The Role of Copper Oxide Nanomaterials on Ruta graveolens Physiological Response,and IRT1 and CAT Gene Expression

Background

Copper oxide nanomaterials’ (NMs) are important for the critical roles of Cu as a micronutrient that itsimproper concentration could cause toxicity or deficiency in plant. The Nano form of CuO could amplify the effectsdue to special characteristic of nano materials.

Method

Treatments of 0.1, 0.5, and 2.5 μM and NM of copper with three replications were applied to plants underhydroponic conditions. Physiological parameters and expression of IRT1 and CAT genes were investigated.

Results

Copper absorption decreased according to MMs-CuO ? NMs-CuO ?? CuSO4 pattern. The positive effectsof MMs-CuO on plant copper content were higher than those of nanomaterials and CuSO4. MMs-CuO effect wasmore significant on plant biomass increase compared to the control. Rue plant needed lower amounts of copper forbetter plant growth. The treatments increased protein and carotenoids content in leaves compared with control.Changes in total chlorophyll content under three copper forms were very low and were only increased in leaves at0.1 μM CuSO4. The NMs-CuO and MMs-CuO similarly reduced leaves’ Cu, MDA and ROS contents, and SODactivities. CAT enzyme activity had a similar pattern in three copper forms. CAT enzyme activity was only inducedunder the lowest level of three forms, while at other levels of Cu, it was reduced. NMs-CuO had a more negativeeffect on IRT1 relative gene expression in root compared with other iron forms. The IRT1 relative gene expressionin shoots was positively affected under 2.5 μM CuSO4, 0.5 μM MMs-CuO, and 0.1 and 2.5 μM NMs CuOtreatments.

Conclusion

The effect of micro- and nano-CuO on physiology and gene expression mechanisms in rue plants is shown to be does-dependent.