Percorrer por autor "Wahbi, S."
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- Combined effect of salicylic acid and calcium application on salt-stressed strawberry plantsPublication . Lamnai, K.; Anaya, Fatima; Fghire, R.; Zine, H.; Janah, I.; Wahbi, S.; Loutfi, K.The salinity of water and agricultural lands is a major environmental factor adversely affecting crop productivity. Strawberry plants have been found to be sensitive to salt stress conditions. Salicylic acid (SA) and Ca2+ are endogenous signal molecules involved in many metabolic processes, which can stimulate the plants defence mechanisms to biotic and abiotic constraints. The main objective of this work was to investigate the impacts of SA (0.25 mM) and calcium nitrate (5 mM) application, singly or in combination, on growth parameters as well as physiological and biochemical markers of strawberry plants (Fragaria ananassa Duch, var. Fortuna) exposed to saline conditions (80 mM NaCl). The results showed that high salinity reduces plant growth and photosynthetic pigment content. Salt stress also induced an accumulation of Na, a decrease in K and Ca concentrations, a reduction in the levels of sugars, total phenol, relative water content, photochemical efficiency (F-v/F-m), and stomatal conductance as well as a decrease in proline, proteins, enzyme activities (catalase, superoxide dismutase and peroxidase) and an accumulation of hydrogen peroxide and malondialdehyde. However, SA and calcium treatments enhanced the plants' tolerance to salt stress by improving the above-mentioned parameters. Additionally, the best results were obtained with combined treatment (Ca + SA) under both salinity conditions. These findings indicated that the combination of calcium supplementation with exogenous application of SA may provide an effective solution to improving the strawberry plant's tolerance to saline conditions.
- Effect of exogenous salicylic acid on growth parameters, gas exchange, and photosynthetic yields in salt-stressed Vicia faba l. plantsPublication . Anaya, F.; Fghire, R.; Lamnai, K.; Loutfi, K.; Wahbi, S.; Carvalho, Isabel S.This study aimed to evaluate the potential effect of salicylic acid (SA) on the photosynthetic performance of faba bean (Vicia faba L.) plants under salt stress conditions. For this purpose, two salinity levels (0 and 120 mM) combined with two concentrations of SA (0 and 0.5 mM) were applied. Results showed that salt stress decreases the growth and gas exchange parameters (P-N, C-i, g(s), and T-r). Chlorophyll fluorescence imaging parameters showed a decrease in the effective photochemical quantum yield of PSII (YPII), photochemical quenching (qP), and electron transport rate (ETR), while the regulated (Y(NPQ) and unregulated dissipation energy Y(NO)) were increased under stress conditions. However, exogenous SA application under salt stress decreases the non-regulated dissipation and improves photosynthetic performance (Y(PSII), ETR, qP, and Y(NPQ)), growth, and gas exchange parameters. Consequently, SA application had a beneficial effect on the faba bean tolerance to salt stress and can be recommended for field application with low concentration.
- Multifaceted impact of exogenous salicylic acid on vicia faba l. under salt stress: plant growth, water status, and photosynthetic performance (OJIP Fluorescence)Publication . ANAYA, FATIMA; Fghire, R.; Wahbi, S.; Carvalho, Inês; Loutfi, K.Purpose This study investigated the effect of salt stress on growth, water status, and photosynthetic activity in faba bean plants and the role of salicylic acid (SA) in mitigating the harmful effects of salt stress. Methods Faba bean plants were subjected to different levels of salt stress (0, 90, 120, and 150 mM NaCl) and salicylic acid (0, 0.5, and 1 mM SA). Salt and SA treatments were applied starting from the seedling stage and continued for two months. Results Results show that salt stress significantly affects the different studied parameters. Salinity strongly decreases the plant weight (fresh and dry) and the plant water status (Leaf Water Potential (LWP), Stomatal conductance (gs), Relative water content (RWC). The analysis of the Photosystem II (PSII) function disruption indicates that salt stress induced an electron transport inhibition at the donor side of the PSII due to the Oxygen-Evolving Complex (OEC) inactivation (positive- K-band) and reduced the PSII unit’s energetic connectivity (positive-L-band). The evaluation of the rate reduction of the end electron acceptor at the Photosystem I (PSI) side revealed that salt stress resulted in gradual decreases in the reduction rates. Nevertheless, the exogenous application of salicylic acid (SA) allowed plants to maintain a high weight/length value with a significant improvement in plant water status. Chlorophyll-a fluorescence analysis shows that SA application improved at the donor side of electron transport (lower intensity of the K and L-band), with a larger pool size under the combination of 0.5 mM SA and high salt stress levels applications. Conclusion These results suggest that the salt stress significantly affects the PSII by the inactivation of the OEC and decreas¬ing the PSII unit’s connectivity. However, SA had a beneficial effect on the PSII and PSI salt stress tolerance in Vicia faba L.