Biochemical and Physiological Characteristics of Citrus under Heat Stress and the Role of Rootstocks in the Context of Climate Chang

• Grant number: 25/09805-9
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: July 01, 2025
• End date: June 30, 2028
• Field of knowledge: Agronomical Sciences - Agronomy - Crop Science
• Principal Investigator: Rodrigo Marcelli Boaretto
• Grantee: Wallace de Paula Bernado
• Host Institution: Instituto Agronômico (IAC). Agência Paulista de Tecnologia dos Agronegócios (APTA). Secretaria de Agricultura e Abastecimento (São Paulo - Estado). Campinas , SP, Brazil
• Associated research grant: 24/00985-1 - Smart B100 Advanced Research Center (CCD-SB100), AP.CCD

Abstract

lobal climate change, notably the increase in air temperature (Tair), has led to productivity losses in key citrus-producing regions. Such losses may be linked to physiological and biochemical disorders that remain unclear in citrus plants, although they are triggered by reduced leaf water status-either due to the roots' inability to meet leaf water demand under high vapor pressure deficit (VPD) and/or low production of osmoprotectants that limit the plant's osmotic adjustment.In this context, the aim of the research is to evaluate the physiological and biochemical changes in citrus under elevated air temperatures. Acclimated plants (day/night temperatures of 30/20 ºC) will be exposed to different elevated air temperature regimes in growth chambers (35/20 ºC, 35/28 ºC, 40/20 ºC, and 40/33 ºC). The following parameters will be assessed: chlorophyll a fluorescence, photosynthesis, stomatal conductance, plant hydraulic conductance, respiration, antioxidant and carbohydrate balance, metabolic profile, proline levels, and antioxidant enzyme activity in recently matured leaves. Carbohydrate contents will also be measured in the roots.These evaluations will help identify physiological and/or biochemical changes that may reveal key mechanisms associated with citrus exposure to high air temperatures. Additionally, the role of rootstocks differing in their ability to synthesize proline will be characterized in relation to scion performance. This research will contribute to the development of improved management practices in citrus cultivation and the selection of plant materials better adapted to adverse environmental conditions.