2.3. Seedling emergence and temperature
Seeds were sown in containers (280 mm × 190 mm) filled with germination sand [Rolfes Silica, 0.4–0.85 grading; dry graded silica sand (SiO2, 98% Fe2 O3 0.18%)] moistened with distilled water for small seeds (0.0675 l kg− 1 sand) and large seeds (0.4675 l kg −1sand). Water was allowed to redistribute in the sand before incubation for 24 h at the designated treatment temperatures to allow the sand to attain the desired temperature. Small seeds were broadcasted evenly on top of moistened sand and firmly pressed into the substratum to allow contact with sand. Large seeds were sown at a depth of 1 cm. Spacer sticks were used to separate sample containers inside the incubators to allow sufficient circulation of air around the containers. Water was replenished as needed. Emergence was recorded every 24 h. Seeds were considered to have emerged once the cotyledons were visible above the surface of the sand (Koger et al., 2004 and Maraghni et al., 2010).