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Article

Seed Dormancy and Germination Characteristics of Scutellaria indica L. var. coccinea S.T.Kim & S.T.Lee., an Endemic Species Found on Jeju Island, South Korea

by
Jae Hui Kim
1,
Hak Cheol Kwon
2 and
Seung Youn Lee
1,3,*
1
Department of Horticulture and Breeding, Graduate School of Gyeongkuk National University, Andong 36792, Republic of Korea
2
Natural Product Informatics Research Center, Korea Institute of Science and Technology, Gangneung 25451, Republic of Korea
3
Major of Smart Horticultural Science, Gyeongkuk National University, Andong 36729, Republic of Korea
*
Author to whom correspondence should be addressed.
Horticulturae 2025, 11(9), 1019; https://doi.org/10.3390/horticulturae11091019
Submission received: 23 July 2025 / Revised: 23 August 2025 / Accepted: 25 August 2025 / Published: 29 August 2025
(This article belongs to the Special Issue Propagation and Flowering of Ornamental Plants)
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Abstract

Globally, biodiversity is declining, meaning that many endemic plants are under threat; therefore, it is essential to develop conservation strategies. Scutellaria indica var. coccinea has great potential as an ornamental ground cover plant, but it is a plant that requires ex situ conservation. This study was conducted in order to investigate the seed germination characteristics and classify the dormancy type of S. indica var. coccinea seeds, with the aim of developing mass propagation protocols for ex situ conservation and preservation of their genetic diversity. Fresh and mature seeds of S. indica var. coccinea are in a dormant state, which is released by low temperatures during winter, resulting in radicle and seedling emergence the following spring. At the time of dispersal, the seeds had fully developed embryos, and the seed coat was permeable. When the seeds were incubated under four different temperature regimes (4, 15/6, 20/10, or 25/15 °C), they showed a low germination percentage (≤20%), indicating that a substantial proportion of the seeds remained in a dormant state. In the cold stratification experiment (0, 4, 8, or 12 weeks at 4 °C), germination increased, and the time required for germination shortened as the duration of cold treatment lengthened. This suggests that low temperatures are the primary environmental signal that induces germination. In the gibberellic acid (GA3) treatment (GA3 0, 10, 100, or 1000 mg·L−1), relatively high concentrations (100 and 1000 mg·L−1) were effective in promoting germination. The highest germination was obtained in GA3 1000 mg·L−1 with 100.0%, which is about 7 times higher than the control (13.6%). Therefore, seeds of S. indica var. coccinea were classified as having non-deep physiological dormancy (PD). Additionally, because the minimum germinable temperature range of the seeds was extended to lower temperatures, the seeds were classified as having type 2 non-deep PD.

Graphical Abstract

1. Introduction

Biodiversity refers to the variety of life, including the number of species, genetic variation, and ecological and evolutionary processes, and it plays a crucial role in maintaining the stability and balance of ecosystems [1,2,3]. Plants play a vital role in the response to and mitigation of climate change by absorbing carbon and reducing greenhouse gases in the atmosphere [4,5]. Therefore, they must be preserved not only for environmental protection but also for both the survival and future of humanity. However, plant biodiversity continues to decline due to human activities (overharvesting and urbanization), habitat changes, invasion of alien species, and climate change [6,7,8,9,10].
South Korea, located in East Asia, has relatively abundant flora and diverse vegetation due to its mountainous terrain (≥62%), climate, and geographical features [11,12]. However, the forest ecosystems of South Korea are threatened by rapid industrialization, overharvesting, and pollution [13]. In order to protect them, the Ministry of Environment, the Ministry of Agriculture, Food, and Rural Affairs, and the Korea Forest Service are designating protected areas through conservation agencies, implementing in situ and ex situ restoration programs for species, and strengthening legal protection and regulations [12,14].
Endemic plants, resulting from genetic diversity, have adapted to the specific environmental conditions of a localized area and are naturally found only in limited areas [15,16,17,18,19]. These plants contribute to the maintenance of biodiversity through their unique genetic traits, and typically exist in small populations, making it necessary to manage and protect them to prevent extinction [5,20]. In South Korea, various ex situ conservation institutes, such as the Korea National Arboretum (KNA), National Institute of Biological Resources (NIBR), and botanical gardens, are operating to protect threatened plant species [21,22]. Among these, botanical gardens are one of the simplest ex situ conservation strategies to secure the safety of threatened plants in their natural habitats. They conduct research on plant protection and conservation and develop propagation methods [10,20,23]. Objective plant propagation techniques based on scientific results are required for botanical gardens to effectively conserve rare or endemic plants ex situ.
Scutellaria is the second largest genus in the Lamiaceae family, consisting of annual or perennial herbaceous plants [24,25], and is mainly distributed in East Asia, including Korea, Japan, Taiwan, and China [26,27,28,29]. The genus Scutellaria contains flavonoids, phenolic compounds, and amino acids and is known for its high medicinal value, including anti-cancer, anti-inflammatory, and antihypertensive effects [30,31,32]. Additionally, S. ocmulgee and S. suffrutescens, which are native to North America, have a long flowering period of 2–5 months, and they have been reported to have potential ornamental value because they produce many flowers [29]. Scutellaria, which is distributed throughout Korea, has 10 species and eight different varieties, including S. dependens, S. insignls, S. indica var. tsusimensis, and S. indica var. coccinea, etc. A new variant of Korean Scutellaria, S. indica var. coccinea, is an endemic plant that was found in a small volcanic crater called ‘Sangumburi’ on Jeju Island [18,25,26]. Jeju Island Sangumburi has been designated as a natural monument and national heritage site, and its surrounding plants are also protected [33]. This perennial herbaceous plant is known for its medicinal properties, including effects on active blood, detoxification, and bruising [34]. It grows to approximately 20–30 cm in height and it blooms from May to July with deep pink flowers [26,35,36], making it potentially suitable for ornamental use. However, because it exists in very small populations, it is particularly vulnerable to climate and deforestation; therefore, it is important to develop conservation techniques to protect it. The Korea Forest Service has enforced the Forest Protection Act to protect plants from their natural habitats, but no research has been conducted on their ex situ conservation [37].
The genetic diversity of plants can be conserved through methods such as seed and vegetative propagation as well as plant tissue culture [38]. Seed propagation is easy to perform and maintains genetic diversity during storage [39]. Understanding the early life history of a plant is important for seed propagation. Seed germination and seedling establishment are the first steps in a plant’s life cycle [40]. Dormancy refers to the state in which seeds do not germinate for a certain period, even when environmental conditions such as temperature and light are favorable for germination [41,42]. Although the seeds in this state are viable and intact, they cannot germinate for several days or months. Plants belonging to the same genus or family may exhibit similar types of seed dormancy; however, the germination conditions required to reach the plant may be different [40,43]. Previous research on seed dormancy and germination characteristics of several species belonging to the Lamiaceae family has been reported. Baskin and Baskin [40] reported that seeds of plants belonging to the genera Scutellaria and Salvia have physiological dormancy (PD). In S. parvula, which is native to the eastern United States, the seeds are in a dormant state at the time of detachment from the parent plant, and dormancy is broken through after-ripening [44]. Seeds of S. rubropunctata that remained ungerminated at 30 °C germinated soon after the temperature was changed to 15 °C, indicating a state of enforced dormancy [45]. The seeds of Salvia aegyptica, widely distributed in temperate and subtropical climates, germinate across a broad temperature range (10–40 °C), with an optimal germination temperature reported to be 30 °C [46]. In the case of Teucrium santae, native to Northwest Algeria, the optimal germination temperature was found to be between 15 and 25 °C, with the highest germination observed at 20 °C [47]. Additionally, Hyptis suaveolens, native to the semi-arid region of Northeastern Brazil, exhibited the highest germination at temperatures between 25 and 30 °C [48]. Since germination traits can vary depending on the environmental characteristics of the plant, customized propagation studies are therefore necessary for each species. However, no studies have been conducted to date on the dormancy and germination characteristics of S. indica var. cocinea seeds native to Jeju Island, so it is important to investigate the germination conditions required for this plant. This study aimed to understand the life cycle and germination characteristics of S. indica var. coccinea seeds and, if dormancy is present, classify the type of dormancy to develop the techniques necessary for propagation.
The following experiments were conducted to understand the life cycle of the target species and investigate seed germination characteristics: (1) phenology of germination and seedling emergence under natural conditions; (2) temperature and light requirements for germination; (3) effects of different periods of cold stratification on germination; and (4) effects of gibberellic acid on germination in the laboratory. The results of this study can be used to develop a seed-based mass propagation technique for S. indica var. coccinea and provide fundamental information for ex situ conservation.

