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Article

Dormancy Characteristics of Euphorbia maculata L. Seeds and Strategies for Their Effective Germination

by
Kyungtae Park
1,2,
Hamin Lee
1,2,
Bo-Kook Jang
3 and
Ju-Sung Cho
1,2,*
1
Division of Animal, Horticultural and Food Sciences, Chungbuk National University, Cheongju 28644, Republic of Korea
2
Brain Korea 21 Center for Bio-Health Industry, Chungbuk National University, Cheongju 28644, Republic of Korea
3
Department of Horticulture, Sunchon National University, Suncheon 57922, Republic of Korea
*
Author to whom correspondence should be addressed.
Horticulturae 2023, 9(9), 990; https://doi.org/10.3390/horticulturae9090990
Submission received: 21 July 2023 / Revised: 14 August 2023 / Accepted: 15 August 2023 / Published: 1 September 2023
(This article belongs to the Collection Seed Dormancy and Germination of Horticultural Plants)
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Abstract

:
Euphorbia maculata L. has been confirmed to have functional properties, including anticytotoxic, anti-inflammatory, and antioxidative effects. However, studies on the dormancy and germination of its seeds for cultivation purposes are lacking. The potential of E. maculata as a valuable plant species has not been fully realized due to the lack of understanding of its seed dormancy and germination characteristics. E. maculata seeds were collected and germination tests were performed at various temperatures to determine their dormant state. Next, seeds were stratified with various temperatures, and treated temperature conditions similar to those of its natural habitat to induce dormancy release. The seeds exhibited very low germination below 30 °C, which indicates the possibility of innate dormancy. Subsequently, dormancy was released by cold stratification, and an expansion in the temperature range suitable for germination was observed, confirming that E. maculata seeds exhibit conditional dormancy. Conversely, high-temperature moist stratification did not effectively break dormancy as it led to seed decay. Therefore, we treated the seeds at various high temperatures in a dry environment. This facilitated dormancy release without the need for moist stratification, allowing for seed storage while ensuring the uniform and rapid production of E. maculata seedlings and minimizing seed wastage. Additionally, seeds with broken dormancy did not require a high temperature for germination, making them more cost-effective. Therefore, comprehensively examining germination and dormancy characteristics may optimize the cultivation process of this valuable plant species, E. maculata.

