Resistance of native oak to recurrent drought conditions simulating predicted climatic changes in the Mediterranean region

• Published in: Plant, cell and environment Vol. 41; no. 10; pp. 2299 - 2312
• Main Authors: Saunier, Amélie, Ormeño, Elena, Havaux, Michel, Wortham, Henri, Ksas, Brigitte, Temime‐Roussel, Brice, Blande, James D., Lecareux, Caroline, Mévy, Jean‐Philippe, Bousquet‐Mélou, Anne, Gauquelin, Thierry, Fernandez, Catherine
• Format: Journal Article
• Language: English
• Published: United States Wiley Subscription Services, Inc 01.10.2018; Wiley
• Subjects: Antioxidants; Biodiversity and Ecology; Carotenoids; Climate Change; Damage accumulation; Dehydration; Drought; Droughts; Environmental Sciences; gas exchanges; Global Changes; growth; Isoprene; isoprene emissions; Mediterranean Region; Oxidative Stress; Photosynthesis; Quercus - metabolism; Quercus - physiology; Time Factors; Tocopherol; Vitamin E; Water potential; Mediterranean Region; Mediterranean Area; gas exchanges; growth; antioxidants; drought; isoprene emissions; Antioxidants; Gas exchanges; Isoprene emissions; Drought; Growth
• ISSN: 0140-7791; 1365-3040
• DOI: 10.1111/pce.13331

The capacity of a Quercus pubescens forest to resist recurrent drought was assessed on an in situ experimental platform through the measurement of a large set of traits (ecophysiological and metabolic) studied under natural drought (ND) and amplified drought (AD) induced by partial rain exclusion. This study was performed during the third and fourth years of AD, which correspond to conditions of moderate AD in 2014 and harsher AD in 2015, respectively. Although water potential (Ψ) and net photosynthesis (Pn) were noticeably reduced under AD in 2015 compared to ND, trees showed similar growth and no oxidative stress. The absence of oxidative damage could be due to a strong accumulation of α‐tocopherol, suggesting that this compound is a major component of the Q. pubescens antioxidant system. Other antioxidants were rather stable under AD in 2014, but slight changes started to be observed in 2015 (carotenoids and isoprene) due to harsher conditions. Our results indicate that Q. pubescens could be able to cope with AD, for at least 4 years, likely due to its antioxidant system. However, growth decrease was observed during the fifth year (2016) of AD, suggesting that this resistance could be threatened over longer periods of recurrent drought. The mains topics of this study are to evaluate the effect of climate change on ecosystem functioning in natural area. Thus, we manipulate an ecosystem forest during 4 years in order to evaluate whether amplified recurrent drought in this region could modify (a) plant investment in defence metabolites (antioxidant metabolites including tocochromanols, carotenoids, volatile organic compounds, and phenolic compounds) and (b) plant processes (gas exchange, aerial growth) in the deciduous model species Quercus pubescens. Our results indicate that, in spite of the recurrent amplified drought, Q. pubescens resists to 4 years of amplified drought with only few changes in metabolites production. However, this capacity of Q. pubescens to cope with drought could be threatened under longer periods of recurrent drought as growth decrease started to be observed during the fifth year (2016) of AD.