The potential of foliar application of nano-chitosan-encapsulated nano-silicon donor in amelioration the adverse effect of salinity in the wheat plant

Unveiling influences of metal-based nanomaterials on wheat growth and physiology: From benefits to detriments

Metal-based nanomaterials (MNs) are widely used in agricultural production. However, our current understanding of the overall effects of MNs on crop health is insufficient. A global meta-analysis of 144 studies involving approximately 2000 paired observations was conducted to explore the impacts of MNs on wheat growth and physiology. Our analysis revealed that the MN type plays a key role in influencing wheat growth. Ag MNs had significant negative effects on wheat growth and physiology, whereas Fe, Ti, and Zn MNs significantly increased wheat biomass and photosynthesis. Our study also observed a clear dose-specific effect, with a decrease in wheat shoot biomass with increasing MN concentrations. Meanwhile, MNs with small sizes (<25 nm) have no significant impacts on wheat growth. Furthermore, both the root and foliar applications significantly improved wheat growth, with no considerable differences. Using a machine learning approach, we found that the MN type was the main driving factor affecting wheat shoot biomass, followed by MN dose and size. Overall, wheat growth and physiology can be negatively influenced by specific MNs, for which a high dose and small size should be avoided in practical applications. Therefore, our study can provide insights into the future design and safe use of MNs in agriculture and increase the public acceptance of nano-agriculture.

Zinc-loaded mesoporous silica nanoparticles mitigate salinity stress in wheat seedlings through silica-zinc uptake, osmotic balance, and ROS detoxification

Abiotic stresses like salinity and micronutrient deficiency majorly affect wheat productivity. Applying mesoporous silica nanoparticles (MSiNPs) as a smart micronutrient delivery system can facilitate better stress management and nutrient delivery. In this purview, we investigated the potential of MSiNPs and Zn-loaded MSiNPs (Zn-MSiNPs) on the growth and physiology of wheat seedlings exposed to salinity stress (200 mM NaCl). Initially, the FESEM, DLS, and BET analysis portrayed nanoparticles' spherical shape, nano-size, and negatively charged mesoporous surface. A sustained release of Zn+2 from Zn-MSiNPs at 30 °C, diffused light, and pH 7 was perceived with a 96.57% release after 10 days. Further, the mitigation of NaCl stress in the wheat seedlings was evaluated with two different concentrations, each of MSiNPs and Zn-MSiNPs (1 g/L and 5 g/L), respectively. A meticulous improvement in the germination and growth of wheat seedlings was observed when treated with both MSiNPs and Zn-MSiNPs. A considerable increase in chlorophyll, total protein, and sugar content was in consort with a substantial decline in MDA, electrolyte leakage, and ROS accumulation, showcasing the nanomaterials' palliating effects. Most importantly, the K+/Na+ ratio in shoots increased significantly by 3.43 and 4.37 folds after being treated with 5 g/L Zn-MSiNPs, compared to their respective control sets (0 and 200 mM NaCl). Therefore, it can be concluded that the Zn-MSiNPs can effectively restrain the effects of salinity stress on wheat seedlings.

Peroxidase like Zn doped Prussian blue facilitates salinity tolerance in winter wheat through seed dressing

Salt stress severely limits the growth and yield of wheat in saline-alkali soil. While nanozymes have shown promise in mitigating abiotic stress by scavenging reactive oxygen species (ROS) in plants, their application in alleviating salt stress for wheat is still limited. This study synthesized a highly active nanozyme catalyst known as ZnPB (Zn-modified Prussian blue) to improve the yield and quality of wheat in saline soil. According to the Michaelis-Menten equation, ZnPB demonstrates exceptional peroxidase-like enzymatic activity, thereby mitigating oxidative damage caused by salt stress. Additionally, studies have shown that the ZnPB nanozyme is capable of regulating intracellular Na+ efflux and K+ retention in wheat, resulting in a decrease in proline and soluble protein levels while maintaining the integrity of macromolecules within the cell. Consequently, field experiments demonstrated that the ZnPB nanozyme increased winter wheat yield by 12.15 %, while also significantly enhancing its nutritional quality. This research offers a promising approach to improving the salinity tolerance of wheat, while also providing insights into its practical application.

