Cryopreservation of Pyrostegia venusta (Ker Gawl.) Miers seeds

Abstract Seeds of Pyrostegia venusta (Ker Gawl.) Miers) were desiccated at 25 °C on silica gel for 0 h (T0), 7 h (T1) and 24 h (T2), reaching moisture contents of 6.5%, 4.4% and 3.8%, respectively. Seeds were frozen rapidly in liquid nitrogen (+LN) at -263 °C.min.-1 and after 72 h, they were thawed slowly at room temperature (25 ± 2 °C) at a speed of 5 °C.min.-1. Seed germinability evaluation before (-LN) and after freezing (+LN) was conducted at 25 °C, on paper roll substrate, and germinated at 16 hrs light/8 hrs dark, normal seedling counts for 38 days. The germinative percentages were 88% (T0-LN), 98% (T0+LN), 61% (T1-LN), 95% (T1+LN), 78% (T2-LN) and 89% (T2+LN). Mean days for seedling formation were 23 (T0-LN), 22 (T1-LN and T2-LN) and 30 days for seeds exposed to LN. Fast freezing, slow thawing, and the three tested moisture contents, were suitable for cryopreservation of Pyrostegia venusta seeds.