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Biochar, a sustainable green technology product, is essential for promoting plant development and growth. Nano biochar emerges as a promising solution for environmental sustainability. Despite its potential, the intricate dynamics between plants and nano-biochar, particularly in finger millet (Eleusine coracana), remain largely unexplored, necessitating a deeper understanding of their interaction. This study investigates the effects of carbon nitride (C3N4) nano-biochar, derived from melamine, on finger millet. A screening setup was employed with varied concentrations of C3N4: 0 µM (control), 500 µM, 1000 µM, 1500 µM, and 2000 µM. Morphological parameters of plants includes root-shoot length, fresh and dry weights, were analysed to determine the optimal dosage. Results reveal that the most effective concentration of C3N4 for enhancing finger millet growth was found to be 1000 µM. Beyond this threshold, higher doses proved to be toxic, impeding plant growth and development. This research sheds light on the unexplored relationship between nano-biochar and plant physiology, offering insights crucial for sustainable agricultural practices.

As population growth accelerates, agriculture’s significance in our lives remains paramount. However, this surge in population has led to land degradation and increased food scarcity. The impact of silicon (Si) on plants has garnered significant attention in agricultural research. This study was aimed at examining the impact of Si on barley (Hordeum vulgare) plants by administering varying concentrations (5µM, 10µM, 20µM, 50µM, 100µM, 200µM, 500µM, 1000µM) and assessing their effects on plant growth parameters, particularly root and shoot lengths, and root fresh weight. Our study employed a controlled experimental setup to observe how barley plants respond to varying concentrations of Si. The data indicates that Si concentrations up to 10µM offer advantageous effects on barley compared to the control group, suggesting its potential in bolstering agricultural productivity. Similarly, concentrations of 20µM, 50µM, and 100µM were identified as safe for plant growth, opening avenues for their agricultural utilization. However, concentrations of 500µM and 1000µM resulted in complete inhibition of plant growth, emphasizing the necessity for cautious Si application in agriculture to prevent adverse impacts on crop yields. These findings underscore the importance of fine-tuning Si concentrations in agricultural practices to optimize benefits while mitigating potential risks to plants.

Biochar, a byproduct of biomass pyrolysis, has gained interest for its wideranging uses in agriculture and environmental remediation. Nano-biochar, in particular, holds promise for enhancing crop productivity and addressing environmental challenges faced by the plants. Its ability to improve soil properties and biological functions underscores its potential in sustainable agriculture. This study investigates the influence of a carbon-based nanobiocharcarbon nitride (C3N4, derived from melamine) on rice (Oryza sativa) growth. Despite the promise of nanostructured biochar materials in bolstering crop yields, their interaction with varying concentrations of C3N4 remains poorly understood. In this study, we studied the impact of five concentrations (0µM, 500µM, 1000µM, 1500µM, and 2000µM) of C3N4 on rice growth. Our results reveal a concentration-dependent response, with 1500µM and 2000µM concentrations exhibiting toxic effects on rice plants, while 500µM and 1000µM concentrations demonstrate positive effects on rice growth parameters (root-shoot length, fresh-dry biomass) with maximum values obtained in case of the latter. This research sheds light on the potential of C3N4 nanobiochars to influence the growth of crop plants, emphasizing the importance of optimizing concentrations for sustainable agricultural practices. Further exploration in this area could lead to finding of solutions for enhancing agricultural productivity in a sustainable manner.

Plants require nitrogen (N) in various forms to facilitate essential physiological functions. Nitrate (NO3-) is one of the most readily absorbed N forms by plants and is preferred in well-aerated soils because it can be easily transported within the plant. Ammonium (NH4+), on the other hand, is utilized especially in waterlogged or acidic soils, where it is directly absorbed by the roots and incorporated into amino acids. Urea (CH4N2O) is another significant N source found in many fertilizers; it is transformed into NH4+ and nitrate in the soil through microbial processes. These diverse forms of N are crucial for supporting photosynthesis, protein synthesis, and energy production in plants. The escalating use of ammonium sulphate (NH4)2SO4) as a N source in agriculture prompts a thorough examination of its impact on crop health and productivity. This study aimed to investigate the NH4+ toxicity on rice (Oryza sativa) plants by administering various dosages (0 mM, 5 mM, 7 mM, 10 mM, 12 mM, and 15 mM) and assessing their effects on plant growth parameters, particularly root-shoot lengths, root-shoot fresh biomass along with dry weight. Our research utilized a controlled experimental setup to monitor the growth responses of rice plants to these NH4+ concentrations. Results indicated a clear threshold of tolerance, with adverse effects becoming significant at concentrations starting from 7 mM. At this concentration and higher, there was a noticeable decline in root-shoot lengths, root-shoot biomass and dry biomass, marking the onset of toxicity symptoms in rice plants. These findings suggest a critical need for regulated application of (NH4)2SO4 in rice cultivation to avoid detrimental effects on plant health and yield. The study underscores the importance of establishing safe usage guidelines for (NH4)2SO4 in agriculture, ensuring sustainable farming practices while maintaining crop productivity.

