Potassium application enhances drought tolerance in sesame by mitigating oxidative damage and regulating osmotic adjustment

Abstract

Potassium (K) is known for alleviating the negative effects of abiotic stresses on plants. To explore the functions of K in controlling reactive oxygen species (ROS), antioxidant activities, and osmoregulation in sesame under drought stress, a pot experiment was conducted with three K levels (0, 60, and 120 kg ha–1, recorded as K0, K1, and K2, respectively) and exposed to well-watered (WW, 75% ± 5% soil relative water content) and drought-stressed (DS, 50% ± 5% soil relative water content) conditions. The results showed that DS stimulated the production of ROS such as increased hydrogen peroxide (H2O2), leading to lipid peroxidation as characterized by higher malondialdehyde (MDA) and, consequently, resulting in the decline in relative water content (RWC) and photosynthetic pigments as compared with WW plants. These adverse effects were exacerbated when drought stress was prolonged. Concurrently, K application alleviated the magnitude of decline in the RWC, chlorophyll a, and chlorophyll b, and plants applied with K exhibited superior growth, with the optimal mitigation observed under K2 treatment. Additionally, DS plants treated with K exhibited lower lipid peroxidation, higher antioxidant activities, and increased osmotic solute accumulation in comparison with plants under K deficiency, which suggested that exogenous K application mitigated the oxidative damages and this was more prominent under K2 treatment. Noteworthily, proline and soluble protein, respectively, dominated in the osmotic regulation at 3 and 6 days of drought stress according to the analysis of the quantitative comparison among different osmotically active solutes. Based on the correlation of the aforementioned traits and the analysis of variance on the interaction effects of drought stress and potassium, we propose that superoxide dismutase (SOD), glutathione reductase (GR), and MDA could be critical indicators in balancing ROS detoxification and reproduction. In summary, our studies suggest that optimized K application keeps a balance between the production of antioxidants and ROS and simultaneously affects osmoregulation to alleviate the damage from drought stress.

Silicon, by promoting a homeostatic balance of C:N:P and nutrient use efficiency, attenuates K deficiency, favoring sustainable bean cultivation

“…3 ), that is, a decrease in the uptake of these elements. This is because K deficiency can impair the water status of plants [ 11 , 45 ] and decrease the activity of aquaporins, causing a reduction in the hydraulic conductance of roots [ 46 ] and resulting in less transpiration, consequently in less uptake of nutrients and physiological damage [ 46 – 48 ]. These processes are widely known, but it is necessary to explain whether the lack of this element causes loss of stoichiometric homeostasis of vital structural nutrients for plant metabolism, such as C, N and P. A study conducted on barley ( Hordeum vulgare L.) aimed to evaluate the impact of potassium deficiency on the dynamics of other nutrients.…”

“…Thus, K deficiency causes well-known physiological damages [ 8 , 9 ]. Examples are osmotic imbalance and losses in photosynthetic rates due to low water use efficiency [ 10 , 11 ]. In addition, K activates dozens of enzymes in different metabolic pathways in plants [ 12 – 15 ], with an emphasis on N metabolism [ 16 ].…”

The Expression of the StNRAMP2 Gene Determined the Accumulation of Cadmium in Different Tissues of Potato

“…Although production and elimination of ROS are balanced, they can accumulate rapidly owing to different abiotic stresses [41]. Such accumulation causes a disruption in the balance between ROS production and antioxidants systems, ultimately leading to damage to the cell membrane, nucleic acid, and chloroplast pigment [42], Malondialdehyde (MDA) is the final product of lipid peroxidation in plant cell membranes caused by abiotic stress and is the main standard by which to measure oxidative damage (lipid peroxidation level) [43,44]. To combat the damage of ROS accumulation and protect macromolecules from oxidative damage, plants have accordingly developed a powerful antioxidant system consisting of catalase (CAT), superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APX), etc.…”

Comparative analysis of drought stress-induced physiological and transcriptional changes of two black sesame cultivars during anthesis

“…Unfortunately, litter attention was given exclusively to black sesame response to drought stress. Moreover, albeit some studies were conducted on sesame response to drought stress ( Dossa et al., 2017 ; Dossa et al., 2020 ; Fang et al., 2022 ), knowledge of drought-responsive mechanisms in sesame plant is still limited and more candidate genes are likely to be identified.…”