supraoptimal

Adjective

 * 1) Greater than the value or amount that would be optimal
 * 2) * "A significant increase in growth, [...] was observed in the shoots exposed to 200 mM salt. [...] In contrast, sub-optimal (0 mM) and supra-optimal concentrations (400–600 mM) of NaCl significantly affected the growth [...]" Lokhande, V.H., Nikam, T.D., Patade, V.Y. et al. Plant Cell Tiss Organ Cult (2011) 104: 41. https://doi.org/10.1007/s11240-010-9802-9