Currently, the growth and yield of crops are restrained due to an increase in the occurrence of ecological stresses globally. Biogenic generation of nanomaterials is an important step in the development of environmentally friendly procedures in the nanotechnology field. Silver-based nanomaterials are significant because of their physical, chemical, and biological features along with their plentiful applications. In addition to useful microbes, the green synthesized Ag nanomaterials are considered to be an ecologically friendly and environmentally biocompatible method for the enhancement of crop yield by easing stresses. In the recent decade, due to regular droughts, infrequent precipitation, salinity, and increased temperature, the climate alternation has changed certain ecological systems. As a result of these environmental changes, crop yield has decreased worldwide. The role of biogenic Ag nanomaterials in enhancing methylglyoxal detoxification, antioxidant defense mechanisms, and generating tolerance to stresses-induced ROS injury has been methodically explained in plants over the past ten years. However, certain studies regarding stress tolerance and metal-based nanomaterials have been directed, but the particulars of silver nanomaterials arbitrated stresses tolerance have not been well-reviewed. Henceforth, there is a need to have a good understanding of plant responses during stressful conditions and to practice the combined literature to enhance tolerance for crops by utilization of Ag nanoparticles. This review article illustrates the mechanistic approach that biogenic Ag nanomaterials in plants adopt to alleviate stresses. Moreover, we have appraised the most significant activities by exogenous use of Ag nanomaterials for improving plant tolerance to salt, low and high temperature, and drought stresses.

Agriculture is the backbone of every developing country. Among various crops, wheat (Triticum aestivum L.) belongs to the family Poaceae and is the most important staple food crop of various countries. Different biotic (viruses, bacteria and fungi) and abiotic stresses (water logging, drought and salinity) adversely affect the qualitative and quantitative attributes of wheat. Among these stresses, salinity stress is a very important limiting factor affecting the morphological, physiological, biochemical attributes and grain yield of wheat. This research work was carried out to evaluate the influence of phytosynthesized TiO₂ NPs on the germination, physiochemical, and yield attributes of wheat varieties in response to salinity. TiO₂ NPs were synthesized using TiO₂ salt and a Buddleja asiatica plant extract as a reducing and capping agent. Various concentrations of TiO₂ nanoparticles (20, 40, 60 and 80 mg/L) and salt solutions (NaCl) (100 and 150 mM) were used. A total of 20 mg/L and 40 mg/L improve germination attributes, osmotic and water potential, carotenoid, total phenolic, and flavonoid content, soluble sugar and proteins, proline and amino acid content, superoxide dismutase activity, and reduce malondialdhehyde (MDA) content at both levels of salinity. These two concentrations also improved the yield attributes of wheat varieties at both salinity levels. The best results were observed at 40 mg/L of TiO₂ NPs at both salinity levels. However, the highest concentrations (60 and 80 mg/L) of TiO₂ NPs showed negative effects on germination, physiochemical and yield characteristics and causes stress in both wheat varieties under control irrigation conditions and salinity stress. Therefore, in conclusion, the findings of this research are that the foliar application of TiO₂ NPs can help to improve tolerance against salinity stress in plants.

The present study was carried out to investigate the beneficial and toxicological effect of plant-based titanium dioxide nanoparticles (TiO ₂ NPs) on the morphophysiological attributes of wheat plants under salinity stress. The biogenesis of titanium dioxide nanoparticles was accomplished by using the extract of Buddleja asiatica L. leaves followed by characterization through UV visible spectroscopy, SEM, FTIR, and EDX. NaCl salt was applied in two different concentrations after 21 days of germination followed by foliar applications of various concentrations of TiO ₂ NPs (20, 40, 60, 80 mg/L) to salinity-tolerant (Faisalabad-08) and salinity-susceptible (NARC-11) wheat varieties after 10–15 days of application of salt stress. Salinity stress showed remarkable decrease in morphophysiological attributes of selected wheat varieties. Magnificent improvement in plant height, dry and fresh weight of plants, shoot and root length, root and shoot fresh and dry weight, number of leaves per plant, RWC, MSI, chlorophyll a and b, and total chlorophyll contents has been observed when 40 mg/L of TiO ₂ NPs was used. However, the plant morphophysiological parameters decreased gradually at higher concentrations (60 and 80 mg/L) in both selected wheat varieties. Therefore, 40 mg/L concentration of TiO ₂ NPs was found most preferable to increase the growth agronomic and physiological attributes of selected wheat varieties under salinity.

