Comparison of Scotch Pine (Pinus sylvestris L.) Origins in terms of Photosynthetic Gas Exchange and Chemical Properties

Abstract

This study was conducted to address the urgent need for identifying drought-tolerant varieties of Pinus sylvestris L. (Scotch pine) in response to the increasing impact of global climate change on forest ecosystems. The aim was to evaluate the physiological and biochemical responses of Scotch pine provenances grown in the Lakes Region of Türkiye in terms of photosynthetic gas exchange and selected stress-related chemical traits. Samples from different origins were analyzed to assess parameters such as adaptation to drought stress, water use efficiency, stomatal conductance, and photosynthesis rate. The data, obtained from long-term provenance trials established in 2000 in Aydoğmuş (Isparta) and Kemer (Burdur), revealed how these traits vary depending on origin and site conditions. Among the provenances, Çatacık, Akyazı, and Mesudiye displayed higher photosynthesis rates, stomatal conductance, and transpiration. Additionally, the accumulation of proline and hydrogen peroxide appeared to play a key role in drought adaptation, with Çatacık and Akyazı showing better performance under arid conditions. The findings provide valuable insights for selecting appropriate Scotch pine provenances for afforestation in arid and semiarid environments and contribute to the development of climate-resilient forest management strategies.