scholarly journals Thermal Analysis of Stomatal Response under Salinity and High Light

2021 ◽  
Vol 22 (9) ◽  
pp. 4663
Author(s):  
Aleksandra Orzechowska ◽  
Martin Trtílek ◽  
Krzysztof Michał Tokarz ◽  
Renata Szymańska ◽  
Ewa Niewiadomska ◽  
...  
Keyword(s):  
Thermal Imaging ◽  
Initial Response ◽  
Co2 Assimilation ◽  
High Light ◽  
Stomatal Aperture ◽  
Imaging Method ◽  
Stomatal Response ◽  
Time Constants ◽  
Net Co2 Assimilation ◽  
Temporary Response

A non-destructive thermal imaging method was used to study the stomatal response of salt-treated Arabidopsis thaliana plants to excessive light. The plants were exposed to different levels of salt concentrations (0, 75, 150, and 220 mM NaCl). Time-dependent thermograms showed the changes in the temperature distribution over the lamina and provided new insights into the acute light-induced temporary response of Arabidopsis under short-term salinity. The initial response of plants, which was associated with stomatal aperture, revealed an exponential growth in temperature kinetics. Using a single-exponential function, we estimated the time constants of thermal courses of plants exposed to acute high light. The saline-induced impairment in stomatal movement caused the reduced stomatal conductance and transpiration rate. Limited transpiration of NaCl-treated plants resulted in an increased rosette temperature and decreased thermal time constants as compared to the controls. The net CO2 assimilation rate decreased for plants exposed to 220 mM NaCl; in the case of 75 mM NaCl treatment, an increase was observed. A significant decline in the maximal quantum yield of photosystem II under excessive light was noticeable for the control and NaCl-treated plants. This study provides evidence that thermal imaging as a highly sensitive technique may be useful for analyzing the stomatal aperture and movement under dynamic environmental conditions.

Stomatal aperture can compensate altered stomatal density in Arabidopsis thaliana at growth light conditions

2006 ◽  
Vol 33 (11) ◽  
pp. 1037 ◽  
Author(s):  
Dirk Büssis ◽  
Uritza von Groll ◽  
Joachim Fisahn ◽  
Thomas Altmann
Keyword(s):  
Arabidopsis Thaliana ◽  
Stomatal Conductance ◽  
Stomatal Density ◽  
Co2 Assimilation ◽  
High Light ◽  
Stomatal Aperture ◽  
Photochemical Quenching ◽  
Light Conditions ◽  
Wild Type ◽  
Light Intensities

Stomatal density of transgenic Arabidopsis thaliana plants over-expressing the SDD1 (stomatal density and distribution) gene was reduced to 40% and in the sdd1-1 mutant increased to 300% of the wild type. CO2 assimilation rate and stomatal conductance of over-expressers and the sdd1-1 mutant were unchanged compared with wild types when measured under the light conditions the plants were exposed to during growth. Lower stomatal density was compensated for by increased stomatal aperture and conversely, increased stomatal density was compensated for by reduced stomatal aperture. At high light intensities the assimilation rates and stomatal conductance of SDD1 over-expressers were reduced to 80% of those in wild type plants. Areas beneath stomata and patches lacking stomata were analysed separately. In areas without stomata, maximum fluorescence yield (Fv / Fm) and quantum yield of photosystem II (Φ PSII) were significantly lower than in areas beneath stomata. In areas beneath stomata, Fv / Fm and Φ PSII were identical to levels measured in wild type leaves. At high light intensities over-expressers showed decreased photochemical quenching (qP) compared with wild types. However, the decrease of qP was significantly stronger in areas without stomata than in mesophyll areas beneath stomata. At high CO2 partial pressures and high light intensities CO2 assimilation rates of SDD1 over-expressers did not reach wild type levels. These results indicate that photosynthesis in SDD1 over-expressers was reduced because of limiting CO2 in areas furthest from stomata at high light.

scholarly journals Successive Harvests Modulate the Productive and Physiological Behavior of Three Genovese Pesto Basil Cultivars

Agronomy ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 560
Author(s):  
Luigi Formisano ◽  
Michele Ciriello ◽  
Christophe El-Nakhel ◽  
Marios C. Kyriacou ◽  
Youssef Rouphael
Keyword(s):  
Dry Matter ◽  
Co2 Assimilation ◽  
Stomatal Resistance ◽  
Matter Content ◽  
Dry Matter Content ◽  
Technological Parameters ◽  
Net Co2 Assimilation ◽  
Dry Biomass ◽  
Crop Cycle ◽  
The Impact

