Hadacidin, a New Plant-Growth Inhibitor Produced by Fermentation.

After screeninig several lhundlred cultures of fungi, actinomvcetes, aid bacteria isolated fromii various soils for plant growtlh regulating activity, a fungus culture. F7-2578 (identified later as Peneicilliumiit pufrpurresceiis), was found( whIiclh had a (lwNarfing effect on pea planits. A foliage spray of the culture filtrate inhibite(d the gro)wvth of the stemls, producing shortened internodes, andl also inhlibitedl the groN-th of the roots. The growth of the young expand(ling leaves of bean plants was greatly inhibited by spraying the fermentation brotlh of cultur-e F7-2578 on tle young