Manipulating Agricultural Plants for a Future High CO2 Environment

1992 ◽  
Vol 40 (5) ◽  
pp. 421 ◽  
Author(s):  
M Badger
Keyword(s):  
Elevated Co2 ◽  
Elevated Temperatures ◽  
Plant Performance ◽  
C3 Plants ◽  
Dry Matter Accumulation ◽  
Plant Resources ◽  
C3 Plant ◽  
High Co2 ◽  
Net Assimilation ◽  
Co2 Environment

This paper discusses the potential ways in which C3 plant performance may benefit from a future high-CO2 environment. These include increases in the efficiencies for light, nitrogen and water utilisation, particularly at elevated temperatures, resulting from the improvement which will occur in the performance of the primary carboxylating enzyme, Rubisco. However, while growth experiments at elevated CO2 indicate that C3 plants show stimulation of dry matter accumulation, the potential gains are greatly ameliorated by a redistribution of plant resources. This primarily occurs via a reduction in the leaf area ratio which offsets increases in the net assimilation rate. In addition, there may be an overcommitment of nitrogen in key photosynthetic components such as Rubisco and the thylakoid electron transport system. It is concluded that plants may not be genetically adapted to optimise their growth and performance at elevated CO2 and that consideration should be given to exploring avenues for manipulating plants for more optimal responses. Targets for improvement of growth at elevated CO2 include (1) altering source-sink relations; (2) improving the redistribution of nitrogen between the photosynthetic machinery and the rest of the plant; and (3) changing the response of stomata to CO2 and humidity to increase water-use efficiency even further than is currently predicted.

scholarly journals Endophytes alleviate the elevated CO2-dependent decrease in photosynthesis in rice, particularly under nitrogen limitation

2019 ◽  
Vol 71 (2) ◽  
pp. 707-718 ◽  
Author(s):  
Hyungmin Rho ◽  
Sharon Lafferty Doty ◽  
Soo-Hyung Kim
Keyword(s):  
Elevated Co2 ◽  
Effective Means ◽  
Photosynthetic Electron Transport ◽  
C3 Plants ◽  
Response Curves ◽  
Down Regulation ◽  
Co2 Response ◽  
High Co2 ◽  
Positive Effects ◽  
Regulation Of Photosynthesis

Abstract The positive effects of high atmospheric CO2 concentrations [CO2] decrease over time in most C3 plants because of down-regulation of photosynthesis. A notable exception to this trend is plants hosting N-fixing bacteria. The decrease in photosynthetic capacity associated with an extended exposure to high [CO2] was therefore studied in non-nodulating rice that can establish endophytic interactions. Rice plants were inoculated with diazotrophic endophytes isolated from the Salicaceae and CO2 response curves of photosynthesis were determined in the absence or presence of endophytes at the panicle initiation stage. Non-inoculated plants grown under elevated [CO2] showed a down-regulation of photosynthesis compared to those grown under ambient [CO2]. In contrast, the endophyte-inoculated plants did not show a decrease in photosynthesis associated with high [CO2], and they exhibited higher photosynthetic electron transport and mesophyll conductance rates than non-inoculated plants under high [CO2]. The endophyte-dependent alleviation of decreases in photosynthesis under high [CO2] led to an increase in water-use efficiency. These effects were most pronounced when the N supply was limited. The results suggest that inoculation with N-fixing endophytes could be an effective means of improving plant growth under high [CO2] by alleviating N limitations.

Elevated temperature and CO2 cause differential growth stimulation and drought survival responses in eucalypt species from contrasting habitats

2019 ◽  
Vol 39 (11) ◽  
pp. 1806-1820 ◽  
Author(s):  
Deborah M G Apgaua ◽  
David Y P Tng ◽  
Samantha J Forbes ◽  
Yoko F Ishida ◽  
Nara O Vogado ◽  
...  
Keyword(s):  
Elevated Temperature ◽  
Stomatal Conductance ◽  
Elevated Co2 ◽  
Elevated Temperatures ◽  
Interactive Effects ◽  
Plant Performance ◽  
Eucalyptus Species ◽  
Climate Change Scenarios ◽  
Differential Growth ◽  
Tropical Regions

