Using a plate induction assay, we demonstrate that alfalfa exudes inducer of Rhizobium meliloti nodulation genes. The inducer is exuded from the infectible zone of the root, accumulates to at least 1 micromolar, and is not affected by 10 millimolar nitrate. No zones of inhibition are observed. A nodulation minus mutant line of alfalfa, MN-1008, exudes normal levels of inducer. R. meliloti grown...

The ethyl acetate extract of Amygdalus persica L. flowers (family Rosaceae) was fractionated by silica gel and Sephadex LH-20 column chromatography, and, after recrystallization, oleanolic acid (1), ursolic (2), quercetin (3), kaempferol (4), hesperetin (5), naringenin (6), kaempferol-3- O-glucoside (7) were isolated. Their identities elucidated spectral techniques from their physicochemical pr...