2. Materials and Methods

2.1. Plant Materials

The mature seeds of S. indica var. coccinea with dark brown seed coats were collected from cultivated plants grown from wild-collected seed sources on 21 July 2021, cultivated plants present in the Hantaek Botanical Garden in Gyeonggi-do, Korea, a conservation agency designated by the Korea Forest Service and the Ministry of Environment for ex situ conservation. The collected seeds were dried for 2 weeks at room temperature (23 ± 2 °C). The dried seeds were then sealed in a sterile plastic bottle with silica gel and stored in cold storage (1 °C) until they were required for the experiments.

2.2. Basic Characteristics of Seed

Randomly selected seeds were measured for characteristics including size, weight, and internal and external shapes. Twenty seeds were measured using Vernier calipers (Digital caliper 150 mm, Kangalu, Shenzhen, Guangdong, China). The weight of 100 seeds was measured in triplicate using an electronic balance (PGA214, OHAUS Corporation, Parsippany, NJ, USA). The external morphology of the seeds was observed after cutting the seeds in half with a razor blade, and the internal morphology was observed using a USB electron microscope (AM3111 Dino-Lite Premier; ANMO Electronics Co., Hsinchu, Taiwan).

2.3. Phenology Experiments

In order to assess the seed germination patterns and life cycle under natural conditions, two experiments (seed germination and seedling emergence) were conducted in outdoor phenology experiment plots of Gyeongkuk National University, Andong, Korea (36°32′40.41888″ N, 128°48′2.67516″ E). For the seed germination experiment, a 9 × 8 cm (diameter × height) plastic pot was filled with horticultural soil (Baroker; cocopeat: 68%, peat moss: 14.73%, zeolite: 4%, perlite: 7%, vermiculite: 6%, fertilizer: 0.201%, wetting agent: 0.064%, and pH regulator: 0.005%), followed by placing 20 seeds in a mesh bag containing sand, sealing the bag, and burying it in the pot at a depth of approximately 3 cm. The pot was buried in the ground to ensure that its height was level with the ground surface. For the seedling emergence experiment, a 9 × 8 cm plastic pot was filled with 2/3 horticultural soil, followed by 1 cm of sand, 20 seeds, and 1 cm of horticultural soil. The pot was buried in the ground to ensure that its height was level with the ground surface. The phenology plot was set up to simulate the natural environment in which the seeds grew, with a 30% shade canopy installed (height of 120 cm) during the summer and a thermal nonwoven fabric covering it during the winter. Considering the timing of seed dispersal, this experiment started on 16 July 2023. This experiment lasted for approximately one year and was checked every two weeks. For the germination experiment, the bags were taken out to check for individuals with emerged radicles, while for the seedling emergence experiment, only the number of seedlings that had emerged above the substrate surface was recorded. The reason why distinct evaluation metrics were applied in the two experiments (seed germination and seedling emergence) is as follows: (1) In the case of germination experiment, since it was only necessary to confirm whether the radicle broke through the seed coat, the seeds were tied in the mesh bag and germination was observed, and (2) in the case of seedling emergence, a slightly different method was applied for observation because tying the seeds in the mesh bag would have hindered the growth and emergence of cotyledons and hypocotyls after germination. A data logger (WatchDog Model 540; Spectrum Technologies, Inc., Plainfield, IL, USA) was installed below the soil (2–3 cm) in the phenology plot and set to measure the soil temperatures every 30 min.

2.4. Water Absorption Test

To determine the presence of physical dormancy caused by impermeability of the seed coat, a water absorption experiment was conducted. Distilled water was added to a 50 mL glass beaker to fully submerge the seeds, and this experiment was conducted with 20 seeds in three replicates at room temperature (23 ± 2 °C). Seed weight was measured before water absorption and after 3, 6, 9, 12, 24, 48, and 72 h of water absorption, after removing the seeds from the beaker and thoroughly drying the surface. The water absorption percentages were calculated using the following formula:
Ws (%) = [(Wi − Wd)/Wd] × 100
where Ws is the mass of the increased seeds, Wi is the seed mass after a given imbibition interval, and Wd is the initial seed mass at 0 h.

