Submergence of Rice. I. Growth and Photosynthetic Response to CO2 Enrichment of Floodwater

1989 ◽  
Vol 16 (3) ◽  
pp. 251 ◽  
Author(s):  
TL Setter ◽  
I Waters ◽  
I Wallace ◽  
P Bhekasut ◽  
H Greenway

Growth and photosynthetic response of lowland rice following complete submergence is related to the concentration of CO2 dissolved in floodwater. Submergence of plants in stagnant solution at low CO2 concentration or solution gassed with air at 0.03 kPa CO2 (equilibrium of 0.01 mol m-3 dissolved CO2) decreased carbohydrates, and little or no growth occurred. Plants submerged in solutions gassed with 3-20 kPa CO2 in air (equilibrium of 0.9-6 mol m-3 CO2) showed at most small decreases in carbohydrates, and growth was up to 100% of the non-submerged plants. At pH 7.5, there was little net photosynthetic O2 evolution by detached submerged leaves even at high HCO3- concentrations, which suggests that these rice leaves could utilise only CO2 and not HCO3-. At pH 6.5, O2 evolution in solutions in equilibrium with 7.4 kPa CO2 was 3-4 fold higher than in solutions in equilibrium with 0.6 kPa CO2. Photorespiration was indicated by a decrease in the rate of net O2 evolution with increasing external O2. In stagnant solutions this reduction of O2 evolution was pronounced; at a CO2 concentration of 0.25 mol m-3 net O2 evolution ceased when the O2 concentration in the water had reached only 0.125 mol m-3. The requirement of photosynthesis for a combination of high CO2 concentrations and low external O2 was presumably due to slow diffusion of these gases in the unstirred layer of solution around the leaves.

1997 ◽  
Vol 24 (3) ◽  
pp. 407 ◽  
Author(s):  
Oula Ghannoum ◽  
Susanne von Caemmerer ◽  
Edward W. R. Barlow ◽  
Jann P. Conroy

The effect of CO2 enrichment and irradiance on the growth and gas exchange of two tropical grasses, Panicum laxum (C3) and Panicum antidotale (C4) were investigated. The two species were grown at either 350 (low) or 700 (high) µL L-1 CO2 concentration, under 40% (low) or 100% (high) of direct sunlight and supplied with ample water and nutrition. Elevated CO2 enhanced plant dry weight at both irradiances in the C3 species (1.41-fold and 1.71-fold increase at low and high light, respectively) but only at high light in the C4 species (1.28 fold increase). CO2 enrichment had no effect on the dry weight of P. antidotale, when stem development was suppressed by growth under artificial lighting. When measured at the CO2 concentration at which they were grown, assimilation rates were similar in the low and high CO2 grown plants, for both species. However, when measurements made at low CO2 were compared, CO2 assimilation rates of the high light, high CO2 grown C3 and C4 species were lower than those of their low CO2 grown counterparts. High CO2 strongly reduced the stomatal conductance of both species, while it affected the Rubisco content (30% decrease) of the high light C3 species only. This work shows clearly that C4 species can respond to CO2 enrichment under favourable growth conditions, and that acclimation to elevated CO2 in pasture grasses does not necessarily involve accumulation of non-structural carbohydrates or reduction of total N or soluble proteins in source leaves.


1997 ◽  
Vol 24 (2) ◽  
pp. 227 ◽  
Author(s):  
Oula Ghannoum ◽  
Susanne von Caemmerer ◽  
Edward W. R. Barlow ◽  
Jann P. Conroy

The effect of CO2 enrichment and irradiance on the growth and gas exchange of two tropical grasses, Panicum laxum (C3) and Panicum antidotale (C4) were investigated. The two species were grown at either 350 (low) or 700 (high) µL L-1 CO2 concentration, under 40% (low) or 100% (high) of direct sunlight and supplied with ample water and nutrition. Elevated CO2 enhanced plant dry weight at both irradiances in the C3 species (1.41-fold and 1.71-fold increase at low and high light, respectively) but only at high light in the C4 species (1.28 fold increase). CO2 enrichment had no effect on the dry weight of P. antidotale, when stem development was suppressed by growth under artificial lighting. When measured at the CO2 concentration at which they were grown, assimilation rates were similar in the low and high CO2 grown plants, for both species. However, when measurements made at low CO2 were compared, CO2 assimilation rates of the high light, high CO2 grown C3 and C4 species were lower than those of their low CO2 grown counterparts. High CO2 strongly reduced the stomatal conductance of both species, while it affected the Rubisco content (30% decrease) of the high light C3 species only. This work shows clearly that C4 species can respond to CO2 enrichment under favourable growth conditions, and that acclimation to elevated CO2 in pasture grasses does not necessarily involve accumulation of non-structural carbohydrates or reduction of total N or soluble proteins in source leaves.


