• Journal of Environmental Science International
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• v.30 no.1
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• pp.77-85
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• 2021

This study was carried out to establish optimal conditions for breaking dormancy of Agastache rugosa O. Kuntze seeds. A series of experiments according to seed maturity and treatment with plant growth regulators were performed to improve germination percentage and synchronize germination of the seeds. In addition, it was conducted to test whether the useful effect of seed treatment before sowing leads to healthy seedling and early vigorous growth. The average seed size was 1.85 mm (length) × 0.82 mm(width). The seed size was much smaller than other vegetable seeds. Seeds colorappeared dark brown, the shape of the seeds was oval and the weight of 1,000seeds was 352.8 mg. The optimum germination temperature was 22℃. Light exposure during germination did not affect germination promotion, suggesting that A. rugosa seeds are a kind of dark germinating seeds. Seed dormancy lasted for 40 days after harvesting, and GA3 treatment of dormant seeds could break dormancy. There were significant differences in germination percentage and rate according to the maturity of seeds. The germination percentage of mature seeds was 10 - 18% higher than that of immature seeds, and germination rate was 2 days faster. GA3 treatment during growth regulator treatment improved germinability, but BAP or ethephone treatment did not. The optimal growth regulator concentration of for germination was the combination treatment of 100 mM GA3 ＋ 100 mM BAP.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.4
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• pp.297-303
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• 1993

Seedling emergence and .stand establishment in dry-seeded rice is unstable at present due to deep seeding, low temperature at seeding time, excessive drought or raining etc. This experiment was conducted to elucidate the effect of gibberellic acid(GA$_3$) on the seedling emergence and growth in dry-seeded rice. GA$_3$, IBA and Metalaxyl were treated by seed-soaking or-spray. Hwaseongbyeo, a japonica rice, was used. The seed-soaking treatment with GA$_3$ significantly increased the seedling emergence and plant height as compared with untreated seed. However, no difference was observed in IBA and Metalaxyl treatment. The optimum concentration of GA$_3$ to promote the seedling emergence and growth in dry-seeded rice was about 100ppm for seed-soaking and about 200ppm for seed-spray treatment. The seed-spray treatment of GA$_3$ with 200ppm promoted earlier and faster seedling emergence and elongated seedling height as compared with untreated seed.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.284-284
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• 2022

The overall effects of gibberellic acid (GA3) with NaCl on different rice genotypes are inadequately understood. The present study determines the effect of different GA3 concentrations on the morphophysiological, molecular and biochemical effects of 120 mM NaCl salt stress in rice seedlings. Salt stress reduced germination percentages and seedling growth and decreased bioactive GA content. It also downregulated the relative expression of a-amylase-related genes - OsAmy1A, OsAmy1C, and OsAmy3C in the salt-sensitive IR28 cultivar. Salt stress differentially regulated the expression of GA biosynthetic genes. Salt stress increased antioxidant activity in all rice genotypes tested, except in IR28. GA3 (50 and 100 µM) mitigates the effect of salt stress, rescuing seed germination and growth attributes. GA3 significantly increased bioactive GA content in Nagdong and pokkali (50 µM) and Cheongcheong and IR28 (100 µM) cultivars. The a-amylase genes were also significantly upregulated by GA3. Similarly, GA3 upregulated OsGA2oxl and OsGA2ox9 expression in the Cheongcheong and salt-sensitive IR28 cultivars. The present study demonstrated that salt stress inactivates bioactive GA - inhibiting germination and seedlings growth - and decreases bioactive GA content and GSH activity in IR28 and Pokkali cultivars. Further, GA3 significantly reversed the effects of 120 mM NaCl salt stress in different rice genotypes. The current study also suggests if we know the coastal area water NaCl concentration we can apply the exogenous GA3 accordingly. Thus, we would be able to grow rice cultivars near the coastal area and reduce the rice damage by salinity.