Graphical Abstract

1. Introduction

Most plants contain components that are useful to humans, and since ancient times, humans have been taking advantage of such plants [1]. Recent advancements in analytical techniques and their reduced cost have facilitated extensive studies aiming to explore the chemical and pharmacological properties of diverse wild plants [2,3,4]. There has also been an increase in the number of studies on plants in different countries owing to the evaluation of the value of the biological resources of these countries according to the Convention on Biological Diversity and the Nagoya Protocol. Thus, the high pharmacological value of various plants has been confirmed. However, several challenges are still associated with the use of these plants for medicinal purposes. Specifically, it is still challenging to cultivate and maintain several wild plants despite the growing demand for them, and over-collection can further lead to habitat loss and species extinction [5,6]. Therefore, alongside the discovery of their value, studies on their propagation and cultivation are necessary [7].
The Euphorbia L. genus, one of the biggest plant genera, comprises over 2000 species that are distributed almost everywhere on Earth, except for a few areas [8,9]. They are very diverse in their morphological and ecological characteristics, and many of them have been used for various purposes since ancient times owing to their excellent pharmacological properties [10,11,12]. For example, it has been reported that Euphorbia hirta, also known as garden spurge, shows antidiarrhoeic and anti-inflammatory activities and can also be used to treat digestive problems, respiratory system disorders, injuries, and skin cellular tissue disorders [13,14,15,16,17]. There are also several reports on the use of various plants of the Euphorbia genus for medicinal purposes [10].
E. maculata L. (spotted spurge), which is native to North America and is a naturalized plant in Korea, can be found in various areas as a weed; however, its negative impact is not significant. Further, E. maculata L. has been studied for its medicinal value [18,19,20] and diverse pharmacological effects owing to the triterpenoids it contains [21,22]. Studies have confirmed its anticytotoxic, anti-inflammatory [23,24], and antioxidative [25] effects, and recently, it was reported that its extracts can be used for the degradation of organic pollutants [26,27]. However, studies on the propagation and cultivation of this plant and others of the same genus are very limited. Moreover, while these plants may be considered weeds, they do not germinate under all circumstances.
Reportedly, understanding seed dormancy increases the possibilities for plant utilization. Seeds exhibit dormancy to prevent germination under unfavorable environmental conditions; thus, they can wait to germinate only under suitable conditions. If dormant seeds are sown without breaking dormancy, they show uneven germination and require a long time for seedling production [28]. They are also associated with a limited range of germination conditions. In the worst-case scenario, dormant seeds may fail to germinate after sowing. Therefore, appropriate dormancy-breaking treatments can be employed to enable uniform and rapid seedling production, leading to healthy plant production and more efficient cultivation [29].
Seed dormancy is classified according to the Nikolaeve–Baskin scheme [28,30], which is very useful for accurately determining the dormancy state of seeds and applying appropriate dormancy-breaking conditions, thereby increasing the efficiency of plant production. Based on this scheme, the specific dormancy state of various seeds is determined with respect to their dormancy and germination responses. The system is divided into 5 classes and numerous sub-types according to dormancy-breaking response and germination conditions [28,31]. Therefore, it is necessary to observe the dormancy characteristics of the seed to identify the detailed dormancy type and apply appropriate breaking conditions.
Higher plants, which inhabit all major climatic regions, show dormancy and have also evolved to adapt to their diverse habitats [32,33,34]. Seed dormancy is a successful strategy for them to survive in their habitat. Therefore, the ecological characteristics of a habitat, such as climate, environmental characteristics, and other factors, serve as important clues for obtaining information regarding the germination and reproduction characteristics of a given seed [35,36,37].
The habitat of E. maculata is predominantly sunny, dry, and arid areas without shade. Particularly, this plant is commonly seen along pedestrian roads, roadsides, and footpaths and in rock crevices with such characteristics [38]. Owing to these habitat features, in summer, the plant experiences a rapid rise in temperature, which is maintained for an extended period and reaches values higher than the soil temperature [39]. Reportedly, there also exists a close correlation between seed dormancy and habitat environmental conditions [28].
In this study, the goal was to investigate the relationship between the environmental characteristics of the habitat of E. maculata and the germination of its seeds. To verify this hypothesis, various experiments were conducted to study the germination traits of E. maculata seeds and develop suitable methods for breaking their dormancy. This process provides information on the breaking of dormancy and germination of E. maculata, and can be utilized as important data for plant production and cultivation of this species.

2. Materials and Methods

2.1. Plant Material

Ripe E. maculata seeds were collected in August 2020 from plants growing in Haneggu-dong, Wonju-si, Gangwon-do, Korea (37°20′13.5″ N, 128°00′02.7″ E). At the time of collection (13:00), the air and ground surface temperatures of the habitat were 32.3 and 47.3 ± 1.83 °C, respectively. The seeds thus collected were dried at room temperature (25 ± 1.0 °C) for 7 days and then stored at 4 °C under dry conditions until the experiments.

