Comparison of two chickpea varieties regarding their responses to direct and induced Fe deficiency

The effects of Fe deficiency (whether direct or bicarbonate-induced) on plant morphology, growth parameters, photosynthesis-related pigment contents, gas exchange, and water relations were addressed in two contrasting chickpea varieties (INRAT88 and Chetoui, respectively tolerant and sensitive to Fe deficiency). A marked decrease in the whole plant Fe content was observed in the Fe deprived plants of both varieties, especially the bicarbonate-treated ones, which showed a slower growth development and water deficit stress symptoms (increased leaf tissue osmolality associated with decreased shoot height, increased leaf mass to area ratio, and decreased water content). Both Fe shortage and bicarbonate addition resulted in both varieties in the decline of the photosynthetic pigment contents, contributing to lower photosynthetic efficiency (φc) and lower net photosynthesis (A). Fe deficiency reduced the water use efficiency and physiological availability of water too. However, INRAT88 was more tolerant to Fe deficiency than Chetoui, by maintaining a higher growth rate associated with lower respiration rate (RD), higher chlorophyll a and b concentrations, higher A, lower transpiration rate (E) and a higher water use efficiency (A/E). The present data suggest that the efficient utilisation of Fe for the synthesis of chlorophyll together with the effective control of electron-transport chains at chloroplasts (high A) and mitochondria (low RD) may account for the higher tolerance of INRAT88 to direct Fe deficiency. Further investigations with respect to oxidative stress and ROS generation, or about photorespiration would be helpful for a better understanding of their interaction with Fe deficiency in this grain legume.