• Journal of Plant Biotechnology
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• v.30 no.3
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• pp.275-279
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• 2003

Excised cotyledons and embryo axises of zygotic embryos of Rhus vemicifera were cultured on Murashige and Skoog(MS) medium with various concentrations of 2,4-D. About 3-5% of explants produced callus. Embryogenic callus was preferentially induced from basal parts of embryo axis of zygotic embryos seeds when they were cultured without removal of seed coats. Somatic embryos were developed from embryogenic callus in growth regulator-free medium after 2-3 subcultures on medium with 1.0mg/L 2,4-D and these embryos were matured to cotyledonary stage. Plantlets with well-developed shoots and roots from embryos were obtained on $\frac{1}{4}$MS medium with GA$_{3}$. After acclimatization of plantlets on artificial soil, they were exposed to soil pots.

• Korean Journal of Plant Tissue Culture
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• v.22 no.3
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• pp.165-168
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• 1995

The embryos formed from anther culture of peony exhibited divergent morphologies. The frequency of normal embryos with two cotyledons was about two times higher in the embryos formed through direct embryogenesis than those formed from callus. About 69% of the embryos with two cotyledons converted into normal plants, but convention rate of the abnormal embryos with one and three or four cotyledons was only 4 to 9%. The embryos of hem and bowling pin shape did not undergo development into normal plants.

• Korean Journal of Plant Tissue Culture
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• v.28 no.1
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• pp.21-24
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• 2001

Peucedanum japonicum $T_{HUNB}$ used as a edible and medicinal plants was investigated for in uitro regeneration. Callus formation occurred on leaf and stem explant cultures and showed spontaneous embryogenic and organogenic capability on MS basal medium supplemented with 0.1~5 mg/L NAA and 0~10 mg/L BA in dark. The regeneration was highest on the condition supplemented with 2.5 mg/L NAA and 10 mg/L BA. Development of the somatic embryo progressed through the globular, heart-shaped, torpedo-shaped and cotyledonary stage, typical of zygotic embryos. When the first somatic embryos was cultured on the medium supplemented with 0.2 mg/L NAA, secondary somatic embryo were induced with higher frequency on the hypocotyl then on the cotyledon and root.t.

• Journal of Plant Biotechnology
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• v.29 no.4
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• pp.241-246
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• 2002

Somatic embryos or adventitious buds were formed from the segments of zygotic embryo of Lycium chinense Mill. on Murashige and Skoog (MS) medium supplemented with auxins (2,4-D, NAA, IAA) and / or cytokinins (zeatin, kinetin, BAP). Embryogenic callus formed on MS medium containing 0.5 mg/L 2,4-D and then differentiated into somatic embryos without transfer to hormone free medium. On the other hand, adventitious buds were formed on medium with 0.01 mg/L 2,4-D and 0.5 mg/L zeatin. Among various parts of zygotic embryos, the morphogenic potential was higher in the cotyledonary region, and the most organogenic potential was found in cotyledon followed by radicle, hypocotyl, and whole embryo. Histologically, bipolar structure of the heart-shaped embryos were confirmed and in adventitious buds only shoot apical meristems were found to exist.

• Korean Journal of Plant Tissue Culture
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• v.24 no.6
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• pp.345-349
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• 1997

Somatic embryos were induced through embryogenic callus derived from immature zygotic embryo culture of native Prunus yedoensis in Mt. Halla and regenerated into plantlets successfully. Embryogenic callus was induced most effectively on MS medium with 1.0 mg/L 2, 4-D and 0.1 mg/L BAP at an efficiency of approximately 60% using 45 day-old zygotic embryos after full blooming. Globular somatic embryos were induced from embryogenic callus on MS medium with 1.0 mg/L 2, 4-D and 0.1 mg/L BAP and these globular embryos developed to heart-shaped and cotyledonary embryos on hormone-free MS medium. Normal somatic embryos germinated 49% on 1/2 MS medium and the plants regenerated from the somatic embryos were morphologically normal.

