scholarly journals For a Better Understanding of the Effect of N Form on Growth and Chemical Composition of C3 Vascular Plants under Elevated CO2—A Case Study with the Leafy Vegetable Eruca sativa

Horticulturae ◽  
2021 ◽  
Vol 7 (8) ◽  
pp. 251
Author(s):  
Lilian Schmidt ◽  
Jana Zinkernagel

Plant responses to elevated atmospheric CO2 (eCO2) are well studied, but the interactions of the carbon and nitrogen metabolism in the process are still not fully revealed. This is especially true for the role of nitrogen forms and their assimilation by plants under eCO2. This study investigated the interacting metabolic processes of atmospheric CO2 levels and N form in the short-term crop arugula. The effects on physiological processes and their consequences for crop growth, yield and nutritional value were elucidated. Two varieties of arugula were grown in climate cabinets under 400 or 800 ppm CO2, respectively. The plants were fertilized with either pure nitrate or ammonium-dominated-N. Photosynthetic CO2 assimilation increased in response to eCO2 regardless of the N form. This did not affect the assimilation of nitrate and consequently had no impact on the biomass of the plants. The extra photosynthates were not invested into the antioxidative compounds but were probably diverted towards the leaf structural compounds, thereby increasing dry mass and “diluting” several mineral elements. The fertilization of arugula with ammonium-dominated N had little benefits in terms of crop yield and nutritional quality. It is therefore not recommended to use ammonium-dominated N for arugula production under future elevated CO2 levels.

1999 ◽  
Vol 26 (8) ◽  
pp. 737 ◽  
Author(s):  
Marcus Schortemeyer ◽  
Owen K. Atkin ◽  
Nola McFarlane ◽  
John R. Evans

The interactive effects of nitrate supply and atmospheric CO2 concentration on growth, N2 fixation, dry matter and nitrogen partitioning in the leguminous tree Acacia melanoxylon R.Br. were studied. Seedlings were grown hydroponically in controlled-environment cabinets for 5 weeks at seven 15N-labelled nitrate levels, ranging from 3 to 6400 mmol m–3. Plants were exposed to ambient (~350 µmol mol–1) or elevated (~700 µmol mol–1) atmospheric CO2 for 6 weeks. Total plant dry mass increased strongly with nitrate supply. The proportion of nitrogen derived from air decreased with increasing nitrate supply. Plants grown under either ambient or elevated CO2 fixed the same amount of nitrogen per unit nodule dry mass (16.6 mmol N per g nodule dry mass) regardless of the nitrogen treatment. CO2 concentration had no effect on the relative contribution of N2 fixation to the nitrogen yield of plants. Plants grown with ≥50 mmol m–3 N and elevated CO2 had approximately twice the dry mass of those grown with ambient CO2 after 42 days. The rates of net CO2 assimilation under growth conditions were higher per unit leaf area for plants grown under elevated CO2. Elevated CO2 also decreased specific foliage area, due to an increase in foliage thickness and density. Dry matter partitioning between plant organs was affected by ontogeny and nitrogen status of the plants, but not by CO2 concentration. In contrast, plants grown under elevated CO2 partitioned more of their nitrogen to roots. This could be attributed to reduced nitrogen concentrations in foliage grown under elevated CO2.


Cells ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 2329
Author(s):  
Shun-Ling Tan ◽  
Xing Huang ◽  
Wei-Qi Li ◽  
Shi-Bao Zhang ◽  
Wei Huang

