Flowering Responses to Vernalization and Photoperiod in Minuartia laricina (L.) Mattf., a Perennial Herb in the Korean Peninsula

This study investigated the flowering physiology of Minuartia laricina (L.) Mattf. to provide fundamental information for the development of flowering control techniques. A phenology test was conducted in an open field, where M. laricina overwintered from December to February. Flower buds began to form in late March as temperatures and photoperiods increased. Flowering started in late April and continued until mid-June, with seeds maturing in capsule-shaped fruits by mid-August. In a greenhouse experiment, M. laricina was subjected to cold treatments at 5 °C for 0, 2, 4, 8, or 12 weeks, followed by photoperiod treatments of 9/15, 11/13, 13/11, 16/8, 24/0 h day/night photoperiod, or night interruption (9 h + 4 h). Plant growth and flowering were measured during the photoperiod treatments. The results showed 100% flowering with 8 weeks of cold treatment and under 16 h or longer photoperiod conditions. However, without cold treatments flowering was not observed across all photoperiods. These findings align with outdoor conditions, where M. laricina flowers experience a cold winter and under long photoperiods. Thus, M. laricina is classified as an obligate vernalization and long-day plant, requiring at least eight weeks of cold and a 16/8 h photoperiod to flower.