• Korean Journal of Plant Tissue Culture
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• v.27 no.3
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• pp.175-180
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• 2000

Cotyledonary somatic embryos after being cultured in a liquid MS medium for 1 week were subcultured on a solid MS medium and then the embryos germinated at a rate of 92%, but the rate was lowered by extending the culture period of the embryos on a liquid medium: 26% germination on a liquid medium culture for 4 weeks. Somatic embryos subcultured on the liquid medium showed the normal elongation of hypocotyl and radicle but in part showed secondary embryogenesis on hypocotyl and callus formation on and around the root-hypocotyl juncture. Through observation of scanning electron microscope, apical meristem in plumule showed the loose arrangement of cells, and abnormal leaf primordium formation and growth arrest of the primordium or no leaf primordium formation. Therefore, it is suggested that the germination arrest of carrot somatic embryos on liquid medium culture is due to the structural abnormality of the apical meristem in plumule.

• Journal of Plant Biotechnology
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• v.32 no.1
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• pp.37-44
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• 2005

Microspores were isolated from pepper (Capsicum annuum L.) anthers by using a micro-blender and cultured in modified NLN medium at $25^{\circ}C$. The influence of pretreatment period at $32^{\circ}C$, adding the 2-hydroxynicotinic acid to a pretreatment medium, and co-pretreatment anthers with microscopes on the induction of embryo were examined. Globular and torpedo embryos were observed from 3 weeks after culture. Embryo development was not synchronized within culture. After 4 weeks in culture, in addition to globular and torpedo embryos, cotyledonary embryos were observed. Normal cotylodonary embryos developed into plantlets when transferred to a solid hormone free B5 medium containing $2\%$ sucrose. Embryo yields were significantly higher after 1- and 2-day pretreatment at $32^{\circ}C$. However the development of embryo ceased at the globular or heart stage. In contrast, embryo yields were lower after 3- to 6-day pretreatment at $32^{\circ}C$ and embryo developed at the cotyledonary stage. After adding the 2-hydroxynicotinic acid to anther pretreatment solution, embryo yields were slightly increased. However most embryos occurred were at the globular or heart stage. Co-pretreatment of microspores with anthers was deleterious for embryo induction and development. AS far as we know, this is the first report of success in obtaining high frequency of embryogenesis and plantlets formation from isolated microspores of pepper. Although the culture conditions have to be optimized further, this promising microspore culture system can be used for genetic transformation, selection for dominant and recessive traits as well as for the production of homozygous doubled haploid plants.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2003.04a
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• pp.61-62
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• 2003

Clonal propagation of high-value forest trees through somatic embryogenesis (SE) has the potential to rapidly capture the benefits of breeding or genetic engineering programs and to improve raw material uniformity and quality. A major barrier to the commercialization of this technology is the low quality of the resulting embryos. Several factors limit commercialization of SE for Corsican pine, including low initiation rates, low culture survival, culture decline causing low or no embryo production, and inability of somatic embryos to fully mature, resulting in low germination and reduced vigour of somatic seedlings. The objective was to develop a Corsican pine maturation medium that would produce cotyledonary embryos capable of germination. Treatments were arranged in a completely randomized design. Data were analyzed by analysis of variance, and significant differences between treatments determined by multiple range test at P=0.05. Corsican pine (Pinus nigra var. maritima) cultures were initiated on modified !P6 medium. Modifications of the same media were used for culture multiplication and maintenance. Embryogenic cultures were maintained on the same medium semi solidified with 2.5 g/l Gelrite. A maturation medium, capable of promoting the development of Corsican pine somatic embryos that can germinate, is a combination of iP6 modified salts, 2% maltose, 13% polyethylene glycol (PEG), 5 mg!l abscisic acid (ABA), and 2.5 g/l Gelrite. After initiation and once enough tissue developed they were grown in liquid medium. Embryogenic cell suspensions were established by adding 0.951.05 g of 10- to 14-day-old semisolid-grown embryogenic tissue to 9 ml of liquid maintenance media in a 250ml Erlenmeyer flask. Cultures were then incubated in the dark at 2022$^{\circ}$C and rotated at 120 rpm. After 2.53 months on maturation medium, somatic embryos were selected that exhibited normal embryo shape. Ten embryos were placed horizontally on 20 ml of either germination medium ($\frac{2}{1}$strength Murashige and Skoog (1962) salts with 2.5 g/l activated charcoal) or same medium with copper sulphate adjusted to 0.25 mg/1 to compensate for copper adsorption by activated carbon. 2% and 4% maltose was substituted by 7.5% and 13% PEG respectively to improve the yield of the embryos. Substitution of' maltose with PEG was clearly beneficial to embryo development. When 2% of the maltose was replaced with 7.5% PEG, many embryos developed to large bullet-shaped embryos. At latter stages of development most embryos callused and stopped development. A few short, barrel-shaped cotyledonary embryos formed that were covered by callus on the sides and base. When 4% of the maltose was removed and substituted with 13% PEG, the embryos developed further, emerging from the callus and increasing yield slightly. Microscopic examination of the cultures showed differing morphologies, varying from mostly single cells or clumps to well-formed somatic embryos that resembled early zygotic embryos only liquid cultures with organized early-stag. A procedure for converting and acclimating germinants to growth in soil and greenhouse conditions is also tested. Seedling conversion and growth were highly related to the quality of the germinant at the time of planting. Germinants with larger shoots, longer, straighter hypocotyls and longer roots performed best. When mature zygotic embryos germinate the root emerges, before or coincident with the shoot. In contrast, somatic embryos germinate in reverse sequence, with the cotyledons greening first, then shoot emergence and then, much later, if at all, the appearance of the root. Somatic seedlings, produced from the maturation medium, showed 100% survival when planted in a field setting. Somatic seedlings showed normal yearly growth relative to standard seedlings from natural seed.

