of gas exchange parameters were made as before (20). Leaf to air water vapor pressure differences were maintained at about 8 to 12 mbar at 20 to 23°C and at 20 to 23 mbar at 30°C in most experiments.Light Responses of Photosynthesis. Net rate of CO2 assimilation (A) was measured in wheat leaves for 1 h at a PPFD of 1000 jiE *m-2.s-' to open stomata. Incident PPFD was measured with a quantum sensor (Lambda Instruments, model . PPFD was then decreased by interposing copper screens, and A was measured at every step. Finally, dark CO2 efflux was measured. Leaf temperature was kept constant during these procedures. These measurements were repeated after a period of 4 h

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“…This may increase the concentration of P, in the chloroplast stroma and enhance photophosphorylation (Viil, Ivanova, and Parnik, 1985). Product inhibition of photosynthesis due to increased levels of organic phosphates and decreased P, in the chloroplast stroma seems to occur more easily in the absence of oxygen than in its presence since less P ( in the chloroplastic environment is required for assimilate export from chloroplasts if p(O 2 ) is increased (Usuda and Edwards, 1982). The risk of product inhibition of photosynthesis due to decreased assimilate export from chloroplasts increases as temperature is decreased: A higher P, level in the chloroplastic environment is required for assimilate export from chloroplasts if temperature is low (Machler, Schnyder, and Nosberger, 1984).…”

Section: Atp Contentmentioning

confidence: 99%

Regeneration of Ribulose 1,5-bisphosphate and Ribulose 1,5-bisphosphate carboxylase/oxygenase Activity Associated with Lack of Oxygen Inhibition of Photosynthesis at Low Temperature

1986

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Schnyder, H., Machler, F. and Nosberger, J. 1986. Regeneration of ribulose 1,5-bisphosphate and ribulose 1,5-bisphosphate carboxylase/oiygenase activity associated with lack of oxygen inhibition of photosynthesis at low temperature.-J. exp. Bot. 37: 1170-1179.The nature of the lack of oxygen inhibition of C 3 -photosynthesis at low temperature was investigated in white clover (Trifolium repens L.). Detached leaves were brought to steady-state photosynthesis in air (34 Pa p(CO 2 ), 21 kPa p(O 2 ), balance N 2 ) at temperatures of 20 °C and 8°C, respectively. Net photosynthesis, ribulose 1,5-bisphosphate (RuBP) and ATP contents, and ribulose 1,5-bisphosphate carboxylase/oxygenase (RuBPCO) activities were followed before and after changing to 2-0 kPa At 20 °C, lowering /^Oj) increased net photosynthesis by 37%. This increase corresponded closely with the increase expected from the effect on the kinetic properties of RuBPCO. Conversely, at 8 °C net photosynthesis rapidly decreased following a decrease in p(O 2 ) and then increased again reaching a steady-state level which was only 7% higher than at 21 kPa piOJ. The steady-state rates of RuBP and associated ATP consumption were both estimated to have decreased. ATP and RuBP contents decreased by 18% and 33% respectively, immediately after the change in p(O 2 ), suggesting that RuBP regeneration was reduced at low piOJ) due to reduced photophosphorylation. Subsequently, RuBP content increased again. Steady-state RuBP content at 2-0 kPa p(O 2 ) was 24% higher than at 21 kPa p(Oj). RuBPCO activity decreased by 22%, indicating control of steady-state RuBP consumption by RuBPCO activity.It is suggested that lack of oxygen inhibition of photosynthesis at low temperature is due to decreased photophosphorylation at low temperature and low p (O 2 ). This may be due to assimilate accumulation within the chloroplasts. Decreased photophosphorylation seems to decrease RuBP synthesis and RuBPCO activity, possibly due to an acidification of the chloroplast stroma.

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Influence of Varying CO₂ and Orthophosphate Concentrations on Rates of Photosynthesis, and Synthesis of Glycolate and Dihydroxyacetone Phosphate by Wheat Chloroplasts

Cited by 36 publications

References 16 publications

Effects of Mannose on Photosynthetic Gas Exchange in Spinach Leaf Discs

Effects of Mannose on Photosynthetic Gas Exchange in Spinach Leaf Discs

Inhibition of Photosynthesis by Carbohydrates in Wheat Leaves

Regeneration of Ribulose 1,5-bisphosphate and Ribulose 1,5-bisphosphate carboxylase/oxygenase Activity Associated with Lack of Oxygen Inhibition of Photosynthesis at Low Temperature

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Influence of Varying CO2 and Orthophosphate Concentrations on Rates of Photosynthesis, and Synthesis of Glycolate and Dihydroxyacetone Phosphate by Wheat Chloroplasts

Cited by 36 publications

References 16 publications

Effects of Mannose on Photosynthetic Gas Exchange in Spinach Leaf Discs

Effects of Mannose on Photosynthetic Gas Exchange in Spinach Leaf Discs

Inhibition of Photosynthesis by Carbohydrates in Wheat Leaves

Regeneration of Ribulose 1,5-bisphosphate and Ribulose 1,5-bisphosphate carboxylase/oxygenase Activity Associated with Lack of Oxygen Inhibition of Photosynthesis at Low Temperature

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Influence of Varying CO₂ and Orthophosphate Concentrations on Rates of Photosynthesis, and Synthesis of Glycolate and Dihydroxyacetone Phosphate by Wheat Chloroplasts