Lack of downregulation of photosynthesis in a tropical root crop, cassava, grown under an elevated CO2 concentration

2002 ◽  
Vol 29 (7) ◽  
pp. 805 ◽  
Author(s):  
María Dolores Fernández ◽  
Wilmer Tezara ◽  
Elizabeth Rengifo ◽  
Ana Herrera
Keyword(s):  
Elevated Co2 ◽  
Starch Content ◽  
Soluble Sugar ◽  
Co2 Concentration ◽  
Gas Exchange Parameters ◽  
Manihot Esculenta Crantz ◽  
Root Shoot Ratio ◽  
Leaf N Content ◽  
Source Sink ◽  
Soluble Sugar And Starch

We evaluated the effects of an elevated [CO2] on photosynthesis and growth of cassava plants grown in open-top chambers with an adequate supply of water and N and a sufficient rooting volume. Cassava plants (Manihot esculenta Crantz. cv. Motilona) showed higher photosynthetic rates (Pn) when grown and measured at elevated [CO2] (680 µmol mol-1) than when grown and measured at ambient [CO2] (480 µmol mol-1). No downregulation of photosynthesis due to elevated [CO2] was found, since carboxylation efficiency increased after 220 d in spite of a decrease in leaf soluble protein, Rubisco, and leaf N content. Soluble sugar and starch contents decreased with time under elevated [CO2], the decrease in starch content coinciding with the beginning of the increase in root mass. Canopy Pn by leaf area decreased with time under elevated [CO2] but, when canopy Pn was expressed by ground area, higher and constant rates were observed, suggesting a higher productivity in plants grown at elevated [CO2]. The absence of differences between growth [CO2] in root : shoot ratio observed suggests that elevated [CO2], while causing increases in the shoot as well as the root, did not affect the pattern of biomass allocation. Acclimation responses of gas exchange parameters changed during the experiment. The absence of downregulation of photosynthesis was associated with a decrease in leaf sugar and starch contents of plants grown at elevated [CO2], which suggests a favourable source/sink relationship.

Effect of elevated CO2 concentration and nitrate: ammonium ratios on gas exchange and growth of cassava (Manihot esculenta Crantz)

2013 ◽  
Vol 374 (1-2) ◽  
pp. 33-43 ◽  
Author(s):  
Jailson L. Cruz ◽  
Alfredo A. C. Alves ◽  
Daniel R. LeCain ◽  
David D. Ellis ◽  
Jack A. Morgan
Keyword(s):  
Gas Exchange ◽  
Elevated Co2 ◽  
Manihot Esculenta ◽  
Co2 Concentration ◽  
Manihot Esculenta Crantz ◽  
Elevated Co2 Concentration

scholarly journals Physiological and Transcriptome Responses to Elevated CO2 Concentration in Populus

Forests ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 980
Author(s):  
Tae-Lim Kim ◽  
Hoyong Chung ◽  
Karpagam Veerappan ◽  
Wi Young Lee ◽  
Danbe Park ◽  
...  
Keyword(s):  
Elevated Co2 ◽  
High Throughput Sequencing ◽  
Global Climate ◽  
Transcriptome Assembly ◽  
Soluble Sugar ◽  
Model Organism ◽  
Co2 Concentration ◽  
Total Soluble Sugar ◽  
Elevated Atmospheric Co2 ◽  
Co2 Concentrations

Global climate change is heavily affected by an increase in CO2. As one of several efforts to cope with this, research on poplar, a representative, fast growing, and model organism in plants, is actively underway. The effects of elevated atmospheric CO2 on the metabolism, growth, and transcriptome of poplar were investigated to predict productivity in an environment where CO2 concentrations are increasing. Poplar trees were grown at ambient (400 ppm) or elevated CO2 concentrations (1.4× ambient, 560 ppm, and 1.8× ambient, 720 ppm) for 16 weeks in open-top chambers (OTCs). We analyzed the differences in the transcriptomes of Populusalba × Populus glandulosa clone “Clivus” and Populus euramericana clone “I-476” using high-throughput sequencing techniques and elucidated the functions of the differentially expressed genes (DEGs) using various functional annotation methods. About 272,355 contigs and 207,063 unigenes were obtained from transcriptome assembly with the Trinity assembly package. Common DEGs were identified which were consistently regulated in both the elevated CO2 concentrations. In Clivus 29, common DEGs were found, and most of these correspond to cell wall proteins, especially hydroxyproline-rich glycoproteins (HRGP), or related to fatty acid metabolism. Concomitantly, in I-476, 25 were identified, and they were related to heat shock protein (HSP) chaperone family, photosynthesis, nitrogen metabolism, and carbon metabolism. In addition, carbohydrate contents, including starch and total soluble sugar, were significantly increased in response to elevated CO2. These data should be useful for future gene discovery, molecular studies, and tree improvement strategies for the upcoming increased-CO2 environments.