Abstract Climate change scenarios predict increasing atmospheric CO2 concentrations ([CO2]), temperatures and droughts in tropical regions. Individually, the effects of these climate factors on plants are well established, whereas experiments on the interactive effects of a combination of factors are rare. Moreover, how these environmental factors will affect tree species along a wet to dry gradient (e.g., along tropical forest–savanna transitions) remains to be investigated. We hypothesized that under the simulated environmental conditions, plant growth, physiological performance and survivorship would vary in a manner consistent with the species’ positions of origin along this gradient. In a glasshouse experiment, we raised seedlings of three Eucalyptus species, each occurring naturally in a wet forest, savanna and forest–savanna ecotone, respectively. We evaluated the effect of drought, elevated temperature (4 °C above ambient glasshouse temperature of 22 °C) and elevated temperature in combination with elevated [CO2] (400 ppm [CO2] above ambient of 400 ppm), on seedling growth, survivorship and physiological responses (photosynthesis, stomatal conductance and water-use efficiency). Elevated temperature under ambient [CO2] had little effect on growth, biomass and plant performance of well-watered seedlings, but hastened mortality in drought-affected seedlings, affecting the forest and ecotone more strongly than the savanna species. In contrast, elevated [CO2] in combination with elevated temperatures delayed the appearance of drought stress symptoms and enhanced survivorship in drought-affected seedlings, with the savanna species surviving the longest, followed by the ecotone and forest species. Elevated [CO2] in combination with elevated temperatures also enhanced growth and biomass and photosynthesis in well-watered seedlings of all species, but modified shoot:root biomass partitioning and stomatal conductance differentially across species. Our study highlights the need for a better understand of the interactive effects of elevated [CO2], temperature and drought on plants and the potential to upscale these insights for understanding biome changes.

Elevated CO2 Improves the Growth of Wheat Under Salinity

1993 ◽  
Vol 20 (3) ◽  
pp. 349 ◽  
Author(s):  
ME Nicolas ◽  
R Munns ◽  
AB Samarakoon ◽  
RM Gifford
Keyword(s):  
Leaf Area ◽  
Elevated Co2 ◽  
Dry Matter ◽  
Stomatal Closure ◽  
Dry Weight ◽  
Primary Component ◽  
Dry Matter Accumulation ◽  
Salt Tolerant ◽  
High Co2 ◽  
Sodium Accumulation

Wheat plants (Triticum aestivum cv. Matong and T. durum cv. Modoc) were grown at ambient and elevated CO2 (350 cm3 m-3 above ambient) in soil with or without 150 mol m-3 NaCl for 6 weeks. The increase in dry matter, leaf area and tillering under high CO2 was relatively greater under saline than non-saline conditions for both cultivars. Tillering was the primary component of growth affected by both salinity and high CO2. Salinity greatly reduced tillering and high CO2 partly reversed the effects of salinity. High CO2 increased dry matter accumulation of the salt-sensitive Modoc to a greater extent (+104%) than that of the more salt-tolerant Matong (+73%) in the salt treatment. Transpiration rates were greatly reduced by salinity for both cultivars. Under high CO2, increased leaf areas compensated for reduced transpiration rates per unit leaf area (i.e. greater stomatal closure), and total transpiration was little affected by CO2 level within each treatment. The more salt-tolerant Matong showed greater stomatal closure and higher transpiration efficiencies than the salt-sensitive Modoc under salinity. High CO2 reduced transpiration rate (per unit dry weight) by 40 to 50%, but did not significantly change the rate of sodium accumulation (per unit dry weight), indicating that salt uptake was largely independent of water uptake, and that high CO2 did not increase growth by reducing the salt load. Our results suggest that high CO2 increased growth by stimulating the development of tiller buds that would otherwise have been inhibited.

Influence of Elevated Atmospheric CO2 Concentrations on Plant Nutrition

1992 ◽  
Vol 40 (5) ◽  
pp. 445 ◽  
Author(s):  
JP Conroy
Keyword(s):  
Elevated Co2 ◽  
Critical Concentration ◽  
Atmospheric Co2 ◽  
C3 Plants ◽  
Natural Ecosystems ◽  
Nitrogen And Phosphorus ◽  
Absolute Increase ◽  
High Co2 ◽  
Co2 Concentrations ◽  
C3 Species

