Unveiling the potential of nanobubbles in water: Impacts on tomato's early growth and soil properties

Nanobubbles (NBs) in water have been proven to improve plant growth and seed germination, potentially reducing both water and fertilizer consumption. To unravel the promotion mechanism of NBs on plant growth, this study investigated the characteristics of NBs in tap water and their impacts on tomato's early growth, soil chemical properties, enzymatic activity and electrochemical properties of plant roots. Oxygen NBs (ONBs) were found to increase the seed germination by 10 % and plant growth by 30 %-50 % (e.g., stem and diameter), whereas nitrogen NBs (NNBs) only had a significant promotion (7 %-34 %) on plant height. Additionally, compared to control group, irrigation with ONBs increased the peroxidase activities by 500 %-1000 % in tomato leaves, which may increase the expression of genes for peroxidase and promote cell proliferation and plant growth. Moreover, electrical impedance spectroscopy (EIS) revealed that the ONBs could reduce the interfacial impedance due to the increased active surface area and electrical conductivity of root.