• Korean Journal of Plant Tissue Culture
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• v.21 no.5
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• pp.303-308
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• 1994

Shoot apical meristem dome explants from cassava plants (Ghanaian local variety) produced somatic embryos at a frequency of 32% when cultured on MS medium supplemented with 2 mg/L 2,4-D. Somatic embryo segments formed secondary embryos at frequencies of up to 93% when cultured on medium containing 1 mg/L 2,4-D for 2 to 3 weeks. Since the somatic embryos were not capable of converting into plantlets, adventitious shoot were induced from the sliced embryo segments by culturing them on medium containing 0.1 to 5 mg/L BA. After 8 weeks of culture, numerous shoots formed on the segments at frequencies up to 100%. The shoots were rooted and successfully transplanted to potting soil.

• Journal of Plant Biology
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• v.15 no.1
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• pp.28-32
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• 1972

Young haploid leaf derived from the anthers of tobacco plant was cultuerd and plantlets of various ploidies were obtained. When the leaf was put on the medium supplemented with kinetin as growth regulator, plantlets developed directly from the leaf, and the plants coming out in early stage of culture were all haploid. Plants developing in later stage were mostly haploids with some exception of diploid and aneuploid. Leaves were also cultured on the callus-inducing media supplemented with 2,4-D and kinetiion, and the calluses were sub-cultured for six months. Plants developed from these calluses were mostly aneuploids of various chromosome numbers. In view of the fact that the plants directly developed from the leaf were all haploid, the tissue of the original leaf explant was assumed to be uniform as far as chromosome number was concerned. On the other hand, it seemed that the occurrence of various ploidies in the plants derived from the calluses of same origin was the result of the influence of in vitro culture. Apical meristem tissues and various multicellular bodies were formed in the epidermal and inner mesophyll tissues as well as in the sub-epidermal cells.

• Korean Journal of Plant Resources
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• v.17 no.1
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• pp.1-6
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• 2004

Apical meristems tissue were cultured on LS medium with different zeatin and NAA concentrations to compare their potential to regenerate shoots, roots and bulblet formation. Shoot regeneration from apical meristem was effective on LS medium added with zeatin 0.1, 0.5, 1.0 mg/L alone treatment or zeatin 0.5 mg/L and NAA 1.0 mg/L combination treatment. A high frequency of root regeneration was obtained on LS medium supplemented with zeatin 0.5 mg/ and NAA 1.0 combination treatment. Linsmaier and Skoog(LS) medium with NAA 3.0 mg/L and zeatin 1.0 mg/L combination treatment gave the best results for normal bulblet formation#KW=Allium wakegi ; plant regeneration ; bulblet formation

• Journal of Plant Biotechnology
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• v.44 no.4
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• pp.401-408
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• 2017

Herein, we report the meristem-tip culture from dormant buds of grape 'Kyoho' single-infected with Grapevine fleck virus (GFkV), which is phloem-limited and transmitted by graft inoculation. We produced GFkV-free shoots without thermo- or chemotherapy using meristem-tip explants approximately 0.3 mm (73 explants) and 0.8 mm long (five explants) including shoot apical meristem, 2-5 leaf primordia, and 1-4 uncommitted primordia from dormant buds of the infected woody cuttings (stored at $4^{\circ}C$). Explants were cultured 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). After 16 weeks of culture, shoot (10-mm long) regeneration frequency achieved from 0.3-mm explants was 4.1% and that obtained from 0.8-mm explants was 40.0%. Virus-free efficiency (expressed as the percentage of RT-PCR negative shoots regenerated) from 0.3- and 0.8-mm explants was 100% and 50%, respectively. Following in vitro multiplication, RT-PCR assays revealed identical results to assays of the first regenerated shoots. Our new methodological approach could be applied for eliminating other viruses in grapevines, as well as for producing virus-free plants in many other deciduous tree species, including fruit trees.

• Journal of Plant Biotechnology
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• v.40 no.1
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• pp.55-58
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• 2013

Immature embryos of Glycine max L. was cultured on Murashige and Skoog's (MS) medium supplemented with 1 mg/L 2,4-dichlorophenoxy acetic acid (2,4-D). After 6 to 8 weeks of culture, immature embryos produced somatic embryos. Of somatic embryos, two cotyledonary embryo (14%), one cotyledonary embryo (37%), fused cotyledonary embryo (43%), and stunted globular embryos (6%) were observed. The procambial strand of cotyledons originated from circular procambial tissues of lower hypocotyl. The circular procambial tissues were independently divided into one or two procambial strand at the edge of cotyledonary-node, and then connected to each cotyledon to form somatic embryos with one or two cotyledons. When cotyledon was a fused type, the circular procambial strand in lower hypocotyl was continuously connected to the cotyledon. Also, somatic embryos with two cotyledons developed a functional shoot apex with the tunica-corpus structure. In contrast, somatic embryos with one or fused cotyledon formed an abnormal shoot apex without the tunica-corpus structure or with non-dome shape in the inter-cotyledonary area. These results indicated that the variation of cotyledon in somatic embryos is closely related to procambial differentiation and shoot apical meristem development.

• Journal of Plant Biology
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• v.37 no.1
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• pp.17-25
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• 1994

Two potato (Solanum tuberosum L.) cultivars were transformed by Agrobacterium tumefaciens harboring cauliflower mosaic virus (CaMV) 35S promoter and $\beta$-glucuronidase (GUS) gene. Expression patterns of the CaMV 35S promoter according to tissue types and developmental stages, and genetic stability of GUS gene were investigated in the clonal progenies of transgenic potatoes. Kanamycin-resistant shoot emerged from tuber disc after 4 weeks of culture, and root was induced 6 weeks after culture on the selection medium. Shooting frequency of cvs. Superior and Dejima were 43% and 27%, respectively. Mature transformants and their clonal progenies showed no phenotypical abnormality. GUS activity was expressed primarily at parenchymatous cells of phloem tissue around the vascular cambium in the stem and root, and higher activity was found at the apical meristem of shoot, root and adventious shoot bud. GUS activity was higher at tubers of young explants than at stored tubers. These facts indicate that expression level of the CaMV 35S promoter differed according to tissue types and developmental stages of the organs. The GUS gene was stably inherited to each clonal progeny and normally expressed.

• 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.

• 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 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.

• 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.