2.2. Seed Properties and Morphological Characteristics

After cleaning, the morphological characteristics of the seeds were investigated. First, their weights and sizes were determined using a microbalance (AS220, Radwag, Radon, Poland) and a stereomicroscope (SZ61; Olympus Corporation, Tokyo, Japan), respectively. The stereomicroscope was equipped with a CMOS camera (eXcope F630; Dixi Sci., Daejeon, Republic of Korea). Second, their viability was confirmed using a 1% tetrazolium solution (triphenyl tetrazolium chloride, TTC; Sigma-Aldrich, St. Louis, MO, USA). Next, the seeds were placed in a conical tube filled with distilled water and subjected to imbibition at 20 °C for 12 h. Subsequently, the moistened seeds were allowed to sit in a 1% TTC solution at 30 °C for 12 h after which they were observed using a stereomicroscope. Their embryo length-to-seed length (E:S) ratios were also measured immediately after collection and after germination using the CMOS camera and eXcope software version 3.7.12277. Further, to visualize their mucilages, staining was performed using 0.01% Congo red (Samchun Pure Chemical Co., Ltd., Pyeongtaek, Republic of Korea). The microstructure images of the seed coats were also obtained using a field-emission scanning electron microscope (Zeiss Ultra Plus, Zeiss, Oberkochen, Germany).

2.3. Seed Germination under Various Temperatures

To determine the dormancy state of the seeds, fresh samples were sown under various temperature conditions. Specifically, the seeds were placed in a Petri dish (cat. No. 11010; SPL Life Sciences, Pocheon, Korea) containing two sheets of qualitative filter paper (Whatman no. 1, Bucks, London, UK) and cultured for 14 days under different temperature conditions: 15, 20, 25, 30, and 35 °C (continuous light or dark) and 25/15 °C (16-h/8-h light/dark; White-LED, 30 µmol·m−2·s−1 PPFD/Dark). Thereafter, the number of seeds that germinated was recorded daily, and the germinated seeds were removed from the Petri dish.

2.4. Stratification (Temperature Treatment) for Dormancy Release

The seeds were stratified at 4 °C (cold) and 15 °C (warm) for 14 days in a Petri dish, using the same method described in Section 2.3. The Petri dishes containing the seeds were sealed with Parafilm to prevent moisture loss and thereafter placed in a refrigerator at 4 °C and a chamber at 15 °C. After stratification, the Petri dishes were transferred to different chambers at 15, 20, 25, 30, and 35 °C, and seed germination was observed daily.

2.5. High-Temperature Exposure for Dormancy Release

To expose the seeds to high temperatures, we also used the stratification method described in Section 2.3. However, owing to this treatment, the seeds decayed due to their structures (mucilage). Therefore, we used a constant-temperature water bath to handle the high temperatures by keeping the seeds dry. Thus, the seeds were placed in microtubes and treated in a water bath set at 40, 50, and 60 °C for 12 and 24 h. After these treatments, the seeds were sown at 25, 25/15, and 35 °C.

2.6. Maintaining Dormancy Release Status during Storage

To confirm whether the seeds re-entered dormancy during storage, seeds with released dormancy were stored in dry conditions at 4 °C. Specifically, the seeds were placed in a plastic bag alongside silica gel, and sealed to block oxygen escape, and stored. After 1, 2, 4, 7, and 14 days of storage, they were sown at 25 or 15 °C to confirm germination.

2.7. Statistical Analyses

Statistical analyses were performed using SAS software version 9.4 (SAS Institute Inc., Cary, NC, USA). Data were presented as mean ± standard error of the mean for each treatment, and factorial analysis (one-way ANOVA) was performed using Tukey’s honestly significant difference (HSD) test, with a significance level of p < 0.05.

3. Results

3.1. Seed Properties

The investigation of the characteristics of E. maculata seeds showed that the seeds are small in size and that their long and short axes do not exceed 1 mm (Table 1). Additionally, the weight of a thousand seeds was determined to be 0.112 g, and the coat of the seeds was found to have a mucilage structure that became sticky following moisture absorption (Figure 1). The seeds were also found to have fully developed embryos with an E:S ratio of 0.84, indicating the absence of morphological dormancy. Further, prior to the experiments, the viability of the seeds was confirmed to be 100%.