Silicon nanoparticles in sustainable agriculture: synthesis, absorption, and plant stress alleviation

Silicon (Si) is a widely recognized beneficial element in plants. With the emergence of nanotechnology in agriculture, silicon nanoparticles (SiNPs) demonstrate promising applicability in sustainable agriculture. Particularly, the application of SiNPs has proven to be a high-efficiency and cost-effective strategy for protecting plant against various biotic and abiotic stresses such as insect pests, pathogen diseases, metal stress, drought stress, and salt stress. To date, rapid progress has been made in unveiling the multiple functions and related mechanisms of SiNPs in promoting the sustainability of agricultural production in the recent decade, while a comprehensive summary is still lacking. Here, the review provides an up-to-date overview of the synthesis, uptake and translocation, and application of SiNPs in alleviating stresses aiming for the reasonable usage of SiNPs in nano-enabled agriculture. The major points are listed as following: (1) SiNPs can be synthesized by using physical, chemical, and biological (green synthesis) approaches, while green synthesis using agricultural wastes as raw materials is more suitable for large-scale production and recycling agriculture. (2) The uptake and translocation of SiNPs in plants differs significantly from that of Si, which is determined by plant factors and the properties of SiNPs. (3) Under stressful conditions, SiNPs can regulate plant stress acclimation at morphological, physiological, and molecular levels as growth stimulator; as well as deliver pesticides and plant growth regulating chemicals as nanocarrier, thereby enhancing plant growth and yield. (4) Several key issues deserve further investigation including effective approaches of SiNPs synthesis and modification, molecular basis of SiNPs-induced plant stress resistance, and systematic effects of SiNPs on agricultural ecosystem.

Chitosan and Chitosan Nanoparticles Differentially Alleviate Salinity Stress in Phaseolus vulgaris L. Plants

Salinity stress can significantly cause negative impacts on the physiological and biochemical traits of plants and, consequently, a reduction in the yield productivity of crops. Therefore, the current study aimed to investigate the effects of chitosan (Cs) and chitosan nanoparticles (CsNPs) to mitigate salinity stress (i.e., 25, 50, 100, and 200 mM NaCl) and improve pigment fractions, carbohydrates content, ions content, proline, hydrogen peroxide, lipid peroxidation, electrolyte leakage content, and the antioxidant system of Phaseolus vulgaris L. grown in clay-sandy soil. Methacrylic acid was used to synthesize CsNPs, with an average size of 40 ± 2 nm. Salinity stress negatively affected yield traits, pigment fractions, and carbohydrate content. However, in plants grown under salt stress, the application of either Cs or CsNPs significantly improved yield, pigment fractions, carbohydrate content, proline, and the antioxidant system, while these treatments reduced hydrogen peroxide, lipid peroxidation, and electrolyte leakage. The positive effects of CsNPs were shown to be more beneficial than Cs when applied exogenously to plants grown under salt stress. In this context, it could be concluded that CsNPs could be used to mitigate salt stress effects on Phaseolus vulgaris L. plants grown in saline soils.

Enhanced adaptation to salinity stress in lentil seedlings through the use of trehalose-functionalized silica nanoparticles (TSiNPs): Exploring silica-sugar absorption and oxidative balance

Silica nanoparticles (SiNPs) confer better growth and development of plants under salinity stress. Moreover, the surface-functionalization of SiNPs with bioactive molecules is expected to enhance its efficacy. The present study thus aimed to modify the surface of SiNPs, by attaching a bioactive molecule (trehalose) to obtain TSiNPs. The successful surface functionalization was confirmed using FTIR, XRD, and EDS. The spherical shape and amorphous nature of the nanoparticles were confirmed using SEM. The TEM image analysis revealed that the size of SiNPs and TSiNPs ranged between 20-50 nm and 200-250 nm, respectively. A novel bioassay experiment designed to study the release of silica and trehalose from nanoparticles elucidated that the TSiNPs improved the release and uptake of silica. Also, trehalose uptake significantly improved after 72 h of application due to enhanced release of trehalose from TSiNPs. Further, this study also aimed to investigate the potential benefits of SiNPs and TSiNPs in promoting the growth and development of plants under salinity stress. In this context, the nanoparticles were applied to the saline-stressed (0, 200, 300 mM) lentil seedlings for the in-planta experiments. The results revealed that both SiNPs and TSiNPs improved the growth of seedlings (shoot, and root length), ionic balance (K+/Na+ ratio), and osmolyte status (sugars, proline, glycine betaine, trehalose). Additionally, increased antioxidant enzyme activities helped scavenge ROS (H2O2, O2.-) generated in NaCl-stressed seedlings, ultimately improving the membrane integrity (by reducing MDA and EL). However, the TSiNPs exhibited a much-enhanced activity in stress alleviation compared to the SiNPs.

Recent Trends in Foliar Nanofertilizers: A Review

It is estimated that 40-70%, 80-90% and 50-90% of the conventional macronutrients N, P and K applied to the soil are lost, respectively, resulting in considerable loss of resources. Compared to conventional fertilizers, nanofertilizers have the advantages of controlled release, high nutrient utilization, low cost and relatively low environmental pollution due to their small size (1-100 nm) and high specific surface area. The application of nanofertilizers is an up-and-coming field of agricultural research and is an attractive and economical substitute for common fertilizers which can boost global food productivity sustainably. Foliar fertilization is a popular way to satisfy the needs of higher plants. Because of its small application dose, faster nutrient uptake than soil application and relatively less environmental pollution, foliar fertilization is more popular among plants. It can be seen that nanofertilizers and foliar fertilization are the hotspots of attention at present and that current research on the foliar application of nanofertilizers is not as extensive as that on soil application. Based on this background, this paper provides an overview of various applications of foliar spraying of nanofertilizers in agriculture, including applications in improving crop yield and quality as well as mitigating heavy metal stress, salt stress and drought stress.

