RT Journal Article T1 Characterization of Citrus Rootstock Under Conditions of Boron Toxicity A1 Navarro Gochicoa, María Teresa A1 Aparicio Durán, Lidia A1 Delfín, Alba A1 Ceacero Ruiz, Carlos Juan A1 Herrera Rodríguez, María Begoña A1 Arenas-Arenas, Francisco J. A1 Camacho-Cristóbal, Juan José A1 González-Fontes, Agustín A1 Rexach, Jesús K1 Boron (B) K1 Toxicity K1 Citric K1 Rootstock K1 Tolerance antioxidant mechanisms AB Boron (B) is an essential element for an adequate development of citrus orchards. However, citrus trees are vulnerable to high B concentrations, generating morphological and physiological alterations incompatible with the proper production of citrus. In this sense, citrus rootstocks can provide valuable capabilities to citrus trees including tolerance to different stresses. The objective of this work is the characterization of 2247 × 6070–02–2 citrus rootstock using as a reference Carrizo citrange rootstock under B toxicity conditions (2.5 mM boric acid). Carrizo citrange is a diploid hybrid, and 2247 × 6070–02–2 is a novel low-HLB-sensitive tetraploid. B excess effects were analyzed after four weeks of treatment using 0.05 (control) and 2.5 mM (toxicity) H3BO3 concentrations, respectively, in hydroponic growth conditions. The characterization of 2247 × 6070–02–2 rootstock compared to Carrizo citrange was performed by measuring physiological parameters in leaves related to photosynthesis, stress oxidative responses, B content, and gene expression. The lower transpiration rate and, especially, the higher expression of the CsXIP1;1 gene and the better antioxidant defense mechanisms shown by 2247 × 6070–02–2 make this rootstock more tolerant to high B content than Carrizo citrange. PB MDPI YR 2024 FD 2024 LK https://hdl.handle.net/10433/25504 UL https://hdl.handle.net/10433/25504 LA en NO Agronomy 2024, 14, 2741 NO Departamento de Fisiología, Anatomía y Biología Celular DS RIO RD Apr 27, 2026