scholarly journals Physiological Plasticity of Green Gram Stomata to Photosynthesis Traits under Interactive Effects of Elevated CO2, Drought and Heat Stress

2021 ◽  
pp. 109-119
Author(s):  
J. Ranjani Priya ◽  
D. Vijayalakshmi ◽  
A. Vinitha ◽  
M. Raveendran ◽  
V. Babu Rajendra Prasad
Keyword(s):  
Gas Exchange ◽  
Elevated Co2 ◽  
Heat Waves ◽  
Co2 Concentration ◽  
Interactive Effects ◽  
Green Gram ◽  
Combined Stress ◽  
Gas Exchange Parameters ◽  
Randomized Design ◽  
Drought And Heat Stress

Heat waves and droughts are projected to become more widespread as a result of climate change. At the same time, CO2 levels are predicted to have doubled by 2100. The stomatal regulation and gas exchange characteristics were assessed in 25 days old plants of green gram (var Co 8) by exposing them to six different treatments namely, T1: a [CO2] + a T+ irrigation (100%), T2: a [CO2] + a T+ irrigation (50%), T3: a [CO2] + e T (40ºC) + irrigation (100%), T4: e [CO2] – 800 ppm + a T+ irrigation (100%), T5: a [CO2] + combined stress [e T (40ºC) + irrigation (50%) T6: e [CO2] – 800 ppm + combined stress [e T (40ºC) + irrigation (50%)]. The experiment was carried out using Completely Randomized Design (CRD) with three replications. All gas exchange parameters viz., ((photosynthesis rate, stomatal conductance, and transpiration rate) were determined before imposing stress and two weeks after imposing stress. Stomatal characters was examined two weeks after imposing stress. Elevated CO2 stress caused a reduction in stomatal frequency accompanied by larger stomatal size. The study revealed the positive effect of higher CO2 concentration on gas exchange traits of the C3 crops viz., green gram.

scholarly journals Nitrogen management under increased atmospheric CO2 concentration in cucumber (Cucumis sativus L.): ameliorating environmental impacts of fertilization

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
María Carmen Piñero ◽  
Ginés Otálora ◽  
Josefa López-Marín ◽  
Francisco M. del Amor
Keyword(s):  
Environmental Impacts ◽  
Starch Content ◽  
Soluble Sugar ◽  
Nitrogen Sources ◽  
Co2 Concentration ◽  
Nitrogen Fertilizers ◽  
Cation Composition ◽  
Cucumis Sativus L ◽  
Biochemical Processes ◽  
N Assimilation

AbstractIn the last years, the atmospheric CO2 concentration has increased significantly, and this increase can cause changes in various physiological and biochemical processes of plants. However, the response of plants to elevated CO2 concentration (e[CO2]) will be different depending on the nitrogen form available and the plant species. Therefore, hydroponic trials on cucumber plants, with two CO2 concentrations (400 and 1000 ppm) and two nitrogen sources (NO3−/NH4+; 100/0 and 90/10), were conducted. Physiological parameters—such as gas exchange, GS, GOGAT and GDH activities, cation composition, soluble sugar and starch content- were measured. The results showed that when plants were grown with NH4+ and e[CO2], parameters such as photosynthesis rate (ACO2), instantaneous water use efficiency (WUEi), the content of NH4+, Ca2+ and Mg2+, and the concentration of starch, were higher than in control plants (irrigated with nitrate as sole nitrogen source and ambient CO2 concentration (a[CO2])). Furthermore, an improvement in N assimilation was observed when the GS/GOGAT pathway was enhanced under these conditions (NH4+ and e[CO2]). Thus, our results contribute to the reduction of the negative environmental impacts of the use of nitrogen fertilizers on this crop, both by reducing nitrogen leakage (eutrophication) and greenhouse gas emissions.

scholarly journals Physiological and Expressional Regulation on Photosynthesis, Starch and Sucrose Metabolism Response to Waterlogging Stress in Peanut

2021 ◽  
Vol 12 ◽  
Author(s):  
Ruier Zeng ◽  
Tingting Chen ◽  
Xinyue Wang ◽  
Jing Cao ◽  
Xi Li ◽  
...  
Keyword(s):  
Starch Content ◽  
Soluble Sugar ◽  
Branch Length ◽  
Dry Weight ◽  
Sucrose Metabolism ◽  
Dry Matter Accumulation ◽  
Negative Effects ◽  
Chlorophyll Metabolism ◽  
Waterlogging Stress ◽  
Source Sink

