scholarly journals Salinity Stress Affects Photosynthesis, Malondialdehyde Formation, and Proline Content in Portulaca oleracea L.

Plants ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 845
Author(s):  
Helena Hnilickova ◽  
Kamil Kraus ◽  
Pavla Vachova ◽  
Frantisek Hnilicka
Keyword(s):  
Salt Stress ◽  
Water Potential ◽  
Co2 Concentration ◽  
Co2 Assimilation ◽  
Proline Content ◽  
Portulaca Oleracea ◽  
Control Group ◽  
Malondialdehyde Formation ◽  
Salinity Levels ◽  
Mda Content

In this investigation, the effect of salt stress on Portulaca oleracea L. was monitored at salinity levels of 100 and 300 mM NaCl. At a concentration of 100 mM NaCl there was a decrease in stomatal conductance (gs) simultaneously with an increase in CO2 assimilation (A) at the beginning of salt exposure (day 3). However, the leaf water potential (ψw), the substomatal concentration of CO2 (Ci), the maximum quantum yield of photosystem II (Fv/Fm), and the proline and malondialdehyde (MDA) content remained unchanged. Exposure to 300 mM NaCl caused a decrease in gs from day 3 and a decrease in water potential, CO2 assimilation, and Fv/Fm from day 9. There was a large increase in proline content and a significantly higher MDA concentration on days 6 and 9 of salt stress compared to the control group. After 22 days of exposure to 300 mM NaCl, there was a transition from the C4 cycle to crassulacean acid metabolism (CAM), manifested by a rapid increase in substomatal CO2 concentration and negative CO2 assimilation values. These results document the tolerance of P. oleracea to a lower level of salt stress and the possibility of its use in saline localities.

scholarly journals Assessment of Morpho-Physiological, Biochemical and Antioxidant Responses of Tomato Landraces to Salinity Stress

Plants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 696
Author(s):  
Reem H. Alzahib ◽  
Hussein M. Migdadi ◽  
Abdullah A. Al Ghamdi ◽  
Mona S. Alwahibi ◽  
Abdullah A. Ibrahim ◽  
...  
Keyword(s):  
Salt Stress ◽  
Salinity Stress ◽  
Dry Weight ◽  
Proline Content ◽  
Enzymatic Antioxidants ◽  
Sod Activity ◽  
Carotene Content ◽  
Antioxidants Activity ◽  
Solanum Lycopersicum L ◽  
Salinity Levels

Understanding salt tolerance in tomato (Solanum lycopersicum L.) landraces will facilitate their use in genetic improvement. The study assessed the morpho-physiological variability of Hail tomato landraces in response to different salinity levels at seedling stages and recommended a tomato salt-tolerant landrace for future breeding programs. Three tomato landraces, Hail 548, Hail 747, and Hail 1072 were tested under three salinity levels: 75, 150, and 300 mM NaCl. Salinity stress reduced shoots’ fresh and dry weight by 71% and 72%, and roots were 86.5% and 78.6%, respectively. There was 22% reduced chlorophyll content, carotene content by 18.6%, and anthocyanin by 41.1%. Proline content increased for stressed treatments. The 300 mM NaCl treatment recorded the most proline content increases (67.37 mg/g fresh weight), with a percent increase in proline reaching 61.67% in Hail 747. Superoxide dismutase (SOD) activity decreased by 65% in Hail 548, while it relatively increased in Hail 747 and Hail 1072 treated with 300 mM NaCl. Catalase (CAT) activity was enhanced by salt stress in Hail 548 and recorded 7.6%, increasing at 75 and 5.1% at 300 mM NaCl. It revealed a reduction in malondialdehyde (MDA) at the 300 mM NaCl concentration in both Hail 548 and Hail 1072 landraces. Increasing salt concentrations showed a reduction in transpiration rate of 70.55%, 7.13% in stomatal conductance, and 72.34% in photosynthetic rate. K+/Na+ ratios decreased from 56% for 75 mM NaCl to 85% for 300 mM NaCl treatments in all genotypes. The response to salt stress in landraces involved some modifications in morphology, physiology, and metabolism. The landrace Hail 548 may have better protection against salt stress and observed protection against reactive oxygen species (ROS) by increasing enzymatic “antioxidants” activity under salt stress.

scholarly journals Salt stress on physiology, biometry and fruit quality of grafted Passiflora edulis

