MODE OF ACTION OF MALEIC HYDRAZIDE ON THE GROWTH OF ESCHERICHIA COLI AND AVENA COLEOPTILE SECTIONS

1. MH was found to suppress the growth and respiration of E. colias well as the IAA-induced growth of Avena coleoptile sections.
2. These suppressions could be reversed more or less strikinglyby the addition of a trace of heavy metals such as Co, Mn, Ni,Zn, Cu, or Mo.
3. The reversal could also be achieved by cysteine,thioglycollate,or fumarate, the latter two substances being,however, lesseffective.
4. The inhibition of the growth of E.coli by MH was completelyrelieved by the addition of IAA. Conversely,the inhibitionof the microbial growth by high concentrationsof IAA couldbe relieved by the addition of MH.
5. It was inferredthat MH may block certain heavy metal-catalyzedprocess, inwhich some thiol substance and IAA are participating,probablyby combining with the heavy metal.

(Received June 23, 1960; )