NITRATE ALTERS THE FLAVONOID PROFILE AND NODULATION IN PEA (PISUM-SATIVUM L)

A rhizosphere application of NO3- and/or naringenin affected the Pisum sativum - Rhizobium leguminosarum biovar viciae symbiosis. NO3- (5 mM ) lowered while naringenin raised the nodulation status (nodule number s and weight) and nodule efficiency (C2H2 reduction activity). However , the inhibitory effect of NO was to some extent alleviated when appli ed in combination with naringenin. The plant biomass was increased by the application of NO3- and naringenin, either alone or in combination , while a higher root: shoot ratio was observed only in the naringenin -treated plants. Root flavonoids are known to regulate the expression of nod genes; their high-performance liquid chromatography profile was influenced in different ways by NO3- and naringenin.