Effect of 2(N-morpholino)ethane)sulfonic acid (MES) on the growth and tissue composition of cucumber

The effect of 2(N-morpholino)ethane)sulfonic acid (MES) on the growth of cu cumber (Cucumis sativa L. var. Marketer) in hydroponic culture was determin ed at 0, 1, 5, and 10 mM concentrations. The effect of adding: the MES to t he solution at the time of transfer to hydroponic culture or waiting one we ek was also determined. MES was observed to strongly affect plant growth wi th increasing concentration in nutrient solution. Tissue and nutrient solut ion analysis determined that MES affects manganese (Mn) uptake. MES appears to be reduced by Mn precipitating the Mn out of solution. The suitability of MES as a pH buffer in hydroponic culture is discussed in terms of this e ffect.