• Horticultural Science & Technology
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• v.32 no.4
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• pp.550-557
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• 2014

Heloniopsis koreana and Heloniopsis tubiflora (Melanthiaceae) are endemic herbaceous species of the Korean Peninsula. The Melanthiaceae family has been described as having seeds with small, underdeveloped embryos at the time of dispersal, and morphological (MD) or morphophysiological dormancy (MPD). However, there are few reports on embryo growth, morphology, and seed germination in Heloniopsis species. The aims of this study were to investigate embryo growth and seed dormancy, and to determine the type of dormancy exhibited by these species. The effects of incubation temperatures, light conditions, and gibberellic acid ($GA_3$) on dormancy break and seed germination were tested. Freshly matured seeds of the two species had small embryos that occupied about 9-11% of the length of the endosperm, and which increased by more than 300% in length before radicle emergence, indicating that the embryos are underdeveloped at the time of dispersal. Embryos in the seeds grew under warm temperature regimes (between $25/15^{\circ}C$ and $30/20^{\circ}C$). $GA_3$ application (tested only in the light) overcame seed dormancy and promoted germination. Approximately 30% of the seeds of H. koreana and approximately 40% of the seeds of H. tubiflora germinated in suitable environmental conditions (light and temperature) within 4 weeks. Therefore, 30-40% of the seeds of the two species exhibited MD, and the rest of the seeds had non-deep simple MPD. Light was found to be one of the critical factors for germination because no seed of either of the two Heloniopsis species germinated under constant dark conditions, and thus, these species have the potential to form a persistent soil seed bank. Understanding these germination requirements will help in development of effective strategies to increase the establishment of seedlings in their native habitat.

• Horticultural Science & Technology
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• v.32 no.3
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• pp.310-317
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• 2014

This study was conducted to find basic information for the research of morphological dormancy in seeds of two genera (Heloniopsis and Thalictrum) native to Korea. Seeds of Heloniopsis koreana, Heloniopsis tubiflora, Thalictrum rochenbrunianum, Thalictrum uchiyamai, and Thalictrum coreanum were collected, and embryo morphology and seed germination were investigated. All seeds of five species had underdeveloped embryos which occupied about 10-20% of the full seed length at maturity. The seeds of H. koreana and H. tubiflora had rudimentary embryos. The seeds of T. rochenbrunianum, T. uchiyamai, and T. coreanum had intermediate type between rudimentary and linear embryo. The small embryos of all seeds of five species grew to a critical length before radicles emerge from the seeds. At 30 days after sowing, the seeds of H. koreana and H. tubiflora germinated to 22.7% and 40.7%, respectively. On the other hand, the seeds of T. rochenbrunianum, T. uchiyamai, and T. coreanum germinated to 12.5%, 3.3%, and 0%, respectively. If embryo growth and germination in seeds are completed in approximately 30 days, the seed are said to have morphological dormancy (MD). However, if the seeds require > 30 days for germination, they are considered to have morphophysiological dormancy (MPD). Thus, the seeds of H. koreana and H. tubiflora had about 78% and 60% MPD, respectively. On the other hand, the seeds of T. rochenbrunianum, T. uchiyamai, amd T. coreanum had about 87%, 96%, and 100% MPD, respectively. There was a different level of dormancy (MD and MPD) within the same seed population examined. Therefore, germination of the seeds was delayed due to the underdeveloped embryos. This result could contribute to determine morphological seed dormancy and germination mechanism in seeds of the Korean Peninsula.

• Korean Journal of Plant Resources
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• v.36 no.6
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• pp.580-587
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• 2023

Androsace septentrionalis is a grass species restricted to North Korea; however, it is at the brink of extinction due to habitat loss and environmental changes caused by natural disasters and anthropogenic activities. This study was conducted to characterize the dormancy conditions of A. septentrionalis in an effort to conserve this North Korean plant resource. For this purpose, the morphological characteristics and vigor of A. septentrionalis seeds were examined, and its germination characteristics under different temperature conditions (15/6℃ and 25/15℃ ), low-temperature stratification, and gibberellin (GA₃) treatment were determined. The results revealed that A. septentrionalis exhibits non-deep type morpho-physiological dormancy, and low-temperature stratification treatment was not effective in breaking the dormancy of A. septentrionalis seeds. Meanwhile, GA₃ treatment significantly increased the mean germination time, rate, and speed of the seeds. The optimal conditions for the germination of A. septentrionalis seeds were 25/15℃ fluctuating temperature and 500 mg·L¹ GA₃ treatment. The results of this study are useful for the mass propagation of A. septentrionalis.

