Foliar Concentrations of Selected Elements,Assessment of Oxidative Stress Markers and Role of Antioxidant Defense System is Associated with Fly Ash Stress Tolerance in Withania somnifera

Journal of Plant Growth Regulation - Increased dependence on thermal power has resulted in a significant increase in the generation of fly ash (FA), which exacerbates environmental...     

Foliar application of ascorbic acid enhances salinity stress tolerance in barley (Hordeum vulgare L.) through modulation of morpho-physio-biochemical attributes,ions uptake,osmo-protectants and stress response genes expression

Barley (Hordeum vulgare L.) is a major cereal grain and is known as a halophyte (a halophyte is a salt-tolerant plant that grows in soil or waters of high salinity). We therefore conducted a pot experiment to explore plant growth and biomass, photosynthetic pigments, gas exchange attributes, stomatal properties, oxidative stress and antioxidant response and their associated gene expression and absorption of ions in H. Vulgare. The soil used for this analysis was artificially spiked at different salinity concentrations (0, 50, 100 and 150 mM) and different levels of ascorbic acid (AsA) were supplied to plants (0, 30 and 60 mM) shortly after germination of the seed. The results of the present study showed that plant growth and biomass, photosynthetic pigments, gas exchange parameters, stomatal properties and ion uptake were significantly (p < 0.05) reduced by salinity stress, whereas oxidative stress was induced in plants by generating the concentration of reactive oxygen species (ROS) in plant cells/tissues compared to plants grown in the control treatment. Initially, the activity of antioxidant enzymes and relative gene expression increased to a saline level of 100 mM, and then decreased significantly (P < 0.05) by increasing the saline level (150 mM) in the soil compared to plants grown at 0 mM of salinity. We also elucidated that negative impact of salt stress in H. vulgare plants can overcome by the exogenous application of AsA, which not only increased morpho-physiological traits but decreased oxidative stress in the plants by increasing activities of enzymatic antioxidants. We have also explained the negative effect of salt stress on H. vulgare can decrease by exogenous application of AsA, which not only improved morpho-physiological characteristics, ions accumulation in the roots and shoots of the plants, but decreased oxidative stress in plants by increasing antioxidant compounds (enzymatic and non-enzymatic). Taken together, recognizing AsA's role in nutrient uptake introduces new possibilities for agricultural use of this compound and provides a valuable basis for improving plant tolerance and adaptability to potential salinity stress adjustment.     

Salicylic acids: Local,systemic or inter-systemic regulators?

Salicylic acid is well known phytohormone, emerging recently as a new paradigm of an array of manifestations of growth regulators. The area unleashed yet encompassed the applied agriculture sector to find the roles to strengthen the crops against plethora of abiotic and biotic stresses. The skipped part of integrated picture, however, was the evolutionary insight of salicylic acid to either allow or discard the microbial invasion depending upon various internal factors of two interactants under the prevailing external conditions. The metabolic status that allows the host invasion either as pathogenesis or symbiosis with possible intermediary stages in close systems has been tried to underpin here.     

Combined effect of 24-epibrassinolide and salicylic acid mitigates lead (Pb) toxicity by modulating various metabolites in <Emphasis Type="BoldItalic">Brassica juncea</Emphasis> L. seedlings

The present study demonstrated the combined effect of 24-epibrassinolide and salicylic acid against lead (Pb, 0.25, 0.50, and 0.75 mM) toxicity in Brassica juncea seedlings. Various parameters including water status, metal uptake, total water- and lipid-soluble antioxidants, metal chelator content (total thiols, protein-bound thiols, and non-protein-bound thiols), phenolic compounds (flavonoids, anthocyanins, and polyphenols), and organic acids were studied in 10-day-old seedlings. Dry matter content and the heavy metal tolerance index were reduced by 42.24 and 52.3%, respectively, in response to Pb treatment. Metal uptake, metal-chelating compounds, phenolic compounds, and organic acids were increased in Pb-treated seedlings as compared to control plants. The treatment of Pb-stressed seedlings with combination of EBL and SA resulted in enhancement of heavy metal tolerance index by 40.07%, water content by 1.84%, and relative water content by 23.45%. The total water- and lipid-soluble antioxidants were enhanced by 21.01 and 2.21%, respectively. In contrast, a significant decline in dry weight, metal uptake, thiol, and polyphenol contents was observed following the application of 24-epibrassinolide and salicylic acid. These observations indicate that Pb treatment has an adverse effect on B. juncea seedlings. However, co-application of 24-epibrassinolide and salicylic acid mitigates the negative effects of Pb, by lowering Pb metal uptake and enhancing the heavy metal tolerance index, water content, relative water content, antioxidative capacities, phenolic content, and organic acid levels.     

