Fig. 1From: Optimal seed water content and storage temperature for preservation of Populus nigra L. germplasmEffect of storage temperature (3 °C, −3 °C, −10 °C, −20 °C, and −196 °C) and time of storage (0, 3, 6, 9, 12, 18 and 24 months) on Populus nigra seed germination. Seed water content was 0.07 g H2O g−1 dry mass. Means with the same letter are not significantly different at P < 0.05, according to the Tukey’s test. Seeds were collected in 2010Back to article page