Background Copper oxide nanomaterials’ (NMs) are important for the critical roles of Cu as a micronutrient that its
improper concentration could cause toxicity or deficiency in plant. The Nano form of CuO could amplify the effects
due to special characteristic of nano materials. MethodTreatments of 0.1, 0.5, and 2.5 μM and NM of copper with three replications were applied to plants under
hydroponic conditions. Physiological parameters and expression of IRT1 and CAT genes were investigated. ResultsCopper absorption decreased according to MMs-CuO ? NMs-CuO ?? CuSO4 pattern. The positive effects
of MMs-CuO on plant copper content were higher than those of nanomaterials and CuSO4. MMs-CuO effect was
more significant on plant biomass increase compared to the control. Rue plant needed lower amounts of copper for
better 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 at
0.1 μM CuSO4. The NMs-CuO and MMs-CuO similarly reduced leaves’ Cu, MDA and ROS contents, and SOD
activities. CAT enzyme activity had a similar pattern in three copper forms. CAT enzyme activity was only induced
under the lowest level of three forms, while at other levels of Cu, it was reduced. NMs-CuO had a more negative
effect on IRT1 relative gene expression in root compared with other iron forms. The IRT1 relative gene expression
in shoots was positively affected under 2.5 μM CuSO4, 0.5 μM MMs-CuO, and 0.1 and 2.5 μM NMs CuO
treatments. ConclusionThe effect of micro- and nano-CuO on physiology and gene expression mechanisms in rue plants is shown to be does-dependent. |