• Korean Journal of Plant Tissue Culture
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• v.25 no.2
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• pp.99-102
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• 1998

The most effective medium for shoot initiation in vitro of peach cv. Baekmijosaeng, Yumyeong and nectarine cv. Cheonhong was Quoirin and Lepoivre medium(LP). 20 g/L and 30 g/L sorbitol as carbon source were effective for shoot proliferation of cv. Baekmijosaeng. Addition of 500 mg/L lacto albumin enzymatic hydrolysate(LH) increased shoot number per explant of cv. Baekmijosaeng peach. Removing the apical meristem and horizontal placing of explants on the medium increased cv. Baekmijosaeng shoot.

• Molecules and Cells
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• v.38 no.3
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• pp.243-250
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• 2015

Patterning of the polar axis during the early leaf developmental stage is established by cell-to-cell communication between the shoot apical meristem (SAM) and the leaf primordia. In a previous study, we showed that the DRL1 gene, which encodes a homolog of the Elongator-associated protein KTI12 of yeast, acts as a positive regulator of adaxial leaf patterning and shoot meristem activity. To determine the evolutionally conserved functions of DRL1, we performed a comparison of the deduced amino acid sequence of DRL1 and its yeast homolog, KTI12, and found that while overall homology was low, well-conserved domains were presented. DRL1 contained two conserved plant-specific domains. Expression of the DRL1 gene in a yeast KTI12-deficient yeast mutant suppressed the growth retardation phenotype, but did not rescue the caffeine sensitivity, indicating that the role of Arabidopsis Elongator-associated protein is partially conserved with yeast KTI12, but may have changed between yeast and plants in response to caffeine during the course of evolution. In addition, elevated expression of DRL1 gene triggered zymocin sensitivity, while overexpression of KTI12 maintained zymocin resistance, indicating that the function of Arabidopsis DRL1 may not overlap with yeast KTI12 with regards to toxin sensitivity. In this study, expression analysis showed that class-I KNOX genes were downregulated in the shoot apex, and that YAB and KAN were upregulated in leaves of the Arabidopsis drl1- 101 mutant. Our results provide insight into the communication network between the SAM and leaf primordia required for the establishment of leaf polarity by mediating histone acetylation or through other mechanisms.

• Journal of Life Science
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• v.25 no.10
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• pp.1091-1097
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• 2015

We have isolated and characterized an ascorbate peroxidase (APx) gene, OsAPx1 from rice. Northern and Western blot analyses indicated that at young seedling stage, OsAPx1 mRNA was expressed highly in root, shoot apical meristem (SAM) and leaf sheath than leaf. In mature plant, OsAPx1 gene expressed highly in root, stem and flower but weakly in leaf. OsAPx1 gene and protein expression level was induced in leaves inoculated with Magnaporthe oryzae (M. oryzae) and Xanthomonas oryzae pv. oryzae (Xoo). Phytohormones treatment showed that OsAPx1 was up-regulated by jasmonic acid (JA), but was down regulated by ABA and SA co-treatments with JA, resulting that they have antagonistic effect on pathogen responsive OsAPx1 expression. Phylogenetic analysis illustrated that Arabidopsis AtAPx1 has a close relationship with OsAPx1. In AtAPx1 knock out lines, the accumulation of O₂^- and H₂O₂ are all highly detected than wild type, revealing that the high concentration of exogenous H₂O₂ cause the intercellular superoxide anion and hydrogen peroxide accumulation in AtAPx1 knockout plant. These results suggested that OsAPx1 gene may be associated with the pathogen defense cascades as the mediator for balancing redox state by acting ROS scavenger and is associated with response to the pathogen defense via Jasmonic acid signaling pathway.

