• Molecules and Cells
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• v.41 no.4
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• pp.311-319
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• 2018

The gaseous hormone ethylene influences many aspects of plant growth, development, and responses to a variety of stresses. The biosynthesis of ethylene is tightly regulated by various internal and external stimuli, and the primary target of the regulation is the enzyme 1-aminocyclopropane-1-carboxylic acid (ACC) synthase (ACS), which catalyzes the rate-limiting step of ethylene biosynthesis. We have previously demonstrated that the regulation of ethylene biosynthesis is a common feature of most of the phytohormones in etiolated Arabidopsis seedlings via the modulation of the protein stability of ACS. Here, we show that various phytohormones also regulate ethylene biosynthesis from etiolated rice seedlings in a similar manner to those in Arabidopsis. Cytokinin, brassinosteroids, and gibberellic acid increase ethylene biosynthesis without changing the transcript levels of neither OsACS nor ACC oxidases (OsACO), a family of enzymes catalyzing the final step of the ethylene biosynthetic pathway. Likewise, salicylic acid and abscisic acid do not alter the gene expression of OsACS, but both hormones downregulate the transcript levels of a subset of ACO genes, resulting in a decrease in ethylene biosynthesis. In addition, we show that the treatment of the phytohormones results in distinct etiolated seedling phenotypes, some of which resemble ethylene-responsive phenotypes, while others display ethylene-independent morphologies, indicating a complicated hormone crosstalk in rice. Together, our study brings a new insight into crosstalk between ethylene biosynthesis and other phytohormones, and provides evidence that rice ethylene biosynthesis could be regulated by the post-transcriptional regulation of ACS proteins.

• The Plant Pathology Journal
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• v.25 no.1
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• pp.95-98
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• 2009

The incidence and occurrence of virus infecting paprika (Capsicum annuum var. grossum) in Jeonnam province, the main areas of cultivation in Korea is undetermined. In this study, a total of 1,020 samples with virus-like symptoms were collected in Jeonnam province during summer season for 3 consecutive years (2002-2005) and were tested using enzyme linked immunosorbent assay (ELISA). Results showed that Pepper mottle virus (PepMoV), Broad bean wilt virus (BBWV), and Cucumber mosaic virus (CMV) were found to be the most prevalent viruses with a 3-year average percent incidence of 41.3, 19.8, and 4.4 respectively. Mixed infection with more than two viruses was also found with 3.5%, 17.0%, and 8.3%, respectively. Symptoms of these virus diseases were not evident at the seedling stage but slowly appeared at the transplanting stage and increased to the middle stage (4-5 months after transplanting) during the 3-year cultivation periods. Symptom appearance of infected plants however varied largely with transplanting time. Those plants transplanted from November to January were found to be infected with viruses in June, whereas symptoms appeared with in a month those plants transplanted from June to August. There were differences in the virus incidence from primary factor such as district, type of green house and variety, but these were not statistically significant (data not shown). Recommended control measures of paprika against these viruses is also discussed in this paper.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.1
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• pp.51-58
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• 2012

Salinity is one of the most relevant abiotic factor limiting crop yield and its net primary productivity. In addition, salinity induces an increased stress ethylene synthesis in plants which, in turn, exacerbate the responses to the stressor. Bacterial single or co-inoculation effect was tested using previously characterized plant growth promoting (PGP) bacteria Brevibacterium iodinum RS16 and Methylobacterium oryzae CBMB20 on maize and sorghum-sudan grass hybrid under different concentrations of NaCl. Non-inoculated maize and sorghum-sudangrass hybrid showed 33.4% and 20.0% reduction in seed germination under highest NaCl (150 mM) level tested. However, under the same NaCl concentration, co-inoculation with B. iodinum RS16 and M. oryzae CBMB20 PGP strains increased the seed germination in maize (16.7%) and sorghum-sudangrass hybrid (4.4%). In Gnotobiotic growth pouch experiments conducted for maize and sorghum-sudangrass hybrid, co-inoculation of PGP B. iodinum RS16 and M. oryzae CBMB20 mitigated the salinity stress and promoted root length by 22.9% and 29.7%, respectively. Thus the results of this study could help in development of potential bioinoculants that may be suitable for crop production under saline conditions.

