Unsuitable availability of nutrients in germinating bean embryos exposed to copper excess.

The influence of copper excess on germination rate, growth, minerals, carbohydrates, and amino acids supply in embryonic axis of bean seed was investigated. Compared to the control, Cu treatment caused a reduction in germination percent, embryo length, and accumulation of Ca, Fe, K, Mn, Zn, total soluble sugars, glucose, fructose, sucrose, and amino acids. Moreover, the nutrient concentrations, as well as the electrical conductivity were determined in the germination medium to quantify the extent of solute leakage. Such nutrients were lost in the imbibition medium at the expense of suitable mobilization to the growing embryonic axis. This was associated with an enhancement in accumulation of malondialdehyde, major product of lipoperoxidation process which can be due to the stimulation in lipoxygenase activity in Cu-poisoned tissues.