3.2. Optimal Germination Temperature

The germination percentage of E. maculata seeds at different sowing temperatures were compared. Thus, we observed higher percent germination at relatively high temperatures (Figure 2). Specifically, 78.5 and 80.5% of the seeds germinated at 30 and 35 °C, respectively. However, germination was poor at low temperatures. Only 22.5 and 19% of the seeds germinated at 25 and 25/15 °C, respectively, and hardly any seeds germinated at temperatures below 20 °C. A similar trend was observed under dark conditions; however, the germination was significantly lower than that observed under light conditions. In particular, only 21.5% of the seeds germinated at 35 °C under dark conditions. Taken together, our results confirmed that E. maculata seeds require relatively high temperatures to germinate and that light conditions, rather than dark conditions promote their germination.

3.3. Stratification Can Expand Germination Temperatures

Stratification can promote germination by changing the dormant state of seeds. To further confirm whether the promotion and inhibition of germination observed at high and low temperatures, respectively, could be attributed to seed dormancy, we performed stratification treatments. Thus, we observed an expansion in the germination temperature range of E. maculata (Figure 3). Specifically, after cold stratification, the germination of seeds sown at 25 °C increased to 66%. Cold stratification also promoted germination even under dark conditions, with percent germination increasing to 79.5% at 35 °C (Figure 3A). However, warm stratification was ineffective in this regard. The germination percentage observed following warm stratification was similar to the initial germination under light conditions (Figure 3B). We also observed an increase in germination percentage under dark conditions following warm stratification, but the temperature range did not widen significantly. These findings indicated that E. maculata shows conditional dormancy (CD), which was released under specific conditions.

3.4. Effect of High Temperatures on Dormancy and Germination

We simulated high summer temperatures to investigate whether the CD of E. maculata seeds is affected by conditions similar to those of the plant’s natural habitat. Using a method similar to the moist stratification method, the treatment of the seeds at high temperatures did not result in germination. Additionally, we noted a foul odor that could be attributed to the decay of the mucilage of the seeds’ external structure emanating from the treated seeds. Therefore, to address this issue, we treated the seeds under high-temperature and dry conditions. Thus, we observed an increase in germination relative to that observed for the untreated seeds (Figure 4). Additionally, the germination percentage varied depending on the treatment temperature and duration, with germination increasing as the treatment temperature increased. Specifically, in a sowing environment at 25 °C, the highest germination percentage was observed for seeds treated at 60 °C for 12 h (Figure 4A). This germination was also observed in the 25/15 °C environment (Figure 4B). However, treatment at 60 °C for 24 h resulted in a decrease in percent germination and seed damage was observed even when the sowing environment temperature was maintained at 35 °C (control temperature). Therefore, pre-sowing high-temperature treatments can break the CD of E. maculata seeds and promote their germination.

3.5. Maintain Dormancy Release

After breaking CD, seeds may revert to a dormant state owing to various factors. Here, we conducted experiments to check whether dormancy was maintained after storage. As shown in Figure 5, the seeds that were released from dormancy due to the high-temperature treatment did not re-enter dormancy after storage but maintained a constant germination percentage. The percent germination before storage was 63.2%, and after 14 days of storage, it was 61.0%, indicating that dormancy release was maintained.

