Effect of Drought Stress on Physio-biochemical Traits and Secondary Metabolites Production in the Woody Species Pinus Halepensis Mill. At a Juvenile Development Stage

ABSTRACT The characterization of the drought stress responses of plants is essential to understand the interactions of these effects with key life processes, such as growth and reproduction. The capability of plants to respond to abiotic stress is associated with their plasticity as well as the adaptableness of plant traits to fluctuating bioclimatic conditions. In this study, the response of Pinus halepensis seedlings to the different water irrigation regimes was assessed based on various ecophysiological, biochemical, and metabolic traits. This approach aims to identify different traits capable of predicting the ability of formerly uncharacterized seedlings to cope with drought stress. The obtained results revealed that drought stress affects the vital metabolic processes in Aleppo pine plants, such as transpiration, photosynthesis, and respiration at their early development stage. These variations were accompanied by changes in chlorophyll pigment contents and an accumulation of organic solutes (sugar and proline). Both drought stress levels induced an increase over the control of the amounts of total secondary metabolites and essential oil contents. These findings are of particular interest in the comprehension of seedlings response to drought stress which provides valuable background knowledge for the success of reforestation programs based on this woody species.