Physiological significance of stress-induced changes in polyamines in plants

Polyamines (putrescine, spermidine, and spermine) are present in all living organisms. The possible role of polyamines under stress conditions is reviewed. Recent experiments indicate that polyamine levels are not associated with growth inhibition caused by nitrogen deficiency, sucrose starvation, and NaCl stress. Putrescine accumulation seems to be a factor causing growth inhibition under potassium deficiency and phosphate deprivation. Spermidine and spermine seem to be involved in protection against paraquat toxicity in rice leaves.