In recent years, applications of nanotechnology in plant systems, such as phyto-nanotechnology, have received increasing attention. Phytoengineering deals with exploiting plants and green resources to provide solutions to various applications of science and engineering. Plant-mediated biological methods are being used by various researchers to synthesize nanoparticles of metals, metal oxides, and other materials with different size, shape, and quantity due to their easy availability and eco-friendliness. The appropriate application of nanoscience to plants and crops can provide improved outcomes and an exploration of their bioavailability and toxicity in the environment. These nanoparticles are explored for various applications as potent antimicrobial agents. They can be used as electrochemical sensors and biosensors, in medicine and health care (e.g., in vitro anticancer efficiency) and in agriculture and crop biotechnology. These nanoparticles can also be applied for pests, nutrients and plant hormones.

Nanoparticles possess unusual characteristics due to their large surface area-to-volume ratio and extraordinary catalytic activity, electronic properties, optical properties, and antimicrobial activity while they are constructed at the atomic level. Because physical and chemical methods of nanoparticle synthesis are too expensive and environmentally unsound, there is a better possibility of green synthesis of nanoparticles using plants, bacteria, and fungi, which are emerging as novel eco-friendly techniques. The growth rate of the bacterial culture, the extract of the plant secondary metabolites, and the mycelial surface area of fungus are the main comprehensible mechanisms in the green synthesis of nanoparticles. Nanofertilizers, nanopesticides, and nanoinsecticides are safe and hold a better possibility to be administered for the agricultural industry for increased food production as nutraceuticals. Phyto-nanotechnology has great potential to revolutionize agriculture and general plant sciences. Despite these promising perspectives, challenges are also pressing, including the impacts of diverse plant cellular structures on nanomaterial delivery and the induction of various levels of phytotoxicity to plants.

The aim of this Special Issue is to bring together original research and review articles focusing on the effects of these applications on plant morphology, physiology, biochemistry, ecology, and genetics. The Special Issue covers the impact on plant yield, techniques, a review of positive and negative impacts and an overview of current policies regarding the use of nanotechnology on plants. It will also cover medicinal applications including biomedical, biosensors, and drug delivery. We hope that this Special Issue highlights the promising applications and major obstacles of plant-based phytonanotechnology.

Potential topics include but are not limited to the following:

• Phytonanoparticles-based microbiological study
• Phytonanoparticles drug delivery
• Nanotoxicity-based studies (phytotoxicity, cytotoxicity, genotoxicity, and ecotoxicity) in plant sciences
• Phytonanotechnology antioxidant activity
• Nanomaterial-plant interactions
• Nanofertilizers
• Nanopesticides
• Engineered phytonanomaterials: classification and strategies for physico-chemical characterization
• Phytosynthesis of nano-scale materials
• Advanced analytical techniques for the measurement of nanomaterials in plant samples
• Morphological, physiological and biochemical responses of plants to nanoparticle exposure under different environmental factors
• Nanoagrochemicals in plant production sector
• Sensor nanotechnologies in plant sciences
• Effect of nanoparticles on phytopathogens
• Phytonanotechnology for sustainable agriculture