The rising levels of atmospheric CO2 are likely to increase biomass production of C3 species in both natural and managed ecosystems because photosynthetic rates will be higher. The greatest absolute increase in productivity will occur when nitrogen and phosphorus availability in the soil is high. Low nitrogen does not preclude a growth response to high CO2, whereas some C3 species fail to respond to high CO2 when phosphorus is low, possibly because insufficient phosphorus is available to maintain maximum photosynthetic activity at high CO2. C3 plants response to high CO2 because the flux of carbon through the photoreductive cycle is increased and photorespiration is suppressed. This change in metabolism appears to alter the foliar nutrient concentration required to promote maximum productivity (critical concentration). Higher phosphorus concentrations are needed at elevated CO2, whereas the nitrogen requirement is reduced by CO2 enrichment. Since critical concentrations are used to evaluate nutrient status of crop and forest species and to manage fertiliser programs, they will need reassessing as the atmospheric CO2 concentration rises. Another consequence of the altered nutrient requirement at high CO2 is that the nitrogen concentrations of foliage, roots and grain are consistently lower in plants grown at elevated CO2, irrespective of availability of nitrogen in the soil. In natural ecosystems, the lower nitrogen to carbon ratio of the litter may alter rates of nutrient cycling. For farmers, the rising CO2 concentrations could cause reductions in grain nitrogen, and therefore protein content. This could have important implications for baking quality of hard wheats as well as affecting the nutrient value of grain such as rice.

Influence of Rising Atmospheric CO2 Concentrations and Temperature on Growth, Yield and Grain Quality of Cereal Crops

1994 ◽  
Vol 21 (6) ◽  
pp. 741 ◽  
Author(s):  
JP Conroy ◽  
S Seneweera ◽  
AS Basra ◽  
G Rogers ◽  
B Nissen-Wooller
Keyword(s):  
Grain Yield ◽  
Elevated Co2 ◽  
High Temperatures ◽  
Atmospheric Co2 ◽  
Yield Enhancement ◽  
C3 Plants ◽  
High Co2 ◽  
Co2 Concentrations ◽  
Flower Abortion

A possible scenario for the end of the 21st century is that the atmospheric CO2 concentration will be in the range of 510-760 μL L-1 and that the mean global temperature will be 1.5-4.5�C higher. Further, there may be greater incidences of extreme climatic events, which together with the CO2 and temperature changes will influence development, growth and grain yield of cereals such as rice and wheat. For these C3 plants, the driving force for the growth response to elevated CO2 is higher leaf CO2 assimilation rates (A). However, the response of A to CO2 depends on temperature with maximum absolute increases occuring at temperatures which do not cause flower abortion, while negligible increases are observed at low temperatures. At high temperatures, where A is reduced because of partial inactivation of photosynthetic enzymes, the increase in A due to CO2 enrichment is still observed. Other factors, such as changes in shoot water relations or hormone concentrations, may influence growth at elevated CO2 concentrations. Wheat and rice development is accelerated by high temperature and consequently grain yield is reduced because there is less time for radiation to be intercepted during the vegetative phase. Although high CO2 also accelerates development in rice and, to a lesser extent in wheat, the extra carbohydrate produced by increases in A results in at least a 40% increase in grain yield at temperatures which do not cause flower abortion. This is due mainly to increased tiller numbers rather than increases in the number or weight of individual grains. However, the yield enhancement due to high CO2 will not necessarily compensate for decreases in yield caused by accelerated development at high temperatures. As predicted by the response of A to high CO2, the relative increase in yield, due to rising CO2 concentrations, is smaller at lower temperatures. Elevated atmospheric CO2 may improve the tolerance of plants to heat-induced drought stress by facilitating the maintenance of cell volume and photosynthetic function in the leaves. Increased carbohydrate storage in the stems may also be an advantage during grain filling if the flag leaves senesce prematurely. However, it is unlikely that the effect of very high temperatures on flower abortion will be ameliorated by high CO2. For bread making, the quality of flour produced from grain developed at high temperatures is poorer. High CO2 may also have an effect through a reduction in the protein content of wheat grain. For rice, the amylose content of the grain, a major determinant of cooking quality is increased under elevated CO2.

scholarly journals Physiological resilience of pink salmon to naturally occurring ocean acidification

2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Andrea Y Frommel ◽  
Justin Carless ◽  
Brian P V Hunt ◽  
Colin J Brauner
Keyword(s):  
British Columbia ◽  
Elevated Co2 ◽  
Condition Factor ◽  
Pacific Salmon ◽  
Pink Salmon ◽  
Hypoxia Tolerance ◽  
High Co2 ◽  
The North ◽  
Naturally Occurring ◽  
Co2 Levels