2.5. Laboratory Experiments

2.5.1. General Procedure

Seeds used in this experiment were rinsed alternately with distilled water and 70% ethanol for 10 s. They were then placed in 15 mL tubes containing 2000 mg·L−1 Benomyl (Farm Hannong, Seoul, Republic of Korea), a fungicide, solution, and stirred on a shaker for 24 h. The seeds were then rinsed twice with distilled water for 10 s. Two layers of filter paper were placed in Petri dishes (90 × 15 mm), and distilled water was added to keep them moist before the seeds were placed. The experiments were conducted with 20 seeds in four replicates. The photosynthetic photon flux density (PPFD) of the Cold-Lab Chamber (4 °C) and Multi-Room Chamber (15/6, 20/10, and 25/15 °C) averaged approximately 1 and 34 µmol·m−2·s−1. The Petri dishes were wrapped in Parafilm to prevent water evaporation during this experiment. The Petri dishes were continuously supplied with distilled water when needed to prevent them from drying during this experiment. Germination was defined as when the radicle emerged through the seed coat and protruded by more than 1 mm. During the germination assessment, germinated seeds were immediately removed from the Petri dishes, and dead seeds were discarded and excluded from the final germination calculation. When the seeds split in half at the end of this experiment, seeds with white and firm embryos were considered viable and included in the total number of seeds, and the overall percentage of viable seeds was 80–90%. Final germination percentage was calculated using the following formula:
Final germination (%) = (n/N) × 100
where n is the number of germinated seeds at the end of the incubation period, and N is the total number of viable seeds at the end of this experiment.

2.5.2. Effect of Light on Germination

An experiment was conducted to assess the germination characteristics of the seeds under different light regimes. The light conditions were incubated in light/dark (12 h photoperiod) at 25/15 °C, and the dark conditions were maintained by wrapping the Petri dishes with two layers of aluminum foil to block light and then incubating them in the same environment as the light conditions. Seed germination was checked weekly for 12 weeks, and under dark conditions, light was blocked in the laboratory during the assessment and monitored using a green LED light source.

2.5.3. Effect of Temperature on Germination

To assess the seed germination characteristics under different incubation temperatures, this experiment was conducted under constant temperature (4 °C) and fluctuating temperature (15/6, 20/10, or 25/15 °C) conditions. These four temperature conditions were used to simulate four seasons in Korea, where 4 °C represents winter, 15/6 °C represents early spring and late autumn, 20/10 °C represents late spring and early autumn, and 25/15 °C represents summer. To maintain constant temperature conditions, a Cold-Lab Chamber (HB-603CM, Hanbaek-Scientific Co., Bucheon-si, Republic of Korea) set to 4 °C and a Multi-Room Chamber (HB-302S-4, Hanbeak-Scientific Co., Bucheon-si, Republic of Korea) set to 15/6, 20/10, or 25/15 °C, were used. Seed germination was checked weekly for 12 weeks, and the criteria and methods for the assessment were the same as those described in Section 2.5.1.

2.5.4. Effect of Cold Stratification on Germination

An experiment was conducted to assess germination characteristics under the cold stratification (CS) treatment. The CS experiments were conducted twice. In the first experiment (Experiment 1), the seeds were treated in a Cold-Lab Chamber (4 °C) for 0, 4, or 8 weeks, respectively. In the second experiment (Experiment 2), the seeds were treated at 4 °C for 0, 4, 8, or 12 weeks, respectively, to investigate the increase in germination rate with longer cold stratification periods. During the CS period, the seeds were placed in Petri dishes lined with two layers of filter paper, distilled water was added to keep the filter paper constantly moist, and the Petri dishes were sealed with Parafilm to prevent moisture loss during the experiment. After each CS period, the seeds were incubated in a Multi-Room Chamber (25/15 °C). Both experiments were completed when no further changes for more than 3 weeks in germination occurred. Seed germination was checked weekly during this experiment, and the criteria and methods for assessment were the same as those described in Section 2.5.1. At the end of the germination period, the mean germination time (MGT) [49,50,51], time to reach 50% germination (T50) [52], and germination index (GI) [53] were calculated according to the following formula:
MGT (days) = ∑(n * t)/∑n
where n is the number of newly germinated seeds on survey day t, and t is the time from the beginning of the germination test in hours or days.
T50 (days) = ti + [(N/2 − ni)(tj − ti)]/(nj − ni)
where N is the final number of germination, and ni and nj are the cumulative number of seeds germinated by adjacent counts at times ti and tj, respectively, when nj < N/2 < ni.
GI = ∑ ni/ti
where ni is the number of germinated seeds on survey day ti.

2.5.5. Effect of GA3 Treatment on Germination

To assess the seed germination characteristics following GA3 treatment, the seeds were immersed in GA3 solution of 10, 100, or 1000 mg·L−1 for 24 h, respectively. The control, which was not treated with GA3, was immersed in distilled water for 24 h. After treatment, the seeds were sterilized using the method described in Section 2.5.1 and incubated in a Multi-Room Chamber at 25/15 °C. Seed germination was checked weekly for 12 weeks, and the criteria and methods for the assessment were the same as those described in Section 2.5.1.

2.6. Statistical Analysis

Data were analyzed using the Statistical Analysis System (SAS 9.4, SAS Institute Inc., Cary, NC, USA). The significance among treatments was tested using analysis of variance (ANOVA), and when significant differences were confirmed, means were compared using Duncan’s multiple-range tests at p < 0.05 as a post hoc analysis. Graphs were plotted using SigmaPlot 12.5 (SPSS Inc., Chicago, IL, USA).

3. Results

3.1. Basic Characteristics of Seed

The fruits of S. indica var. coccinea have a schizocarp consisting of four mericarps. Each seed was dark brown and had papillate protuberances on its surface (Figure 1B,C). The seed length and width were approximately 1.27 ± 0.03 mm and 0.82 ± 0.02 mm, respectively, and the average weight of 100 seeds was 51.17 ± 0.54 mg. The embryo was foliate, bent, and fully developed (Table 1 and Figure 1D).

3.2. Phenology Experiment

In the field environment, the first germination was observed on 30 July 2023, two weeks after burying (8.1%). At this time, the average daily soil temperature is 26.5 °C (Figure 2A,B). No changes were observed from August 2023 to early February of the following year; however, on 3 March 2024, germination began to increase, and by 7 July 2024, the final germination reached 100.0%. The seedlings emerged seven weeks after the first germination on 17 September 2023, with a 4.2% emergence. Similarly, no changes were observed from late September 2023 to mid-March of the following year; however, on 31 March 2024, the seedling emergence rate began to increase, reaching a final rate of 73.7% on 7 July 2024 (Figure 2B).

