The influence of temperature stress on the viability of beech (Fagus sylvatica L.) from different geographical regions

This study investigated the impact of thermal stress on the viability of beech (Fagus sylvatica L.) seedlings from different origins: Codru (Republic of Moldova) and Băiuţ (Romania). Seeds stratified for two months were germinated, and the seedlings were exposed to 40°C, 45°C, and 48°C for 15 minutes. The results showed that the survival rate of seedlings not exposed to heat stress was 75%, but it decreased to 55% at 40°C and to 25% at 48°C. Seedlings with longer roots (7 cm) tolerated the stress better than those with shorter roots (1 cm). Heat stress inhibited root growth and adaptation, and a mere 5°C increase (from 40°C to 45°C) significantly affected seedling viability. These findings highlight the importance of selecting genotypes resistant to high temperatures for reforestation and the conservation of European beech in the context of climate change.