PHYSIOLOGICAL ACTIVITIES OF HELMINTHOSPOROL AND HELMINTHOSPORIC ACID: II. EFFECTS ON EXCISED PLANT PARTS

Effects of H-ol and H-acid were observed using excised partsof several plant species. Both H-ol and H-acid were active inelongation of oat coleoptile and mesocotyl, expansion of Raphanusleaf disk, but were inactive in elongation of wheat coleoptileand of green stem of pea. They gave also negative results inthe standard Avena curvature test and in the split pea test.In expansion of lettuce cotyledon, H-ol was inactive while H-acidwas active. In excised plant parts, as in intact plants, theactivity of H-ol and H-acid resembles rather gibberellins thanauxins and cytokinins. (Received August 20, 1966; )