Phytotoxicity of Carbon Nanotubes Assessed by Brassica Juncea and Phaseolus Mungo

Two agronomic plant species were evaluated for the phytotoxicity of multi-walled carbon nanotubes (CNTs) using germination and seedling growth of Brassica juncea and Phaseolus mungo. Both B. juncea and P. mungo seeds showed 100% germination with the application of CNTs, which indicated their non-hazardous nature for the germination of the seeds. As the B. juncea seed was grown with CNTs at 10 g/ml, 20 g/ml, and 40 g/ml, the enhancement of root growth was evidenced up to 138%, 202%, and 135%, respectively, compared to the control. In the case of B. juncea, the heights of the shoot and root were not affected at all by the studied CNTs' concentrations; however, phytotoxicity was evidenced at 40 g/ml CNTs by optical microscopy of the hairy root system, since a severe reduction in both the number of root hairs and their length was observed.