3.3. Water Absorption Test

The mass of the seed increased by 28.7% after 6 h when compared with the initial weight. The seed absorption curve showed a typical pattern of initial mass increase, followed by a plateau phase and a subsequent increase (Figure 3).

3.4. Laboratory Experiments

3.4.1. Effect of Light on Germination

The results showed that the first germination was observed after 2 weeks of incubation under light conditions, and after 4 weeks, germination was 8.9% (Figure 4). The final germination rate was 23.3% after 12 weeks of incubation, and a significant number of seeds remained dormant without germination. In the dark, the seeds germinated after 4 weeks of incubation, and the final germination rate was 17.8%. The ANOVA results showed no significant differences between treatments under light conditions.

3.4.2. Effect of Temperature on Germination

The results showed that the seeds did not germinate under any of the temperature conditions except for 25/15 °C, after 4 weeks of incubation (Figure 5). At 25/15 °C, the seeds germinated after 3 weeks of incubation, with a rate of 1.7%, but there was no statistically significant difference when compared to the other temperature treatments. The final germination rates at 4, 15/6, 20/10, and 25/15 °C were 0.0, 0.0, 10.3, and 13.6%, respectively, but there were no statistically significant differences between the temperature treatments.

3.4.3. Effect of Cold Stratification on Germination

The cold stratification (CS) experiments were conducted twice. In both Experiments 1 and 2, the final germination increased as the CS period increased (Figure 6). In Experiment 1, the mean germination time (MGT) decreased from 61.5 d (CS for 0 weeks) to 12.8 d (CS for 8 weeks). For the control (CS for 0 weeks), the germination percentage did not reach 50%, and there was no significant difference in the time to reach 50% germination (T50) values between the CS for 4 weeks and 8 weeks (Table 2). Similarly, in Experiment 2, the MGT decreased from 45.7 (control) d to 5.8 d. Additionally, T50 decreased from 10.5 (CS for 4 weeks) d to 2.6 (CS for 12 weeks), indicating that the extended the CS period, the shorter the time required for germination (Table 2). In Experiment 1, the germination index (GI) increased from 0.06 (control) to 1.48 (12 weeks of CS), and in Experiment 2, it increased from 0.14 (control) to 7.11 (12 weeks). The germination percentage was significantly affected by the cold stratification treatment, as indicated by the one-way ANOVA (Table 3).

3.4.4. Effect of GA3 Treatment on Germination

Germination was promoted as the GA3 concentration increased (Figure 7). In the second week of incubation, germination began to increase in the 100 and 1000 mg·L−1 GA3 treatments. The final germination rates were the highest at 97.4 and 100.0%, respectively, and there was no significant difference between the two treatments. In the 10 mg·L−1 GA3 treatment, similarly, germination started in the second week of incubation, but the germination was lower than the 100 and 1000 mg·L−1 GA3, with a final germination of 17.8%, which was not different from the 0 mg·L−1 GA3.