2020 ◽  
Vol 36 (3) ◽  
Author(s):  
Regiana Dos Santos Moura ◽  
Hans Raj Gheyi ◽  
Everaldo Moreira Da Silva ◽  
Elisson de Araújo Dias ◽  
Caliane Silva Da Cruz ◽  
...  
Keyword(s):  
Salt Stress ◽  
Fruit Quality ◽  
Titratable Acidity ◽  
Co2 Concentration ◽  
Co2 Assimilation ◽  
Soluble Solids ◽  
Water Salinity ◽  
Physiological Variables ◽  
Number Of Leaves

The production of grafted passion fruit is an alternative for plant adaptation to saline environments. The objective of this study was to evaluate the effect of salt stress on physiology, biometry and fruit quality of P. edulis grafted on Passiflora spp. The experiment was conducted in completely randomized design, in a 3 x 2 factorial scheme, corresponding to three species of Passiflora (P. edulis, P. gibertii and P. cincinnata) with P. edulis scion and two levels of irrigation water salinity (0.5 - control and 4.5 dS m-1), with four repetitions. Water salinity compromises gas exchanges (CO2 assimilation raste and transpiration) and physiological variables (total chlorophyll and total water consumption) in grafted P. edulis. The interaction between the factors (water salinity x species) compromised only the growth in plant height and number of leaves. In relation to the species, auto-grafted P. edulis stood out from the other species, with higher internal CO2 concentration, number of leaves, stem dry mass, peel thickness, total soluble solids (TSS) of the pulp and TSS/TA ratio (titratable acidity). Auto-grafted P. edulis under saline conditions develops vital mechanisms (TSS and TSS/TA), which attenuates the effects of salt stress on the physico-chemical quality of the fruits.

scholarly journals Antioxidant Protection of Photosynthesis in Two Cashew Progenies Under Salt Stress

2018 ◽  
Vol 10 (10) ◽  
pp. 388
Author(s):  
Anselmo F. da Silva ◽  
Valéria F. de O. Sousa ◽  
Gisele L. dos Santos ◽  
Eugênio S. Araújo Júnior ◽  
Sérgio L. F. da Silva ◽  
...  
Keyword(s):  
Salt Stress ◽  
Quantum Efficiency ◽  
Salinity Stress ◽  
Intercellular Co2 Concentration ◽  
Co2 Concentration ◽  
Co2 Assimilation ◽  
Photochemical Activity ◽  
Photochemical Quenching ◽  
Tree Seedlings ◽  
Cashew Tree

The present work evaluated the indicators of photosynthetic efficiency and antioxidative protection in cashew tree seedlings subjected to salinity stress. The study was conducted with seedlings of two advanced dwarf cashew clones (CCP09 and CCP76) subjected to salt stress with increasing doses of NaCl (0, control; 25; 50; 75; 100 mM) in the nutrient solution for 30 days under greenhouse conditions. The variables of gas exchange, CO2 assimilation (PN), stomatal conductance (gS), transpiration (E), intercellular CO2 concentration (CI), photochemical activity, potential quantum efficiency (Fv/Fm), effective quantum efficiency (ΔF/Fm’) of photosystem II (PSII), photochemical quenching (qP), non-photochemical quenching (NPQ) electron transport rate (ETR) as well as the indicators of damage and oxidative protection were measured. Under these conditions, there was an intense accumulation Na+ associated with a reduction in the K+/Na+ ratio in the leaves of both clones in response to salt, with higher values for this ratio in clone CCP09 than in CCP76 the highest concentration of NaCl (100 mM). Salinity reduced PN, gS and E in the two clones evaluated, with lower reductions in CCP09 than in CCP76 at the highest salt dose. Instantaneous carboxylation (PN/CI) and water use (PN/E) efficiencies were strongly restricted by salinity but were less affected in CCP09 than in CCP76. Salinity stress also increased hydrogen peroxide (H2O2) levels in CCP09, whereas lipid peroxidation decreased in both progenies. The clones presented specific antioxidant responses due to greater enzymatic and non-enzymatic activity in CCP76, in addition to the activity of phenol peroxidase (POX) in CCP09.

scholarly journals Salt stress and exogenous application of hydrogen peroxide on photosynthetic parameters of soursop

2019 ◽  
Vol 23 (4) ◽  
pp. 257-263 ◽  
Author(s):  
André A. R. da Silva ◽  
Geovani S. de Lima ◽  
Carlos A. V. de Azevedo ◽  
Luana L. de S. A. Veloso ◽  
Hans R. Gheyi ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Salt Stress ◽  
Irrigation Water ◽  
Sandy Loam ◽  
Block Design ◽  
Co2 Concentration ◽  
Co2 Assimilation ◽  
Carboxylation Efficiency ◽  
Photosynthetic Parameters ◽  
Exogenous Application

