• 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.

• Journal of Plant Biology
• /
• 제38권3호
• /
• pp.281-288
• /
• 1995

The progressive differentiation of interfascicular cambium from residual meristem in the first internode of Ginkgo biloba seedlings was elucidated by light and electron microscopy. The cells of residual meristem were small and homogeneous and heterogeneous in their arrangement but those of the adjacent cortex and pith were large and homogeneous. Some interprocambial residual meristem progressively became elongated and vacuolated during the process of the differentiation. In tangential section, residual meristem composed of long and short cells. The eventual interfascicular cambium had long fusiform initials and short ray initials. Storage materials in the cells progressively disappeared from the interprocambial residual meristem and were absent in early interfascicular cambium. Both the radial and tangential walls of cells of the interprocambial residual meristem were almost the same, but the radial wall became progressively thicker than the tangential wall during differentiation of interfascicular cambium. From these results, it is clear that interfascicular cambium is gradually differentiated from residual meristem.

• Journal of Plant Biotechnology
• /
• 제6권4호
• /
• pp.221-227
• /
• 2004

Protocol was established for production of virus free healthy seeds using meristem ($0.3-0.5\;\cal{mm}$ in size) culture and field management under net house condition in tomato. The isolated meristem was found well established in MS liquid medium containing $0.1\;\cal{mg}\;1^{-1}\;of\;GA_3$. For shoot and root development either from primary meristem or from nodal segment of meristem derived plants, semisolid MS medium having $0.5\;\cal{mg}\;1^{-1}$ of IBA was found most effective. The elimination of the studied viruses (ToMV, CMV, ToLCV) in meristem-derived plants was confirmed by DAS-ELISA test. For field management of the virus eradicated meristem-derived plants, use of net house was found very effective measures to check viral vector visit and eventually infection. The meristem-derived plants were vigor and high yielder than the native seed derived plants and produced healthy seeds. Due to stop vector visit, no viral symptoms were observed in both $R_1\;and\;R_2$ plants cultivated in net house condition. Starting of viral infestation was observed in $R_2$ generation when they were planted in open house condition without control of vector visit. Therefore, for management of viral diseases, use of virus free meristem derived plantlets and their subsequent cultivation in soil under net house condition without using any vector killing insecticide can be recommended for producing healthy seeds in tomato. The developed protocol for environmentally healthy tomato seed production in Bangladesh may be used in the countries having similar tropical like environment conducive for viral vector visit.

• Plant Resources
• /
• 제7권3호
• /
• pp.200-205
• /
• 2004

Sweet potato infected with a viral disease (SPFMV) showed irregular chlorotic patterns, so called feathering associated with faint or distinct ring spots that have purple-pigmented borders. SPFMV was eliminated from sweet potato plants using meristem tip culture. MS medium supplemented with BAP (2mg/L) and NAA (0.05 mg/L) was used for shoot proliferation and 1/2 MS medium for rooting of the plants. Highest percentage of regenerated plants (60%) was obtained from the optimum size (0.3-0.5mm) meristem tips. Of these, 60% plants were found negative for SPFMV by RT-PCR. Virus detection by RT-PCR was found to be a reliable method. Meristem-tip culture to produce SPFMV-free quality sweet potato and virus detection by RT-PCR is an efficient, time saving and reliable method for production of SPFMV-free tissue culture raised plants.

• Journal of Plant Biology
• /
• 제35권3호
• /
• pp.273-281
• /
• 1992

잔존분열조직으로부터 유관속간형성층의 기원은 접선 및 횡단면 관찰로 밝힐 수 있다. 전형성층간 및 유관속간 잔존분열조직과 인접 유조직 사이의 구조적인 특징이 분명하게 나타난다. 따라서 잔존분열조직은 유조직으로 전환되지 않고 유관속간형성층의 발생으로 이어진다. 접선면 관찰에서 초기의 유관속간 잔존분열조직의 균일구조는 후기에 점진적으로 비균일구조로 변하는데, 이 경우에 방추형시원세포의 기원이 될 긴세포와 방사조직시원세포의 기원이 될 짧은 세포를 갖추게 된다. 그러나 유관속간잔존분열조직에 인접한 유조직의 균일구조는 비균일구조로 변화되지 않고 발생과정의 전시기에 걸쳐서 균일구조를 유지하게 된다. 그러므로 유관속간형성층은 잔존분열조직과 직접적인 연속성을 갖게 되며, 분화된 유조직으로부터 2차적인 기원을 갖는 것이 아니다. 더욱이 유관속간형성층의 분화유형은 유관속내형성층의 분화유형과 거의 같다.

