Lime-induced iron chlorosis is a major nutritional disorder causing severe plant growth and yield reduction in the calcareous soils of Tunisia. The understanding the behavior of key metabolic functions of peas on calcareous soils, the identification of useful traits of tolerance, and the exploration of the genotypic differences in response to this constraint remain the most efficient approaches due to their coast, environmental benefits, and sustainability. For this purpose, a greenhouse experiment was conducted on three pea genotypes (Alexandra: Alex, Douce de provence: DP, and Merveille de Kelvedon: MK) cultivated on calcareous soil (Fe-deficient) and fertile soil (control). Plant growth, SPAD index, iron nutrition and distribution, photosynthesis, and antioxidant enzymes were deeply analyzed to discriminate genotypic differences. Calcareous-induced iron deficiency reduced SPAD index, plant growth, net photosynthesis, and tissue Fe content against a significant stimulation of the oxidative stress indicators, H 2 O 2 and Malondialdehyde (MDA). Moreover, we reported a significant induction of SOD and CAT activity in shoots and roots of the Alexandra genotype. Fe use efficiency increased on calcareous soil and clearly discriminated the studied genotypes. Alexandra genotype was found to be the most tolerant to lime-induced iron chlorosis. This genotype protects its tissues against oxidative stress by stimulating enzyme activities (SOD and CAT) and develops significant efficiency of Fe uptake, translocation to shoots and use when cultivated on calcareous soil.

Background Lime-induced iron deficiency in Pea plants is a major nutritional disorder causing severe plant growth and yield reduction in calcareous soils of Tunisia. Other the chemical fertilization for iron chlorosis correction, the exploration of the genotypic differences in response to this constraint remains the most efficient approach due to its coast, environmental benefits, and sustainability. This approach allows as to screen tolerant genotypes and identify useful traits of tolerance. Results calcareous-induced iron deficiency reduced SPAD index, plant growth, net photosynthesis, and tissues Fe concentration against a significant stimulation of the oxidative stress indicators, H2O2 and Malondialdehyde (MDA). In the same time, we have reported significant induction of SOD activity in shoots and CAT activity in roots of the genotype Alexandra (ne clear behavior observed in the other genotypes). Fe use efficiency increased on calcareous soil and clearly discriminates the studied genotypes. Conclusion Genotypic differences were observed, and Alex was found to be the most tolerant. This genotype protect its tissues against oxidative stress by stimulating SOD activity in shoots and CAT içn roots, and expressed significant efficiency of Fe uptake and use on calcareous soil. The Fe use efficiency for photosynthesis and for SOD and CAT activities clearly discriminates the studied genotypes and can be used as a useful trait for further screening programs.