Today, nanosciences and nanotechnologies promise remarkable progress in the areas of health, environment and energy. In recent years, the scientific community has shown a growing interest in these "new sciences" human and financial resources are being used for their development. However, nanotechnology raises many concerns about their impact on the environment and human health.

Toxicologists and designers have addressed this issue from the very beginning of nanoscience development to anticipate their impacts and establish rules of use. This task, however, is very complex: there are many nanoparticles and it has been shown that each physico-chemical characteristic can influence their effects.

Carbon nanotubes were discovered a decade ago. Since then, the development of applications has been considerable and research has been applied to different fields (medicine, industry, etc).

Very little knowledge is currently available on the toxicity of carbon nanotubes to humans, most toxicological data from in vitro or in vivo studies in animal.                                                                                                  
The objective of our work is to study the impact of carbon nanotubes on the growth of plants. The model plant of our study is the common bean: Phaseolus vulgaris.

The carbon nanotubes used in this study were dispersed using a dispensing agent, their stability was demonstrated, and then mixed with the soil where the bean seeds were sown, and thereafter
parameters such as morphological parameters (length of both aerial and underground parts, weight) and physical parameters such as pigment synthesis were studied.

The first stage of germination of the plant species studied; The Djadida variety revealed a positive action on all the parameters studied. In fact, for a CNT content of 2 mg / L, a 34% increase in germination rates was observed. The fresh biomass of radicles showed an increase of 62.5%.
Carbon nanotubes caused an increase in soluble sugars in the leaves and roots of the plant; The amount of proline accumulated in all organs of the selected plant does not indicate a great influence.

The results have been very beneficial, which can encourage farmers, but it is very far away to claim that carbon nanotubes are not toxic.