• Journal of Life Science
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• v.20 no.2
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• pp.298-303
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• 2010

In this work, the effects of $Cs^+$ on root growth of 2-day-old maize seedlings were scrutinized. CsCl (5 mM - 30 mM) decreased the fresh weight of the primary root and of the shoot above the coleoptilar node. The elongation growth of the primary root was also inhibited by CsCl. The CsCl-inhibited growth was partially restored by 60 mM KCl. Lineweaver-Burk plot of the reaction in the presence and absence of 60 mM KCl displayed competitive interaction of CsCl (at higher than 10 mM). However, the Reversal of the inhibition by 60 mM KCl did not follow the competitive relationship with 5 mM CsCl, indicating the presence of differential mechanisms of $K^+$ influence depending on the concentration of CsCl. The differential effects of CsCl dependent on the concentrations were also observed in the CsCl-evoked radial expansion of the subapical region of the root. In spite of the decrease in length of the root, shrinkage of the root apical meristem was not observed. CsCl above 10 mM induced the expression of ZmKUP1, indicating functional deficiency of $K^+$ due to competition with Cs. However, the expression of ZmKUP1 by 5 mM CsCl was unclear. Conclusively, exogenously applied $Cs^+$ decreased root elongation and fresh weight and caused radial expansion of the subapical region of the primary root in 2-day-old maize seedlings by complex mechanisms including competitive and noncompetitive interactions with $K^+$. Because the shrinkage of the root apical meristem was not observed, it is concluded that the effects of CsCl on maize root growth was mainly related to cell expansion.

• Journal of Plant Biotechnology
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• v.44 no.4
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• pp.379-387
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• 2017

Various sizes (0.2 ~ 1.2 mm) and developmental stages (referred to as Stage 1 ~ 3) of apical and lateral meristems were excised, together or separately, directly from dormant buds of apple 'Hongro'. They were mixed infected by Apple scar skin viroid (ASSVd), Apple chlorotic leaf spot virus (ACLSV), Apple stem pitting virus (ASPV) and Apple stem grooving virus (ASGV), which are major viruses attacking apples. A total of 31 callus lines (> 10 mm in diameter) were obtained by culturing the explants on Murashige and Skoog (MS) medium supplemented with 3% sucrose, 3.0 mg/L benzyladenine (BA) and 0.1 mg/L indole-3-butyric acid (IBA), and they were subjected to RT-PCR analysis for virus detection. A high rate of virus elimination (expressed as the percentage of calli that did not amplify during RT-PCR, i.e., RT-PCR negative calli per total number of calli obtained) was achieved for ACLSV (100%), ASSVd (93.7%), and ASPV (93.7%), whereas it was only 25.8% for ASGV. ASPV was detected in the presence of 2 ~ 3 bracts. Simultaneous virus elimination of ASSVd, ASPV, ACLSV, and ASGV occurred during the meristem culture, in which the early stages of the dormant buds (Stage 1) were used, because ASGV was mostly eliminated during that stage. The results of the present study will be valuable for the production of virus-free apple trees.

• Korean Journal of Plant Tissue Culture
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• v.24 no.1
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• pp.43-48
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• 1997

Apical meristems of Wasabia japonica were cultured on Murashige and Skoog's medium supplemented with cytokinins alone or together with 1.0 mg/L IAA. Shoot initials could be induced from leaf primordia on apical meristems. Calli and roots were formed on the medium containing cytokinins and 1.0 mg/L IAA in combination after 30 days of culture, but there were no callus proliferation. Shoot organogenesis began after 60 days of culture and these small shoots elongated when transferred to a medium containing 1.0 mg/L BA or kinetin. Shoots were formed directly without callus induction from apical meristems all the explants on the medium containing cytokinins variously, and most of the shoots proliferated multiple shoots which could be divided to obtain plantlets. Shoot multiplication rate in response to cytokinins was best on the medium containing 1.0 mg/L BA or 2.0 mg/L zeatin. Divided plantlets rooted well on MS medium containing 0.01 mg/L IBA after 15~30 days of subculture and the rooted plantlets developed into whole plants with multiple shoots. After rooting, the regenerated plants were washed and transferred to the pots containing sterilized soil.

