SUMMARYThe concentrations of three amines (putrescine, spernaidine and spermine) were much increased in first leaves of barley infected with powdery mildew, whilst the concentrations of putrescine and spermidine in roots of mildewed barley were significantly decreased. Although no significant change in the activities of three polyamine biosynthetic enzymes (ADC, arginine decarboxylase; ODC, ornithine decarboxylase; and SAMDC, S-adenosyl methionine decarboxylase) could be detected in roots of mildewed barley, the activities of ADC, ODC and SAMDC were increased in infected first leaves. The significance of these alterations in poly amines and their biosynthetic enzymes in mildewed barley is discussed.

Summary The concentrations of three amines (putrescine, spermidine and spermine) are much increased in ‘clubbed’ regions of roots of turnip infected by Plasmodiophora brassicae, whilst the concentrations, particularly that of putrescine, decreased in regions of infected roots not exhibiting symptoms of clubroot development. The possible involvement of these polyamines in the formation of ‘clubs’ on infected roots is discussed.