ABSTRACT This study aimed to evaluate the gas exchanges and photosynthetic pigments of soursop seedlings cv. ‘Morada Nova’ irrigated with saline waters and subjected to exogenous application of hydrogen peroxide by seed soaking and foliar spraying. The study was carried out using plastic bags under greenhouse conditions at the Center of Technology and Natural Resources of the Federal University of Campina Grande, PB, Brazil, using a eutrophic Regolithic Neosol of sandy loam texture. Treatments were arranged in a randomized block design, in 5 x 5 factorial scheme, which consisted of five levels of electrical conductivity – ECw (0.7; 1.4; 2.1; 2.8 and 3.5 dS m-1) of irrigation water and five concentrations of hydrogen peroxide - H2O2 (0, 25, 50, 75 and 100 µM), with four replicates and three plants per plot. As the salt stress increased, there were reductions in internal CO2 concentration, instantaneous carboxylation efficiency and water use efficiency, and instantaneous carboxylation efficiency was the most sensitive variable. Hydrogen peroxide at concentrations of 25 and 50 µM attenuated the deleterious effects of water salinity on stomatal conductance, CO2 assimilation rate and chlorophyll a content, and the concentration of 25 µM was the most efficient. The content of chlorophyll b and carotenoids of soursop cv. ‘Morada Nova’ had the deleterious effects caused by the salinity of irrigation water mitigated by the exogenous application of hydrogen peroxide in the concentration of 25 μM.

Changes in photosynthetic rate, water potential, and proline content in kenaf seedlings under salt stress

2012 ◽  
Vol 92 (2) ◽  
pp. 311-319 ◽  
Author(s):  
Cheng-Wu Jin ◽  
Yan-Lin Sun ◽  
Dong-Ha Cho
Keyword(s):  
Salt Stress ◽  
Water Potential ◽  
Treatment Period ◽  
Photosynthetic Rate ◽  
Salt Concentration ◽  
Proline Content ◽  
High Salt ◽  
Hibiscus Cannabinus ◽  
Salt Adaptation ◽  
Salt Treatment

Jin, C.-W., Sun, Y.-L. and Cho, D.-H. 2012. Changes in photosynthetic rate, water potential, and proline content in kenaf seedlings under salt stress. Can. J. Plant Sci. 92: 311–319. As irrigation water salinization has become a serious constraint for crop production, as well as soil salinity, the selection and use of salt-tolerant species is urgently required. In this study, we describe the salt responses of three kenaf (Hibiscus cannabinus L.) cultivars and select the cultivar with high salt tolerance. Responses to salt stress were investigated in terms of growth, water potentials, photosynthesis, and proline contents. Photosynthesis, evaluated by net CO2 assimilation rate, stomatal conductance, and intercellular CO2 concentration, did not show any significant effects among the cultivars. Leaf water potential decreased depending on salt concentration and salt treatment period. Proline accumulation was enhanced, particularly depending on salt concentration, but not salt treatment period. As salt concentration increased, seedling growth was inhibited to a certain extent, and the inhibition of growth depended mainly on salt concentration. At the early stage of treatment, Dowling was more tolerant to salt stress than Everglade-41 and Tainung-2. Although Dowling showed a lower decrease in fresh weight, Tainung-2 always maintained a relatively high vegetative yield, even under high salt stress. Tainung-2, having greater salt adaptation, was therefore considered an ideal cultivar for popularization and farm cultivation.

scholarly journals Gas exchange, growth, and production of mini-watermelon under saline water irrigation and phosphate fertilization

2020 ◽  
Vol 41 (6supl2) ◽  
pp. 3039-3052
Author(s):  
Geovani Soares de Lima ◽  
◽  
Charles Macedo Félix ◽  
Saulo Soares da Silva ◽  
Lauriane Almeida dos Anjos Soares ◽  
...  
Keyword(s):  
Salt Stress ◽  
Gas Exchange ◽  
Saline Water ◽  
Block Design ◽  
Intercellular Co2 Concentration ◽  
Co2 Concentration ◽  
Co2 Assimilation ◽  
Northeastern Brazil ◽  
Randomized Block Design ◽  
Semi Arid Region

