Impact of Combined Heat and Salt Stresses on Tomato Plants—Insights into Nutrient Uptake and Redox Homeostasis
Bruno Sousa,
Francisca Rodrigues,
Cristiano Soares,
Maria Martins,
Manuel Azenha,
Teresa Lino-Neto,
Conceição Santos,
Ana Cunha,
Fernanda Fidalgo
Affiliations
Bruno Sousa
GreenUPorto-Sustainable Agrifood Production Research Centre & INOV4AGRO, Biology Department, Faculty of Sciences, University of Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal
Francisca Rodrigues
GreenUPorto-Sustainable Agrifood Production Research Centre & INOV4AGRO, Biology Department, Faculty of Sciences, University of Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal
Cristiano Soares
GreenUPorto-Sustainable Agrifood Production Research Centre & INOV4AGRO, Biology Department, Faculty of Sciences, University of Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal
Maria Martins
GreenUPorto-Sustainable Agrifood Production Research Centre & INOV4AGRO, Biology Department, Faculty of Sciences, University of Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal
Manuel Azenha
CIQ-UP, Chemistry and Biochemistry Department, Faculty of Sciences, University of Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal
Teresa Lino-Neto
Biology Department and CBMA-Centre of Molecular and Environmental Biology, School of Sciences, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
Conceição Santos
LAQV/REQUIMTE, Laboratory of Integrative Biology and Biotechnology (IB2), Biology Department, Faculty of Sciences of University of Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal
Ana Cunha
Biology Department and CBMA-Centre of Molecular and Environmental Biology, School of Sciences, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
Fernanda Fidalgo
GreenUPorto-Sustainable Agrifood Production Research Centre & INOV4AGRO, Biology Department, Faculty of Sciences, University of Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal
Currently, salinity and heat are two critical threats to crop production and food security which are being aggravated by the global climatic instability. In this scenario, it is imperative to understand plant responses to simultaneous exposure to different stressors and the cross-talk between underlying functional mechanisms. Thus, in this study, the physiological and biochemical responses of tomato plants (Solanum lycopersicum L.) to the combination of salinity (100 mM NaCl) and heat (42 °C; 4 h/day) stress were evaluated. After 21 days of co-exposure, the accumulation of Na+ in plant tissues was superior when salt-treated plants were also exposed to high temperatures compared to the individual saline treatment, leading to the depletion of other nutrients and a harsher negative effect on plant growth. Despite that, neither oxidative damage nor a major accumulation of reactive oxygen species took place under stress conditions, mostly due to the accumulation of antioxidant (AOX) metabolites alongside the activation of several AOX enzymes. Nonetheless, the plausible allocation of resources towards the defense pathways related to oxidative and osmotic stress, along with severe Na toxicity, heavily compromised the ability of plants to grow properly when the combination of salinity and heat was imposed.