In view of the current and expected future rise in atmospheric CO2 concentrations, we examined the effect of elevated CO2 on photoinhibition of photosystem I (PSI) under fluctuating light in Arabidopsis thaliana. At 400 ppm CO2, PSI showed a transient over-reduction within the first 30 s after transition from dark to actinic light. Under the same CO2 conditions, PSI was highly reduced after a transition from low to high light for 20 s. However, such PSI over-reduction greatly decreased when measured in 800 ppm CO2, indicating that elevated atmospheric CO2 facilitates the rapid oxidation of PSI under fluctuating light. Furthermore, after fluctuating light treatment, residual PSI activity was significantly higher in 800 ppm CO2 than in 400 ppm CO2, suggesting that elevated atmospheric CO2 mitigates PSI photoinhibition under fluctuating light. We further demonstrate that elevated CO2 does not affect PSI activity under fluctuating light via changes in non-photochemical quenching or cyclic electron transport, but rather from a rapid electron sink driven by CO2 fixation. Therefore, elevated CO2 mitigates PSI photoinhibition under fluctuating light at the acceptor rather than the donor side. Taken together, these observations indicate that elevated atmospheric CO2 can have large effects on thylakoid reactions under fluctuating light.


2007 ◽  
Vol 34 (8) ◽  
pp. 730 ◽  
Author(s):  
Timothy R. Cavagnaro ◽  
Shannon K. Sokolow ◽  
Louise E. Jackson

Arbuscular mycorrhizas are predicted to be important in defining plant responses to elevated atmospheric CO2 concentrations. A mycorrhiza-defective tomato (Solanum lycopersicum L.) mutant with reduced mycorrhizal colonisation (rmc) and its mycorrhizal wild-type progenitor (76R MYC+) were grown under ambient and elevated atmospheric CO2 concentrations (eCO2) in a controlled environment chamber-based pot study. Plant growth, nutrient contents and mycorrhizal colonisation were measured four times over a 72-day period. The 76R MYC+ plants generally had higher concentrations of P, N and Zn than their rmc counterparts. Consistent with earlier studies, mycorrhizal colonisation was not affected by eCO2. Growth of the two genotypes was very similar under ambient CO2 conditions. Under eCO2 the mycorrhizal plants initially had higher biomass, but after 72 days, biomass was lower than for rmc plants, suggesting that in this pot study the costs of maintaining carbon inputs to the fungal symbiont outweighed the benefits with time.


2000 ◽  
Vol 27 (1) ◽  
pp. 13 ◽  
Author(s):  
John R Evans ◽  
Marcus Schortemeyer ◽  
Nola McFarlane ◽  
Owen K Atkin

Ten contrasting Acacia species were grown in glasshouses with normal ambient CO2 or ele-vated to 700 µL L–1. Plants were grown in sand with a complete nutrient solution, including 5 mМ nitrate. Our objective was to determine the degree to which photosynthesis, and the efficiency of nitrogen and water use, were affected by growth under elevated CO2 in contrasting plant species that differ in specific foliage area (foliage area per unit foliage dry mass). Photosynthetic characteristics were measured at several stages. Growth and measurement of gas exchange under 700 mL L–1 CO2 resulted in enhanced rates of CO2 assimilation per unit foliage area in nine of the species. The degree of enhancement was independent of specific foliage area. The exception was the slow-growing A. aneura, which had lower rates of CO2 assimilation when grown and measured at 700 µL L–1 CO2 compared to plants grown and measured at 350 µL L–1 CO2, at 50, 78 and 93 d after transplanting. Leaf conductance was reduced by growth in elevated CO2 in only six of the species. Overall, elevated CO2 improved the ratio of CO2 assimi-lation to conductance by 78% and increased CO2 assimilation per unit of foliage nitrogen by 30% at a given specific foliage area. Detailed study of A. saligna and A. aneura revealed that the effects of the CO2 treatment were similarly evident on all fully expanded phyllodes, regardless of their age. Intercellular CO2 response curves were analysed on four species and revealed no change in the ratio of electron transport to Rubisco activities. However, for A. aneura and A. melanoxylon, both electron transport and Rubisco activities were reduced per unit foliage nitrogen, by growth under elevated CO2 . For A. saligna and A. implexa, these activities per unit nitrogen, were not altered by the elevated CO2 treatment. To relate CO2 assimilation rates to net assimilation rates (dry matter increment per unit foliage area per day) derived from growth analysis, between 30 and 50% of daily photosynthesis appeared to be consumed in respiration. This proportion was not altered by CO2 treatment for seven of the Acacia species, but appeared to be reduced in the other three. The increase in CO2 assimilation rate by growth under 700 com-pared to 350 µL L–1 CO2 that was measured (26%, mean of all species from two surveys), matched the increase in net assimilation rate that had been derived from destructive sampling (30%). We conclude that the increase in CO2 assimilation rate in the selected Acacia species was independent of species, growth rate and foliage area per unit foliage dry mass.


