Nanomaterials as an alternative to increase plant resistance to abiotic stresses

Nanomaterials in plant physiology: main effects in normal and under temperature stress

Global climate change and high population growth rates lead to problems of food security and environmental pollution, which require new effective methods to increase yields and stress tolerance of important crops. Nowadays the question of using artificial chemicals is very relevant in theoretical and practical terms. It is important that such substances in low concentrations protect plants under stress conditions, but at the same time inflict minimal damage on the environment and human health. Nanotechnology, which allows the production of a wide range of nanomaterials (NM), provides novel techniques in this direction. NM include structures less than 100nm. The review presents data on the methods of NM production, their properties, pathways for arrival in plants and their use in human life. It is shown that NM, due to their unique physical and chemical properties, can cross biological barriers and accumulate in cells of live organisms. The influence of NM on plant organism can be both positive and negative, depending on the NM chemical nature, their size and dose, the object of study, and the environmental conditions. This review provides a comparative analysis of the effect of artificial metal nanoparticles (NPm), the commonly employed NMs in plant physiology, on two important aspects of plant life: photosynthetic apparatus activity and antioxidant system function. According to studies, NM affect not only the functional activity of photosynthetic apparatus, but also structural organization of chloroplats. In addition, the literature analysis reflects the dual action of NM on oxidative processes, and antioxidant status of plants. These facts considerably complicate the ideas about possible mechanisms and further use of NPm in biology. In this regard, data on the effects of NM on plants under abiotic stressors are of great interest. Separate section is devoted to the use of NM as adaptogens that increase plant stress tolerance to unfavorable temperatures. Possible mechanisms of NM effects on plants are discussed, as well as the strategies for their further use in basic science and sustainable agriculture.

Review on interactions between nanomaterials and phytohormones: Novel perspectives and opportunities for mitigating environmental challenges

Nanotechnology offers the potential to provide innovative solutions for sustainable crop production as plants are exposed to a combination of climate change factors (CO2, temperature, UV radiation, ozone), abiotic (heavy metals, salinity, drought), and biotic (virus, bacteria, fungi, nematode, and insects) stresses. The application of particular sizes, shapes, and concentration of nanomaterials (NMs) potentially mitigate the negative impacts in plants by modulation of photosynthetic rate, redox homeostasis, hormonal balance, and nutrient assimilation through upregulation of anti-stress metabolites, antioxidant defense pathways, and genes and genes network. The present review inculcates recent advances in uptake, translocation, and accumulation mechanisms of NMs in plants. The critical theme of this review provides detailed insights into different physiological, biochemical, molecular, and stress tolerance mechanism(s) of NMs action and their cross-talk with different phytohormones. The role of NMs as a double-edged sword for climate change factors, abiotic, and biotic stresses for nutrients uptake, hormones synthesis, cytotoxic, and genotoxic effects including chromosomal aberration, and micronuclei synthesis have been extensively studied. Importantly, this review aims to provide an in-depth understanding of the hormesis effect at low and toxicity at higher doses of NMs under different stressors to develop innovative approaches and design smart NMs for sustainable crop production.

Engineered nanomaterials for carbon capture and bioenergy production in microbial electrochemical technologies: A review

The mounting threat of global warming, fuelled by industrialization and anthropogenic activities, is undeniable. In 2017, atmospheric carbon dioxide (CO2), the primary greenhouse gas, exceeded 410 ppm for the first time. Shockingly, on April 28, 2023, this figure surged even higher, reaching an alarming 425 ppm. Even though extensive research has been conducted on developing efficient carbon capture and storage technologies, most suffer from high costs, short lifespans, and significant environmental impacts. Recently, the use of engineered nanomaterials (ENM), particularly in microbial electrochemical technologies (METs), has gained momentum owing to their appropriate physicochemical properties and catalytic activity. By implementing ENM, the MET variants like microbial electrosynthesis (MES) and photosynthetic microbial fuel cells (pMFC) can enhance carbon capture efficiency with simultaneous bioenergy production and wastewater treatment. This review provides an overview of ENMs' role in carbon capture within MES and pMFC, highlighting advancements and charting future research directions.