• Molecules and Cells
• /
• 제19권3호
• /
• pp.342-349
• /
• 2005

Cytokinins are adenine derivatives that regulate numerous plant growth and developmental processes, including apical and floral meristem development, stem growth, leaf senescence, apical dominance, and stress tolerance. However, not much is known about how cytokinin biosynthesis and metabolism is regulated. We identified a novel Arabidopsis gene, ALL, encoding an aldolase-like enzyme that regulates cytokinin signaling. An Arabidopsis mutant, all-1D, in which ALL is activated by the nearby insertion of the 35S enhancer, exhibited extreme dwarfism with rolled, dark-green leaves and reduced apical dominance, symptomatic of cytokinin-overproducing mutants. Consistent with this, ARR4 and ARR5, two representative primary cytokinin-responsive genes, were significantly induced in all-1D. Whereas SHOOT MERISTEMLESS (STM) and KNAT1, which regulate meristem development, were also greatly induced, expression of REV and PHV that regulate lateral organ polarity was inhibited. ALL encodes an aldolase-like enzyme that belongs to the HpcH/HpaI aldolase family in prokaryotes and is down-regulated by exogenous cytokinin, possibly through a negative feedback pathway. We propose that ALL is involved in cytokinin biosynthesis or metabolism and acts as a positive regulator of cytokinin signaling during shoot apical meristem development and determination of lateral organ polarity.

• 한국자원식물학회지
• /
• 제23권3호
• /
• pp.233-241
• /
• 2010

In vitro elimination of Sweet potato leaf curl virus (SPLCV) from infected sweet potato is difficult due to low number of virus-free plants obtained from meristem tip culture and long growth period required for the virus detection. In this study, efficient production of the SPLCV-free sweet potato by in vitro therapy coupled with a PCR assay for virus detection was investigated. Infected shoots cultured on Murashige and Skoog medium were treated at three different temperatures for 7 weeks followed by meristem tip culture on the medium with or without ribavirin at 50 mg/L. The regenerated plantlets were tested for virus infection by a PCR assay. The results showed that the both heat- and cold-treatments, and addition of the ribavirin did not have significant effect on efficiency of the virus elimination. The meristem size, however, greatly affected the survival rate. Meristems sized over 0.4 mm survived better than smaller ones (0.2-0.3 mm). The PCR assay was approved to be a rapid, sensitive and reliable for the SPLCV detection in regenerated plantlets. Therefore, combination of cultivating meristem tips sized 0.4-0.5 mm on the medium at $22^{\circ}C$ without ribavirin and detection of SPLCV in the regenerated plantlets by the PCR assay was an efficient system for the SPLCV elimination from infected sweet potato.

• 한국자원식물학회지
• /
• 제17권3호
• /
• pp.331-338
• /
• 2004

본 연구에서는 카네이션과 고구마의 무병 종묘를 생산하고자 정단분열조직배양을 실시하였으며, 생산된 배양종묘의 바이러스 감염여부를 진단하기 위해 ELISA방법을 이용하여 주요 바이러스를 검정하였다. 카네이션의 정단분열조직 배양에 공시 한 'Roland' 등 4품종 중 투명화 현상이 없이 가장 정상적인 잎이 발생하고 절간신장이 이루어지며 뿌리의 발생도 양호한 생장반응을 보인 품종은 석죽계통인 'Giant Gipsy' 이었으며 MS기본배지에 NAA 0.05 ㎎/L와 BA 0.1㎎/L 혹은 kinetin 1.0㎎/L와 조합한 구에서 shoot의 재생이 양호하였다. 배양7주일 후에는 explant 1개체에서 평균 5-6개, 많은 것은 10개체 이상의 multiple shoot가 형성되었고 기내 마디삽목법에 의하여 대량증식할 수 있었다. 투명화현상이 심한 품종은 'Casha'와 'Desio'로 나타났는데 투명화 현상은 kinetin 첨가보다는 BA첨가구에서 현저하게 증가하였다. 카네이션 기내 배양종묘의 바이러스 감염여부는 ELISA방법을 이용하여 CarMV와 CarRSV를 신속하게 다량의 시료를 진단할 수 있었다. 그 결과 정단분열조직의 배양을 통해 65.2%에서 무병 주가 생산되었음을 확인할 수 있었다.

