Catalase activity of nodules in the ureide- and amide-transporting legume plants

The relations of catalase activity to the efficiency of symbiotic dinitroge n fixation and leghemoglobin (Lb) content were investigated in roots and no dules of several legume plant species together with the catalase distributi on between the inner bacteroidal and the outer cortical nodule tissues. The catalase activity in the nodules exceeded that of the roots of the amide- and ureide-synthesizing plant species by one and two orders of magnitude. D uring the growth period, catalase activity and Lb content changed in parall el and reached their highest levels early in the stage of flowering or frui t formation, depending on plant species. In the case of effective symbiosis , catalase activity in the nodules was 2.5-5 times higher than in the case of ineffective symbiosis. Catalase activity in the bacteroidal zone of the nodules was several times higher than that of the cortical tissue, and two nodule tissues differed in catalase activity more notably in the plant spec ies exporting ureides. The authors suggest that high catalase activity in t he nodules, especially in their bacteroidal zone, is essential for the effi cient functioning of the symbiotic system of dinitrogen fixation in both ur eide- and amide-transporting plants.