2004 ◽  
Vol 31 (10) ◽  
pp. 1027 ◽  
Author(s):  
Xiongwen Chen ◽  
Kunshan Gao

Photosynthetic uptake of inorganic carbon and regulation of photosynthetic CO2 affinity were investigated in Skeletonema costatum (Grev.) Cleve. The pH independence of K1/2(CO2) values indicated that algae grown at either ambient (12 μmol L–1) or low (3 μmol L–1) CO2 predominantly took up CO2 from the medium. The lower pH compensation point (9.12) and insensitivity of photosynthetic rate to di-isothiocyanatostilbene disulfonic acid (DIDS) indicated that the alga had poor capacity for direct HCO3– utilisation. Photosynthetic CO2 affinity is regulated by the concentration of CO2 rather than HCO3–, CO32– or total dissolved inorganic carbon (DIC) in the medium. The response of photosynthetic CO2 affinity to changes in CO2 concentration was most sensitive within the range 3–48 μmol L–1 CO2. Light was required for the induction of photosynthetic CO2 affinity, but not for its repression, when cells were shifted between high (126 μmol L–1) and ambient (12 μmol L–1) CO2. The time needed for cells grown at high CO2 (126 μmol L–1) to fully develop photosynthetic CO2 affinity at ambient CO2 was approximately 2 h, but acclimation to low or very low CO2 levels (3 and 1.3 μmol L–1, respectively) took more than 10 h. Cells grown at low CO2 (3 μmol L–1) required approximately 10 h for repression of all photosynthetic CO2 affinity when transferred to ambient or high CO2 (12 or 126 μmol L–1, respectively), and more than 10 h at very high CO2 (392 μmol L–1).


2009 ◽  
Vol 36 (11) ◽  
pp. 893 ◽  
Author(s):  
Olavi Kiirats ◽  
Jeffrey A. Cruz ◽  
Gerald E. Edwards ◽  
David M. Kramer

It was previously shown that photosynthetic electron transfer is controlled under low CO2 via regulation of the chloroplast ATP synthase. In the current work, we studied the regulation of photosynthesis under feedback limiting conditions, where photosynthesis is limited by the capacity to utilise triose-phosphate for synthesis of end products (starch or sucrose), in a starch-deficient mutant of Nicotiana sylvestris Speg. & Comes. At high CO2, we observed feedback control that was progressively reversed by increasing O2 levels from 2 to 40%. The activity of the ATP synthase, probed in vivo by the dark-interval relaxation kinetics of the electrochromic shift, was proportional to the O2-induced increases in O2 evolution from PSII (JO2), as well as the sum of Rubisco oxygenation (vo) and carboxylation (vc) rates. The altered ATP synthase activity led to changes in the light-driven proton motive force, resulting in regulation of the rate of plastoquinol oxidation at the cytochrome b6f complex, quantitatively accounting for the observed control of photosynthetic electron transfer. The ATP content of the cell decreases under feedback limitation, suggesting that the ATP synthesis was downregulated to a larger extent than ATP consumption. This likely resulted in slowing of ribulose bisphosphate regeneration and JO2). Overall, our results indicate that, just as at low CO2, feedback limitations control the light reactions of photosynthesis via regulation of the ATP synthase, and can be reconciled with regulation via stromal Pi, or an unknown allosteric affector.


1983 ◽  
Vol 46 (1) ◽  
pp. 47-51 ◽  
Author(s):  
G. C. SMITH ◽  
S. C. SEIDEMAN ◽  
J. W. SAVELL ◽  
C. W. DILL ◽  
C. VANDERZANT

Lamb loins were allocated (30 loins/treatment) to three packaging treatments: (a) vacuum-packaged, (b) vacuum-packaged followed immediately by injection of a 20% CO2:80% N2 atmosphere, and (c) vacuum-packaged followed immediately by injection of a 40% CO2:60% N2 atmosphere. Loins in each packaging treatment were then assigned (6 loins/period) to one of five storage periods--0, 7, 14, 21 or 28 d. During storage, the CO2 concentration increased in vacuum packages (initial vs. 21 d) and decreased in modified atmosphere packages (initial vs. 7 or 28 d); O2 concentration was higher in vacuum packages than in modified atmosphere packages at every storage period. Vacuum packaging was superior to modified atmosphere packaging for maintaining desirable appearance of wholesale loins, particularly if the atmosphere contained a high CO2 concentration. Appearance of retail chops was not substantively affected by the method used to package (vacuum vs. modified atmosphere) the wholesale loin from which they originated. Palatability of cooked chops was not affected by packaging method in 28 or 30 comparisons among product from loins that had been stored for 0 to 28 d before organoleptic testing.


