POLYAMINES IN NODULES FROM VARIOUS PLANT-MICROBE SYMBIOTIC ASSOCIATIONS

Polyamine compositions of root or stem nodules collected from varieties of nitrogen-fixing leguminous (22 species) and non-leguminous (5 species) plants were investigated. Relatively high concentrations of homospermidine were observed in root or stem nodules of all the leguminous plants. Based on the ratio of homospermidine to spermidine, legume nodules were generally characterized into two major groupes; one containing almost equal amounts of homospermidine and spermidine, and the other a high homospermidine/spermidine ratio. Root nodules from pigeon pea (Cajanus cajan L. Millsp) was the only exception which exhibited very low homospermidine/spermidine ratio. Amongst the legumes, nodules of adzuki bean (Vigna angularis), siratro (Macroptilium atropurpureum DC. Urb.), pea (Pisum sativum L.), and hairly vetch (Vicia hirsuta S.F. Gray) were rich in diamine putrescine. Such characters of nodule polyamine composition were inherent characteristics of each legume species, and not related to the type of infected rhizobia (Rhizobium or Bradyrhizobium). In contrast to herbaceous leguminous plants, nonleguminous woody plants, which symbiotically associate with actinomycete Frankia species, contained little polyamines in their root nodules. Root nodules of non-leguminous Parasponia andersonii infected by bradyrhizobia were found to contain large quantities of putrescine and homospermidine. No significant differences in polyamine composition were observed between root and stem nodules both in Aeschynomene indica and Sesbania rostrata.