Effect of light, temperature, storage duration and conditions on the germination of two Mediterranean conifers: Tetraclinis articulata and Cedrus atlantica

Aim of study: This research aims to determine the optimal germination and storage Conditions for the seeds of two vulnerable Mediterranean conifers, Cedrus atlantica Manetti ex Carrière and Tetraclinis articulata (Vahl) Masters. Area of study: The seeds of C. atlantica and T. articulata were collected in northwestern Algeria. Material and methods: The effect of light [alternation of daylight and darkness (night) vs continuous darkness] and temperature (5, 10, 15, 20, 25, 30, 35, 40 °C) on the germination behavior of the two species was examined. Subsequently, the variation of seeds viability under different storage Conditions (-20 °C, 5 °C, ambient temperature) and throughout various timeframes (6, 12, 18 and 24 months) was assessed. Main results: Daylight presence favored C. atlantica seed germination [final germination percentage (FGP) = 80%] whereas T. articulata germination was light-independent. Overall, temperature significantly affected the majority of the germination parameters of the two species (p < 0.01). The optimal temperature for seed germination of T. articulata and C. atlantica was 15 °C (FGP = 56%) and 20 °C (FGP =80%) respectively. The seeds of the two species were able to retain their viability after 24 months of storage, despite the decline in their germination percentage. The analysis of variance revealed a significant influence of storage Conditions on almost all the germination parameters of both species. Research highlights: The obtained results are crucial for the construction and management of seed banks, as they facilitate the effective conservation of the studied species. This involves the appropriate and well-scheduled renewal of accessions, which is essential to preserve their long-term integrity.