Please have a look at this useful link.

http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-95162016000100011

The effect of Cu toxicity is largely on root growth and morphology. Copper tends to accumulate in the root tissue with little translocated to the shoots.

inhibition of root elongation and damage of root cell membranes are the immediate responses to high Cu levels

Zheng et al. (2004) reported that excessive copper reduced plant root length, root dry weight, total dry weight, root to shoot ratio, leaf area and specific leaf area in three ornamental crops (Dendronthema ´ grandiflorum L. 'Fina', Rosa ´ hybrida L. 'Laulinger', Pelargonium ´ hortorum L. 'Evening Glow') grown in solution culture.

Copper application to soil affects total yield, fruit number, dry root weight, and plant height of tomato (Sonmez et al, 2006). When in excess, Cu causes over-production of oxy- radicals, which has toxic effect in plant cells. Furthermore, Cu-induced cell disturbances may disrupt physiological processes, and impair growth (Marschner, 1986). Application of high levels of Cu usually inhibits root growth before affecting shoot production. However, this does not necessarily mean that roots are more sensitive to high copper concentrations, but probably, derives from the fact that roots are in an environment where copper is in excess (Lexmond & Vorm, 1981).

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1677-04202005000100012

http://www.regional.org.au/au/asssi/supersoil2004/s3/oral/1519_sheldona.htm

https://link.springer.com/article/10.1023/A:1006832321946

i think this articles may give response to your question. 

Dear Etuaful

Please following these papers. I hope it could be helpful

Article The effect of excess copper on growth and physiology of impo...

Article Toxic Effects of Copper-based Nanoparticles or Compounds to ...

Article Toxic Effects of Copper-based Nanoparticles or Compounds to ...

Best wishes