In the semi-arid region of Northeastern Brazil, due to the occurrence of excess salts, both in the water and soil, plants are constantly exposed to various conditions of abiotic stress. Thus, it is extremely important to identify methods capable of minimizing the effects of salt stress on plants as a way to ensure the expansion of irrigated areas. In this context, the objective of this study was to evaluate the gas exchange, growth, and production of mini-watermelon irrigated with saline waters and fertilized with phosphorus. The experiment was conducted in pots under greenhouse conditions in Pombal, PB, Brazil, using a randomized block design in a 5 x 4 factorial scheme, corresponding to five levels of electrical conductivity of irrigation water—ECw (0.3, 1.3, 2.3, 3.3, and 4.3 dS m-1), four phosphorus doses— PD (60, 80, 100, and 120% of the recommendation), and with three replicates. Watermelon plants cv. Sugar Baby were sensitive to water salinity greater than 0.3 dS m-1, with more pronounced inhibition of gas exchange, growth, and production. Reduction in the CO2 assimilation rate of watermelon plants cv. Sugar Baby was associated with factors of stomatal and non-stomatal origin. Phosphorous doses corresponding to 73 and 88% of the recommended values promoted an increase in the intercellular CO2 concentration and stem diameter of mini-watermelon plants. P2O5 doses ranging from 60 to 120% of the recommendation did not mitigate the effects of salt stress on the cultivation of watermelon cv. Sugar Baby.

Effects of salinity on gas exchange, water relations and growth of sunflower (Helianthus annuus)

2002 ◽  
Vol 29 (12) ◽  
pp. 1405 ◽  
Author(s):  
Anna Rita Rivelli ◽  
Stella Lovelli ◽  
Michele Perniola
Keyword(s):  
Electrical Conductivity ◽  
Salt Stress ◽  
Gas Exchange ◽  
Helianthus Annuus ◽  
Water Relations ◽  
Co2 Assimilation ◽  
Ionic Concentration ◽  
Assimilation Rate ◽  
Co2 Assimilation Rate ◽  
Salinity Levels

The aim of this study was to determine the response of sunflower (Helianthus annuus L. cv. Romsum HS90) to salinity in terms of gas exchange, ionic and water relations, and growth. Experiments were carried out in the glasshouse, where sunflower plants were exposed to increasing salinity levels using water with a wide range of electrical conductivity (0.39–20 dS m–1) to provide different degrees of salt stress. The CO2 assimilation rate (A), stomatal conductance and plant aboveground dry weight (DW) significantly decreased as electrical conductivity of the soil increased. The decline in photosynthesis measured in response to salt stress was proportionally greater than the decline in transpiration, resulting in a reduction of water use efficiency, at both the leaf and whole-plant levels. Among the factors inhibiting photosynthetic activity, those of a non-stomatal nature had a greater effect. In particular, an analysis of photosynthetic CO2 assimilation rate vs intercellular CO2 concentration (A vs Ci curves) indicated a reduction in activity of Rubisco (EC 4.1.1.39) as salinity levels increased. Under severe salt-stress conditions, chlorophyll fluorescence showed a slowing of electron transport at the PSII level. Salt accumulation in the rhizosphere caused a reduction in tissue water status that was partly associated with a decline in osmotic potential (Ψπ). Leaf ionic concentration was clearly correlated with values of leaf Ψπ. However, leaf ionic concentration showed discontinuous distribution between younger and older leaves, reflecting a strategy of plants to preserve younger and more metabolically-active leaves from accumulating salt to toxic levels.

Evaluation of Azadirachtin on Arthrospira plantensis Gomont growth parameters and antioxidant enzymes

2020 ◽  
Vol 56 ◽  
pp. 8
Author(s):  
Hatice Tunca ◽  
Ali Doğru ◽  
Feray Köçkar ◽  
Burçin Önem ◽  
Tuğba Ongun Sevindik
Keyword(s):  
Enzyme Activity ◽  
Growth Parameters ◽  
Arthrospira Platensis ◽  
Proline Content ◽  
Enzyme Analysis ◽  
Free Proline ◽  
Sod Activity ◽  
Pesticide Pollution ◽  
Antioxidant Parameters ◽  
Mda Content

Azadirachtin (Aza) used as insecticide due to inhibiting growth of insects and preventing them from feeding on plants. To understand the effects of contamination of this insecticide on phototrophs, and to determine the responses of these organisms against these insecticides are extremely important in understanding how the ecosystem is affected. In this study, chlorophyll-a amount, OD 560 and antioxidant parameters (total SOD, APX, GR, Proline, MDA and H2O2) were determined in order to understand the effect of Aza on Arthrospira platensis Gomont. Aza was applied between 0–20 μg mL−1 concentrations for 7 days in the study. Enzyme analysis was conducted at the end of the 7th day. There was a statistically significant decrease in the absorbance of OD560 and the chlorophyll-a content in A. platensis cultures exposed to the Aza (0–20 μg mL−1) during 7 days due to the increase in pesticide levels. SOD activity decreased at 8, 16 and 20 μg mL−1 concentrations; GR enzyme activity showed a significant decrease compared to the control at a concentration of 20 μg mL−1. APX activity did not change significantly compared to control. The MDA content increased significantly at 16 and 20 μg mL−1 concentrations. The H2O2 content significantly increased at 12, 16 and 20 μg mL−1 concentrations (p < 0.05) while the free proline content decreased at 4 μg mL−1 concentration (p < 0.05). As a result, regarding the Aza concentrations used in this study may be a step to prevent pesticide pollution in the environment.