4. Discussion

Seeds have evolved to prevent germination under poor environmental conditions via dormancy [33,40]. Particularly, seed dormancy is categorized as physiological, morphological, morphophysiological, physical, and combinational (Physical + physiological), with different characteristics [28,30,31]. In this study, it was confirmed that E. maculata seeds do not show morphological dormancy (MD) considering the morphological maturation of their embryos at the time of collection (Figure 1B). Specifically, MD seeds are characterized by underdeveloped embryos at the time of collection [28,29]. Additionally, the E. maculata seeds did not show physical dormancy (PY) as they imbibed water without separate scarification. Therefore, morphophysiological and combinational dormancy was also ruled out. However, additional observation was required to confirm physiological dormancy.
During the initial germination experiment to confirm dormancy, E. maculata seeds showed germination of 80.5% at 35 °C; however, the temperature range for germination was narrow (Figure 2). In a study conducted by Baskin and Baskin [41], the optimal germination temperature for E. supina was reported to be 30–35 °C. Additionally, Asgarpour et al. [42] noted that temperatures above 35 °C are required for E. maculata germination.
Most seeds that exhibit germination over a span of 4 weeks are classified as non-dormant [28]. Such non-dormant seeds do not show increased germination even after dormancy-breaking treatment. Therefore, it was judged that E. maculata seeds may have some innate dormancy. To accurately confirm this reasoning, we stratified the seeds. Stratification is an effective strategy for breaking dormancy by placing seeds in conditions that are similar to those of their natural habitats [43,44,45,46]. Some species with physiological dormancy can germinate at the highest percentage after warm or cold stratification [47]. Additionally, the seeds of some species may lose their light requirements for germination via dormancy-breaking treatment [48]. The results showed that cold moist stratification widened the germination temperature range of E. maculata. Moreover, the germination percentage observed under dark conditions also increased compared to the percentage observed before the treatment (Figure 3). This implied that E. maculata seeds showed CD. Reportedly, fresh matured seeds with CD germinate within a relatively narrow range of conditions; however, this range of conditions increases after dormancy-breaking treatment [28,49]. In another study by Baskin and Baskin [50], Rumex crispus seeds showed higher germination at higher temperatures immediately after collection; however, after 4 months of storage, they showed 100% germination at all temperature ranges. This observation can be attributed to the fact that the seeds can recognize the appropriate environment for their habitat. Therefore, to determine whether seeds are in a state of CD, it is necessary to compare the germination of seeds sown immediately after harvest with that of seeds that have undergone dormancy-breaking treatment [28]. Accordingly, E. maculata was confirmed to be in a conditional dormant state as its seed dormancy was broken via stratification.
The appropriate stratification temperature required to break dormancy varies depending on the species. In our experiments, the highest temperatures among the three used in the moist stratification treatment were identified as unsuitable for E. maculata seeds as they caused the decay of the seeds. This could be attributed to the decay of the mucilage, a sticky external structure present on the seed surface (Figure 1C). Specifically, the mucilage in seeds serves as an external structure that retains water for germination and also plays a role in adherence to moist soils and seed dispersion through animal hosts [51,52,53]. Further, the mucilage, which has been characterized as a polysaccharide-rich hydrophilic hydrogel, primarily contains polysaccharides [54]. It is believed that this composition was responsible for the decay observed at high temperatures. The heat treatment that prevented this decay functioned to broaden the germination temperature of the seeds, as did cold stratification (Figure 4). The interpretation of these findings is that the effect of high temperatures on germination (dormancy release) appears to be closely related to the habitat environment. In general, heat treatment is known to be effective in breaking dormancy in some PY seeds [28,55]. Further, seeds exhibiting these features can become permeable at high temperatures and thus, germinate [28,56]. However, in this study, dormancy breakage in E. maculata was not related to permeability, and it was determined that dormancy was alleviated when the seeds recognized a suitable germination environment.
In natural habitats, E. maculata seeds germinate in spring and summer, and the seeds are dispersed in summer and early autumn, during which they are exposed to high temperatures on the hot ground surface and become dry. At the time of seed collection, the temperature of the soil surface in the habitat of E. maculata was very high, reaching 47.3 °C. Therefore, seeds dispersed in summer experienced a wider range of suitable temperatures for germination due to exposure to high temperatures, which then allowed for subsequent germination following rainfall. According to Moon et al. [57], the temperature during the non-rainfall period of summer in Korea reaches 30 °C or higher, while it was reported to be below 30 °C during the rainfall period. Therefore, considering the experimental results, it can be difficult for E. maculata seeds to germinate without high-temperature treatment. According to Suzuki and Teranishi [58], a study on the occurrence of E. maculata in natural habitats revealed that the highest number of seedlings are obtained in August. This finding is similar to the trend of increased germination observed in this study after the high-temperature treatment.
Conversely, without dormancy alleviation, seeds dispersed within the late summer to autumn period cannot germinate due to the low temperature of the habitat. These seeds exist in a dormant state in the soil seed bank and can only germinate after cold stratification during the winter, which widens their germination temperature range. Therefore, many seeds can germinate in the spring, implying that the seeds exist in the habitat in a CD state from fall to the following spring.
According to Baskin and Baskin [59], some summer annual non-dormant (ND) seeds enter the CD stage and repeat the ND and CD cycles until they eventually die or germinate. In the experiments, it was observed that the dormancy-breaking effect of the high-temperature treatment was maintained even after storage at low temperatures for two weeks (Figure 5). Furthermore, it appeared that E. maculata seeds do not re-enter the CD stage after transitioning to the ND stage. Therefore, the high-temperature treatment for dormancy breaking was found to be more efficient for cultivating and propagating E. maculata seeds than stratification. Additionally, the high-temperature treatment is fast and simple, and can promote germination even under common cultivation temperatures, providing economic benefits. Moreover, given that the seeds are not hydrated, they are not restricted by sowing time, are easy to handle, and can be stored.