• The Korean Journal of Zoology
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• v.32 no.1
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• pp.55-73
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• 1989

The effect of tryptophan or serotonin on the early stage of chick brain development has been morphologically investigated using an electron microscope. The electron micrographs of neural plate cells of 1-day chick embryo treated with tryptophan or serotonin showed irregularity, evagination and disruption of nuclear membrane and nuclear chromatin condenstation, nucleolar margination and segregation. Hypertrophy of stalks, vesicles and vaculoes were seen and dilated and disrupted rough endoplasmic reticulum and underdeveloped neurotubules were also observed. In mesenchyme cells of tryptophan or serotonin administered 18 hr embryo, irregular nuclear membrane, swollen mitochondria, dilated rough endoplasmic reticulum and very large yolk granules were observed. Furthermore, DNA, RNA and protein contents of the embryos treated with typtophan or serotonin were considerably lower than those of control group. The amount of tubulin of the experimental groups was also greatly lower than that of control, suggesting that the impairment of microtubule formation occurred. Tryptophan or serotonin administration might depress the biosynthesis, of nucleic acid and protein including some enzymes tested. It seems that the serotonin formed from exogeneous tryptophan might inhibit the degradation of yolk granule by feedback regulation mechanism so as to impair microtububle and microvilli formation followed by a malformation of chick embryos.

• Journal of Bio-Environment Control
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• v.28 no.4
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• pp.404-410
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• 2019

This study was performed to investigate the seed morphological characteristics and dormancy type of Adenophora triphylla var. japonica Hara that high valued medicinal crop and to select the disinfectants and light quality for germination rate improvement. The seed disinfection was carried out using distilled water (control), NaClO 4%, $H_2O_2$ 4%, and benomyl $500mg{\cdot}L^{-1}$. The light quality treatments were set to dark condition (control I), fluorescent lamp (control II), LEDs [red, blue, green, and combined RB LEDs (red:blue = 8:2, 6:4, 4:6, 2:8)] with a photoperiod of 12/12 (light/dark) and light intensity $150{\pm}10{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ photosynthetic photon flux density. Although the Adenophora triphylla var. japonica Hara seed was an underdeveloped embryo (E) and seed (S) with an embryo (E):seed (S) ratio of 0.4, it is germinated within 30 days, and seed moisture saturation was reached within 6 hours after immersion. After seed disinfection, the mold incidence rate was significantly inhibited, and the final germination rate was the highest at 87% in the benomyl seed disinfection. The final germination rate was the highest at 92% in the red light, and the mean daily germination was the lowest in the R2B8. Therefore, there is almost no dormancy in the Adenophora triphylla var. japonica Hara seed, and benomyl seed disinfectant and red light were effective in the improvement of germination rate. So it is considered to the high value of use for medicinal crop Adenophora triphylla var. japonica Hara cultivation.

• Journal of Korean Society of Forest Science
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• v.102 no.2
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• pp.204-209
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• 2013

This study was conducted to determine types of seed dormancy in Sambucus racemosa subsp. pendula (Nakai) H.I. Lim & C.S. Chang, an endemic tree species of Korea, whose seeds have been considered difficult to germinate. Seeds of S. racemosa subsp. pendula were stratified at 25/15 or $5^{\circ}C$ for 0, 6, or 12 weeks (wks) and incubated at 15/6, 20/10, 25/15, or $30/20^{\circ}C$ (12/12 h) under 14 h photoperiod. To determine the effect of $GA_3$ on seed germination of S. racemosa subsp. pendula, seeds were treated with 0, 500, or 1000 ppm $GA_3$ and then germinated at 25/15 or $5^{\circ}C$. The change in embryo length was investigated at 25/15 or $5^{\circ}C$. Seeds given 12 wks of cold stratification germinated to 33.4% at $15/6^{\circ}C$ and to 25.4% for seeds given 6 wks of warm stratification + 12 wks of cold stratification at $20/10^{\circ}C$. At $25/15^{\circ}C$, seeds given 12 wks of warm stratification + 6 wks of cold stratification germinated to 26.0%, and to 28.2% for seeds given 12 wks of warm stratification + 12 wks of cold stratification at $30/20^{\circ}C$. Warm stratification alone did not germinate seeds throughout the experiment, regardless of the thermoperiod. Linear embryos began to grow after 60 days of incubation at 25/15 or $5^{\circ}C$. The embryo length at day 69 increased from 1.4 mm to 1.50 or 1.62 mm at 25/15 or $5^{\circ}C$, respectively. Embryos of S. racemosa subsp. pendula seeds grew better at $5^{\circ}C$ than at $25/15^{\circ}C$. Gibberellin was effective to break seed dormancy of S. racemosa subsp. pendula. Seeds treated with 500 ppm $GA_3$ germinated up to 40.0% at $25/15^{\circ}C$ and to 62.7% for those treated with 100 ppm $GA_3$ at $5^{\circ}C$. With these results, seeds of S. racemosa subsp. pendula have both nondeep complex and intermediate complex morphophysiological dormancy.

