Influence of the drought on antioxidant and enzymatic activities of two Pinus species in humid and sub-humid climate

Abstract

Pinus genus is widespread in the Mediterranean region and the most common in Tunisia. The impact of high temperatures in the mid-summer period (July 2015 and July 2016) on phenols and biological properties were examined in vitro. The study was carried out in two arboreta, in humid and sub-humid climates, dry needles of Pinus pinea and Pinus pinaster were used for secondary metabolites, antioxidant activities, and enzymatic inhibitory activities. The amount of all measured parameters increased from 2015 to 2016 in the two pine species in the two arboreta. Pinus pinea produced more phenols and showed higher antioxidant activity and α-amylase and lipoxygenase inhibitory activities than Pinus pinaster. Besides, both species generally presented better biological activities and higher phenol amounts in 2016 than in 2015, being 2016 warmer and drier than 2015 in both harvest zones. It was evident that both species in every bioclimatic zones adapted to the new climate conditions producing more secondary metabolites that rendered better antioxidant and inhibitory enzymatic activities. These fi ndings confi rmed the impact of mid-summer water defi cits on pine species in the context of climate change and help to select the most resistant species for future reforestation.