• Korean Journal of Plant Resources
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• v.12 no.2
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• pp.133-138
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• 1999

The structure of shoot apex in zygotic and somatic embryos of Daucus carota L. cv. Hongshim was observed by using SEM and longitudinal sections. Shoot apex of zygotic embryo was of an inverted boat shape, and these of two, three and four cotyledon somatic embryos were of an inverted boat shape, a pyramid shape and a convex diamond shape, respectively. In zygotic embryo shoot apex is consisted of small cells which are arranged in layers (tunica) and show corpus in central region. In somatic embryos shoot apices are consisted of somewhat large cells which are arranged in irregularly or slight regularly.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.48 no.6
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• pp.438-441
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• 2003

The present study was carried out to assess the possibility of rapid multiplication of Curcuma longa Linne through in vitro culture of shoot-apex. The factor investigated was effect of various growth regulators on shoot-apex culture. The shoot-apex cultured of MS(Murashige and Skoog) medium developed into plantlet in 16 Weeks. M.S. medium containing NAA at 0.5 ppm and BA 5.0 ppm was found to be optimal for growth of in vitro plantlet

• Journal of Plant Biology
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• v.17 no.2
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• pp.95-98
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• 1974

This experiment was undertaken with the purpose of investigating effect of gibberellin on the growth and electron microscopic ultrastructure of hop(Humulus lupulus var. Hallertau) shoot apex. The results are as follows. 1) The growth of stem in the plots treated with GA(10, 25, and 50ppm) is more predominant than control. The leaves and cones of treated plots turn to pale green. 10ppm plot of GA treatment is the most effective in growth and yield than the others. 2) Under the GA-treated condition, it is believed that the nucleoplasmic index (NP) are higher than the control, and so nucleus, nucleolus, mitochondria, primary cell wall, middle lamella, and etc. tends to be larger than the control. 3) Mitochondria contained in the cell of shoot apex treated with concentration of 10ppm GA was seemed to increases in number and be larger in size than the control.

• Journal of Plant Biotechnology
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• v.6 no.2
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• pp.103-106
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• 2004

Plantlet regeneration from the shoot apex was studied in three different genotypes of the chinese yam (Dioscorea opposita Thunb) cv. Jnagma and Danma, Dunggunma. The effects of plant growth regulators and inorganic salts concentration of the culture medium on bud induction and shoot growth were examined. The combinations of 0.2 mg/L BAP + 0.2mg/L kinetin, 0.01mg/L NAA + 0.2 mg/L kinetin and a single treatment of 0.2mg/L BAP were equally effective for bud and shoot formation from the shoot apices in the three cultivars. Auxin (2,4-D, NAA) treatment enhanced calli formation from the cultured apices. Also, the shoot apices of the cv. Dunggunma produced more callus and buds on the culture medium (MS) containing 0.05mg/L NAA and 0.5-1.0mg/L SAP. Lower salt strength of medium inhibited shoot elongation but did not have much effect on the shoot and bud induction from the shoot apices. These results will be useful to obtain disease-free plants of the Chinese yam.

• Korean Journal of Medicinal Crop Science
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• v.1 no.1
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• pp.38-42
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• 1993

The present study was carried out to assess the possibility of rapid multiplication of Zingiber mioga ROSC. through in vitro culture of shoot-apex. The factor investigated was effect of various growth regulators on shoot-apex culture. The shoot-apex cultured of M. S. (Murashige and Skoog) medium developed into plantlet in 12 Weeks. M. S. medium containing NAA at 05ppm and BA 5.0ppm was found to be optimal for growth of in vitro plantlet.

• Journal of Korean Society of Forest Science
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• v.97 no.4
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• pp.452-457
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• 2008

In order to develop an efficient micropropagation technique effect of plant growth regulators (PGRs) affecting on shoot proliferation from shoot apex in Pyrus ussuriensis was tested. Generally, there was no conspicuous effect on shoot induction by the treatment of PGRs and one or two shoots/explant were induced when cultured on MS medium supplemented with BA and/or BA plus NAA. Both apical shoot necrosis and hyperhydric shoots were observed frequently in multiplied shoots, and callus was formed at the basal part of shoots. About 20% spontaneous rooting was achieved in growing shoots, however the proliferated shoots exhibited poor rooting rate in gelrite supported media. When we tried to ex vitro rooting of the shoot cutting, the shoot cuttings rooted up to 50% with 100 mg/L IBA application. The rooted plantlets grew normally after acclimatization in the greenhouse.

• Molecules and Cells
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• v.27 no.6
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• pp.615-620
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• 2009

The plant shoot meristem maintains a group of stem cells that remain active throughout the plant life. They continuously generate new cells that are then recruited for organ initiation in the peripheral zone. Stem cell proliferation and daughter cell differentiation has to be integrated with overall growth and development of the diverse functional domains within the shoot apex. Several studies have revealed extensive communication between these domains. The signaling mechanisms employed comprise diffusible peptides, directional transport of plant hormones, but also complex interactions between transcription factors, that together establish a panoply of regulatory inputs that fine-tune stem cell behavior in the shoot meristem.

• Journal of Plant Biotechnology
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• v.5 no.2
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• pp.115-119
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• 2003

To determine the appropriate concentrations of nutrients and growth regulators for shoot proliferation and root initiation, several rose hybrid tea cultivars were cultured. Cultured shoot tips and lateral buds from different cultivars proliferated multiple shoots on Murashige and Skoog (MS) medium supplemented with 0 to 4 mg/L BA and 0 to 0.05 mg/L NAA. The ability of the explants to proliferate shoots and initiate roots was affected by genotype, the nodal position of explant, the strength of MS basal medium and growth regulators used. The buds nearest the apex exhibited the slowest rate of development. Most cultivars had the highest shoot proliferation when cultured on MS medium with 2 mg/L BA and 0.01 mg/L NAA, but the degree varied by cultivars. Root development was enhanced by lowering the concentration of MS salts.

• Korean Journal of Plant Tissue Culture
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• v.21 no.2
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• pp.65-68
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• 1994

Plant regeneration from the stem tissue of Orostachys japonicus A. Beiger was investigated. The calli derived from shoot apex when apex when cultured on Murashige and Skoog (MS) medium supplemented with 4mg/L 2,4-dichlorophenoxyacetic acid (2,4-D)and 2 mg/L benzyl aminopurine (BAP). The calli were developed into shoot to MS medium with 0.5mg/L NAA and 2mg/L and into root with 1mg/L kinetin. The reddish pigment which might be essential for the rootregeneration was observed in the tip of regenerated root.

• 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.