• Korean Journal of Medicinal Crop Science
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• v.12 no.6
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• pp.473-477
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• 2004

Wasabis (Wasabia japonica Matsum.) have been used as a spice with its petioles and rhizomes, but the production of its rhizomes in upland cultivation was very difficult for the severe damage of rotting disease during summer season. This experiment was carried out to increase the yield of marketable rhizome in wasabi when cultured in upland. Seedlings were raised in sub-alpine area for 7 and 12 months and then transplanted to experimental area on Sept. 20 and the yield was investigated on May 12 of the next year. The marketable rhizome(above 40g/plant) was produced in seedlings raised for 7 months. Production rate of marketable rhizome was 13.3% and total yield was 72.9 kg/10a. The content of allylisothiocyanate in rhizome of upland wasabi was 0.777 mg/g and its content was equal to wasabi cultured in water condition for 18 months. These results suggested that the upland cultivation of wasabi seedlings raised in sub-alpine area for 7 months was possible to product marketable rhizome.

• Korean Journal of Soil Science and Fertilizer
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• v.37 no.1
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• pp.25-30
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• 2004

Rice seedlings were used to examine the effect of UV-B radiation on leaf elongation and development. Leaf elongation in both rice seedlings showed differently depending on each leaf age. UV-B radiation strongly reduced leaf elongation, 58-66% compared to without UV-B radiation, of two rice seedlings, therefore, those seedlings could not grow further. Both control and plants grown under UV-B regime showed a diurnial fluctuation in growth rate, showing maximum growth during the light period and minimum during the dark period. Leaf growth at the third leaf stage by UV-B treatment was considerably reduced by 1.7-fold than the control whereas at the fifth leaf stage was not changed. Hydrogen peroxide was considerably increased in the second phase of UV-B-induced response as catalase and peroxidase are deactivated with an increase of UV-B radiation.

• Korean Journal of Environmental Agriculture
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• v.17 no.4
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• pp.358-361
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• 1998

This study was carried out to develop a short term hardening method of tree seedlings of Rhus chinensis Mill., Evodia daniellii Hemsley and Parthenocissus tricuspidata(Sieb. et Zucc.) Planck for afforestation on a concave and a crack of cut-rock slope. The seedlings were grown in a cylinder shaped pot made of polyvinyl net with the soil media of peatmoss, vermiculite, clay, compost, fertilizer, and absorbant(40:25:19:15:1:0.1, v:v). They were cultivated in a greenhouse for four months and in field condition for two months. During the last three months of the growing period the seedlings were hardened by periodic desiccation and irrigation in 4 to 10 days interval. The hardened seedlings showed lower leaf water potential, higher leaf osmotic pressure, and lower T/R ratio than those before the hardening. The hardened seedlings survived well on the soil medium in the concave of cut-rock slope.

• Horticultural Science & Technology
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• v.29 no.6
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• pp.641-644
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• 2011

A new standard red color gerbera (Gerbera hybrida Hort.) 'Red Auction' was developed from a cross of '01-120-195' and 'Misty red' followed by seedling and line selections at the Flower Research Institute, Gyeongsangnam-do Agricultural Research & Extension Services (ARES) in 2008. Characteristics trials were conducted three times from 2006 to 2008. 'Red Auction' has semi-double type in good harmony with red color (RHS 45-A) ray floret and a good stable flower shape and strong peduncle. Its vase life was 11.3 days. The average yield of 'Red Auction' was 48.8 flowers per plant a year in greenhouse yield trials carried out from 2006 to 2008. This cultivar registered for commercialization in 2010.