• Korean Journal of Plant Tissue Culture
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• v.25 no.1
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• pp.51-56
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• 1998

This study was carried out in order to establish plant regeneration via somatic embryogenesis from leaf explant of Ostericum koreanum Kitagawa and to elucidate the effects of NAA and cytokinins (kinetin, BA) on the abnormalities of somatic embryo and the relationship between thecotyledon numberand germinability. Calli were formed on leaf explants cultured on MS agar medium supplemented with various concentrations (0, 0.1, 0.5, 1, 2 mg/L) of NAA and cytokinins. The calli were white, watery and soft, became browning during cultures. Somatic embryos were formed from pale yellowish calli derived browning calli. High frequency somatic embryos were observed on MS medium containing 1 mg/L NAA and 0.1 mg/L BA after 60 days of culture. The mature somatic embryos germinated into plantlets without subculture after 2 weeks. The frequency of normal somatic embryo with two cotyledons was 39.8%. On the other hand, cotyledonary abnormalities of somatic embryos were observed at considerable frequency: 33.6% of somatic embryo with one cotyledon, 15.3% cotyledons with three, 8.2% four cotyledons and 3.1% jar shaped cotyledon. Germination frequency of somatic embryos with two cotyledons was 97.4%, and that of the embryos with abnormal cotyledon was almost similar to that of embryos with two cotyledons, except jar shaped somatic embryos (33.3%).

• Korean Journal of Plant Tissue Culture
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• v.25 no.1
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• pp.1-5
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• 1998

This study describes the effect of the growth regulators such as 2,L-D and BA, on the structural abnormalities of somatic embryos derived from leaf explants of Angelica gigas Nakai, Also, the relationship between the cotyledon number of a somatic embryo and its germinability is explored. Embryogenic calli were selected from calli formed on explants cultured on MS solid basal medium supplemented with 0.5mg/L 2,4-D, 1mg/L 2,4-D, 1mg/L plus 0.1mg/L BA, and 1 mg/L 2,4-D plus 0.5mg/L BA. Cotyledonary abnormalities were observed in somatic embryos which were developed from embryogenic calli cultured on MS medium containing 1mg/L 2,4-D for 8 weeks and then subcultured on 2,4-D free MS medium for 3 weeks. The frequency of abnormalities was as follows: 22.8% one cotyledon, 42.5% two cotyledons, 16.8% three cotyledons, 7.8% four cotyledons, 1.8% five cotyledons, and 8.2% jar shaped cotyledon. In addition, ABA treatment indicated an improvement of the somatic embryo with normal cotyledon (65.3%). ABA was important role to the high production of normal somatic embryos. Two cotyledon embryos showed germinability 77.8%. However the germinability of somatic embryos with anomalous cotyledons was prominently low: One cotyledon, 62.5%; three cotyledons, 43.3%; four cotyledons, 60%; five cotyledons, 50% and jar shaped cotyledon, zero%. Thus, germinability was essentially, inversely proportional to cotyledon number.