Abstract Pacific salmon stocks are in decline with climate change named as a contributing factor. The North Pacific coast of British Columbia is characterized by strong temporal and spatial heterogeneity in ocean conditions with upwelling events elevating CO2 levels up to 10-fold those of pre-industrial global averages. Early life stages of pink salmon have been shown to be affected by these CO2 levels, and juveniles naturally migrate through regions of high CO2 during the energetically costly phase of smoltification. To investigate the physiological response of out-migrating wild juvenile pink salmon to these naturally occurring elevated CO2 levels, we captured fish in Georgia Strait, British Columbia and transported them to a marine lab (Hakai Institute, Quadra Island) where fish were exposed to one of three CO2 levels (850, 1500 and 2000 μatm CO2) for 2 weeks. At ½, 1 and 2 weeks of exposure, we measured their weight and length to calculate condition factor (Fulton’s K), as well as haematocrit and plasma [Cl−]. At each of these times, two additional stressors were imposed (hypoxia and temperature) to provide further insight into their physiological condition. Juvenile pink salmon were largely robust to elevated CO2 concentrations up to 2000 μatm CO2, with no mortality or change in condition factor over the 2-week exposure duration. After 1 week of exposure, temperature and hypoxia tolerance were significantly reduced in high CO2, an effect that did not persist to 2 weeks of exposure. Haematocrit was increased by 20% after 2 weeks in the CO2 treatments relative to the initial measurements, while plasma [Cl−] was not significantly different. Taken together, these data indicate that juvenile pink salmon are quite resilient to naturally occurring high CO2 levels during their ocean outmigration.

scholarly journals Differential Growth Responses of Wheat Seedlings to Elevated CO2

2018 ◽  
Vol 10 (3) ◽  
pp. 400-409 ◽  
Author(s):  
Hamid Reza ESHGHIZADEH ◽  
Morteza ZAHEDI ◽  
Samaneh MOHAMMADI
Keyword(s):  
Leaf Area ◽  
Plant Height ◽  
Elevated Co2 ◽  
Co2 Concentration ◽  
Tolerance Index ◽  
Dry Matter Accumulation ◽  
Wheat Cultivars ◽  
Growth Responses ◽  
Differential Growth ◽  
Wheat Seedlings

Intraspecific variations in wheat growth responses to elevated CO2 was evaluated using 20 Iranian bread wheat (Triticum aestivum L.) cultivars. The plants were grown in the modified Hoagland nutrient solution at a greenhouse until 35 days of age using two levels of CO2 (~380 and 700 µmol mol–1). The shoot and root dry weights of the wheat cultivars exhibited average enhancements of 17% and 36%, respectively, under elevated CO2. This increase was associated with higher levels of chlorophyll a (25%), chlorophyll b (21%), carotenoid (30%), leaf area (54%) and plant height (49.9%). The leaf area (r = 0.69**), shoot N content (r = 0.62**), plant height (r = 0.60**) and root volume (r = 0.53*) were found to have important roles in dry matter accumulation of tested wheat cultivars under elevated CO2 concentration. However, responses to elevated CO2 were considerably cultivar-dependent. Based on the stress susceptibility index (SSI) and stress tolerance index (STI), the wheat cultivars exhibiting the best response to elevated CO2 content were ‘Sistan’, ‘Navid’, ‘Shiraz’, ‘Sepahan’ and ‘Bahar’, while the ones with poor responses were ‘Omid’, ‘Marun’, ‘Sorkhtokhm’ and ‘Tajan’. The findings from the present experiment showed significant variation among the Iranian wheat cultivars in terms of their responses to elevated air CO2, providing the opportunity to select the most efficient ones for breeding purposes.

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 multigenerational exposure and phenotypic variation on a freshwater fish species exposed to elevated carbon dioxide (CO2)

2021 ◽  
Author(s):  
◽  
Jenna Laurel Fleet
Keyword(s):  
Carbon Dioxide ◽  
Freshwater Fish ◽  
Elevated Co2 ◽  
Phenotypic Variation ◽  
Mrna Abundance ◽  
Fish Populations ◽  
High Co2 ◽  
Filial Generation ◽  
Behavioural Phenotypes ◽  
Carbon Dioxide Co2