In the Italian culinary tradition, young and tender leaves of Genovese basil (Ocimum basilicum L.) are used to prepare pesto sauce, a tasty condiment that attracts the interest of the food processing industry. Like other leafy or aromatic vegetables, basil is harvested more than once during the crop cycle to maximize yield. However, the mechanical stress induced by successive cuts can affect crucial parameters associated with pesto processing (leaf/stem ratio, stem diameter, and dry matter). Our research accordingly aimed to evaluate the impact of successive harvests on three field-grown Genovese basil cultivars (“Aroma 2”, “Eleonora” and “Italiano Classico”) in terms of production, physiological behavior, and technological parameters. Between the first and second harvest, marketable fresh yield and shoot dry biomass increased by 148.4% and 172.9%, respectively; by contrast, the leaf-to-stem ratio decreased by 22.5%, while the dry matter content was unchanged. The increased fresh yield and shoot dry biomass at the second harvest derived from improved photosynthetic efficiency, which enabled higher net CO2 assimilation, Fv/Fm and transpiration as well as reduced stomatal resistance. Our findings suggest that, under the Mediterranean environment, “Italiano Classico” carries superior productive performance and optimal technological characteristics in line with industrial requirements. These promising results warrant further investigation of the impact successive harvests may have on the qualitative components of high-yielding basil genotypes with respect to consumer expectations of the final product.

scholarly journals Application of UV-C Irradiation to Rosa x hybrida Plants as a Tool to Minimise Macrosiphum rosae Populations

Agronomy ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 702
Author(s):  
Anastasios I. Darras ◽  
Panagiotis J. Skouras ◽  
Panagiotis Assimomitis ◽  
Chara Labropoulou ◽  
George J. Stathas
Keyword(s):  
Host Resistance ◽  
Insect Pests ◽  
Physiological Responses ◽  
Co2 Assimilation ◽  
Aphid Population ◽  
First Instar ◽  
Net Co2 Assimilation ◽  
Macrosiphum Rosae ◽  
Uv C ◽  
Aphid Fecundity

UV-C irradiation is known to enhance plant resistance against insect pests. In the present study, we evaluated the effects of low doses of UV-C on Macrosiphum rosae infesting greenhouse rose (Rosa x hybrida) plants. The application of 2.5-kJ/m2 UV-C irradiation on rose leaves before infestation induced anti-herbivore resistance and negatively affected the aphid fecundity. No eggs and first instar nymphs were recorded on irradiated leaves, whereas an average of 4.3 and 2.7 eggs and 6.7 and 14 first instars were recorded on vars. “Etoile Brilante” and “Arlen Francis” untreated leaves, respectively. UV-C irradiation reduced the aphid population from naturally infested rose plants by up to 58%. In a greenhouse pot trial (GPT) in 2019, UV-C irradiation minimised the initial aphid population six hours after treatment. UV-C elicited host resistance and, also, helped in aphid repulsion without killing the adult individuals. UV-C did not affect the physiological responses of rose plants. The net CO2 assimilation of the UV-C irradiated plants ranged between 10.55 and 15.21 μmol/m2. sec for “Arlen Francis” and between 10.51 and 13.75 μmol/m2. sec for “Etoile Brilante” plants. These values, with only a few exceptions, were similar to those recorded to the untreated plants.

scholarly journals Salt tolerance and regulation of gas exchange and hormonal homeostasis by auxin-priming in wheat

2013 ◽  
Vol 48 (9) ◽  
pp. 1210-1219 ◽  
Author(s):  
Muhammad Iqbal ◽  
Muhammad Ashraf
Keyword(s):  
Abscisic Acid ◽  
Gas Exchange ◽  
Acid Concentration ◽  
Spring Wheat ◽  
Indoleacetic Acid ◽  
Co2 Assimilation ◽  
Assimilation Rate ◽  
Co2 Assimilation Rate ◽  
Net Co2 Assimilation Rate ◽  
Net Co2 Assimilation