• Korean Journal of Plant Tissue Culture
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• v.24 no.3
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• pp.167-173
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• 1997

The embryogenic callus (EC), from which somatic embryos could be induced, was compared with nonembryogenic callus(NE) to study the origin and features of totipotent cell in water dropwort (Oenanthe stolonifera DC). To induce and maintain of EC and the NE, meristematic stem and immature floret were inoculated in MS media supplemented with 1 mg/L 2,4-D, and with 2.5 mg/L NAA and 5mg/L BA, respectively, The EC was not induced from the NE even after subculturing in MS medium supplemented with 1 mg/L 2,4-D. Plantlets were not regenerated from the NE in hormone-free medium. In histochemical comparison of the EC with the NE by light microscopy, the EC had smaller cells in size, dense cytoplasm, and more starch granules of cells compared to the NE cells. The cell from the EC, as observed by transmission electron microscopy, had smaller vaculoes, well developed ribosomes, mitochondria, and endoplasmic reticulum, whereas the cells from the NE had larger vacuoles and underdeveloped organelles. In protein pattern from NE, EC and Somatic embryo (SE), as analyzed by SDS polyacrylamide gel electrophoresis, different proteins specific for tissue were observed: 17 and 28 KD for NE, 50, 52, 57, 66, 68 KD for EC and 20 KD for SE. DNA polymorphism was also observed between EC and NE as analyzed by RAPD (randomly amplified polymorphic DNA) method. The origin of totipotent stem cell and the relationship between irreversible genomic change arose in differentiation and the loss of totipotency in plant were discussed.

• Journal of Ecology and Environment
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• v.43 no.2
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• pp.254-262
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• 2019

Background: To exploit the ornamental and medicinal purposes of Lonicera harae Makino, L. subsessilis Rehder, L. praeflorens Batalin, and L. insularis Nakai, native to Korea, it is necessary to understand their seed ecology for propagation. In this study, we investigated the seed dormancy type and germination characteristics of seeds of the four Korean native Lonicera species. Results: The seeds of the four Lonicera species imbibed water readily, suggesting that the species do not have physical dormancy. Furthermore, the seeds exhibited underdeveloped embryos with only about 15-25% of the length of the seeds at dispersal. The embryos grew to the critical length with approximately 50-80% of the length of the seeds' development before radicle protrusion. Further, 94.4% and 61.1% of freshly matured seeds of L. insularis and L. harae germinated within 4 weeks after sowing at 15 ℃ and 20 ℃, respectively. Contrarily, L. praeflorens and L. subsessilis seeds did not germinate within 4 weeks under all temperature treatments. At 15 ℃, L. praeflorens seeds started to germinate from 5 weeks and the final germination rate was 51.1% at 13 weeks. At 15 ℃, L. subsessilis seeds started to germinate from 5 weeks after sowing and the final germination rate was 85.6% at 17 weeks after sowing. Embryo growth and germination of L. praeflorens and L. subsessilis occurred at a relatively high temperature (≥ 15 ℃). Conclusions: Overall, L. insularis seeds have only morphological dormancy. The seeds of L. harae have approximately 60% and 40% of morphological dormancy and morphophysiological dormancy, respectively. Contrarily, L. praeflorens and L. subsessilis exhibited non-deep simple-type morphophysiological dormancy that requires relatively high temperature (≥ 15 ℃) for embryo growth and dormancy breaking. The optimum temperature for the germination of seeds of L. insularis, L. harae, L. praeflorens, and L. subsessilis was 15 ℃, 20 ℃, 15 ℃, and 20 ℃, respectively. There was interspecific variation in seed dormancy and germination patterns in the four Lonicera species. The difference in these characteristics within the four Lonicera species could be useful for understanding the seed ecophysiological mechanisms of Lonicera species.

• Korean Journal of Plant Resources
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• v.37 no.1
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• pp.79-86
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• 2024

This study was conducted to determine the conditions for breaking dormancy in the seeds of the North Korean plant resource, Trollius macropetalus, and to investigate its germination characteristics. The morphological characteristics and viability of T. macropetalus seeds were examined. Germination characteristics were investigated based on temperature conditions (15/6℃ & 25/15℃), cold stratification treatment, and GA₃ treatment. The results showed that cold stratification treatment had no effect on breaking the dormancy of T. macropetalus. GA₃ treatment significantly increased the germination rate of T. macropetalus and also improved the mean germination days and germination speed. However, compared to the 15/6℃ condition, the effectiveness of GA₃ treatment for T. macropetalus decreased under the 25/15℃ condition. It was determined that T. macropetalus have a nondeep-type morpho-physiological dormancy. The most effective conditions for breaking dormancy were found to be the 15/6℃ temperature condition and GA₃ treatment at 500 mg·L^-1. The findings of this study are expected to provide valuable information for the mass propagation of T. macropetalus, which has potential applications in landscaping and pharmaceutical materials.