Morphophysiological dormancy in seeds of the ANA grade angiosperm Schisandra arisanensis (Schisandraceae)

We determined the kind of seed dormancy in Schisandra arisanensis, an ANA grade ([A]mborellales [N]ymphaeales [A]ustrobaileyales) angiosperm with medicinal value. Seeds have small underdeveloped embryos, and following seed maturity their length increased approximately 360% before radicle emergence. Germination was delayed 6-8 weeks, and the percentage and rate were much higher at 15/6, 20/10 and 25/15 degrees C than at 30/20 degrees C. For seeds incubated at 5/5 degrees C (8 weeks) -> 15/6 degrees C (4 weeks) -> 20/10 degrees C (8 weeks) -> 25/15 degrees C (12 weeks) -> 20/10 degrees C (5 weeks), embryos grew at 15/6 degrees C -> 20/10 degrees C, and almost all seeds that germinated (89%) did so at 20/10 degrees C -> 25/15 degrees C. When seeds were incubated in a complementary temperature sequence, 25/15 degrees C (12 weeks) -> 20/10 degrees C (8 weeks) -> 15/6 degrees C (4 weeks) -> 5/5 degrees C (9 weeks) -> 15/6 degrees C (4 weeks), embryos grew at 25/15 degrees C -> 20/10 degrees C. Nearly all seeds that germinated (93%) did so at 25/15 degrees C -> 20/10 degrees C and at 15/6 degrees C following 9 weeks at 5/5 degrees C. Based on the temperature requirements for embryo growth and seed germination, seeds of this species have non-deep simple morphophysiological dormancy (C(1b)B).