• 식물조직배양학회지
• /
• 제27권4호
• /
• pp.299-307
• /
• 2000

A large amount of information is currently available for somatic embryogenesis of plants. However, one common problem related to somatic embryos is that the conversion rate can be low for some species. Apical meristems are responsible for post-embryonic growth of the embryo. The low percentage observed is most likely a result of poor apical meristem development or defects in the meristem organization during somatic embryogenesis. In flowering plants, apical meristems are well developed by the late heart stage of zygotic embryo development. In conifers, such as white spruce, apical meristems are formed at the pre-cotyledon stage. Thus, apical meristem development occurs very early, prior to the maturation stage of embryo development. Once formed, meristems are stably determined. In the somatic embryo, as exemplified by white spruce, since embryo development is not synchronous, tissue differentiation including apical meristem formation occurs throughout the“maturation”stage. Different apical meristem organizations can be found among different individuals within a population. In contrast to their zygotic counterparts, the apical meristems appear not to be stably determined as their organization, as the shoot apical meristem especially, can be easily modified or disrupted. Precocious germination seldom results in functional plantlets. All these observations suggest that the conditions for somatic embryo maturation have not been optimized or are not suitable for meristem formation and development. The following strategies could improve meristem development and hence conversion: 1. Simulate in ouuio conditions to promote meristem development prior to the“maturation”treatment.2. Prevent deterioration of apical meristem organization during somatic embryo maturation.3. Promote further meristem development during embryo germination.

• Plant Biotechnology Reports
• /
• 제2권3호
• /
• pp.179-189
• /
• 2008

We established an efficient plant regeneration system for Catharanthus roseus L. (G.) Don through somatic embryogenesis. Embryogenic callus was induced from hypocotyl of seed germinated in vitro. Somatic embryogenesis in Catharanthus has been categorized into three distinct stages: (1) initiation and proliferation of embryo; (2) maturation, and; (3) germination or plantlet conversion. Beside plant growth regulators, various stages of embryogenesis were screened for their response to a wide variety of factors (pH, gelrite, light, sugar alcohols, polyethyleneglycol and amino acids), which affect embryogenesis. All of the tested factors had a small to marked influence on embryogeny and eventual conversion to plantlets. The plantlets were acclimatized successfully in a greenhouse. To our knowledge, this is the first report describing a detailed study of various cultural factors which regulate embryogenesis in C. roseus. The results discussed in this paper may be used in mass propagation to produce medicinal raw material, and the embryo precursor cells could be used in genetic modification programmes that aim to improve the alkaloid yield as well.

• 한국자원식물학회:학술대회논문집
• /
• 한국자원식물학회 2003년도 춘계 학술발표대회
• /
• pp.61-62
• /
• 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.

• 한국산림과학회지
• /
• 제94권1호통권158호
• /
• pp.39-44
• /
• 2005

5본의 백합나무 모수로부터 미숙종자 배양을 통한 체세포 배발생을 시험하였다. 두 가지 배지(MS 및 B5)에 2,4-D 및 TDZ의 농도별 조합처리로 캘러스 및 배발생 조직 유도를 시험하고 체세포배 유도, 발달 및 재분화에 미치는 명 암배양의 효과를 조사하였다. 캘러스 및 배발생 조직의 유도는 두 배지간 유의적인 차이가 없었으나 MS + 2,4-D 1.0 mg/L, TDZ 0.01 mg/L, 3% sucrose 조건에서 양호하게 나타났다. 캘러스 유도는 모수 몇 명 암배양에 따른 차이가 없었으나 배발생 조직의 유도는 암배양이 주효하여 명배양보다 약 2배의 효과가 있었고 모수간 55~72%까지 차이를 나타냈다. 체세포배 유도 및 정상적인 체세포배의 발달에 있어서도 모수의 영향을 받으며, 암배양이 필수적인 것으로 나타났고, 해부학적인 관찰을 통해 확인할 수 있었다. 본 실험 결과는 백합나무 체세포배 유도에 있어 모수의 선택과 암배양이 중요한 요인임을 시사해 준다.

• Journal of Plant Biotechnology
• /
• 제29권2호
• /
• pp.135-138
• /
• 2002

대두 85개 재조합순계주의 미숙배로부터 얻은 자엽절편을 MS salt, B5비타민, 40 mg$^{-1}$ 2,4-dichlorophenoxyacetic acid (2,4-D) 및 30 g$^{-1}$ sucrose로 조성된 체세포배유도배지 (SIM, somatic induce medium)에 치상하여 5주간 배양하였다. 10%이하의 체세포배형성빈도는 36계통에서, 11~49%의 형성빈도는 37계통에서, 50~80%의 형성빈도는 9계통에서 그리고 90% 이상의 형성빈도는 3계통에서 각각 관찰되었다. 90% 이상의 체세포배형성빈도와 자엽당 6.36개의 체세포배를 형성하는 계통으로는 KM1010, KM1032 및 KM1064이었으며, 3계통에서 얻은 일차배를 동일배지상에서 계대배양하면서 2차배 증식방법으로 1년 이상 증식 유지하였다. 체세포배를 성숙배지와 식물체전환배지 (Komatsuda 1992)에 옮겼을 때 약 25% 정도가 정상식물체로 생육하였다.