Waterlogging has negative effects on crop yield. Physiological and transcriptome data of two peanut cultivars [Zhongkaihua 1 (ZKH 1) and Huayu 39 (HY 39)] were studied under normal water supply and waterlogging stress for 5 or 10 days at the flowering stage. The results showed that the main stem height, the number of lateral branches, lateral branch length, and the stem diameter increased under waterlogging stress, followed by an increase in dry matter accumulation, which was correlated with the increase in the soil and plant analysis development (SPAD) and net photosynthetic rate (Pn) and the upregulation of genes related to porphyrin and chlorophyll metabolism and photosynthesis. However, the imbalance of the source–sink relationship under waterlogging was the main cause of yield loss, and waterlogging caused an increase in the sucrose and soluble sugar contents and a decrease in the starch content; it also decreased the activities of sucrose synthetase (SS) and sucrose phosphate synthetase (SPS), which may be due to the changes in the expression of genes related to starch and sucrose metabolism. However, the imbalance of the source–sink relationship led to the accumulation of photosynthate in the stems and leaves, which resulted in the decrease of the ratio of pod dry weight to total dry weight (PDW/TDW) and yield. Compared with ZKH 1, the PDW of HY 39 decreased more probably because more photosynthate accumulated in the stem and leaves of HY 39 and could not be effectively transported to the pod.

scholarly journals Effects of cadmium stress on growth and physiological characteristics of sassafras seedlings

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hongyi Zhao ◽  
Juelan Guan ◽  
Qing Liang ◽  
Xueyuan Zhang ◽  
Hongling Hu ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Sugar Content ◽  
Soluble Sugar ◽  
Cadmium Concentration ◽  
Cadmium Stress ◽  
Proline Content ◽  
Physiological Characteristics ◽  
Control Treatment ◽  
Gas Exchange Parameters ◽  
Photosynthetic Gas Exchange

AbstractThe effects of cadmium stress on the growth and physiological characteristics of Sassafras tzumu Hemsl. were studied in pot experiments. Five Cd levels were tested [CT(Control Treatment) : 0 mg/kg, Cd5: 5 mg/kg, Cd20: 20 mg/kg, Cd50: 50 mg/kg, and Cd100: 100 mg/kg]. The growth and physiological characteristics of the sassafras seedlings in each level were measured. The results showed that soil Cd had negative influences on sassafras growth and reduced the net growth of plant height and the biomass of leaf, branch and root. Significant reductions were recorded in root biomass by 18.18%(Cd5), 27.35%(Cd20), 27.57%(Cd50) and 28.95%(Cd100). The contents of hydrogen peroxide decreased first then increased while malondialdehyde showed the opposite trend with increasing cadmium concentration. Decreases were found in hydrogen peroxide contents by 10.96%(Cd5), 11.82%(Cd20) and 7.02%(Cd50); increases were found in malondialdehyde contents by 15.47%(Cd5), 16.07%(Cd20) and 7.85%(Cd50), indicating that cadmium stress had a certain effect on the peroxidation of the inner cell membranes in the seedlings that resulted in damage to the cell membrane structure. Superoxide dismutase activity decreased among treatments by 17.05%(Cd5), 10,68%(Cd20), 20.85%(Cd50) and 8.91%(Cd100), while peroxidase activity increased steadily with increasing cadmium concentration; these results suggest that peroxidase is likely the main protective enzyme involved in the reactive oxygen removal system in sassafras seedlings. Upward trends were observed in proline content by 90.76%(Cd5), 74.36%(Cd20), 99.73%(Cd50) and 126.01%(Cd100). The increase in proline content with increasing cadmium concentration indicated that cadmium stress induced proline synthesis to resist osmotic stress in the seedlings. Compared to that in CT, the soluble sugar content declined under the different treatments by 32.84%(Cd5), 5.85%(Cd20), 25.55%(Cd50) and 38.69%(Cd100). Increases were observed in the soluble protein content by 2.34%(Cd5), 21.36%(Cd20), 53.15%(Cd50) and 24.22%(Cd100). At different levels of cadmium stress, the chlorophyll content in the seedlings first increased and then decreased, and it was higher in the Cd5 and Cd20 treatments than that in the CT treatment. These results reflected that cadmium had photosynthesis-promoting effects at low concentrations and photosynthesis-suppressing effects at high concentrations. The photosynthetic gas exchange parameters and photosynthetic light-response parameters showed downward trends with increasing cadmium concentration compared with those in CT; these results reflected the negative effects of cadmium stress on photosynthesis in sassafras seedlings.

The impact of elevated atmospheric CO2 and nitrate supply on growth, biomass allocation, nitrogen partitioning and N2 fixation of Acacia melanoxylon

1999 ◽  
Vol 26 (8) ◽  
pp. 737 ◽  
Author(s):  
Marcus Schortemeyer ◽  
Owen K. Atkin ◽  
Nola McFarlane ◽  
John R. Evans
Keyword(s):  
Elevated Co2 ◽  
N2 Fixation ◽  
Dry Matter ◽  
Co2 Concentration ◽  
Dry Mass ◽  
Nitrogen Partitioning ◽  
Atmospheric Co2 ◽  
Acacia Melanoxylon ◽  
Nitrate Supply ◽  
The Impact

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.

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