The increase in the global population has worsened the demand for food significantly. In addition, rapid climatic change and urbanization have adversely impacted agricultural production. Recently, phytonanotechnology has played an important role in promoting sustainable agriculture to meet the global food demand.

A new forthcoming study in Chemosphere has focussed on providing a prospective application of phytonanotechnology in an agroecosystem.

Nanotechnology and Agriculture

Farmers use excessive chemical fertilizers and pesticides to increase crop production, which has a detrimental effect on the environment. Scientists have developed nanotechnology-based novel technologies to enhance food production without affecting the environment. Nanoparticles are inorganic, organic, or hybrid materials whose sizes range between 1 and 100 nm. These possess many unique properties, such as high surface-to-volume ratio, small size, physical, chemical, optical and electrical properties, which are applied in various fields of science and technology.

Phytonanotechnology includes agro-nanotechnology and plant nanotechnology, which play an important role in today’s agroecosystem.

Green synthesis of nanoparticles is an ecofriendly method, where nanoparticles are produced using plant and microbial extracts. These nanoparticles can promote plant growth and protect it from various biotic and abiotic stress.

Phytonanotechnology helps develop “smart crops” and enables the delivery of foreign materials to the targeted site of a plant. The application of nanoformulations and nanosensors has substantially benefitted the agricultural system.

Nanosensors used in precision agriculture help determine soil conditions, pathogenic infestations, growth factors, and environmental conditions of the crop field. Phytonanotechnology has immensely contributed to sustainable agriculture and ecological systems.

Interaction of Plants with Nanoparticles

The introduction of nanoparticles to plants stimulates a series of biological events which determine its effect on the plant. The absorption of nanoparticles depends on the pore size in the plant cell wall.

The amount of nanoparticles accumulated in plants cells depends on the nature of nanoparticles, plant physiology, cellular mechanisms, and plasma membrane stabilization.

Nanoformulations are absorbed by the plant root system and are subsequently translocated to other tissues. Alternatively, nanomaterials are also introduced into plants via foliar spray. In this system, the cuticle of the leaf may act as a barrier. Typically, nanoparticles larger than 10 nm penetrate leaves through stomata and are transported into the plant’s vascular system via apoplastic and symplastic routes.

Nanomaterials Used in Sustainable Agriculture

Nanomaterials have been classified based on their composition, i.e., carbon-based nanomaterials, composites based, dendrimers, and metal-based inorganic materials.

Nanoparticles are produced via green synthesis using plant or microbial extracts. Several studies have indicated fungus, such as  Fusarium oxysporum, Aspergillus furnigatus, Aspergillus flavus, and Phanerochaete chrysoparium, can synthesize metal and metal sulfide nanoparticles. The efficacy of the newly developed nanoparticles on plant management depends on their size, chemical composition, surface charge, physicochemical properties, and susceptibility of the plant species.

Some of the commonly used nanoparticles that enhanced seed germination, and root and shoot growth are silver (Ag), copper (Cu), iron (Fe), copper oxide (CuO), and zinc (Zn). A proper application of these nanoparticles, singly or in combination, enhanced root growth in Brassica napus, Cucumis sativus, Raphanus sativus, Lactuca sativa, and Zea mays by five times.

Smart delivery of chemicals using nanocarriers to the precise plant site in a controlled manner enables optimal delivery of chemicals. This practice inhibits the overuse of chemicals that have a harmful long-term impact on the environment. Gold (Au) nanomaterials were created via green synthesis methods and significantly enhanced the germination of Brassica juncea when applied as a foliar spray.

The nanoparticles improved permeability which permitted more water and di-oxygen to enter the cells. Similarly, the optimal application of Ag nanoparticles has promoted seed germination and plant growth. This is because Ag nanoparticles improve chlorophyll content, photosynthetic quantum efficiency, and enhance the efficiency of water and fertilizer uptake.

Application of low concentration of Ag nanoparticles on Hordeum vulgare and Cucurbita pepo revealed a positive effect on root elongation.

Silicon (Si) nanoparticles were found to protect crop plants from saline and drought conditions. Additionally, these nanoparticles can enhance plants’ pigment content significantly. In Z. mays, the application of Si nanoparticles enhanced the proline content and antioxidant enzyme activity.

Scientists stated that Si nanoparticles can effectively protect plants from biotic and abiotic stress, and as a growth enhancer. Application of carbon nanotube in tomato plant produced twice the number of flowers and fruits compared to the control. Graphene quantum dots-based biosensors are developed for plants’ clinical analysis and disease diagnosis.

Conclusion

In this study, the authors provided a detailed outline of the impact of phytonanotechnology on plant growth promotion and crop protection. The utilization of nanoformulations in the form of nanofertilizers, nanoherbicides, and nanopesticides has significantly improved crop yield and growth by stimulating growth hormones and protecting it from biotic and abiotic stresses.

Various nanomaterial-based biosensors help in the early detection of pathogenic attacks, nutrient deficiency, and abiotic stresses. Nanomaterials are also used for the remediation of pollutants present in the soil. Recently, scientists have integrated nanotechnology and artificial intelligence to promote sustainable and precision agriculture.