• 한국작물학회지
• /
• 제26권4호
• /
• pp.344-349
• /
• 1981

감자의 생장점배양시 기본배지의 종류 및 기본배지에 첨가되는 2,4-D, NAA 및 Benzyladenine이 감자의 생장점으로부터의 기관의 분화 및 생장과 Callus의 유기에 미치는 영향을 구명하고져 본실험을 준행하였던 바 그 결과를 요약하면 다음과 같다. 1. 기본배지중에 Benzyladenine (BA)의 농도를 증가시킬수록 감자 생장점에서 유기된 경의 신장은 현저히 촉진되었으나 BA를 첨가함 배지상에서는 근 및 Callus는 전혀 유기되지 않았다. 2. NAA를 0.5ppm 이상 함유하고 있는 배지상에서는 경의 분화가 완전히 억제되었고 모두 Callus가 유기되었으며 NAA의 농도를 증가시킬수록 Callus의 생장은 촉진되었다. 3. 2.4-D 1.0ppm 이하 함유하는 배지상에서 경의 분화가 완전히 억제되었고 Callus가 유기되었으며 Callus 생장율은 2.4-D 농도가 높을수록 많았는데 2,4-D보다는 NAA 첨가배지사에서 Callus의 생장율은 현저한 증가를 보였다. 4. NAA만을 첨가한 배지상에서는 경의 분화 및 생장이 억제되었으나 BA와 NAA를 조합처리하였을 때는 NAA 0.01ppm에서보다 0.1ppm에서 경의 분화 및 생장이 현저히 증가되었으며 2,4-D와 BA의 조합처리에서도 같은 경향이었던 바 BA와 NAA 혹은 2,4-D의 조합처리시에는 경의 분화 및 신장이 촉진되는 방향으로의 교호작용이 현저하였다. 5. 엽편보다는 경편에서 Callus의 유기 및 생장이 양호하였으며 이들 경엽조직편으로부터의 Callus 유기 및 생장에는 NAA보다는 2,4-D가 더욱 효과적이 었다. 6. MS 표준배지보다는 MS배지의 농도를 $\frac{1}{2}$ 로 희석하여 배지중의 무기성분 농도를 저하시킨 배지상에서 거의 경의 분화 및 신장이 현저히 촉진되었다. 7. 감자 생장점배양시 경의 유기 및 생장에는 MS \frac{1}{2} 배지에 BA 1.0ppm 및 NAA 혹은 2,4-D 0.1ppm을 첨가한 배지가 가장 효과적이었다.

• 한국약용작물학회지
• /
• 제5권3호
• /
• pp.186-190
• /
• 1997

This study was carried out to investigate the effect of polyamines, salt strength. sucrose and gelling agents on the regeneration of plantlets by meristem culture of Aloe arborescens Mill. and Aloe vera L.. Shoot multiplication was more effective when 10mg/ l spermine in Aloe arborescens and 1mg/ l spermidine in Aloe vera added into MS medium than when other polyamines were treated into media. A quarter strength of MS medium was effective for rooting of shoots regenerated. Higher concentration of sucrose (45g/ l) was more effective for shoot regeneration. Addition of 4g/ l gelrite into the medium was effective for induction of multiple shoots from Aloe than that of agar or other concentrations of gelrite. When plantlets regenerated from meristem culture were transferred to pot. survival rate of plantlets was 80% on perlite and was 95% on vermiculite. respectively.