1982 ◽  
Vol 9 (5) ◽  
pp. 553 ◽  
Author(s):  
RT Furbank ◽  
MR Badger

Photosynthetic O2 evolution, O2 uptake and CO2 uptake by intact leaves from plants of the three C4 decarboxylation types were examined using mass-spectrometric gas-exchange and stable isotope techniques. All species showed a relative insensitivity of O2 uptake to CO2 concentration. The uptake rates observed were between 0.2 and 1 nmol O2 cm-2 S-1 at the CO2 compensation point. At ambient external CO2, NADP-malic enzyme type species showed the lowest average O2 uptake, phosphoenolpyruvate carboxykinase types the highest values, and NAD-malic enzyme types showed intermediate values for O2 uptake. These results are discussed in relation to the contributions to O2 uptake of ribulosebisphosphate oxygenase and photoreduction of oxygen.


2017 ◽  
Vol 44 (6) ◽  
pp. 573 ◽  
Author(s):  
Manuel E. Porras ◽  
Pilar Lorenzo ◽  
Evangelina Medrano ◽  
María J. Sánchez-González ◽  
Ginés Otálora-Alcón ◽  
...  

In many plant species, long-term exposure to elevated CO2 concentration results in a reduction in photosynthetic capacity, known as acclimation. This process is mainly explained by a feedback inhibition mechanism. The supply of a fraction of the nitrogen (N) in the nutrient solution as NH4+ can play an important role in the maintenance of photosynthetic activity and could mitigate the acclimation process. The aims of the present work were to study the photosynthetic response of sweet pepper (Capsicum annuum L.) to CO2 enrichment in Mediterranean greenhouse conditions, throughout the crop growth cycle and to evaluate the supply of NH4+ in the nutrient solution as a strategy to enhance the long-term response to CO2 at different levels of salinity. The experiment was conducted in two identical greenhouses: one with CO2 enrichment according to the ventilation, maintaining a high concentration when the vents were closed and a near-atmospheric level when the vents were open and one without. Sweet pepper plants were grown in both greenhouses, being irrigated with two levels of water salinity and two N sources: (i) NO3– and (ii) NO3– plus NH4+. A reduction in the response of photosynthesis to high CO2 concentration was found in the enriched plants after 135 days of CO2 supply, with respect to the reference plants. The leaf photosynthesis rate measured at high CO2 concentration showed a closer relationship with the leaf N concentration than the non-structural carbohydrate concentration. The relative yield gain of the CO2-enriched plants progressively decreased after reaching a maximum value; this was probably associated with the photosynthetic acclimation process. This decrease was delayed by the use of NH4+ in the nutrient solution at low salinity. Knowledge of the crop phase when acclimation to high CO2 concentration occurs can be the basis for deciding when to impose an early cessation of CO2 application, as a strategy to improve the economic efficiency of CO2 supply in Mediterranean conditions.


1996 ◽  
Vol 5 (3) ◽  
pp. 261-270 ◽  
Author(s):  
George Bowes ◽  
Joseph C. V. Vu ◽  
Mian W. Hussain ◽  
Arja H. Pennanen ◽  
L. Hartwell Allen

Although atmospheric CO2 concentration ([CO2]) has been up to 16-fold higher than at present, the past several million years have seen atypically low values. Thus, modern-day plants are adapted to cope with a low [CO2]/[O2] ratio. The present [CO2] does not saturate C3 photosynthesis, so its doubling produces an “efficiency effect”, but it is not always fully realized. Acclimation to high [CO2] during growth can down-regulate photosynthesis, presumably to optimize carbon acquisition and utilization. A primary factor in acclimation is a reduction in rubisco. Two crops, rice and soybean, were used to study this phenomenon. Rice photosynthesis and growth peaked at 500 μmol mol-1 , whereas soybean responded up to 990 μmol mol-1 . Rubisco concentration declined under CO2-enrichment and increasing temperatures, more so in rice than soybean. The rubisco kcat of rice was unaffected by growth [CO2] or temperature, but that from soybean was increased by both. In rice the capacity to handle carbohydrate, as measured by sucrose phosphate synthase activity was up-regulated by CO2 -enrichment, but not by temperature. Leaf carbohydrates were increased by [CO2], but decreased by higher temperatures, starch more so than sucrose. Even though C3 species differ in response to [CO2] and temperature, CO2 -enrichment can moderate adverse effects of temperature extremes.


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