• Horticultural Science & Technology
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• v.29 no.3
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• pp.165-171
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• 2011

Plant growth retardants reduce the plant height by inhibiting stem elongation in Lilium davuricum. To investigate the plant hormones related to stem elongation, we sprayed 50 $mg{\cdot}L^{-1}$ diniconazole to young plants of L. davuricum and quantified the contents of endogenous gibberellic acids (GA) and abscisic acid (ABA). In GA biosynthesis, L. davuricum had not only the early C-13 hydroxylation ($GA_{19}{\rightarrow}GA_{20}{\rightarrow}GA_1$) pathway resulting in $GA_1$ as the active form but also the non C-13 hydroxylation (NCH, $GA_{12}{\rightarrow}GA_{24}{\rightarrow}GA_9{\rightarrow}GA_4$) with $GA_4$ as the active form. However, the main pathway was NCH because $GA_4$ concentration of 55 $ng{\cdot}g^{-1}$ dry wt was much higher than $GA_1$ content of 0.23 $ng{\cdot}g^{-1}$ dry wt in control plant. Diniconazole inhibited GA biosynthesis through NCH pathway from its early stage. $GA_{12}$ content decreased by diniconazole up to 6% level of that of control and this effect continued to $GA_4$. Diniconazole reduced $GA_{12}$ content by 12.7 $ng{\cdot}g^{-1}$ dry wt, whereas that of control plant was 213.8 $ng{\cdot}g^{-1}$ dry wt. ABA content decreased up to one third of control by diniconazole application. From the contents of endogenous $GA_4$, $GA_1$, and ABA in this study, we could conclude that diniconazole reduces the plant height by inhibiting $GA_4$ biosynthesis in L. davuricum.

• Journal of Korean Society of Forest Science
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• v.110 no.1
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• pp.53-63
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• 2021

Sophora koreensis Nakai is an indigenous plant in Koreawith a restricted natural range, part of which is in Gangwon province. The species is known to contain phytochemicals that have beneficial effects on human health, and it is economically important in bioindustry. Because of the limited number of plants in a small range of habitats, the mass-propagation method should be developed for use and conservation. In vitro tissue culture is a reliable method in terms of mass propagation from selected clones of the species. We investigated the optimal conditions of the medium in this process, especially focusing on the concentrations of plant growth regulators(PGRs) in the culture of stem-containing axillary buds. Three statistical methods, i.e., ANOVA, response surface method(RSM), and fuzzy clustering were used to analyze the plant growth, number of shoots induced, and shoot length with various combinations of PGRs. Results from the RSM differed from those of the other two methods; thus, the method was not suitable. ANOVA and fuzzy clustering showed similar results. However, more accurate results were obtained using fuzzy clustering because it provided a probability for each treatment. On the basis of the fuzzy clustering analysis, stem tissue produced the greatest number of shoots(11.03 per explant; 63.33%) on a medium supplemented with 5-��M 6-benzylaminopurine and 2.5-��M thidiazuron(TDZ). Proliferation of shoots(2.18 ± 0.21 cm, 63.33%) was attained on a medium supplemented with 2.5-��M BA, 2.5-��M TDZ, and 2.5-��M gibberellic acid.

• Journal of Plant Biotechnology
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• v.44 no.1
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• pp.69-75
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• 2017

Dormancy-associated protein (DRM) is involved in the dormancy physiology of plants and is conserved in almost all plant species. Recent studies found that DRM genes are involved in the abiotic stress response, and characterization studies of these genes have been conducted in several plants. However, few studies have focused on DRM genes in woody plants. Therefore, in this study, cDNA coding for DRM (PagDRM1) was isolated from poplar (Populus alba ${\times}$ P. glandulosa), and its structure and expression characteristics were investigated. PagDRM1 encodes a putative protein composed of 123 amino acids, and the protein contains two conserved domains (Domain I and Domain II). PagDRM1 is present as one or two copies in the poplar genome. Its expression level was highest in the stem, followed by mature leaves, roots, and flowers. During the growth of cultured cells in suspension, PagDRM1 was highly expressed from the late-exponential phase to the stationary phase. In addition, PagDRM1 expression increased in response to drought, salt stress, and treatment with plant hormones (e.g., abscisic acid and gibberellic acid). Therefore, we suggested that PagDRM1 not only plays an important role in the induction of dormancy, but also contributes to stress tolerance in plants.

