ASHS 2015 Annual Conference

Hydrangea paniculata Sieb. is a popular ornamental plant in the United States for its long-lasting flowers and cold hardiness. To introduce these treats to other Hydrangea species, cross pollination had been carried out with very limited number of seeds. Conventional seed germination by many researches yielded no survival seedlings so far and in vitro seed germination had been investigated in this study. Seeds of H. paniculata were sterilized under 16 combinations of 75% alcohol and 8% NaClO. The perfect germination rate was achieved under treatment of 75% alcohol for 30 seconds and 8% NaClO for 1 minute. All other treatments had 30% to 100% contamination. H. paniculata seeds could be germinated under B-5, MS (full or half strength), and WPM media with 75% or higher germination rates. B-5 media were recommended because it had the biggest root mass (total root lengths of 10 cm). Darkness was not needed for Hydrangea seed germination and light conditions promoted uniform seedlings and shortened overall germination time. The optimized protocol for in vitro seed germination of Hydrangea paniculata was established and we should apply it for the in vitro germination for Hydrangea interspecific hybridization seeds.