Ontogenetic changes in the level of ureides and enzymes of their metabolism in various plantpParts ofpPigeonpea (Cajanus cajan)

Abstract

Levels of allantoin and allantoic acid in shoots, roots, nodules and leaves of pigeonpea plant, in general, followed the pattern of acetylene reduction in nodules, increasing progressively from 15 days after sowing (DAS) and attaining peaks at 75 DAS and 60 DAS, respectively, except in shoots where their contents evinced maximum values at pod-setting (90 DAS). Activity of GS in nodules and shoots reached a maximum at 60 DAS and 75 DAS, respectively. However, in leaves and roots, the enzyme showed a biphasic behaviour with peaks at days 60 and 105 in leaves and at days 75 and 105 in roots. GDH activity in nodules peaked at 60 DAS, whereas, in leaves and roots, the maximum activity was observed at flowering (75 DAS). Uricase was present only in nodules with peak activity at flowering. Allantoinase activity again peaked at flowering, where nodules had maximum activity followed by leaves, roots and shoots. Urease could be detected in all the organs with maximum activity at 60 DAS in leaves followed by roots and nodules. Except uricase, all the enzymes reported above were also present in reproductive structures. Compared to GS, GDH was more active both in flower buds and developing pods. Seeds, compared to podwalls, contained higher activities of GDH, allantoinase and urease at day 105. Only allantoin could be detected in seeds and podwalls at day 105.