Crop productivity worldwide is being hampered by salt stress. Nanotechnology and its applications in agriculture are noteworthy and fruitful. The current work investigates the potential significance of TiO₂ NPs in alleviating salt stress in wheat cultivars. TiO₂ NPs were prepared by green synthesis; their characterizations were carried out by UV–visible spectroscopy, SEM, and EDX. In the greenhouse control condition, different concentrations of salt (NaCl) with and without TiO₂ NPs were administered to wheat crops. Plants treated with TiO₂ NPs showed an enhanced germination rate, morphological, and metabolic profiling with and without salt stress. Different concentrations of TiO₂ NPs (25, 50, 75, and 100 µg/mL) and salt solutions (NaCl 50, 100, and 150 mM) were used. TiO₂ NP concentrations of 25 µg/mL and 50 µg/mL improved the germination attributes, physio-morphic parameters: plant length, the fresh and dry weight of plants, the number of leaves, the leaf area, the RWC, the MSI, and different chlorophyll contents at all saline conditions. These two concentrations also enhanced the biochemical attributes: free amino acids, soluble sugar content, proline content, SOD, and POD, of wheat varieties at all salinity levels. Wheat subjected to salt stress responded best to the application of TiO₂ NPs at a concentration of 50 µg/mL. However, the highest concentrations (75 and 100 µg/mL) of TiO₂ NPs showed detrimental effects on germination, agronomic, physiological, and biochemical attributes, and caused stress in both wheat varieties (Pirsabak-05 and NARC-09) under control and saline conditions. The outcomes of the current research work are notable, and NPs with such capabilities may be a useful supply of fertilizer in the agricultural industry.

Wheat is the most important staple food worldwide, but wheat cultivation faces challenges from high food demand. Fertilizers are already in use to cope with the demand; however, more unconventional techniques may be required to enhance the efficiency of wheat cultivation. Nanotechnology offers one potential technique for improving plant growth and production by providing stimulating agents to the crop. In this study, plant-derived Ag/ZnO nanomaterials were characterized using UV-Vis spectroscopy, SEM, EDX, FTIR, and XRD methods. Various concentrations of phytogenically synthesized Ag/ZnO nanomaterials (20, 40, 60, and 80 ppm) and nitrogen-based fertilizers (urea and ammonium sulphate 50 and 100 mg/L) were applied to wheat varieties (Galaxy-13 and Pak-13). The results obtained from this research showed that application of 60 ppm Ag/ZnO nanomaterials with nitrogenous fertilizers (50 and 100 mg/L) were more effective in improving biochemistry and increasing yield of wheat plants by reducing enzymatic and non-enzymatic antioxidants (proline content, soluble sugar content, malondialdehyde, total phenolic content, total flavonoid content, superoxide dismutase, peroxidase, and catalase); and significantly increasing the protein content, number of grains per pot, spike length, 100-grain weight, grain yield per pot, and harvest index of both wheat varieties, compared to untreated plants. These findings allow us to propose Ag/ZnO nanomaterial formulation as a promising growth- and productivity-improvement strategy for wheat cultivation.

The Journal retracts the article “Exogenous Application of Green Titanium Dioxide Nanoparticles (TiO₂ NPs) to Improve the Germination, Physiochemical, and Yield Parameters of Wheat Plants Under Salinity Stress”