The effect of antibiotics on the infective viability of an alder (Alnus glutinosa L. Gaertn.) crushed nodule inoculum.

The effect of various antibiotic substances, mainly penicillin, streptomycin, tetracycline and chloramphenicol respectively, on the infective viability of an alder crushed nodule inoculum towards the host plant has been studied. Penicillin was inocuous in respect of both plant and nodule endophyte. Its use did not prevent the formation of nitrogen-fixing partnership. The other antibiotics tested showed a harmful effect either inhibiting infection (streptomycin) or causing death in most plants (tetracycline and chloramphenicol). The use of penicillin in isolation trials of the alder nodule endophyte is suggested.