• Korean Journal of Plant Resources
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• v.16 no.1
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• pp.34-39
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• 2003

Corm apical meristem cultures of thirteen glasshouse freesia cultivars were tested to investigate the possibility of micropropagation using MS basal medium supplemented with 2,4-D, NAA(0.1, 0.5, 1.0mg/L, respectively) and BA (0.5∼2.0mg/L). The majority of the tested cultivars could be induced callus and shoot buds in all culture condition. The combinations of NAA and BA appeared superior to that of 2,4-D and BA depending on cultivars for callus induction and shoot formation. Among the cultivars, 'Golden Yellow' showed the highest regeneration capacity on MS media with 0.5mg/L NAA and 1.0 mg/L BA. The highest percentage of regeneration and the greatest number of shoot from calli were obtained through successive subculture on MS medium supplimented with 0.5mg/L BA. In that condition, more than 60 ％ shoot regeneration and average of 25.1 shoots per explant was achieved. Transformed shoots on half-strength MS medium without plant growth regulators rooted easily.

• Korean Journal of Plant Resources
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• v.19 no.2
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• pp.360-364
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• 2006

The gametophytes of Cyrtomium falcatum and Cyrtomium caryoptideum var. coreanum arising from spores were mechanically homogenized and cultured In vitro, to study their gametophyte ontogeny and sporophyte development. Homogenized gametophytic tissues formed as one-dimensional filaments after 2 weeks in culture and then glowed into blanched gamatophytes after 4 weeks. After 6 weeks, which were developed to two dimensional plates with apical notch and meristem in central zone. After 8 weeks in culture, apomictic buds were formed on the midribs without archegonium formation and these buds developed to sporophytes after 10 weeks in culture. Flow cytometric analysis of gametophytes and apomictic sporophytes revealed that both forms had the same ploidy level in C. falcatum and C. caryoptideum vu. coreanum, respectively. This is to certify that C. caryoptideum var. coreanum was an apomictic fern as well as C. falcatum.

• Journal of Integrative Natural Science
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• v.1 no.3
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• pp.234-246
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• 2008

Korean terminologies on stem structures in plant morphology, written incorrectly in many books, were analysed to propose accurately expressed terminologies. 35 books in areas such as general biology, plant biology, plant morphology, and biological dictionaries and glossaries were selected to analyse the accuracy of the terminologies for seed structures, e.g., shoot and shoot system, rhizome, apical dominance, anticlinal and periclinal divisions, and intercalary and lateral meristems. The definition and etymology of the terminologies were traced in 4 textbooks of plant anatomy and 2 dictionaries of biology and botany written in English. On the basis of the definition, etymology, and principles for terminology formation according to the International Organization for Standardization (ISO 704:2000), reasonably expressed Korean terminologies were proposed. All of the 8 terminologies examined in this study were included in the glossary of biological terminologies, published by the Korean Association of Biological Sciences in 2005, and designated as an editorial source for science and biology textbooks for middle and high schools by Ministry of Education in 2007. However, the only 1 of the 8 terminologies described in the glossary were consistent with the proposed expression in the present study. These inconsistencies indicated the need for a reassessment of this glossary of biological terminologies. The validity of the proposed Korean terminologies was tested in a questionnaire sent to 17 professors teaching plant morphology or/and taxonomy at universities. A mean of 91.9% of the total respondents agreed with the Korean expressions proposed in this study. The new, proposed terminologies would facilitate mutual understanding between teachers and students of plant biology.

• Korean Journal of Plant Resources
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• v.26 no.4
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• pp.511-515
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• 2013

Hypocotyls explants of melon seedling were cultured on Murashige and Skoog's (MS) medium supplemented with 1 mg/L 2,4-dichlorophenoxy acetic acid (2,4-D) and 0.5 mg/L benzyl aminopurine (BA) for 6 weeks to produce somatic embryos. In somatic embryos produced through intervening bright yellow friable (BYF) from the explants, somatic embryos with two-cotyledon (26%) and horn-type cotyledon (74%) were observed. The procambial strand of cotyledons was originated from circular procambial tissues of lower hypocotyls. The circular procambial independently divided into two procambial strand at the edge of cotyledonary-node, and then connected to each cotyledon to form somatic embryos with two-cotyledon. When cotyledon was horn-type, the circular procambial strand in lower hypocotyls would continuously remain connected to the cotyledon. However, somatic embryos with two or horn type cotyledon formed an abnormal shoot apex without the tunica-corpus structure or dome shape in the inter-cotyledonary area. These results demonstrated that the variation of cotyledon in somatic embryos was closely related to procambial tissue differentiation and shoot apical formation.