• Journal of Microbiology and Biotechnology
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• v.24 no.8
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• pp.1015-1025
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• 2014

Microorganisms that live in the rhizosphere play a pivotal role in the functioning and maintenance of soil ecosystems. The study of rhizospheric cyanobacteria has been hampered by the difficulty to culture and maintain them in the laboratory. The present work investigated the production of the plant hormone indole-3-acetic acid (IAA) and the potential of biofilm formation on the rhizoplane of pea plants by two cyanobacterial strains, isolated from rice rhizosphere. The unicellular cyanobacteria Chroococcidiopsis sp. MMG-5 and Synechocystis sp. MMG-8 that were isolated from a rice rhizosphere, were investigated. Production of IAA by Chroococcidiopsis sp. MMG-5 and Synechocystis sp. MMG-8 was measured under experimental conditions (pH and light). The bioactivity of the cyanobacterial auxin was demonstrated through the alteration of the rooting pattern of Pisum sativum seedlings. The increase in the concentration of L-tryptophan and the time that this amino acid was present in the medium resulted in a significant enhancement of the synthesis of IAA (r > 0.900 at p = 0.01). There was also a significant correlation between the concentration of IAA in the supernatant of the cyanobacteria cultures and the root length and number of the pea seedlings. Observations made by confocal laser scanning microscopy revealed the presence of cyanobacteria on the surface of the roots and also provided evidence for the penetration of the cyanobacteria in the endorhizosphere. We show that the synthesis of IAA by Chroococcidiopsis sp. MMG-5 and Synechocystis sp. MMG-8 occurs under different environmental conditions and that the auxin is important for the development of the seedling roots and for establishing an intimate symbiosis between cyanobacteria and host plants.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.1
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• pp.132-138
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• 1997

In order to obtain the basic information for seedling production of surf clam, Spisula sachalinensis, annual reproductive cycle was investigated from March 1994 to May 1995. S. sachalinensis was dioecious. The gonads are located between the digestive diverticula and muscle tissue of the foot. The condition factor was reached its maximum (0.19) in June, and then decreased to 0.16 in July. In November, the value was the lowest and then increased slowly. The age and minimum size for sexual maturation were 2 years old and about 50 mm in shell length, respectively. However, less than $10\%$ of sexually undifferentiated individuals were larger than 80 mm in shell length. On the other hand, the size of mature oocytes was ranged to $50\~60{\mu}m$ in diameter and testis-ova was observed in testis of the mature stage. Annual reproductive cycle could be classified into five successive stages : multiplicative (October to January), growing (February to April), mature (April to June), spawning (June and July) and degenerative and resting (August and September) stages.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.10a
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• pp.86-86
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• 2018

This study was conducted to investigate the effects of modified drum priming and 24-Epibrassinolide (24-EBL) treatment to improve the seed quality for export. 40, 50 and 60% seed moisture content (SMC) of hydrated seeds were incubated for 16 and 24 h in a container with a relative humidity of 99% at 26 rpm for a modified drum priming treatment. The treated seeds were sown at $20^{\circ}C$ and $30^{\circ}C$ (12/12h, light/dark) with four replications of 25 seeds on pleated paper. The seeds were hydrated with water or 24-EBL solutions of $10^{-7}$, $10^{-8}$ and $10^{-9}M$, respectively. The germination of the modified drum primed seeds (24 h incubation after 60% SMC hydration) improved to 1.6 days mean germination time (MGT) and $46%{\cdot}day^{-1}$ germination rate (GR), while the untreated seeds showed 2.1 days MGT and $28%{\cdot}day^{-1}$ GR. The modified drum priming (60% SMC and 24 h incubation with $10^{-9}M$ 24-EBL) showed improved results in MGT (1.8 days) and GR (55%) at $20^{\circ}C$, whereas untreated seeds showed 2.3 days MGT and 44% GR. Under $30^{\circ}C$, germination of modified drum primed seeds was significantly improved in GP (80%), GR ($31%{\cdot}day^{-1}$), HS (55%) and MGT (3.3 days), however, untreated seeds showed decreased GP (27%), GR ($22%{\cdot}day^{-1}$), HS (55%) and MGT (4.8 days). This study showed that the germination of lettuce seeds is enhanced by 24 h drum incubation with 24-EBL and this method can be used effectively to achieve the benefits of early germination and uniform seedling development. In addition, these treatments circumvent thermo-dormancy of lettuce seed and have a possibility of high-quality and environment-friendly seed processing.