Deciphering the Role of Carbon Nanotubes in Plants: Functional Benefits, Phytotoxic Risks and Environmental Safety

Abstract

Carbon nanotubes (CNTs) are increasingly being explored as innovative tools in modern agriculture because of their exceptional structural and surface properties. CNTs have been increasingly harnessed in plant science as potent growth stimulators and innovative delivery systems (e.g., nanocarriers). CNTs have been shown to enhance seed germination, plant growth, water and nutrient uptake, biomass accumulation, chlorophyll levels, and photosynthetic performance under both stress and non-stress conditions. CNTs have also been shown to upregulate antioxidant systems, thereby attenuating reactive oxygen species (ROS)-induced oxidative damage and enhancing plant stress tolerance and physiological robustness. At the same time, the expanding use of CNTs raises concerns about plant safety and environmental impact. Their effects are not uniform and depend strongly on factors such as dose, size, surface functionalization, and interactions within soil-plant systems. Under certain conditions, CNTs exposure may disrupt cellular structures, alter metabolic balance, or trigger oxidative stress. Concerns also extend to their environmental persistence, potential accumulation in plant tissues, and possible movement through food chains, highlighting the need for careful risk assessment. This review provides a balanced evaluation of the current understanding of CNT-plant interactions, examining both their growth-promoting potential and associated phytotoxic and ecological risks. It emphasizes the importance of developing evidence-based strategies to ensure the safe and sustainable integration of CNTs into agricultural practices.