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The issue of water scarcity in Pakistan is a significant challenge which is due to exacerbated population growth as well as increase in freshwater demand. The application of wastewater for irrigation, especially in semi-urban regions, can indeed be a practical solution due to its ready availability and affordability. While wastewater can serve as a valuable resource in water-scarce regions, its use must be carefully managed to minimize potential risks to plant health, soil fertility, and human well-being. A study was conducted aiming to assess the seasonal changes in physicochemical properties of irrigated wastewater and their influence on morphological, physiological and biochemical responses of sugarcane (Saccharum officinarum L.). Sugarcane plants were grown for consecutive two years in peri-urban agricultural areas near the water channels. Sugarcane plants were grown in two different fields and irrigation of the crop was done with wastewater and freshwater, respectively. Water (wastewater and freshwater) and plant samples were collected four times in a year in different seasons (winter, spring, summer, fall) for two consecutive years (2016-2017). All the collected data had been subjected to multivariate analysis of variance (MANOVA) for assessing the impa ct of seasonal variation on plant responses under the influence of irrigated wastewater. The findings from the study highlighted the complex relationship between wastewater irrigation and the physiological responses of sugarcane plants. The observed increase in antioxidant activities of wastewater irrigated plants compared to freshwater irrigated plants suggested that sugarcane may undergo biochemical adjustments to cope with the stress induced by the contaminants present in the wastewater. Moreover, the significant differences in plant mineral contents across different seasons were observed which indicated the dynamic nature of nutrient availability in the irrigation water and its impact on plant growth and development. We concluded that wastewater irrigation can affect the potential output of the agriculture sector by altering plant physiology which underscores the importance of considering the quality of irrigation water in agricultural practices. For future prospectives, the study can be extended to other crops to develop comprehensive strategies for sustainable agriculture. [ABSTRACT FROM AUTHOR]

Improving growth and productivity of plants that are vulnerable to environmental stresses, such as heavy metals, is of significant importance for meeting global food and energy demands. Because heavy metal toxicity not only causes impaired plant growth, it has also posed many concerns related to human well-being, so mitigation of heavy metal pollution is a necessary priority for a cleaner environment and healthier world. Hydrogen sulfide (H2S), a gaseous signaling molecule, is involved in metal-related oxidative stress mitigation and increased stress tolerance in plants. It performs multifunctional roles in plant growth regulation while reducing the adverse effects of abiotic stress. Most effective function of H2S in plants is to eliminate metal-related oxidative toxicity by regulating several key physiobiochemical processes. Soil pollution by heavy metals presents significant environmental challenge due to the absence of vegetation cover and the resulting depletion of key soil functions. However, the use of stress alleviators, such as H2S, along with suitable crop plants, has considerable potential for an effective management of these contaminated soils. Overall, the present review examines the imperative role of exogenous application of different H2S donors in reducing HMs toxicity, by promoting plant growth, stabilizing their physiobiochemical processes, and upregulating antioxidative metabolic activities. In addition, crosstalk of different growth regulators with endogenous H2S and their contribution to the mitigation of metal phytotoxicity have also been explored. [ABSTRACT FROM AUTHOR]

Potassium (K) deficiency is becoming a major productivity constraint in semi-arid agriculture. It is an essential mineral nutrient that has key role in various plant physiological and biochemical functions. Balanced nutrient application always tends to ensure better plant growth and development. Therefore, in the present study, efficacy of different K fertilizers for mediating maize plant growth and productivity in the presence and absence of KSB inoculant was assessed. A potassium solubilizing rhizobacterial strain, Klebsiella oxytoca KSB-17, was used in a 5 × 2 factorial pot experiment involving maize plant. The treatments comprised of control, waste mica (WM), K chemical fertilizer (KCF), WM-enriched compost (WMEC) and KCFenriched compost (KCFEC). Compared to control treatment, KCF fertilization increased all plant physiological parameters both in presence and absence of KSB inoculation. From the results obtained, KCFEC followed by CF alone with KSB, demonstrated the most pronounced effect with significant increase in plant height (50%), shoot biomass (59%), root biomass (73%), root length (92%), plant K uptake (154%), grain starch (16%), protein (31%), oil content (22%) as well as photosynthetic rate (104%), transpiration rate (30%) and water use efficiency (54%) compared to control. Potassium solubilizing bacteria (KSB) prompted down-regulation of plant antioxidant enzyme activities against all K fertilizer treatments. Compared to control treatment, catalase (CAT) activity decreased significantly on application of KCF as well as with KCFEC in the presence of KSB inoculation. Regardless of KSB inoculation, plant growth, physiological, antioxidant and K nutritional traits showed slight improvement with either of WM fertilizers compared to control. Our findings concluded that K enriched compost with efficient KSB inoculant can be used to enhance maize growth and productivity in semi-arid agroecosystems. [ABSTRACT FROM AUTHOR]

Phytoremediation, assisted with different amendments, is receiving much attention around the world due to its high efficiency, low cost and ease of handling. The current study was constructed to determine the combined performance of the citric acid (CA) and 5-aminolevulinic acid (5-AA) to enhance chromium (Cr) extraction through sunflower. Healthy seeds of sunflower were grownup in Cr contaminated soil (0, 5, 10 & 20 mgkg-1) and externally provided with CA (0, 2.5 &5 mM) and 5-AA (0, 10 & 20 mg L-1) at juvenile stage. The results showed a significant reduction in sunflower agronomic traits and biomass under Cr stress. In response to Cr stress, higher production of the reactive oxygen species (ROS) significantly reduced soluble proteins, photosynthetic pigments and activities of anti-oxidant enzymes. The combined addition of CA and 5-AA considerably mitigated the Cr-induced toxic effects on sunflower. Citric acid (CA) and 5-AA application enhanced plants' agronomic and physiological attributes by lowering electrolyte leakage and ROS production. Furthermore, the introduction of 5-AA and CA significantly up-regulated the actions of antioxidants enzymes in leaves and root of sunflower. With increasing soil Cr concentration, more Cr uptake and accumulation was observed which was further boosted with mutual applications of CA and 5-AA. Results of our work summarize that, CA and 5-AA combined application can effectively mitigate Cr stress and enhance Cr extraction capability of sunflower. [ABSTRACT FROM AUTHOR]

Improving growth and productivity of plants that are vulnerable to environmental stresses, such as heavy metals, is of significant importance for meeting global food and energy demands. Because heavy metal toxicity not only causes impaired plant growth, it has also posed many concerns related to human well-being, so mitigation of heavy metal pollution is a necessary priority for a cleaner environment and healthier world. Hydrogen sulfide (H 2 S), a gaseous signaling molecule, is involved in metal-related oxidative stress mitigation and increased stress tolerance in plants. It performs multifunctional roles in plant growth regulation while reducing the adverse effects of abiotic stress. Most effective function of H 2 S in plants is to eliminate metal-related oxidative toxicity by regulating several key physiobiochemical processes. Soil pollution by heavy metals presents significant environmental challenge due to the absence of vegetation cover and the resulting depletion of key soil functions. However, the use of stress alleviators, such as H 2 S, along with suitable crop plants, has considerable potential for an effective management of these contaminated soils. Overall, the present review examines the imperative role of exogenous application of different H 2 S donors in reducing HMs toxicity, by promoting plant growth, stabilizing their physiobiochemical processes, and upregulating antioxidative metabolic activities. In addition, crosstalk of different growth regulators with endogenous H 2 S and their contribution to the mitigation of metal phytotoxicity have also been explored., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Arif, Yasmeen, Abbas, Ali, Rizwan, Aljarba, Alkahtani and Abdel-Daim.)