Jasmonic Acid Improves Growth Performance of Soybean Under Nickel Toxicity By Regulating Nickel Uptake,Redox Balance,and Oxidative Stress Metabolism

Soil contamination with nickel (Ni) is a persistent threat to crop production worldwide. The present study examined the putative roles of jasmonic acid (JA) in improving Ni tolerance in soybean. Our findings showed that priming of soybean seeds with JA significantly improved the growth performance of soybean when grown under excessive Ni. The enhanced Ni tolerance of soybean prompted by JA could be ascribed to its ability to regulate Ni uptake and accumulation, and to decrease Ni-induced membrane damage as evidenced by reduced levels of reactive oxygen species (ROS), malondialdehyde, lipoxygenase activity, and electrolyte leakage in Ni-stressed plants. JA also boosted redox states and antioxidant capacity in Ni-stressed plants by maintaining increased levels of ascorbate and glutathione, and enhanced activities of ROS-detoxifying enzymes compared with Ni-stressed alone plants. Additionally, methylglyoxal detoxification system was significantly upregulated in JA-primed and “JA-primed?+?Ni-stressed” plants, indicating an alleviating effect of JA on Ni-induced methylglyoxal toxicity. Our results conclude that JA-mediated regulation of Ni uptake and accumulation, and enhanced ROS metabolism by activating antioxidant defense and glyoxalase systems contributed to improved performance of soybean under excessive Ni, thereby suggesting JA as an effective stress regulator in mitigating Ni toxicity in economically important soybean, and perhaps in other crops.

     

Mitigation of sodium chloride toxicity in Solanum lycopersicum L. by supplementation of jasmonic acid and nitric oxide

We investigated the effects of exogenous application of jasmonic acid (JA) and nitric oxide (NO) on growth, antioxidant metabolism, physio-biochemical attributes and metabolite accumulation, in tomato (Solanum lycopersicum L.) plants exposed to salt stress. Treating the plants with NaCl (200 mM) resulted in considerable growth inhibition in terms of biomass, relative water content, and chlorophyll content, all of which were significantly improved upon application of JA and NO under both normal and NaCl-stress treatments. Salt treatment particularly 200 mM NaCl caused an apparent increase in electrolyte leakage, lipid peroxidation, and hydrogen peroxide production, which were reduced by exogenous application of JA and NO. Salt treatment triggered the induction of antioxidant system by enhancing the activities of antioxidant enzymes like superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), and glutathione reductase (GR). Application of JA and NO separately as well as in combination caused a significant improvement in activities of SOD, CAT, APX, and GR activities. JA and NO either applied individually or in combination boosted the flavonoid, proline and glycine betaine synthesis under NaCl treatments. In conclusion, the exogenous application of JA and NO protected tomato plants from NaCl-induced damage by up-regulating the antioxidant metabolism, osmolyte synthesis, and metabolite accumulation.     

Ameliorative Role of Castasterone on Copper Metal Toxicity by Improving Redox Homeostasis in <Emphasis Type="Italic">Brassica juncea</Emphasis> L.

The transition metal elements like copper act as double-edged sword for living cells. Cu, a redox active metal, is essential for various biological processes, but at higher concentrations it leads to toxicity by inducing production of reactive oxygen species (ROS). Thus, the objective of the present study was to investigate the effects of exogenously applied castasterone on oxidative stress markers and redox homeostasis managers in Brassica juncea plants subject to copper stress for 30 days. Copper-exposed plants showed accumulation of free radicals (H₂O₂ and superoxide anion) and lipid peroxidation. However, the exogenous treatment of seeds via the seed soaking method with different concentrations of castasterone reduced H₂O₂ production, superoxide anion radical content, and lipid peroxidation, thus indicating improved detoxification of ROS. Enzyme activity was increased by 19.19% for guaiacol peroxidase, 16.20% for superoxide dismutase, 35.74% for glutathione peroxidase, 27.58% for dehydroascorbate reductase, and 42.75% for ascorbate peroxidase, with castasterone pre-soaking under copper stress. The levels of non-enzymatic antioxidants were also increased with castasterone pre-treatment under copper stress. It may be concluded that castasterone treatment enhanced redox homeostasis managers in addition to increased levels of osmoprotectants.     

Role of Zinc–Lysine on Growth and Chromium Uptake in Rice Plants under Cr Stress

Journal of Plant Growth Regulation - Chromium (Cr) is a very toxic heavy metal present in agricultural soils. Soils contaminated with Cr are the major source of Cr entrance into the food chain. The...     

Seed Priming with Sodium Nitroprusside and H2O2 Confers Better Yield in Wheat Under Salinity: Water Relations,Antioxidative Defense Mechanism and Ion Homeostasis

Journal of Plant Growth Regulation - To mitigate the deleterious effects of abiotic stresses signaling molecules play a significant role. The present study was aimed to assess the responses of two...     

Role of plant growth promoting Bacteria (PGPRs) as biocontrol agents of Meloidogyne incognita through improved plant defense of Lycopersicon esculentum

Plant and Soil - As a major plant-derived soil organic carbon (SOC) component, lignin-derived phenolic compounds show varying biogeochemical characteristics compared to plant-derived lipid...