5. Conclusions

In conclusion, the dormancy characteristics and release conditions of E. maculata have been examined through our research, and it has been confirmed that their dormancy is alleviated under conditions similar to their natural habitat. After collection, it has been found that E. maculata seeds can only germinate successfully under high-temperature conditions of 30 °C or above. However, this dormant state can be released through cold stratification, lowering the temperature required for germination. This indicates that E. maculata exhibits characteristics of conditional dormancy. In addition, it was confirmed that E. maculata seeds were released from dormancy under high temperatures and dry conditions similar to their native environment at the time of dispersal, and this state was maintained even after short-term cold storage. These results are meaningful in terms of understanding the strategies used by E. maculata to control germination in its native habitat. From another perspective, these findings have significant implications for plant production, conservation efforts, and the potential utilization of E. maculata in the bio-health industry.

Author Contributions

Conceptualization, K.P. and J.-S.C.; Data curation, K.P. and B.-K.J.; Investigation, H.L.; Methodology, K.P.; Project administration, J.-S.C.; Software, H.L.; Writing—original draft, K.P.; Writing—review and editing, B.-K.J. and J.-S.C. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by the National Research Foundation of Korea (NRF) funded by the Korean Government (MSIT), grant number 2021R1G1A1007156, and the Project to foster wide-area cooperative industries, grant number P0014701, from the Ministry of Trade, Industry, and Energy.

Data Availability Statement

The data presented in this study are available on request from the corresponding author.

Conflicts of Interest

The authors declare no conflict of interest.