The amount of dissolved carbon dioxide (CO2) and the acidity of aquatic ecosystems is increasing as atmospheric CO2 concentrations increase due to human activities. Changes in pH and dissolved CO2 can have considerable aversive effects on fish physiology and behaviour, which can result in negative effects on fish populations. Multigenerational studies have found that the conditions experienced by parents can have significant effects on the performance of their offspring and understanding these effects can help to predict how fish populations will cope in future conditions. Additionally, repeatable behavioural phenotypes are good predictors of trends in behaviour, can be useful predictors of other physiological and life history traits, and can be subject to selection pressures. Unfortunately, the effects of elevated CO2 on freshwater fishes over multiple generations, and the effects of behavioural phenotypes, are poorly understood. In my thesis, freshwater Japanese Medaka (Oryzias latipes) were used to investigate the influence of phenotypic variation and differences in time of exposure (generational) on biological responses to elevated CO2. Lab-reared medaka were divided into ‘responsive’ and ‘non-responsive’ groups based on behavioural differences from the population mean during acute exposure to high CO2 in a common shuttling and novel tank behavioural assay. Responsive and non-responsive fish in parental generation (P) were subdivided and exposed to either control (~480 ppm) or high CO2 (~1250 ppm) conditions over a 6-week period. Following this time, eggs from this generation were collected and randomly selected into either high or control conditions, where they were hatched and reared until maturation (filial generation one (F1), 18 weeks). Eggs from F1 were collected and hatched and reared in the same conditions as their parents until adulthood (filial generation two (F2), 24 weeks). Body condition (size, weight and length), behaviour (total distance moved, time spent in the outer zone of the behavioural arena, and swimming direction), reproductive (number of eggs, size of eggs, and survival to hatch) performance, and the relative abundance of various mRNA transcripts in whole brain tissue of fish was measured across these three generations. Behavioural phenotypes influenced reproduction for P and F2 generation fish, and growth for F1 and F2 fish; suggesting that intraspecific variation in behavioural phenotypes may influence how medaka respond to elevated CO2. However, behavioural phenotypes did not have a significant effect on mRNA abundance on genes targeted in my study. Multigenerational exposure to elevated CO2 were shown to improve the performance of offspring in some measures and resulted in changes of mRNA abundance of several genes. Transgenerational exposure, where a parent or grandparent was exposed to elevated CO2 but the offspring were not exposed to elevated CO2, resulted in some deleterious effects suggesting that, generally, exposure to environmental conditions that differ from that of their parents may put fish especially at risk. In my thesis, current CO2 exposure appeared to be the best predictor of overall condition, where fish exposed to elevated CO2 were worse off than fish exposed to control CO2 conditions. The results of this research contribute to filling a current gap of knowledge in understanding how freshwater fish will respond to future conditions over an ecologically-relevant time scale. Importantly, this information will contribute to generating more informed decisions on freshwater ecosystem management and future research directions. Marine and freshwater environments offer food and water security and are of high importance to the economy and the health of our planet, making my research relevant to our broader society.

scholarly journals Growth and Water Relations of Sun-cured Tobacco Irrigated with Saline Water

2003 ◽  
Vol 20 (6) ◽  
pp. 394-401
Author(s):  
G Angelino ◽  
S Ascione ◽  
C Ruggiero
Keyword(s):  
Water Relations ◽  
Irrigation Water ◽  
Saline Water ◽  
Turgor Pressure ◽  
Dry Matter Accumulation ◽  
Saline Irrigation ◽  
Crop Growth Rate ◽  
Leaf Surface Area ◽  
Net Assimilation ◽  
Plant Salt Tolerance

AbstractWe have investigated the effects of saline irrigation on growth and water relations of two sun-cured tobacco genotypes, Xp102 and Px107, which belong to the Xanthia and Perustitza tobacco ecotypes, respectively. We compared three commercial sea salt concentrations of the irrigation water (0.25%, 0.5%, and 1% w/v) plus a non-salinized control, corresponding to an electrical conductivity (ECw) of 4.4, 8.5, 15.7, 0.5 dS m-1 and osmotic potentials of -0.22, -0.35, -0.73, -0.02 MPa, respectively. The ECsoil increased with the salinity of the irrigation water. At high salinity (1%), the soil where Px107 plants were grown showed a significantly higher salinity compared to the soil of Xp102. For both genotypes, the soil water content increased at increasing salinity and during the growth season. Increasing salinity progressively reduced the leaf turgor pressure and enhanced the cellular osmotic adjustment. The latter resulted to be more pronounced in Px107 compared to Xp102 (0.36 vs. 0.20 MPa). At higher salinity (0.5% and 1%), both genotypes showed reduced leaf surface area, dry matter accumulation, water use, net assimilation rate (NAR) and crop growth rate (CGR). Px107 roots were more sensitive than shoot to salinity (3% reduction per dS m-1) and compared to Xp102 roots, which showed a reduced development only at 1% salinity. Assessment of plant salt tolerance according to the Maas and Hoffman model revealed a slope of 1-2% for both genotypes, indicating that these tobaccos are relatively more salt tolerant compared to other species.

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