4. Discussion

Information on germination, bud formation, flowering, and seed development, obtained through phenological studies, is essential for maintaining a proper phenological cycle and ensuring the reproductive success of the species [54]. In our phenological experiments, seeds of S. indica var. coccinea were buried in the field in mid-July and remained ungerminated throughout the winter but began to germinate the following spring when daily soil temperatures reached approximately 2.9 °C (Figure 2A,B), indicating that germination can occur under relatively low temperatures. By contrast, under controlled laboratory conditions, the final germination under light and temperature treatments was only about 20% (Figure 4 and Figure 5), whereas cold stratification (CS) treatment significantly increased germination to more than 90% (Figure 6). Collectively, these findings indicate that freshly matured seeds of S. indica var. coccinea are unable to germinate immediately after dispersal and instead require a period of dormancy release prior to successful germination. The consistent outcomes obtained from both field and laboratory experiments provide strong evidence that this species exhibits physiological dormancy. Therefore, the ecological significance of our results lies in demonstrating that exposure to a natural cold period is an important factor in breaking dormancy, which is supported by laboratory studies showing that CS promotes germination.
Baskin and Baskin classified seed dormancy into five classes: physiological dormancy (PD), morphological dormancy (MD), morphophysiological dormancy (MPD), physical dormancy (PY), and combined dormancy [54]. PD is the most common type of dormancy on Earth. Seeds with PD have a fully developed embryo at the time of dispersal from the mother plant; however, their germination is delayed by more than 30 d, even under favorable environmental conditions for germination. Several past studies have reported that many species belonging to the Lamiaceae family exhibit PD or nondormancy (ND). Especially in temperate regions, seeds of many species exhibit PD of varying depths, which gradually break during winter and germinate the following spring [40,55,56]. Seeds with MD had underdeveloped embryos at the time of dispersal from the mother plant. Once the embryo has grown sufficiently, the seeds can germinate within 30 days under favorable environmental conditions, without the need for any special treatments. MPD is a combination of the characteristics of PD and MD, and seeds with MPD require a longer period of embryonic growth and germination than those with MD. Seeds exhibiting PY can delay germination due to the presence of water-impermeable cell layers in the seed coat or fruit coat. Seeds with combinational dormancy combine the characteristics of PY and PD and have both a water-impermeable seed coat and a physiologically dormant embryo [42,57,58]. For example, Teucrium santae of the Lamiaceae family is known to exhibit this type of dormancy. Physical dormancy could be broken through chemical scarification with sulfuric acid, and physiological dormancy could be overcome with 1500 mg·L−1 GA for 72 h [47].
Mature seeds of S. indica var. coccinea embryos are fully developed at the time of dispersal from the mother plant (Figure 1D). This indicates that the seeds do not require additional time for embryo growth and therefore do not exhibit MD or MPD. In the water absorption experiment conducted to determine the permeability of the seed coat, seed mass increased by more than 20% within 6 h (Figure 3). This indicates that the seed coat of S. indica var. coccinea is permeable, and therefore, the seeds do not exhibit PY or combinational dormancy [59]. Based on our light and temperature treatment experiments, the majority of seeds showed a delay in germination of more than 30 d, even under favorable environmental conditions (Figure 4 and Figure 5). Therefore, mature seeds of S. indica var. coccinea can be considered to exhibit PD, as they do not germinate due to the low growth potential of the embryo [42].
PD is classified into three levels (non-deep, intermediate, and deep) based on dormancy depth [60,61]. This classification is determined by the seed response to treatments, such as cold or warm stratification, gibberellic acid (GA3), and dry after-ripening [60,62]. Non-deep PD is broken down by cold or warm stratification and gibberellic acid (GA3) treatment. Intermediate PD showed varying responses to GA treatment depending on the species, and dormancy was disrupted by CS for 2–3 months. Deep PD does not respond to GA3 treatment and requires CS for more than three months to break dormancy [42]. The performed CS experiments were conducted twice (Experiments 1 and 2). In both Experiments 1 and 2, CS for more than four weeks was effective in reducing the dormancy depth of S. indica var. coccinea seeds and promoted germination (Table 2 and Table 3 and Figure 6). As a result of cold stratification at 4 °C, in Experiment 1, as the CS period expanded, mean germination time (MGT) shortened from an average of 61.5 d to 12.8 d, and time to reach 50% germination (T50) showed no significant difference. In Experiment 2, as the CS period increased, MGT decreased from an average of 45.7 d to 5.8 d, and T50 shortened from 10.5 d to 2.6 d. As a result of the GA3 treatment experiment, germination was promoted with increasing concentrations of GA3. Similar results were observed for the germination characteristics of two Polygonella species, which have non-deep PD of seeds by Heather et al. [63]. In that study, P. polygama seeds treated with 1000 mg·L−1 GA3 reached a final germination of 32.5%, which was about double that of the control. Many previous studies have demonstrated the positive effects of gibberellic acid on seed germination in species belonging to the Lamiaceae family. For example, Szekely-Varga et al. [64] reported that two Lavandula angustifolia cultivars (Codreanca and Sevtopolis) recorded germination of over 90% with 300 mg·L−1 GA3, approximately 2.5 times higher than the control. In addition, the seeds of photoblastic species Nepeta rtanjensis showed enhanced germination under dark conditions when treated with approximately 350 mg·L−1 GA3, indicating that GA3 was able to fully substitute the light requirement for seed germination in N. rtanjensis [65]. Based on our results, we classified the seeds of S. indica var. coccinea as having a non-deep form of PD since germination was promoted by a relatively short period of CS and GA3 treatment. Similar effects have been observed in temperate montane wetland plants in China, including Betula ovalifolia, Carex limosa, Hypericum longisylum, and Lobelia sessilifolia. When the seed germination characteristics of the four plant species and their dormancy types were investigated, it was found that germination was promoted through CS and that germination was effectively promoted by inducing mechanical damage to the seed coat through sulfuric acid pre-treatment and removing potential PD through GA3 treatment [66]. In conclusion, all four species exhibited non-deep PD, supporting the claim that PD is a common adaptive strategy in plants native to temperate regions.
Despite the wide geographical distribution of plants in the genus Scutellaria, many species in this genus are known to exhibit similar classes of seed dormancy (PD or ND) [42,55]. This suggests that seed dormancy traits inherited from their common ancestor have been evolutionarily conserved over an extended period. This phenomenon can be interpreted as a representative example of trait stasis in which certain physiological and ecological traits remain almost unchanged over long evolutionary periods [43]. Physiological traits are regulated by genes; therefore, species belonging to the same family or genus are likely to exhibit similar characteristics, such as seed germination [67]. Although the level of PD has not been classified, previous studies on closely related species have shown similar effects, where dormancy was broken and germination was promoted by CS. According to Liu et al. [67] and Baskin and Baskin [40], seeds of Ajuga lupulina and Scutellaria baicalensis, which belong to the Lamiaceae family, exhibit PD, and CS is effective in promoting germination under dry conditions [40,67]. In addition, the PD of Agstache foeniculum seeds is broken through CS, and in the case of Amthystea caerulea seeds, the PD can be broken by 40 d of CS. In contrast, in some species such as Scutellaria parvula, which belongs to the same genus, dormancy is broken by high summer temperatures [44,68], thus indicating that germination can vary slightly even among species within the same genus [40,62]. These differences in environmental responses to dormancy breaking may be the result of trait divergence, in which the basic physiological traits are preserved, but responsiveness varies according to the climatic conditions [43,69]. Therefore, the genus Scutellaria can be regarded as an example in which traits of stasis and divergence coexist. Therefore, understanding the germination requirements of seeds during dormancy breaking and induction is essential, as they play a crucial role in the control of germination timing, seedling establishment, and survival [70].
Based on our experiment results, we classified the seeds of S. indica var. coccinea as exhibiting non-deep PD. It is a common type found in many herbaceous plants and some woody species, and it has been estimated that more than 90% of seeds exhibiting PD have this level of PD [71]. There are six types of non-deep PD that are further classified based on the dormancy-breaking process and the temperature requirements for germination after dormancy have been broken [40,42,72]. When seed germination is restricted by specific environmental factors, resulting in conditional dormancy (CD) within a narrow range of conditions, it is classified as type 1, 2, or 3. If the seeds do not exhibit CD, they are classified as types 4, 5, or 6 [40,42,70]. Under field conditions, the S. indica var. coccinea germinated at a low rate of 8.1%, whereas most of the seeds remained in a dormant state. By mid-July of the following year, all seeds had germinated, suggesting that S. indica var. coccinea remained in a dormant (D) state and gradually transitioned from a dormant through a CD state to a non-dormant (ND) state as dormancy was broken by exposure to low temperatures. This pattern (D ↔ ND) reflects the typical dormancy cycle observed in non-deep PD species native to temperate regions [73]. Based on these aforementioned observations, we demonstrate that the seeds of S. indica var. coccinea exhibit CD; therefore, we can narrow the non-deep PD types of the target species to types 1, 2, and 3. According to Baskin and Baskin (2014) and Soltani et al. (2017), species with type 1 non-deep PD initially germinate only at low temperatures, and as dormancy breaks down, the maximum germination temperature increases [40,70]. Seeds with type 2 non-deep PD initially germinate only at high temperatures, and as dormancy is broken, the germinable minimum temperature decreases, whereas seeds with type 3 non-deep PD initially germinate only at intermediate temperatures, and as dormancy is broken, both the lower and upper temperature limits for germination expand. Mature seeds of S. indica var. coccinea can germinate initially at a low rate only under the high temperatures (≥20 °C) of summer (Figure 2 and Figure 5). However, increased germination with the CS treatment indicated that the temperature range for germination expanded to lower temperatures as the seeds were exposed to low temperatures (Figure 6). If the temperature range for seed germination is broadened, seeds may become less dependent on specific climatic conditions and thus be able to germinate in a wider range of environments. Therefore, the range of favorable conditions for both survival and reproduction is expanded, thus allowing for greater reproductive success. This may be a common characteristic in regions with large temperature fluctuations and may play an important role in maintaining species reproduction and diversity in response to climate change [74,75]. In fact, under field conditions, the first day on which the germination of S. indica var. coccinea seeds exceeded 50% was in early March, 35 weeks after being buried, when the daily average soil temperature was 9.6 °C (Figure 2). This indicates that low temperatures are the primary environmental signals for breaking dormancy in S. indica var. coccinea, and the minimum temperature required for germination decreased. Therefore, it can be concluded that the seeds of S. indica var. coccinea exhibited type 2 non-deep PD (Table 4). This type is commonly found in the seeds of summer annual plants and many perennial plants in temperate regions [70,73,76]. In temperate regions with distinct seasonal changes, such as Korea, plant survival and reproduction depend on germination strategies that are well-adapted to the environment [77,78,79]. By maintaining dormancy from dispersal to winter and by germinating in early spring, S. indica var. coccinea uses a strategy that selects a favorable period for survival. This characteristic may not merely be an individual species response but rather a common evolutionary trait shared among the genus Scutellaria in temperate climates. The ecological traits of perennial herbaceous plants native to temperate forests in eastern Asia and eastern North America remain in a state of evolutionary stasis and maintain stable ecological requirements [80,81]. This supports the results of the present study, thus indicating that the genus Scutellaria has maintained germination traits adapted to temperate climates over long evolutionary periods. In this way, the unique germination traits of each species not only help maintain genetic diversity but also serve as a strategy for adapting more effectively to changing environmental conditions [82,83].
Such survival strategies have also been observed in the life cycles of plants transplanted into the field. After the plants matured, they flowered in spring and produced seeds (Figure 1H). The fresh seeds of S. indica var. coccinea dispersed in summer exhibited dormancy (Figure 1I), with most remaining dormant in the soil, thereby forming a soil seed bank. Soil seed banks are broadly categorized into transient and persistent types [84]. A transient seed bank consists of seeds that do not remain viable in the soil for more than one year before germination, whereas a persistent seed bank comprises seeds that remain dormant in the soil for at least one year before germination [85,86]. Transient seed banks can be classified into two types. Type 1 transient seed banks involve seeds that undergo dormancy release in late spring and summer and typically germinate in autumn. In contrast, type 2 transient seed banks consist of seeds that experience dormancy release during winter and germinate in the early spring of the following year [84,87]. This type of seed bank is commonly observed in species inhabiting northern and continental temperate regions [84,88]. Our observations indicate that the seeds of S. indica var. coccinea exhibit the characteristics of a type 2 transient seed bank, undergoing dormancy release during winter and germinating the following spring. This suggests that S. indica var. coccinea has developed a type 2 transient seed bank as an adaptation to the geographical features of temperate regions. Through the repetition of their life cycle, the plants can adapt to seasonal changes and environmental factors, thereby maintaining the diversity of their clusters [70,89]. The results of the present study provide important baseline data for the mass propagation of S. indica var. coccinea.
In our phenology experiment, the seedling emergence percentage (73.7%) was lower than the germination percentage (100.0%), indicating that not all germinated seeds successfully developed into seedlings. Similar discrepancies have been reported in other species, as seed germination does not necessarily ensure successful recruitment due to intrinsic and extrinsic factors [75,90]. Post-germination mortality can be caused by fungal pathogens such as Pythium and Rhizoctonia, abiotic stressors like insufficient precipitation and soil desiccation, or other environmental constraints [91,92]. Most of the deceased individuals were either dry or had rotted with a dark black seed coat. Since our observations were made under natural field conditions, the precise causes of mortality between germination and emergence remain unclear. Nevertheless, this discrepancy highlights the importance of monitoring both germination and seedling establishment when evaluating recruitment dynamics. This study confirmed that strategies such as prescreening seed quality, maintaining adequate soil moisture, applying pathogen control, and minimizing predation risk are essential to reduce post-germination mortality and enhance propagation efficiency.

