Seed dormancy and germination characteristics of the endangered species Cicuta virosa L. in South Korea

Abstract

Cicuta virosa L. has significant medicinal, ecological, and research potential, however there is little research history about seed dormancy. We characterized morphological changes during the embryo maturation stages of C. virosa L. seeds to better understand its dormancy type and germination characteristics, which is necessary for optimizing seed propagation. In addition, water absorption measurements, germination tests, cold moist stratification, and GA₃ or kinetin were used to determine dormancy and germination characteristics. C. virosa seed dormancy presents a morphophysiological dormancy (MPD) with an undeveloped embryo. Since cold moist stratification at 4 °C caused the embryo to develop and the radicle to break through seed coat, its dormancy was determined to be of a non-deep complex type. For dormancy-broken seeds, the optimal germination condition was incubation at 25 °C in the light, with a pretreatment of GA₃ and kinetin. Indeed, GA₃ improved the germination rate up to 90% regardless of its concentration, and kinetin at least doubled the germination rate of C. virosa seeds compared to that of the controls. Additionally, KNO₃ improved germination rates by 50% with respect to that of the controls regardless of the concentration at which it was added. Our results indicate that C. virosa seeds have MPD and can be planted consistently en masse with cold stratification, GA₃, kinetin, and KNO₃ treatments. In particular, once the embryo has developed sufficiently, a combined administration of 500 mg L⁻¹ GA₃ and 20 mg L⁻¹ kinetin was much more effective than either treatment alone; therefore, an appropriate method must be used based on the stage of embryo development.