• Korean Journal of Medicinal Crop Science
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• v.8 no.1
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• pp.14-20
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• 2000

This experiment was conducted to investigate the effects of length of storage period under low temperature, $CO_2$ enrichment and addition of plant growth regulators in Murashige and Skoog medium on the plant regeneration of Korean ginseng (Panax ginseng C. A. Meyer). Seeds were treated for 60 and 80 days respectively under $5^{\circ}C$ environment. 2500ppm of $CO_2$ was enriched by ventilation. Three plant growth regulators added to the medium were Indolbutyric acid, Benzyladenin and Gibberellic acid (GA3). The result indicated that : The capacity of differentiation was higher in the aged cotyledons from the seeds treated for 80 days under low temperature condition than in those treated for 60 days. $CO_2$ enrichment had stimulating effects on the growth and development of shoot primordium significantly but less effects on the formation of adventitious buds. From one zygotic embryo hundreds of plantlets were differentiated. $CO_2$ enrichment had effects on the formation of both indirect somatic embryo and direct somatic embryo. Indirect somatic embryo showed little growth and differentiation, being undifferentiated vascular stele and epicotyl. Direct somatic embryos were formed on the epidermis of backside basal part of cotyledon. Those embryos developed to whole plant having latent bud.

• Korean Journal of Weed Science
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• v.6 no.1
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• pp.18-24
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• 1986

This study was conducted to determine the possible role of growth regulators and the effect of foliar part cutting on the tuber formation of C. serotinus. Foliar application of 6-benzylaminopurine (BA) increased tuber number and fresh weight of C. serotinus by an average of 24.7% and 32.4%, respectively, as compared with the untreated control. However, the tuberization of C. seratinus was inhibited by single treatment of abscisic acid (ABA) and gibberellic acid (GA) as the concentrations increased. As compared with the untreated control, BA at $10^{-4}$M and combination of BA $10^{-5}$ + GA $10^{-5}$M increased 31.8% and 53.7% of tuber number, respectively, but GA at $10^{-5}$M decreased tuber number by 21.9%. 15㎏/10a of nitrogen under three levels of BA resulted in the highest number of tuber formation of C. serotinus, an increase of 24.7% as compared with the untreated control. GA treated increased flowering of C. serotinus by an average of 4.8% based on the untreated control. Tuber number and fresh weight of C. serotinus was markedly inhibited as the number of cutting times increased. Three times cutting inhibited tuber number and fresh weight of C. serotinus by 76.1% and 96.6%, respectively, under nitrogen of 15kg per 10a as compared with the untreated control.

• Korean Journal of Weed Science
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• v.3 no.2
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• pp.137-142
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• 1983

The effects of various factors on germination of dormant Digitaria sanguinalis seeds were studied to obtain the basic informations on establishing an effective control method in upland crops. Germination of dormant seeds was most significantly promoted by light treatment, about 88-89%, and followed by the treatment of alternating temperatures (15 or 20$^{\circ}C$ to 35$^{\circ}C$), showing the similar effects like light. Removal of seed coats also increased germination of dormant seeds by 72%, next to the treatments of light and altering temperature. Potassium nitrate ($KNO_3$) at $10^{-2}M$ and concentrated sulfuric acid ($H_2SO_4$) treatment at the duration of 8 minutes resulted in 20% and 37.8% of germination of dormant seeds, respectively, which were significantly higher than that of the untreated control. Under the conditions of altering temperature, gibberellic acid (GA) at $10^{-3}M$ to $10^{-6}M$, benzylandenin (BA) at $10^{-4}$ to $10^{-7}M$ and their combination had no effect on breaking of dormant weed seeds, and instead inhibited the promotive effects induced by the alternating temperature. However, under the constant temperature at 35$^{\circ}C$ in dark, all these treatments increased germination as much as 20% over the untreated control.

• Korean Journal of Weed Science
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• v.6 no.2
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• pp.162-167
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• 1986

This experiment was conducted to determine the effect of light, organophosphorus compounds and plant growth regulators on phytotoxicity of pendimethalin (3,4-dimethyl-2,6-dinitro-N-1-ethyl propylamine) in rice (Oryza saliva L.). The phytotoxicity of pendimethalin on post-germination growth of rice was greatly reduced by light treatment. This effect resulted from photodecomposition of pendimethalin. Antidoting activity on phytotoxicity of pendimethalin varied with the kind of organophosphorus compounds used and the application time. The greatest antidoting effect was obtained from edifenphos (0-3thy1 S,S-diphenylphosphorothioate). However, the effect was not observed when edifenphos was applied prior to pendimethalin. There was no antidoting effect of indole acetic acid (IAA), gibberellic acid ($GA_3$) and kinetin used alone, but combinations of 3 ppmw IAA + either 3 or 5 ppmw $GA_3$ and 1 ppmw kinetin + 10 ppmw $GA_3$ reduced the phytotoxicity of pendimethalin.