STUDIES ON THE UPTAKE AND TRANSLOCATION OF STREPTOMYCIN BY PEACH SEEDLINGS

Measurements of the antibiotic activity in the foliage of peach seedlings, kept with their roots in mineral nutrient solutions containing streptomycin, showed that streptomycin passed into the foliage and sometimes reached concentrations above those of the solutions surrounding the roots. The amount of the antibiotic in leaves varied with the time that roots were kept in the solutions and with the streptomycin concentrations of the solutions. Lower leaves contained much more than upper leaves. Adding macerated leaf tissue to streptomycin solutions decreased the amount of streptomycin detectable in the supernatant liquid more than could be accounted for by dilution or alteration of pH. Streptomycin first affected plants by decreasing apical growth, but at higher concentrations it caused chlorotic and necrotic areas on leaves and stems.