This study aimed to investigate the phytotoxic effect of copper (Cu) and copper nanoparticles (CuONPs) and ameliorative potential of nitric oxide (NO) against these toxic materials in Sorghum vulgare Pers. seedlings. Data suggested that exposure of Cu and CuONPs significantly reduced growth, chlorophyll, carotenoids and protein in root and shoot, which coincided with increased Cu accumulation. However, addition of sodium nitroprusside (SNP, a donor of NO) lowered Cu and CuONPs mediated toxicity through restricting Cu accumulation and improving photosynthetic pigments and total soluble protein contents. Data further suggested that exposure of Cu and CuONPs significantly increased hydrogen peroxide (H2O2), superoxide radicals (O2•−), and malondialdehyde (MDA) contents. Enhanced level of oxidative stress severely inhibited the enzymatic activities of glutathione reductase (GR), ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR) and monodehydroascorbate reductase (MDHAR) but enhanced superoxide dismutase (SOD) and catalase (CAT) activity. However, addition of SNP positively regulated antioxidants enzymes activity, particularly the enzymes involved in the ascorbate-glutathione cycle to overcome Cu- and CuONPs-induced stress in Sorghum seedlings. Further, Cu and CuONPs enhanced accumulation of free proline through inducing Δ1-pyrroline-5-carboxylate synthetase (P5CS) activity while lowering the proline dehydrogenase (PDH) activity. However, addition of SNP reversed these responses. Therefore, overall results revealed that SNP has enough potential of reducing the toxicity of Cu and CuONPs in Sorghum seedlings through regulation of proline metabolism and activity of enzymes of the ascorbate-glutathione cycle. These findings can be employed in developing new resistant varieties of Sorghum having enhanced tolerance against Cu or CuONP stress and improved productivity. Enhancing crop productivity under the prevalent stressful environment is needed to meet global food demand. Copper (Cu) and copper oxide nanoparticles (CuONPs) pose adverse effects on Sorghum vulgare Pers. productivity. This study delineates that exogenous nitric oxide can mitigate their toxicity and improve the plant growth parameters. The findings of this research can be employed in developing new resistant varieties of sorghum having enhanced tolerance against Cu or CuONPs stress. [ABSTRACT FROM AUTHOR]

Genetic modification allows engineering of important traits in crops through expensive and tedious procedures to alter their genetic background. Recently, Thagun et al. developed a nanocarrier-based foliar spray method to translocate bioactive molecules of interest into plant cells to engineer important traits without introducing a transgene. [ABSTRACT FROM AUTHOR]

Nanoparticles (NPs) have garnered increasing attention for their applications in agriculture and plant science, particularly for their interactions with reactive oxygen species (ROS) and nitric oxide ( • NO). NPs, owing to their novel physicochemical properties, can be used to uniquely modulate ROS levels, enabling great control over redox homeostasis and signaling cascades. In addition, NPs may act as carriers for • NO donors, thus facilitating controlled and synchronized release and targeted delivery of • NO within plant systems. This opinion article provides insights into the current state of knowledge regarding NP interactions with ROS and • NO homeostasis in plants, highlighting key findings and knowledge gaps, as well as outlining future research directions in this rapidly expanding and potentially transformative field of research., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Along with the rapidly increasing environmental contamination by heavy metals, the exposure of plants to chromium has also magnified, resulting in a declined productivity. Hexavalent chromium [Cr(VI)], the most toxic form of Cr, brings about changes in plant processes at morpho-physiological and biochemical levels. However, silicon (Si) is known to mitigate the impact of abiotic stresses in plants. Here, we demonstrate Si-mediated alleviation of Cr(VI) toxicity and its effects on root hair formation in rice seedlings. Reduced glutathione (GSH) and indole-3 acetic acid (IAA, an important auxin) were assessed for their involvement in root hair formation after the application of Si to Cr(VI)-stressed plants, and our results confirmed their crucial significance in such developmental processes. The expression analysis of genes involved in GSH biosynthesis (OsGS2) and regeneration (OsGR1), and auxin biosynthesis (OsTAA1 and OsYUCCA1) and transport (OsAUX1 and OsPIN1) corroborated their positive role in Si-mediated root hair formation in Cr(VI)-stressed rice seedlings. Moreover, the results indicated that nitric oxide (NO) seems a probable but not fundamental component in Si-mediated formation of roots in rice during exposure to Cr(VI) stress. In this study, the indispensable role of GSH and IAA, redox homeostasis of GSH and IAA biosynthesis and transport are discussed with regard to Si-mediated formation of root hairs in rice under Cr(VI) stress. The results of the study suggest that Si is a protective agent against Cr(VI) stress in rice, and the findings can be used to develop Cr(VI) stress-tolerant varieties of rice with enhanced productivity., (© The Author(s) 2022. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

