Effects of Fe Deficiency on Organic Acid Metabolism in Pisum sativum Roots

Iron deficiency induces several responses to iron shortage in plants. Metabolic changes occur to sustain the increased iron uptake capacity of Fe-deficient plants. The aim of this work was to investigate the impact of Fe deficiency on the organic acid metabolism in Pisum sativum roots. For this purpose, seedlings of Pisum sativum (cv. Douce) were grown under controlled conditions, in the presence of iron sufficient (C) or deficient (D) mediums. Our results showed that PEPC activity increased by 290% in root extracts of Fe deficient plants, compared to the control. Citrate concentration increased in Fe deficient Pisum roots (114% of the control). As well, MDH, CS and ICDH activities showed a marked increase in roots subjected to D treatment. However, the extent of stimulation was especially important for MDH and ICDH activities (99% and 150% of the control, respectively). These data suggest that the capacity of Douce cultivar to increase organic acid metabolism enzyme activities under iron deficiency is related to its better Fe-use efficiency, which indicate the tolerance level of this cultivar to iron chlorosis.