Practical Conservation Applications

For S. indica var. coccinea, the results of this study provide a practical propagation protocol that can be directly applied to conservation programs. Dormancy can be effectively relieved by cold stratification of seeds at 4 °C for 4 weeks or by treating them with 100 mg·L−1 GA3, a cost-effective alternative to the commonly used 1000 mg·L−1 concentration. Once dormancy is relieved, optimal germination occurs under light conditions at temperatures ranging from 20/10 °C to 25/15 °C. For successful field establishment, transplanting seedlings is effective when soil temperatures rise above approximately 10 °C. Careful monitoring of post-germination mortality during the early stages of seedling development is also important, as this can significantly impact establishment success. These recommendations provide a concise and practical framework that enhances the applicability of this study to conservation professionals.

5. Conclusions

Based on the experimental results of the various treatments on the germination characteristics of S. indica var. coccinea seeds were classified as exhibiting type 2 non-deep PD. Freshly mature seeds contain fully developed embryos that remain dormant. In the field, dormancy was released during winter and germinated the following spring. In laboratory experiments, cold stratification (CS) for more than 4 weeks effectively broke dormancy, thus resulting in a germination rate of nearly 100.0%. These results confirmed that low temperature is a crucial environmental factor in breaking the PD of S. indica var. coccinea seeds, and the minimum temperature required for germination increased as dormancy was released. GA3 was able to substitute for the requirements of low temperatures, and germination was promoted at concentrations of 100 and 1000 mg·L−1, allowing all of the seeds to germinate. Considering the efficiency, time, and cost, we suggest breaking seed dormancy and promoting propagation through either CS for 4 weeks or 100 mg·L−1 of GA3 treatment. The results of this study provide fundamental information for developing mass propagation techniques for S. indica var. coccinea and can serve as a valuable resource for ex situ conservation efforts in botanical gardens.

Author Contributions

Conceptualization, H.C.K. and S.Y.L.; Investigation and Formal analysis, J.H.K. and S.Y.L.; Data curation, J.H.K.; Funding acquisition, H.C.K. and S.Y.L.; Methodology, Supervision, an Project administration, S.Y.L.; Writing—original draft preparation, J.H.K. and S.Y.L.; Writing—review and editing, H.C.K. and S.Y.L. All authors have read and agreed to the published version of the manuscript.

Funding

This work was supported by the Korea Institute of Science and Technology (KIST) ORP program [BlueBell Research Project (grant number 2E33511-25-022)] and the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (grant number NRF-2018R1A6A1A0302482).

Data Availability Statement

The original contributions presented in this study are included in the article. Further inquiries can be directed to the corresponding author.