Exogenously Applied Cyclitols and Biosynthesized Silver Nanoparticles Affect the Soluble Carbohydrate Profiles of Wheat (Triticum aestivum L.) Seedling

Cyclitols, such as myo-inositol and its isomers and methyl derivatives (i.e., d-chiro-inositol and d-pinitol (3-O-methyl-chiro-inositol)), are classified as osmolytes and osmoprotectants and are significantly involved in plant responses to abiotic stresses, such as drought, salinity and cold. Moreover, d-pinitol demonstrates a synergistic effect with glutathione (GSH), increasing its antioxidant properties. However, the role of cyclitols in plant protection against stresses caused by metal nanoparticles is not yet known. Therefore, the present study examined the effects of myo-inositol, d-chiro-inositol and d-pinitol on wheat germination, seedling growth and changes in the profile of soluble carbohydrates in response to biologically synthesized silver nanoparticles ((Bio)Ag NPs). It was found that cyclitols were absorbed by germinating grains and transported within the growing seedlings but this process was disrupted by (Bio)Ag NPs. Cyclitols applied alone induced sucrose and 1-kestose accumulation in seedlings slightly, while (Bio)Ag NP doubled the concentrations of both sugars. This coincided with a decrease in monosaccharides; i.e., fructose and glucose. Cyclitols and (Bio)Ag NPs present in the endosperm resulted in reductions in monosaccharides, maltose and maltotriose, with no effect on sucrose and 1-kestose. Similar changes occurred in seedlings developing from primed grains. Cyclitols that accumulated in grain and seedlings during grain priming with d-pinitol and glutathione did not prevent the phytotoxic effects of (Bio)Ag NPs.

Insight into the biochemical and physiological mechanisms of nanoparticles-induced arsenic tolerance in bamboo

INTRODUCTION

Arsenic (As) contamination in soil, sediments, and water poses a significant threat to the growth of bamboo plants. However, nanoparticles with high metal absorbance capacity can play a key role in the reduction of heavy metals toxicity in plants as well as maintaining their growth under toxicity.

METHODS

Hence, an in vitro experiment was conducted to determine the influence of three types of nanoparticles: 150 µM silicon nanoparticles (SiO₂ NPs), 150 µM titanium nanoparticles (TiO₂ NPs), and 150 µM zinc oxide nanoparticles (ZnO NPs) on As (150 µM and 250 µM) tolerance enhancement of a one-year-old bamboo species (Pleioblastus pygmaeus).

RESULTS AND DISCUSSION

The results showed that while As at 150 µM and 250 µM significantly disrupted the plant growth by excessive generation of reactive oxygen species (ROS) components, and inducing cell membrane peroxidation, the addition of NPs increased both enzymatic and non-enzymatic antioxidant activities, upregulated glyoxalase defense system, and improved gas exchange parameters and photosynthetic pigments content, leading to the enhanced plant shoot and root dry weight. These were achieved by lowering levels of ROS, electrolyte leakage (EL), malondialdehyde (MDA), hydrogen peroxide (H₂O₂) and the superoxide radical ( O 2 • - ), as well as decreasing As accumulation in the plant organs. Thus, it might be concluded that ZnO NPs, SiO₂NPs, and TiO₂NPS alone or in combination can significantly increase the bamboo plant tolerance to As toxicity via key mechanisms, including induction of various antioxidants and glyoxalase defense systems, scavenging of ROS and methylglyoxal (MG), increasing phytochelatins production, reduction of As accumulation and translocation, and improving photosynthetic pigments under As toxicity. Additionally, the results showed that the combined application of 150 µM ZnO NPs, SiO₂ NPs, and TiO₂ NPs had the greatest effect on enhancing the plant tolerance to As at 150 µM and 250 µM.

Elicitation of Bacillus cereus-Amazcala (B.c-A) with SiO2 Nanoparticles Improves Its Role as a Plant Growth-Promoting Bacteria (PGPB) in Chili Pepper Plants

Agriculture needs to decrease the use of agrochemicals due to their high toxicity and adopt new strategies to achieve sustainable food production. Therefore, nanoparticles (NPs) and plant growth-promoting bacteria (PGPB) have been proposed as viable strategies to obtain better crop yields with less environmental impact. Here, we describe the effect of silica nanoparticles (SiO₂-NPs) on survival, antioxidant enzymatic activity, phosphate solubilization capacity, and gibberellin production of Bacillus cereus-Amazcala (B.c-A). Moreover, the effect of the co-application of SiO₂-NPs and B.c-A on seed germination, physiological characteristics, and antioxidant enzymatic activity of chili pepper plants was investigated under greenhouse conditions. The results indicated that SiO₂-NPs at 100 ppm enhanced the role of B.c-A as PGPB by increasing its phosphate solubilization capacity and the production of GA7. Moreover, B.c-A catalase (CAT) and superoxide dismutase (SOD) activities were increased with SiO₂-NPs 100 ppm treatment, indicating that SiO₂-NPs act as a eustressor, inducing defense-related responses. The co-application of SiO₂-NPs 100 ppm and B.c-A improved chili pepper growth. There was an increase in seed germination percentage, plant height, number of leaves, and number and yield of fruits. There was also an increase in CAT and PAL activities in chili pepper plants, indicating that bacteria-NP treatment induces plant immunity.