The global increase in nanotechnology applications has been unprecedented and has now moved into the area of agriculture and food production. Applications with promising potential in sustainable agriculture include nanobiosensors, nanofertilizers, nanopesticides, nano-mediated remediation strategies for contaminated soils and nanoscale strategies to increase crop production and protection. Given this, the impact of nanomaterials/nanoparticles (NPs) on plant species needs to be thoroughly evaluated as this represents a critical interface between the biosphere and the environment. Importantly, phytohormones represent a critical class of biomolecules to plant health and productivity; however, the impact of NPs on these molecules is poorly understood. In addition, phytohormones, and associated pathways, are widely explored in agriculture to influence several biological processes for the improvement of plant growth and productivity under natural as well as stressed conditions. However, the impact of exogenous applications of phytohormones on NP-treated plants has not been explored. The importance of hormone signaling and cross-talk with other metabolic systems makes these biomolecules ideal candidates for a thorough assessment of NP impacts on plant species. This article presents a critical evaluation of the existing yet limited literature available on NP-phytohormone interactions in plants. In addition, the developing strategy of nano-enabled precision delivery of phytohormones via nanocarriers will be explored. Finally, directions for future research and critical knowledge gaps will be identified for this important aspect of nano-enabled agriculture., (© The Author(s) 2022. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

The phytohormone auxin acts as an important signaling molecule having regulatory functions during the growth and development of plants. Reactive oxygen species (ROS) are also known to perform signaling functions at low concentrations; however, over-accumulation of ROS due to various environmental stresses damages the biomolecules and cell structures and leads to cell death, and therefore, it can be said that ROS act as a double-edged sword. Nitric oxide (NO), a gaseous signaling molecule, performs a wide range of favorable roles in plants. NO displays its positive role in photomorphogenesis, root growth, leaf expansion, seed germination, stomatal closure, senescence, fruit maturation, mitochondrial activity and metabolism of iron. Studies have revealed the early existence of these crucial molecules during evolution. Moreover, auxin, ROS and NO together show their involvement in various developmental processes and abiotic stress tolerance. Redox signaling is a primary response during exposure of plants to stresses and shows a link with auxin signaling. This review provides updated information related to crosstalk between auxin, ROS and NO starting from their evolution during early Earth periods and their interaction in plant growth and developmental processes as well as in the case of abiotic stresses to plants., (© The Author(s) 2022. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Developments in the field of nanotechnology over the past few years have increased the prevalence of silver nanoparticles (AgNPs) in the environment, resulting in increased exposure of plants to AgNPs. Recently, various studies have reported the effect of AgNPs on plant growth at different concentrations. However, identifying the mechanisms and signaling molecules involved in plant responses against AgNPs stress is crucial to find an effective way to deal with the phytotoxic impacts of AgNPs on plant growth and development. Therefore, this study was envisaged to investigate the participation of ethylene in mediating the activation of AgNPs stress tolerance in rice (Oryza sativa L.) through a switch that regulates endogenous nitric oxide (NO) accumulation. Treatment of AgNPs alone hampered the growth of rice seedlings due to severe oxidative stress as a result of decline in sulfur assimilation, glutathione (GSH) biosynthesis and alteration in the redox status of GSH. These results are also accompanied by the higher endogenous NO level. However, addition of ethephon (a donor of ethylene) reversed the AgNP-induced effects. Though the application of silicon nanoparticles (SiNPs) alone promoted the growth of rice seedlings but, interestingly their application in combination with AgNPs enhanced the AgNP-induced toxicity in the seedlings through the same routes as exhibited in the case of AgNPs alone treatment. Interestingly, addition of ethephon reversed the negative effects of SiNPs under AgNPs stress. These results suggest that ethylene might act as a switch to regulate the level of endogenous NO, which in turn could be associated with AgNPs stress tolerance in rice. Furthermore, the results also indicated that addition of l-NG-nitro arginine methyl ester (l-NAME) (an inhibitor of endogenous NO synthesis) also reversed the toxic effects of SiNPs together with AgNPs, further suggesting that the low level of endogenous NO was associated with AgNPs stress tolerance. Overall, the results indicate that the low level of endogenous NO triggers AgNPs stress tolerance, while high level leads to AgNPs toxicity by regulating sulfur assimilation, GSH biosynthesis, redox status of GSH and oxidative stress markers. The results revealed that ethylene might act as a switch for regulating AgNPs stress in rice seedlings by controlling endogenous NO accumulation., (© The Author(s) 2023. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Constitutively active immunity against pathogen infection affects the growth and yield of plants. Gao and colleagues recently demonstrated that a Ca 2+ sensor, RESISTANCE OF RICE TO DISEASES1 (ROD1), regulates an immune suppression network that consolidates reactive oxygen species (ROS) metabolism and Ca 2+ -sensing to equilibrate both defense responses and optimal growth in plants., Competing Interests: Declaration of interests No interests are declared., (Copyright © 2022 Elsevier Ltd. All rights reserved.)