Acknowledgments

Thanks to every member of the Floriculture and Landscape Plants Lab (FLPL, Gyeongkuk National University).

Conflicts of Interest

The authors declare no conflicts of interest.

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Figure 1. Photos of a native habitat of Scutellaria indica L. var. coccinea S.T.Kim & S.T.Lee (A), a capsule containing four mericarps (i.e., seeds) (B), external morphology of a seed (C), internal morphology of a seed with a fully developed embryo (D), germination stages from the emergence of the radicle to the seedlings (E), propagules after the transplanted seedlings in a greenhouse (F), flowering from the propagules in a greenhouse (G), flowering and capsules (H), and seed maturation (I) in the field. Scale bars indicate 1 mm.
Figure 1. Photos of a native habitat of Scutellaria indica L. var. coccinea S.T.Kim & S.T.Lee (A), a capsule containing four mericarps (i.e., seeds) (B), external morphology of a seed (C), internal morphology of a seed with a fully developed embryo (D), germination stages from the emergence of the radicle to the seedlings (E), propagules after the transplanted seedlings in a greenhouse (F), flowering from the propagules in a greenhouse (G), flowering and capsules (H), and seed maturation (I) in the field. Scale bars indicate 1 mm.
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Figure 2. Phenology experiments of Scutellaria indica L. var. coccinea S.T.Kim & S.T.Lee. Mean daily soil temperature (A), cumulative germination, and seedling emergence (B). The data was recorded from 16 July 2023 to 21 July 2024. Error bars indicate mean ± standard error of four replicates of 20 seeds.
Figure 2. Phenology experiments of Scutellaria indica L. var. coccinea S.T.Kim & S.T.Lee. Mean daily soil temperature (A), cumulative germination, and seedling emergence (B). The data was recorded from 16 July 2023 to 21 July 2024. Error bars indicate mean ± standard error of four replicates of 20 seeds.
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Figure 3. Water uptake by the intact seeds of Scutellaria indica L. var. coccinea S.T.Kim & S.T.Lee as represented by an increase in mass. Seeds were incubated at room temperature (23 ± 2 °C) in beakers containing distilled water for 72 h. Error bars indicate mean ± standard error of three replicates of 20 seeds.
Figure 3. Water uptake by the intact seeds of Scutellaria indica L. var. coccinea S.T.Kim & S.T.Lee as represented by an increase in mass. Seeds were incubated at room temperature (23 ± 2 °C) in beakers containing distilled water for 72 h. Error bars indicate mean ± standard error of three replicates of 20 seeds.
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Figure 4. Germination of Scutellaria indica L. var. coccinea S.T.Kim & S.T.Lee seeds as affected by the performed light regimes. The seeds were incubated in light (12 h photoperiod) and darkness (24 h) regimes at 25/15 °C for 12 weeks. Error bars indicate mean ± standard error of four replicates of 20 seeds. NS means non-significant at p < 0.05 (Duncan’s multiple range tests).
Figure 4. Germination of Scutellaria indica L. var. coccinea S.T.Kim & S.T.Lee seeds as affected by the performed light regimes. The seeds were incubated in light (12 h photoperiod) and darkness (24 h) regimes at 25/15 °C for 12 weeks. Error bars indicate mean ± standard error of four replicates of 20 seeds. NS means non-significant at p < 0.05 (Duncan’s multiple range tests).
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Figure 5. Germination of Scutellaria indica L. var. coccinea S.T.Kim & S.T.Lee seeds as affected by the performed temperature treatments. The seeds were incubated in light/dark (12 h photoperiod) at four temperature conditions (4, 15/6, 20/10, or 25/15 °C) for 12 weeks. Error bars indicate mean ± standard error of four replicates of 20 seeds. NS means non-significant at p < 0.05 (Duncan’s multiple range tests).
Figure 5. Germination of Scutellaria indica L. var. coccinea S.T.Kim & S.T.Lee seeds as affected by the performed temperature treatments. The seeds were incubated in light/dark (12 h photoperiod) at four temperature conditions (4, 15/6, 20/10, or 25/15 °C) for 12 weeks. Error bars indicate mean ± standard error of four replicates of 20 seeds. NS means non-significant at p < 0.05 (Duncan’s multiple range tests).
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Figure 6. Germination of Scutellaria indica L. var. coccinea S.T.Kim & S.T.Lee seeds as affected by the cold stratification period (0, 4, 8, or 12 weeks) at 4 °C. After the treatment, the seeds were incubated at 25/15 °C and the final germination was investigated when there was no change in germination over 3 weeks; seeds were incubated for 12, 8, or 4 weeks (A) and 12, 8, 6, or 6 weeks (B), respectively. Error bars indicate mean ± standard error of four replicates of 20 seeds. The different lowercase letters represent significant difference at p < 0.05 (Duncan’s multiple range tests).
Figure 6. Germination of Scutellaria indica L. var. coccinea S.T.Kim & S.T.Lee seeds as affected by the cold stratification period (0, 4, 8, or 12 weeks) at 4 °C. After the treatment, the seeds were incubated at 25/15 °C and the final germination was investigated when there was no change in germination over 3 weeks; seeds were incubated for 12, 8, or 4 weeks (A) and 12, 8, 6, or 6 weeks (B), respectively. Error bars indicate mean ± standard error of four replicates of 20 seeds. The different lowercase letters represent significant difference at p < 0.05 (Duncan’s multiple range tests).
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Figure 7. Germination of Scutellaria indica L. var. coccinea S.T.Kim & S.T.Lee seeds as affected by GA3 (0, 10, 100, or 1000 mg·L−1). The seeds treated with GA3 for 24 h were incubated at 25/15 °C for 12 weeks. Error bars indicate mean ± standard error of four replicates of 20 seeds. The different letters indicate significant differences at p < 0.05 (Duncan’s multiple range tests).
Figure 7. Germination of Scutellaria indica L. var. coccinea S.T.Kim & S.T.Lee seeds as affected by GA3 (0, 10, 100, or 1000 mg·L−1). The seeds treated with GA3 for 24 h were incubated at 25/15 °C for 12 weeks. Error bars indicate mean ± standard error of four replicates of 20 seeds. The different letters indicate significant differences at p < 0.05 (Duncan’s multiple range tests).
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Table 1. Seed characteristics of Scutellaria indica L. var. coccinea S.T.Kim & S.T.Lee.
Table 1. Seed characteristics of Scutellaria indica L. var. coccinea S.T.Kim & S.T.Lee.
Scientific NameCollection
Location		Collection DateLength
(mm)		Width
(mm)		100 Seed Weight
(mg)
Scutellaria indica L. var. coccinea S.T.Kim & S.T.LeeHantaek Botanical Garden
(37°09′ N, 127°41′ E)		26 June 20211.27 ± 0.03 10.82 ± 0.0251.17 ± 0.54 2
1 Values of the length and width indicate mean ± standard error (n = 20). 2 Values indicate mean ± standard error (n = 3).
Table 2. Mean germination time (MGT), time to reach 50% germination (T50), and germination index (GI) of Scutellaria indica L. var. coccinea S.T.Kim & S.T.Lee seeds as affected by cold stratification at 4 °C for various periods. This experiment was conducted twice. In Experiment 1, the data were collected at 12, 8, or 4 weeks after incubation at 25/15 °C following cold stratification treatment for 0, 4, or 8 weeks, respectively. In Experiment 2, the data were collected at 12, 8, 6, or 6 weeks after incubation at 25/15 °C following cold stratification treatment for 0, 4, 8, or 12 weeks, respectively. Both experiments were ended when the germination rate showed no further changes for more than 3 weeks.
Table 2. Mean germination time (MGT), time to reach 50% germination (T50), and germination index (GI) of Scutellaria indica L. var. coccinea S.T.Kim & S.T.Lee seeds as affected by cold stratification at 4 °C for various periods. This experiment was conducted twice. In Experiment 1, the data were collected at 12, 8, or 4 weeks after incubation at 25/15 °C following cold stratification treatment for 0, 4, or 8 weeks, respectively. In Experiment 2, the data were collected at 12, 8, 6, or 6 weeks after incubation at 25/15 °C following cold stratification treatment for 0, 4, 8, or 12 weeks, respectively. Both experiments were ended when the germination rate showed no further changes for more than 3 weeks.
ExperimentCold Stratification Period
(Weeks)		MGT
(Days)		T50
(Days)		GI
1061.46 ± 6.33 1a 2NG 3 0.06 ± 0.01b
411.80 ± 0.82b7.25 ± 1.88a1.38 ± 0.05a
812.79 ± 0.58b10.50 ± 0.00a1.48 ± 0.19a
2045.68 ± 4.82aNG 0.14 ± 0.02b
415.32 ± 0.27b10.50 ± 0.00a1.34 ± 0.03b
811.88 ± 1.42c6.13 ± 1.68b2.08 ± 0.07b
125.79 ± 1.14c2.63 ± 0.88c7.11 ± 1.12a
1 Values indicate mean ± standard error (n = 4). 2 The different lowercase letters indicate significant differences (p < 0.05), Duncan’s multiple-range test. 3 NG: Not germinated to 50%.
Table 3. One-way ANOVA was conducted to examine the effects of cold stratification (Experiment 1 and Experiment 2) on the final germination, mean germination time (MGT), T50 (time to reach 50% germination), and GI (germination index) and the effects of GA3 on the final germination of the Scutellaria indica L. var. coccinea S.T.Kim & S.T.Lee seeds.
Table 3. One-way ANOVA was conducted to examine the effects of cold stratification (Experiment 1 and Experiment 2) on the final germination, mean germination time (MGT), T50 (time to reach 50% germination), and GI (germination index) and the effects of GA3 on the final germination of the Scutellaria indica L. var. coccinea S.T.Kim & S.T.Lee seeds.
DFSSMSF-Valuep-Value
Cold stratification (Experiment 1)Germination210,556.1985278.09921.380.0004
MGT26438.0103219.00558.79<0.0001
T50121.12521.1253.000.1340
GI25.0782.53936.48<0.0001
Cold stratification (Experiment 2)Germination313,181.0464393.68262.37<0.0001
MGT33793.9971264.66647.56<0.0001
T502124.54262.27113.070.0022
GI3112.99537.6659.160.0020
GA3Germination333,398.15211,132.717358.33<0.0001
Table 4. Evaluation and summary of seed dormancy and germination traits in Scutellaria indica var. coccinea based on Baskin & Baskin’s criteria for non-deep physiological dormancy.
Table 4. Evaluation and summary of seed dormancy and germination traits in Scutellaria indica var. coccinea based on Baskin & Baskin’s criteria for non-deep physiological dormancy.
Seed TraitsObservation in S. indica var. coccinea
Embryo developmentEmbryo was foliate, bent, and fully developed
(no morphological dormancy)
Water absorptionPermeable seed coat
(no physical and combinational dormancy)
Effect of temperature regimes
on germination		≤20% germination
(seeds were dormant)
Effect of cold stratification
on germination		4 °C, ≥8weeks → ≥80% germination at 25/15 °C
Effect of GA3 treatment
on germination		GA3 100, 1000 mg·L−1 → ≥80% germination at 25/15 °C
Germination phenologyAfter exposure to cold winter temperatures,
spring germination at low soil temperatures (≤10 °C)
(temperature range at which seeds can germinate gradually increases from high to low)
Dormancy typeType 2 non-deep physiological dormancy 1
1 Type 2 non-deep PD was classified according to the references [40,42].
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MDPI and ACS Style

