• Korean Journal of Plant Tissue Culture
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• v.21 no.6
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• pp.347-351
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• 1994

To measure the time required for ginseng explants to become determined to form flower buds, we cultured zygotic embryos, seedlings, and cotyledonary nodes on MS medium supplemented with BA and GA$_3$of 5 ${\mu}$M each (flower inducing medium, FIM) for various periods and transferred to the basal medium. The explants required a minimum of 10 days on FIM to be determined. Histological observations revealed that the axillary meristem to be fated to develop into flower bud remained in a state of shoot meristem during the first 10 days of culture and differentiated into flower bud after 15 days of culture. We suggest that the in-vitro flowering system described in this study is useful in investigating (a) regulatory element(s) to cause the phase change from the vegetative to reproductive state by comparing predetermined explants with determined ones at the molecular level.

• Korean Journal of Plant Tissue Culture
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• v.28 no.1
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• pp.33-36
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• 2001

The experiments were conducted to establish the in vitro culture system of apple rootstock M.9. The meristem tissue of M.9 were pre-treated in antiox: dant solution containing 100 mgL$^{-1}$ ascorbic acid and 150 mgL$^{-1}$ citric acid for 30 minutes, transferred to the MS liquid medium added with 0.1 mgL$^{-1}$ IBA, 0.5 mgL$^{-1}$ GA, and 30 gL$^{-1}$ sucrose, which shaked by 50 rpm for 2 weeks, and then, cultured in same composition of MS agar medium. This treatment stimulated shooting from the tissue, the most favorably, compared with other treatments. All young shoots produced normal roots when they were shake-cultured on the 1/2MS liquid medium added with 0.5 mgL$^{-1}$ IBA, 30 gL$^{-1}$ sucrose and 1,000 times diluted solution of Hormex by 50 rpm for one week, and subsequently transferred to the 8 gL$^{-1}$ agar medium of the same composition as pre-culture medium minus Hormex.

• Korean Journal of Plant Tissue Culture
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• v.21 no.3
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• pp.131-135
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• 1994

This experiment was designed to improve the in vitro production system of apple rootstock M.26 as being influenced by the growth regulators, TDZ, BA, IAA, IBA, zeatin, and GA$_3$. Different levels of potassium humate (KH), known as cytokinin and auxin-like substance, were also supplemented to the MS basal medium along with IBA 0.6 mg/L to find out it effect on root formation in apple rootstock M.26. ID initiate and establish the in vitro multiplication of shoots byway of meristem culture, MS medium added with zeatin 1.0 mg/L was found to be the most suitable, showing the 100% of survival rate of shoot tips. A combination of thidiazuron (TDZ) 0.2 mg/L and NAA 0.5 mg/L promoted the shoot proliferation when shoot tips were used as explants. MS basal medium plus IBA 0.6 mg/L was very effective for root induction, but an addition of potassium humate (250 mg/L) to the medium containing IBA 0.6 mg/L stimulated the induction and proliferation of the rook by far the better.

• 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.

• Applied Microscopy
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• v.5 no.1
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• pp.9-19
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• 1975

In order to clarify the mecahnism of histological barriers to pathogens of witches' broom diseased in sweet potatoes, this experiment has been conducted to observe the relationship between pathological characters and the transfer of mycoplasmae in the shoot apex. The material used the experiment is the sweet potato (Ipomoea batatas (L.) Lamm. Suwon 147). In the experiment regarding of mycoplasmae, the upper limit zone of transfer of mycoplasmae is examined by way of the process of free stock and the shoot apex of a infected part in nature, observed in the culture of each part of the diseased plant which is cut to a certain length. The pathological change pattern of tissues infected with mycoplasmae has been observed under the light and electron microscopes. As a result of this experiment, the following conclusion was arrived at. 1. It has been ascertained that the mycoplasmae are not existent in a promeristem and primary meristem zone from the meristem dome, and is existent in the lower part of the vascular differentiation zone, after which differential tissues the mycoplasmae become progressively enlarged, and before which undifferential tissues it become progressively immatured and diminished in size. 2. It can be suggested that mycoplasmae may not be existed in the shoot meristem, be cause the passing structures such as sieve area and plasmodesma which can be pass ed immatured mycoplasmae is undifferentiated. 3. In the tissue culture, free stock can be obtained in the zone between 1.0-1.5mm of the shoot apex, while it cannot in the 2.0-3.0mm zone, because of infection by mycoplasmae. It is suggested that immature mycoplasmae may be diffused according to temperature ($28{\pm}1^{\circ}C$) in tissue culture process.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2003.10a
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• pp.161-161
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• 2003

• Proceedings of the Plant Resources Society of Korea Conference
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• 1995.01a
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• pp.41-41
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• 1995

• 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 Tissue Culture
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• v.21 no.5
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• pp.299-302
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• 1994

Immature zygotic embryos (up to 4mm in length) were cultured on MS medium supplemented with 0.5 to 8mg/L 2,4-D. Up to 87% of them formed somatic embryos on the plumule without producing an intervening callus. The site of somatic embryo formation was confirmed by culturing plumule explants, which consisted of shoot apical meristem domes with 1 or 2 leaf primordia excised from 2-week-old seedlings. When the concentration of 2,4-D was increased over 4 mg/L, the plumule explants produced nonembryogenic calli only, whereas the distal end of the cotyledons directly formed numerous somatic embryos at frequencies of up to 60%. Upon transfer onto MS basal medium,2 out of 15 somatic embryos converted into plantlets. The plantlets were potted to a soil mixture and grown to maturity in a phytotron.

• Korean Journal of Agricultural Science
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• v.5 no.1
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• pp.1-5
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• 1978

Aseptic meristem of Fragaria ananassa 'Hokowase' were inoculated on Murashige and Skoog medium containing various levels of Benzylamiro purine(BA), IAA, and 2.4-D. Formations of shoots plantlets, roots and callus depend on hormone levels used. On medium containing high level of BA 1.0mg/l, multiple plantlets were formed, however, elongation of shoots was inhibited than on BA 0.5 mg/l. 1.0mg/l IAA induced root formation and 1.0mg/l+1.0mg/l BA inhibited root formation. Callus formation was occurred on the medium added 2.4-D. When plantlets were subcultured, formation of callus or shoot depend on BA/2.4-D ratio. 2.0mg/l 2.4-D+0.2mg/l BA and 0.5 mg/l 2.4-D+0.2mg/l BA induced callus formation and 2.0mg/l BA induced plantlet and shoot vigorously.