Encapsulation with Natural Polymers to Improve the Properties of Biostimulants in Agriculture

Encapsulation in agriculture today is practically focused on agrochemicals such as pesticides, herbicides, fungicides, or fertilizers to enhance the protective or nutritive aspects of the entrapped active ingredients. However, one of the most promising and environmentally friendly technologies, biostimulants, is hardly explored in this field. Encapsulation of biostimulants could indeed be an excellent means of counteracting the problems posed by their nature: they are easily biodegradable, and most of them run off through the soil, losing most of the compounds, thus becoming inaccessible to plants. In this respect, encapsulation seems to be a practical and profitable way to increase the stability and durability of biostimulants under field conditions. This review paper aims to provide researchers working on plant biostimulants with a quick overview of how to get started with encapsulation. Here we describe different techniques and offer protocols and suggestions for introduction to polymer science to improve the properties of biostimulants for future agricultural applications.

Sugar-terminated carbon-nanodots stimulate osmolyte accumulation and ROS detoxification for the alleviation of salinity stress in Vigna radiata

In recent times, nanotechnology has emerged as an efficient tool to manage the adverse effect of environmental stresses on plants. In this connection, carbon-nanodots (CNDs) have been reported to ameliorate the negative impacts of salinity stress. Further, surface modification of CNDs is believed to augment their stress-alleviating potential, however, very little has been known about the potential of surface-functionalized CNDs. In this purview, two sugar (trehalose and glucose) terminated CNDs (CNPT and CNPG) have been synthesized and assessed for their stress-alleviating effects on Vigna radiata (a salt-sensitive legume) seedlings subjected to different concentrations of NaCl (0, 50, and 100 mM). The synthesized CNDs (CNPT and CNPG) exhibited a hydrodynamic size of 20-40 nm and zeta potential of up to - 22 mV with a 5-10 nm core. These water-soluble nanomaterials exhibited characteristic fluorescence emission properties viz. orange and greenish-yellow for CNPT and CNPG respectively. The successful functionalization of the sugar molecules on the CND cores was further confirmed using FTIR, XRD, and AFM. The results indicated that the application of both the CNDs improved seed germination, growth, pigment content, ionic and osmotic balance, and most importantly, the antioxidant defense which decreased ROS accumulation. At the same time, CNPT and CNPG exhibited no toxicity in the Allium cepa root tip bioassay. Therefore, it can be concluded that sugar-terminated CNDs improved the plant responses to salinity stress by facilitating sugar uptake to the aerial part of the seedlings.

Effects of silicon application on leaf structure and physiological characteristics of Glycyrrhiza uralensis Fisch. and Glycyrrhiza inflata Bat. under salt treatment

BACKGROUND

Soil salinization leads to a significant decline in crop yield and quality, including licorice, an important medicinal cash crop. Studies have proofed that the application of exogenous silicon can significantly improve the ability of licorice to resist salt stress, however, few studies concentrated on the effects of foliar silicon application on the morphology, physiological characteristics, and anatomical structure of licorice leaves under salt stress. In this study, the effects of Si (K₂SiO₃) on the structural and physiological characteristics of Glycyrrhiza uralensis Fisch. and G. inflata Bat. leaves under different salt concentrations (medium- and high-salt) were studied.

RESULTS

Compared with the control (without salt), the plant height, total dry weight, leaf area, leaf number, relative water content, xylem area, phloem area, ratio of palisade to spongy tissue, gas exchange parameters, and photosynthetic pigment content of both licorice varieties were significantly reduced under high-salt (12S) conditions. However, the thickness of the leaf, palisade tissue, and spongy tissue increased significantly. Applying Si to the leaf surface increased the area of the vascular bundle, xylem, and parenchyma of the leaf's main vein, promoted water transportation, enhanced the relative leaf water content, and reduced the decomposition of photosynthetic pigments. These changes extended the area of photosynthesis and promoted the production and transportation of organic matter. G. uralensis had a better response to Si application than did G. inflata.

CONCLUSIONS

In conclusion, foliar application of Si can improve water absorption, enhance photosynthesis, improve photosynthetic capacity and transpiration efficiency, promote growth and yield, and alleviate the adverse effects of salt stress on the leaf structure of the two kinds of licorice investigated.