In addition to foliar manganese concentration, both iron and zinc provide proxies for rhizosheath carboxylates in chickpea under low phosphorus supply

Plants deploying a phosphorus (P)-mobilising strategy via carboxylate release have relatively high leaf manganese concentrations ([Mn]). Thus, [Mn] is proxy for the amount of rhizosheath carboxylates. Whether other micronutrient, such as iron ([Fe]), zinc ([Zn]) and copper ([Cu]), show similar signal carboxylates unclear. We grew large number chickpea genotypes in two glasshouse studies with different growth media, P sources levels. Seven weeks after sowing, we determined micronutrients mature leaves, quantity composition For 100 grown river sand low supply, [Fe] (R2 = 0.36) [Zn] 0.22), like 0.38), were positively correlated total 20 soil mixture, [Fe], [Zn], [Cu] showed positive correlations that stronger under moderately 0.59, 0.54, 0.72) than severely 0.39, 0.28, 0.20, or sufficient 0.36, 0.00, 0.01, 0.50) supply. Malonate was predominant significantly micronutrient both experiments. In addition to [Mn], can be used alternative easily measurable proxies belowground carboxylate-releasing processes low-P particularly on soils.