Effect of Chloramphenicol on Growth, Chemical Composition and Chlorophyll Content of Intact Plants

SUMMARY The growth of perennial ryegrass and lucerne was inhibited by d‐threo‐chloramphenicol at concentrations generally considered safe for preventing bacterial contamination. Inhibition of growth was the result more of a reduction in photosynthetic activity than of a specific effect on ion absorption. Young plants were more susceptible to chloramphenicol than older plants and the cumulative effect of repeated applications of the bactericide at low concentrations depressed growth and chlorophyll content to the same extent as a single concentrated application. The present results have been related to known effects of chloramphenicol on protein synthesis, leading to the conclusion that its use to prevent bacterial contamination in studies on the growth of green plants is inadvisable. Recognition of this fact makes suspect much published work where chloramphenicol has been used for this purpose.