Seed dormancy and germination in Jeffersonia dubia (Berberidaceae) as affected by temperature and gibberellic acid

Abstract

The genus Jeffersonia, which contains only two species, has a trans-Atlantic disjunct distribution. The aims of this study were to determine the requirements for breaking dormancy and germination of J. dubia seeds and to compare its dormancy characteristics with those of the congener in eastern North America. Ripe seeds of J. dubia contain an underdeveloped embryo and were permeable to water. In nature, seeds were dispersed in May, while embryos began to grow in September, and were fully elongated by late November. Germination started in March of the next year, and seeds emerged as seedlings soon after germination. In laboratory experiments, incubation at high temperatures (25 °C, 25/15 °C) for at least 8 weeks was required to initiate embryo growth, while a transfer to moderate temperatures (20/10 °C, 15/6 °C) was needed for the completion of embryo growth. At least 8 weeks at 5 °C was effective in overcoming physiological dormancy and for germination in seeds after the embryos had fully elongated. Thus, both high and low temperatures were essential to break dormancy. Gibberellic acid (GA3 ) treatment could substitute for the high temperature requirement, but not for the low temperature requirement. Based on the dormancy-breaking requirements, it is confirmed that the seeds have deep simple morphophysiological dormancy. This dormancy type is similar to that of seeds of the eastern North American species J. diphylla. Although seeds require 10-11 months from seed dispersal to germination in nature, under controlled conditions they required only 3 months after treatment with 1000 mg·l(-1) GA3 , followed by incubation at 15/6 °C. This represents practical knowledge for propagation of these plants from seed.

Exogenous GA3 Application Enhances Xylem Development and Induces the Expression of Secondary Wall Biosynthesis Related Genes in Betula platyphylla

“…Seed dormancy and germination are regulated by a number of genes and environmental factors [ 17 ]. Various methods have been used to terminate seed dormancy, including hormonal, light and/or temperature treatments [ 18 , 19 ]. Endogenous GAs have previously been used to terminate dormancy and promote seed germination [ 20 ].…”

Genetic diagnosis of a rare myrmecochorous species, Plagiorhegma dubium (Berberidaceae): Historical genetic bottlenecks and strong spatial structures among populations

“…P. dubium may also vegetatively spread through rhizomes under harsh conditions (Smith et al., ). Due to a showy light violet flower and heart shape leaves in mature plants, about 10–30 cm long, the plants have been recognized as a potential ornamental species (Rhie et al., ; Song, ). The species also has been well known for its medicinal uses.…”

“…Plagiorhegma dubium Maxim. (Figure 1) is an herbaceous perennial that belongs to family Berberidaceae (Kim, Lee, Kim, & Kim, in press;Rhie et al, 2015). P. dubium is the only species in the genus Plagiorhegma Maxim.…”

“…In Korea, P. dubium was rarely found in natural habitats and it is listed as an “endangered species” by the Ministry of Environment of South Korea in part due to limited migration ability as a myrmecochorous plant (Ministry of Environment, ). The species only inhabits dense deciduous forests mostly along the north side of shady valleys (Ghimire & Heo, ; Rhie, Lee, & Kim, ). However, the species was removed from the list in 2012 based on the recent population growth observed throughout the nation within the past 10 years (3rd National Environmental Survey, Ministry of Environment unpublished data; Suh & Kim, ).…”

Factors affecting the dormancy and germination of bleeding heart [Lamprocapnos spectabilis (L.) Fukuhara] seeds

“…Spring ephemerals are perennial plants that bloom during the early spring in order to produce seeds and they have a very short growth cycle. Some examples of spring ephemerals native to South Korea are Adonis amurensis , Hepatica nobilis , Erythronium japonicum and Jeffersonia dubia (Kim et al ; Keddy ; Rhie et al ). The seeds of these ephemeral plants are known to be dispersed when the embryo is underdeveloped (Nomizu et al ; Vandelook et al, ) and are normally classified as morphophysiologically dormant (MPD) seeds (Baskin & Baskin , ).…”