Carbon-based nanomaterials as growth enhancers in plant tissue culture systems: Mechanisms, applications, and future prospects

The process of plant tissue culture is commonly utilized for making secondary metabolites, enhancing crop quality, and conserving plant genetic material (germplasm). However, due to some limiting factors such as the difficulty of regenerating plants, differences in genotypes, somaclonal variation, and cellular damage through stress, the overall viability of plant tissue culture is relatively low. Therefore, recent advances in nanotechnology suggest that carbon-based nanomaterials (including carbon nanotubes (CNTs), graphene oxide (GO), fullerenes, and carbon quantum dots (CQDs)) could be utilized as effective in vitro growth stimulators. These nanomaterials have unique physical and chemical properties that allow them to interact with plant tissues to regulate signal transduction through phytohormone balance, nutrient uptake, and water movement, as well as regulating homeostasis of reactive oxygen species (ROS). Nanomaterials such as fullerenes, CNT's, GO's and CQD's provide a number of functions when combined with plant tissue culture systems. Fullerenes have an antioxidant function, CNT's support the process of organogenesis and absorption of nutrients, GO's assist with nutrient availability and tolerance to stress and CQD's increase the rates of photosynthesis and gene expression. When these materials are used in combination, they can improve the formation and regeneration of callus while decreasing the need for chemical growth regulators. While there are still issues with factors such as solubility, toxicity of nanomaterials, responses to different species and standardisation of methodologies, the integration of nanotechnology with cultivar & species specific omics and a sustainable approach presents good opportunities to develop innovative methods within herbaceous plant tissue culture.