2006 ◽  
Vol 10 (2) ◽  
pp. 1-20 ◽  
Author(s):  
Mustapha El Maayar ◽  
Navin Ramankutty ◽  
Christopher J. Kucharik

Abstract Terrestrial ecosystem models are built, among several reasons, to explore how the Earth’s biosphere responds to climate change and to the projected continual increase of atmospheric CO2 concentration. Many of these models adopt the Farquhar et al. approach, in which leaf carbon assimilation of C3 plants is regulated by two limitations depending on the rate of Rubisco activity and ribulose-1, 5-bisphosphate regeneration (RuBP). This approach was expanded upon by others to include a third limitation that expresses the occurrence, in some plant species, of a photosynthetic downregulation under high concentrations of ambient CO2. Several ecosystem models, however, constrain leaf photosynthesis using only two limitations according to the original formulation of Farquhar et al. and thus neglect the limitation that represents the downregulation of photosynthesis under elevated atmospheric CO2. In this study, the authors first reviewed the effect of elevated CO2 on photosynthesis of C3 plants, which illustrated that short-term observations are likely to considerably underestimate the number of plant species that exhibit a photosynthetic downregulation. Several recent long-term field observations have shown that such downregulation starts to be effective only after several seasons/years of plant exposure to elevated CO2. Second, an ecosystem model was used to illustrate that neglecting the photosynthetic downregulation may significantly bias predictions of net primary production of the middle and high latitudes under high atmospheric CO2 concentrations. Based on both review of field observations and results of simulations, the authors conclude that a more appropriate representation of plant physiology and choice of plant functional types may be required in ecosystem models in order to accurately simulate plant responses to changing environmental conditions.


Plants ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 491
Author(s):  
Zulfira Rakhmankulova ◽  
Elena Shuyskaya ◽  
Kristina Toderich ◽  
Pavel Voronin

A significant increase in atmospheric CO2 concentration and associated climate aridization and soil salinity are factors affecting the growth, development, productivity, and stress responses of plants. In this study, the effect of ambient (400 ppm) and elevated (800 ppm) CO2 concentrations were evaluated on the C4 xero-halophyte Kochia prostrata treated with moderate salinity (200 mM NaCl) and polyethylene glycol (PEG)-induced osmotic stress. Our results indicated that plants grown at elevated CO2 concentration had different responses to osmotic stress and salinity. The synergistic effect of elevated CO2 and osmotic stress increased proline accumulation, but elevated CO2 did not mitigate the negative effects of osmotic stress on dark respiration intensity and photosystem II (PSII) efficiency. This indicates a stressful state, which is accompanied by a decrease in the efficiency of light reactions of photosynthesis and significant dissipative respiratory losses, thereby resulting in growth inhibition. Plants grown at elevated CO2 concentration and salinity showed high Na+ and proline contents, high water-use efficiency and time required to reach the maximum P700 oxidation level (PSI), and low dark respiration. Maintaining stable water balance, the efficient functioning of cyclic transport of PSI, and the reduction of dissipation costs contributed to an increase in dry shoot biomass (2-fold, compared with salinity at 400 ppm CO2). The obtained experimental data and PCA showed that elevated CO2 concentration improved the physiological parameters of K. prostrata under salinity.


2015 ◽  
Vol 6 ◽  
Author(s):  
Takashi Okubo ◽  
Dongyan Liu ◽  
Hirohito Tsurumaru ◽  
Seishi Ikeda ◽  
Susumu Asakawa ◽  
...  

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