Polyamines and peroxidase activity in micropropagated colocasia esculentatreated with NaCl

Abstract

The effect of salinity on plants of Colocasia esculenta (taro) has been investigated through the determination of polyamines content and peroxidase activity. Micropropagated plants were subbmitted to three treatments : 0, 50, and 00 mmol L^- NaCl, for 30 days, and the putrescine, spermidine and spermine levels, peroxidase acitivity and Na concentrations were analized. Putrescine was the most abundant polyamine in the aerial part (leaves), and in the roots of the control, while spermidine showed the largest variations in plants cultivated with NaCl. The peroxidase activity was highest at 30 days both in leaves and roots but that found in roots was larger than that found in leaves. The largest Na concentrations ocurred in plants cultivated in 50 and 00 mmol L^- NaCl. The increase of sodium concentrations occurred parallel to the increase of the activity of peroxidase, suggesting a survival capacity due to a possible reaction of detoxification promoted by enzymes, among which the peroxidase. All the studied polyamines tend to vary directly with saline concentration. Espermine both from the aerial (leaves) and root parts showed the biggest correlation with the increase of salinity in the culture medium. Additional keywords: taro, peroxidase activity; salinity; putrescine; spermidine; spermine.