Drought stress, peroxidase activity and formaldehyde metabolism in bean plants

In our investigations we have studied the changes of total peroxidase and isozyme activities, peroxidase isozyme pattern and the level of endogenous formaldehyde and trigonelline. We have examined the effect of drought stress resulted by Carbowax treatment (2, 5, 7, 10%) of two different snap bean (Phaseolus vulgaris L.) genotypes [drought tolerant (T) and drought sensitive (S)]. There were no detectable differences in the peroxidase isozyme patterns but the total peroxidase activity was increased. We have found similar steep enhancement in the peroxidase activities of one of three peroxidase fractions while the increase in the other isozyme fractions was not so significant in the two genotypes. Increasing peroxidase activities and changes in the amount of endogenous formaldehyde and trigonelline were detectable with increasing Carbowax treatment in both genotypes, but in different ways. According to our experiments, the total peroxidase and some isozyme activity correlated with the concentration of endogenous formaldehyde and trigonelline, playing an important role during drought stress.