Kim, J.H.; Kwon, H.C.; Lee, S.Y. Seed Dormancy and Germination Characteristics of Scutellaria indica L. var. coccinea S.T.Kim & S.T.Lee., an Endemic Species Found on Jeju Island, South Korea. Horticulturae 2025, 11, 1019. https://doi.org/10.3390/horticulturae11091019

AMA Style

Kim JH, Kwon HC, Lee SY. Seed Dormancy and Germination Characteristics of Scutellaria indica L. var. coccinea S.T.Kim & S.T.Lee., an Endemic Species Found on Jeju Island, South Korea. Horticulturae. 2025; 11(9):1019. https://doi.org/10.3390/horticulturae11091019

Chicago/Turabian Style

Kim, Jae Hui, Hak Cheol Kwon, and Seung Youn Lee. 2025. "Seed Dormancy and Germination Characteristics of Scutellaria indica L. var. coccinea S.T.Kim & S.T.Lee., an Endemic Species Found on Jeju Island, South Korea" Horticulturae 11, no. 9: 1019. https://doi.org/10.3390/horticulturae11091019

APA Style

Kim, J. H., Kwon, H. C., & Lee, S. Y. (2025). Seed Dormancy and Germination Characteristics of Scutellaria indica L. var. coccinea S.T.Kim & S.T.Lee., an Endemic Species Found on Jeju Island, South Korea. Horticulturae, 11(9), 1019. https://doi.org/10.3390/horticulturae11091019

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