The objective of this work was to assess the regulatory effects of auxin-priming on gas exchange and hormonal homeostasis in spring wheat subjected to saline conditions. Seeds of MH-97 (salt-intolerant) and Inqlab-91 (salt-tolerant) cultivars were subjected to 11 priming treatments (three hormones x three concentrations + two controls) and evaluated under saline (15 dS m-1) and nonsaline (2.84 dS m-1) conditions. The priming treatments consisted of: 5.71, 8.56, and 11.42 × 10-4 mol L-1 indoleacetic acid; 4.92, 7.38, and 9.84 × 10-4 mol L-1 indolebutyric acid; 4.89, 7.34, and 9.79 × 10-4 mol L-1 tryptophan; and a control with hydroprimed seeds. A negative control with nonprimed seeds was also evaluated. All priming agents diminished the effects of salinity on endogenous abscisic acid concentration in the salt-intolerant cultivar. Grain yield was positively correlated with net CO2 assimilation rate and endogenous indoleacetic acid concentration, and it was negatively correlated with abscisic acid and free polyamine concentrations. In general, the priming treatment with tryptophan at 4.89 × 10-4 mol L-1 was the most effective in minimizing yield losses and reductions in net CO2 assimilation rate, under salt stress conditions. Hormonal homeostasis increases net CO2 assimilation rate and confers tolerance to salinity on spring wheat.

scholarly journals Foliar phosphorus supply and CO2 assimilation in common bean (Phaseolus vulgaris L.) under water deficit

2006 ◽  
Vol 18 (3) ◽  
pp. 407-411 ◽  
Author(s):  
Mauro G. dos Santos ◽  
Rafael V. Ribeiro ◽  
Marcelo G. Teixeira ◽  
Ricardo F. de Oliveira ◽  
Carlos Pimentel
Keyword(s):  
Phaseolus Vulgaris ◽  
Common Bean ◽  
Water Deficit ◽  
Co2 Assimilation ◽  
Assimilation Rate ◽  
Phaseolus Vulgaris L ◽  
Co2 Assimilation Rate ◽  
Net Co2 Assimilation ◽  
Foliar Phosphorus ◽  
Regulation Of Photosynthesis

Two common bean cultivars were grown in pots under greenhouse conditions. Plants were submitted to a foliar Pi spray two days before suspending irrigation, what enhanced net CO2 assimilation rate of Ouro Negro cultivar but did not change significantly the photosynthesis of Carioca cultivar under both water deficit and rehydration periods. The results revealed that a foliar Pi spray induced an up-regulation of photosynthesis in common bean under mild water deficit, with this effect being genotype-dependent.

scholarly journals The direct and indirect effects of nitrogen shortage on photosynthesis and transpiration in maize and sunflower.

1979 ◽  
Vol 27 (3) ◽  
pp. 227-234
Author(s):  
J. Goudriaan ◽  
H. van Keulen
Keyword(s):  
Indirect Effects ◽  
Leaf Tissue ◽  
Co2 Assimilation ◽  
Direct And Indirect Effects ◽  
Stomatal Behaviour ◽  
Net Co2 Assimilation ◽  
Similar Relation ◽  
Use Efficiency ◽  
Different Levels ◽  
N Status

Experiments with maize and sunflower in sol. culture were carried out to investigate the effect of N shortage in the leaf tissue on stomatal behaviour. In maize a linear relation existed between the rate of net CO2 assimilation and the conductance of water vapour, independently of the N status of the tissue. In sunflower a similar relation existed although the evidence was less conclusive. It was concluded that stomatal behaviour cannot explain differences in water-use efficiency between plants growing at different levels of N. (Abstract retrieved from CAB Abstracts by CABI’s permission)

scholarly journals Indications for a Central Role of Hexokinase Activity in Natural Variation of Heat Acclimation in Arabidopsis thaliana

2020 ◽  
Author(s):  
Vasil Atanasov ◽  
Lisa Fürtauer ◽  
Thomas Nägele
Keyword(s):  
Arabidopsis Thaliana ◽  
Metabolic Regulation ◽  
Co2 Assimilation ◽  
High Light ◽  
Plant Performance ◽  
Hexokinase Activity ◽  
South Italy ◽  
Single Stress ◽  
Photosynthetic Capacities

Diurnal and seasonal changes of abiotic environmental factors shape plant performance and distribution. Changes of growth temperature and light intensity may vary significantly on a diurnal, but also on a weekly or seasonal scale. Hence, acclimation to a changing temperature and light regime is essential for plant survival and propagation. In the present study, we analyzed photosynthetic CO2 assimilation and metabolic regulation of the central carbohydrate metabolism in two natural accessions of Arabidopsis thaliana originating from Russia and south Italy during exposure to heat and a combination of heat and high light. Our findings indicate that it is hardly possible to predict photosynthetic capacities to fix CO2 under combined stress from single stress experiments. Further, capacities of hexose phosphorylation were found to be significantly lower in the Italian than in the Russian accession which could explain an inverted sucrose-to-hexose ratio. Together with the finding of significantly stronger accumulation of anthocyanins under heat/high light these observations indicate a central role of hexokinase activity in stabilization of photosynthetic capacities within a changing environment.

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