Effects of Desiccation and Storage Temperature on Seed Germination in Kapok

Abstract

Kapok (Bombax ceiba) is a deciduous tree that can grow in the dry-hot valley of southwestern China where its natural regeneration by seedlings is difficult. As mature fruit split open and seeds disperse by wind, it is difficult to collect fully mature seeds. The effects of seed moisture content (MC) and storage temperatures on seed germination of dark-brown seeds collected from split fruit and light-brown seeds collected ≈10–15 days earlier than the time of fruit split were studied to determine the effective germplasm preservation via the seeds. Dark-brown mature seeds could tolerate desiccation to less than 5% MC and could tolerate −20 and −80 °C. Seeds of kapok showed orthodox storage behavior. They can be stored at subzero temperatures with low MC for a long time. For light-brown seeds, germination percentage (GP), germination index (GI), seedling fresh weight (SFW), and vigor index (VI) decreased significantly after seed desiccation. Germination percentage of light-brown seeds with different MC increased to a different extent after being stored at different temperatures for 1 year (76% to 99%), compared with the fresh seeds (73%). Storing fresh seeds at 4 °C was most favorable to keep seed viability and seed vigor of light-brown seeds. Seed collection could be done several days earlier than the time of fruit burst to ensure increased quantity of collected seeds.