Sesbania spp., aeschynomene indica and crotalaria spp. are amide-exporters

Abstract

Extract Leguminous plants consist of two groups, amide-exporting and ureide-exporting plants. The former legumes export a large fraction of fixed-N in the form of amides (asparagine and glutamine), and the latter legumes in the form of ureides (allantoic acid and allantoin). Another characteristic of the nodules is the enrichment in 15N. There are two types of legumes: one characterized by the enrichment with 15N in N2-fixing nodules, in contrast to the other where the enrichment does not occur. The first investigation by Shearer et al. (1982) suggested that the nodules exporting fixed-N in the form of ureides were enriched in 15N unlike those exporting it in the form of amides. Soybeans, mungbean, and cowpea belong to the former group and groundnut, alfalfa, white clover to the latter. Although pea and faba bean were first classified into the latter group (Shearer et al. 1982), a recent investigation (Yoneyama 1988) showed that these nodules were also enriched in 15N. © 1990 Taylor & Francis Group, LLC.