Penconazole and calcium ameliorate drought stress in canola by upregulating the antioxidative enzymes

2020 ◽  
Vol 47 (9) ◽  
pp. 825 ◽  
Author(s):  
Maryam Rezayian ◽  
Vahid Niknam ◽  
Hassan Ebrahimzadeh
Keyword(s):  
Oxidative Stress ◽  
Lipid Peroxidation ◽  
Drought Stress ◽  
Drought Tolerance ◽  
Antioxidative Enzymes ◽  
Proline Content ◽  
Fresh Weight ◽  
Negative Effects ◽  
Mda Content ◽  
Effects Of Drought

The aim of this research was to gauge the alternations in the lipid peroxidation and antioxidative enzyme activity in two cultivars (cv. RGS003 and cv. Sarigol) of canola under drought stress and drought tolerance amelioration by penconazole (PEN) and calcium (Ca). Plants were treated with different polyethylene glycol (PEG) concentrations (0, 5, 10 and 15%) without or with PEN (15 mg L–1) and Ca (15 mM). The Ca treatment prevented the negative effects of drought on fresh weight (FW) in RGS003 and Sarigol at 5 and 15% PEG respectively. Ca and PEN/Ca treatments caused significant induction in the proline content in Sarigol at 15% PEG; the latter treatment was accompanied by higher glycine betaine (GB), lower malondialdehyde (MDA) and growth recovery. Hydrogen peroxide (HO2) content in Sarigol was proportional to the severity of drought stress and all PEN, Ca and PEN/Ca treatments significantly reduced the H2O2 content. PEN and PEN/Ca caused alleviation of the drought-induced oxidative stress in RGS003. RGS003 cultivar exhibited significantly higher antioxidative enzymes activity at most levels of drought, which could lead to its drought tolerance and lower MDA content. In contrast to that of Sarigol, the activity of catalase and superoxide dismutase (SOD) increased with Ca and PEN/Ca treatments in RGS003 under low stress. The application of PEN and Ca induced significantly P5CS and SOD expression in RGS003 under drought stress after 24 h. Overall, these data demonstrated that PEN and Ca have the ability to enhance the tolerance against the drought stress in canola plants.

scholarly journals Sublethal concentrations of clothianidin affect honey bee colony growth and hive CO2 concentration

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
William G. Meikle ◽  
John J. Adamczyk ◽  
Milagra Weiss ◽  
Janie Ross ◽  
Chris Werle ◽  
...  
Keyword(s):  
Honey Bee ◽  
Pesticide Exposure ◽  
Co2 Concentration ◽  
Colony Growth ◽  
Control Group ◽  
Brood Production ◽  
Weight Losses ◽  
Bee Colony ◽  
The Impact ◽  
Bee Colonies

AbstractThe effects of agricultural pesticide exposure upon honey bee colonies is of increasing interest to beekeepers and researchers, and the impact of neonicotinoid pesticides in particular has come under intense scrutiny. To explore potential colony-level effects of a neonicotinoid pesticide at field-relevant concentrations, honey bee colonies were fed 5- and 20-ppb concentrations of clothianidin in sugar syrup while control colonies were fed unadulterated syrup. Two experiments were conducted in successive years at the same site in southern Arizona, and one in the high rainfall environment of Mississippi. Across all three experiments, adult bee masses were about 21% lower among colonies fed 20-ppb clothianidin than the untreated control group, but no effects of treatment on brood production were observed. Average daily hive weight losses per day in the 5-ppb clothianidin colonies were about 39% lower post-treatment than in the 20-ppb clothianidin colonies, indicating lower consumption and/or better foraging, but the dry weights of newly-emerged adult bees were on average 6–7% lower in the 5-ppb group compared to the other groups, suggesting a nutritional problem in the 5-ppb group. Internal hive CO2 concentration was higher on average in colonies fed 20-ppb clothianidin, which could have resulted from greater CO2 production and/or reduced ventilating activity. Hive temperature average and daily variability were not affected by clothianidin exposure but did differ significantly among trials. Clothianidin was found to be, like imidacloprid, highly stable in honey in the hive environment over several months.

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