Iron-deficiency specifically limits nodule development in peanut inoculated with Bradyrhizobium sp

• Published in: The New phytologist Vol. 108; no. 1; pp. 51 - 57
• Main Authors: O'Hara, G.W, Dilworth, M.J, Boonkerd, N, Parkpian, P
• Format: Journal Article
• Language: English
• Published: Oxford, UK Cambridge University Press 1988; Blackwell Publishing Ltd; Blackwell
• Subjects: Agricultural soils; Agronomy. Soil science and plant productions; Alkynes; Arachis hypogaea; Aratahis hypogaea; Bacteroids; Biological and medical sciences; Calcareous soils; Economic plant physiology; Fundamental and applied biological sciences. Psychology; iron; iron‐deficiency; leghaemoglobain; Legumes; nitrogen fixation; nodulation; Nodules; nutrient deficiencies; Parasitism and symbiosis; Peanuts; Plant physiology and development; Plant roots; Plants; Rhizobium; Symbiosis; Symbiosis (nodules, symbiotic nitrogen fixation, mycorrhiza...); Leguminosae; Asia; Dicotyledones; Deficiency; Angiospermae; Arachis hypogaea; Spermatophyta; Iron; Plant nodule; Fodder crop; Thailand; Oil plant(vegetal); bacteroids; Aratahis hypogaea; iron-deficiency; leghaemoglobain; nitrogen fixation
• ISSN: 0028-646X; 1469-8137
• DOI: 10.1111/j.1469-8137.1988.tb00203.x

Severely iron-deficient peanuts (Arachis hypogaea L.) grown on calcareous soils in central Thailand failed to nodulate until given foliar iron applications. Glasshouse experiments were conducted on two cultivars (Tainan 9 and Robut 33-1) to identify which stage of the nodule symbiosis was most sensitive to iron-deficiency. Iron-deficiency did not limit growth of soil or rhizosphere populations of peanut Bradyrhizobium. Similar numbers of root nodule initials formed in the roots of both control and iron-sprayed plants, showing that iron-deficiency did not directly affect root infection and nodule initiation. Plants sprayed with iron produced greater numbers of excisable nodules and carried a greater nodule mass than untreated plants. Five days after iron application, nodules on sprayed plants of cv. Tainan 9 contained 200-fold higher bacteroid numbers per unit weight and 14-fold higher concentrations of leghaemoglobin. The onset of nitrogenase activity was also delayed by iron deficiency in both cultivars. Tainan 9 appeared more sensitive to iron-deficiency than Robut 33-1 in terms of nodule mass produced, but both cultivars showed the same effect of iron-deficiency on nitrogenase activity per plant. It is concluded that the failure of the infecting rhizobia to obtain adequate amounts of iron from the plant results in arrested nodule development and a failure of nitrogen fixation.