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Figure 1. Observation of the morphological characteristics of Euphorbia maculata seeds using a stereo microscope (A–C) and scanning electron microscope (D–F). Seed outer (A) and inner (B) structures. Seed mucilage after water absorption is stained with Congo red (C). Microstructure of the seed coat surface (D). change in seed coat structure before (E) and after (F) water absorption. Bar size (A,B) 0.5 mm, (C) 1 mm, (D) 100 μm, (E,F) 20 μm.
Figure 1. Observation of the morphological characteristics of Euphorbia maculata seeds using a stereo microscope (A–C) and scanning electron microscope (D–F). Seed outer (A) and inner (B) structures. Seed mucilage after water absorption is stained with Congo red (C). Microstructure of the seed coat surface (D). change in seed coat structure before (E) and after (F) water absorption. Bar size (A,B) 0.5 mm, (C) 1 mm, (D) 100 μm, (E,F) 20 μm.
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Figure 2. Final germination of Euphorbia maculata seeds according to different sowing temperatures after collection. The gray and pattern columns represent light and dark conditions, respectively. Different upper and lowercase letters indicate significant differences based on Tukey’s honestly significant difference (HSD) test (p < 0.05) under light and dark conditions, respectively. In the light condition, uppercase letters represent groups with significantly different germination percentages, while in the dark condition, lowercase letters represent groups with significantly different germination percentages.
Figure 2. Final germination of Euphorbia maculata seeds according to different sowing temperatures after collection. The gray and pattern columns represent light and dark conditions, respectively. Different upper and lowercase letters indicate significant differences based on Tukey’s honestly significant difference (HSD) test (p < 0.05) under light and dark conditions, respectively. In the light condition, uppercase letters represent groups with significantly different germination percentages, while in the dark condition, lowercase letters represent groups with significantly different germination percentages.
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Figure 3. Final germination of Euphorbia maculata seeds at different temperatures after stratification treatment. (A) Cold stratification, (B) warm stratification. Gray and pattern columns represent the light and dark conditions, respectively. Different upper and lowercase letters indicate significant differences based on Tukey’s HSD test (p < 0.05) under light and dark conditions, respectively. In the light condition, uppercase letters represent groups with significantly different germination percentage, while in the dark condition, lowercase letters represent groups with significantly different germination percentage.
Figure 3. Final germination of Euphorbia maculata seeds at different temperatures after stratification treatment. (A) Cold stratification, (B) warm stratification. Gray and pattern columns represent the light and dark conditions, respectively. Different upper and lowercase letters indicate significant differences based on Tukey’s HSD test (p < 0.05) under light and dark conditions, respectively. In the light condition, uppercase letters represent groups with significantly different germination percentage, while in the dark condition, lowercase letters represent groups with significantly different germination percentage.
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Figure 4. Percent germination at each sowing temperature of Euphorbia maculata seeds treated at different high temperatures and for different durations. (A) 25, (B) 25/15, (C) 35 °C. Non, non-treated seeds. Different letters indicate significant differences based on Tukey’s HSD test (p < 0.05).
Figure 4. Percent germination at each sowing temperature of Euphorbia maculata seeds treated at different high temperatures and for different durations. (A) 25, (B) 25/15, (C) 35 °C. Non, non-treated seeds. Different letters indicate significant differences based on Tukey’s HSD test (p < 0.05).
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Figure 5. Percent germination of Euphorbia maculata seeds sown at 25/15 °C after storage at 4 °C for different durations following heat treatment.
Figure 5. Percent germination of Euphorbia maculata seeds sown at 25/15 °C after storage at 4 °C for different durations following heat treatment.
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Table 1. Euphorbia maculata seed characteristics in this study.
Table 1. Euphorbia maculata seed characteristics in this study.
Length (mm)Width (mm)Weight 1 (g)E:S 2 RatioViability (%)
0.855 ± 0.012 0.505 ± 0.0050.112 ± 0.0030.84 ± 0.01100
1 weight of 1000 seeds, 2 embryo to seed length.
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Park, K.; Lee, H.; Jang, B.-K.; Cho, J.-S. Dormancy Characteristics of Euphorbia maculata L. Seeds and Strategies for Their Effective Germination. Horticulturae 2023, 9, 990. https://doi.org/10.3390/horticulturae9090990

AMA Style

Park K, Lee H, Jang B-K, Cho J-S. Dormancy Characteristics of Euphorbia maculata L. Seeds and Strategies for Their Effective Germination. Horticulturae. 2023; 9(9):990. https://doi.org/10.3390/horticulturae9090990

Chicago/Turabian Style

Park, Kyungtae, Hamin Lee, Bo-Kook Jang, and Ju-Sung Cho. 2023. "Dormancy Characteristics of Euphorbia maculata L. Seeds and Strategies for Their Effective Germination" Horticulturae 9, no. 9: 990. https://doi.org/10.3390/horticulturae9090990

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