2019 ASHS Annual Conference
Interspecific Variation of Seed Dormancy in Four Lonicera species Native to Korea
Interspecific Variation of Seed Dormancy in Four Lonicera species Native to Korea
Tuesday, July 23, 2019: 2:45 PM
Partagas 1 (Tropicana Las Vegas)
Seed dormancy type and germination characteristics of four Korean native Lonicera species (Lonicera insularis Nakai, Lonicera praeflorens Batalin, Lonicera harae Makino and Lonicera subsessilis Rehder) were investigated. Imbibition test of the seeds was conducted, and the seeds were incubated at constant temperatures of 5, 15, 20, or 25ºC. Embryo morphology was observed at seed dispersal and just before germination. Because seeds of four Lonicera species imbibed water readily, they have no physical dormancy (PY). Four Lonicera species had underdeveloped embryos with length of 0.13-0.26mm at dispersal. The embryos were grown to critical length of 0.46-0.81mm just before germination. Freshly matured seeds of L. insularis Nakai and L. harae Makino germinated over 90% at 15 and 20ºC respectively within 4 weeks after sowing. On the other hand, no germination of L. pareflorens Batalin and L. subssesilis Rheder was observed within 4 weeks after sowing at all temperature treatments. Therefore, L. insularis Nakai and L. harae Makino have only morphological dormancy (MD) and L. pareflorens Batalin and L. subssesilis Rheder have morphophysiological dormancy (MPD). At 15ºC, the germination of L. praeflorens Batalin started on the fifth week after sowing and completed on the ninth week with the final germination rate of 52.2%. Seeds of L. subsessilis Rheder began germinating on the fifth week after sowing at 15ºC and on the fourteenth week where the germination was complete, the final germination rate were 80.0%. Embryo growth and germination of L. praeflorens Batalin and L. subsessilis Rheder were occurred at relative high temperature (≥15ºC). Thus, seeds of L. praeflorens Batalin and L. subsessilis Rheder have non-deep simple type MPD that dormancy breaking and embryo growth require only relative high temperature (≥15ºC). Optimum temperature for germination of seeds of L. insularis Nakai and L. harae Makino was 15ºC and L. praeflorens Batalin and L. subsessilis Rheder was 20ºC. The dispersal patterns of seeds in habitat correspond with germination characteristics and seed dormancy type. These results could be useful to study eco-physiological mechanisms of Lonicera species.