Lovrekovich, L., Research Institute for Plant Protection, Budapest, Hungary
Klement, Z., Research Institute for Plant Protection, Budapest, Hungary
Farkas, G.L., Research Institute for Plant Protection, Budapest, Hungary

Treatment of intact tobacco leaves with toxin-containing culture filtrates of Pseudomonas tabaci markedly reduced the ribonucleic acid content of the leaves. The decrease was counteracted by spraying the leaves with 10 -4M kinetin. Simultaneously with the decrease in RNA, the ribonuclease activity of extracts from tissues treated with toxin increased. Experiments on the effect of kinetin on the ribonuclease activity of toxin-treated tissues gave no consistent results.