• 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.

• 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.

• 한국자원식물학회:학술대회논문집
• /
• 한국자원식물학회 2019년도 춘계학술대회
• /
• pp.55-55
• /
• 2019

Strawberry which is the genus Fragaria under family Rosaceae is one of the most important fruit plants for both fresh consumption and food processing in the temperate and subtropical countries. Propagation of strawberry is achieved either through runners or by in vitro micropropagation. Meristem tips, generally obtained from runners of virus-free plants, are commonly used to establish in vitro cultures, which are employed for mass propagation or as a source of plant material for regeneration and transformation experiments. This study was conducted to determine the optimal natural additives strength to improve sprouting shoot rate of apical meristem of strawberry 'Seolhyang'. Strawberry apical meristem at size (0.2 mm to 0.3 mm) with leaf primordials were cultured on the 1/3MS(Murashige & Skoog) medium supplemented with five natural additives such as coconut milk, maple sap, banana powder and peptone. The sprouting ratio and growth characteristics were evaluated after eight weeks after in vitro culture. Shoot ratio of 'Seolhyang' apical meristem was 72.9% in 1/3MS medium supplemented with maple sap. On the other hand, the low shoot ratio was observed 47.7% in 1/3MS medium supplemented with banana powder. Shoot length was different as natural additives but numbers of leaf was not significantiy different among the natural additives. As a result, the sprouting ratio and plant growth were enhanced effectively in 1/3MS medium with maple sap compared to the others.

• 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.

• Journal of Plant Biology
• /
• 제11권3호
• /
• pp.23-30
• /
• 1968

Using several varieties of Cymbidium, investigations were carried out to make clear how the protocormic tissue develops from the cultured explant. Explant to be cultured were prepared in several ways: exclusively apical meristem, apical meristem dissected out with the basal part attached, axillary bud primordia in their initial stage of development, or apical or axillary bud dissected out as a whole etc. It was observed that protocorms or protocormic tissues were developed from the explant's meristematic tissues regardless of where these tissues were located. Apical meristem, leaf primordia, leaf axil, or internodal part of young bud turned easily protocormic, while the scaly leaves of axillary bud or stem tissue of mother shoot turned quickly brwonish and died away. Both in axillary and apical bud explant alike, whether they were cultured whole or divided, some took quickly green color while others were slower, and some developed protocorms easily while others remained unchanged for months. Varietal difference as well as environmental factors seemed to be responsible for it. Further details should be clarified by histogenetical investigations.

• 한국자원식물학회:학술대회논문집
• /
• 한국자원식물학회 2021년도 춘계학술대회
• /
• pp.23-23
• /
• 2021

Apple (Malus×domestica Borkh.; Rosaceae) is an important fruit crop grown mainly in temperate regions of the world. Tissue culture in vitro is a biotechnological technique that has been used to genetically improve cultivars (scions) and rootstocks. This could be important in the production of genetically uniform scions and rootstocks for commercial apple production. In nurseries, apple plants are produced by grafting scions onto rootstocks. The Cornell-Geneva (Geneva® series) breeding program has bred several dwarf rootstocks that are resistant to diseases and pests and are also cold hardy. This study was conducted to determine the optimal medium strength to improve sprouting shoot rate of apical meristem of the apple rootstocks of fire blight resistance. The apple rootstocks apical meristem at size (0.2 mm to 0.3 mm) with axillary buds were cultured on the MS(Murashige & Skoog) medium supplemented with plant growth regulators. The sprouting ratio and growth characteristics was evaluated after eight weeks in vitro culture. The highest rate of bud differentiation and shoot formation were 23.8% and 55.6%, respectively. After 6 weeks, shoots were regenerated from apical meristem, and their growth characteristics was significantly varied on the respective basal medium with different plant growth regulators. Our studies showed that the apple rootstocks the apple rootstocks of fire blight resistance plantlets could be successfully produced from apical meristem differentiated out of young twigs via organogenic regeneration.

• Journal of Plant Biotechnology
• /
• 제31권1호
• /
• pp.67-72
• /
• 2004

고구마의 정단배양에 의한 배발생 캘러스로부터 대량증식 체계가 개발되어져 왔다. 고구마 정단분열조직은 1mg/L 2,4-D가 첨가된 MS배지에서 배양 4주 경에 최적의 배발생 캘러스가 형성되었다. 또한 2,4-D가 첨가된 배지에 casein을 첨가함으로써 고구마 신천미 품종의 배발생 효율을 최고 90%이상으로 2.4-D단독처리보다 현저하게 증가시켰다. 배발생 캘러스로부터 체세포배의 유도는 식물생장조절제가 제거된 MS 기본배지에서 효과적으로 형성되었으며 300∼500mg/L casein을 첨가한 배지에서는 더 높은 형성 빈도와 녹색의 단단한 체세포배가 발달하였다. 한편, 2mm이하의 체세포배로부터 이차 배발생 캘러스 형성 및 체세포배의 발달이 100∼300mg/L casein의 첨가에 의해 증가하였다 배발생 캘러스에서 얻어진 체세포배는 직접 MS기본배지에서 쉽게 각 기관이 형성되었으며, 발근과 shoot를 발달시켜 정상적인 식물체로 하여 토양에 성공적으로 옮겨 심을 수 있었다.

• 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.

• 한국자원식물학회지
• /
• 제6권2호
• /
• pp.171-179
• /
• 1993

This study was conducted to investigate the effect of growth regulators and medium composition on the growth of each stage in apical meristem culture for mass propagation of Zanthoxylum piperitum var. inerme Makino. The source material, shoot tip segments were taken from three-years old graft trees. Apical meristems were cultured in vitro on basal MS, GD, WS, half strength MS(1/2MS) and half strength GD(1/2GD) media supplemented with various concentrations for growth regulators(BA, IBA) and inorganic nutrients. The results summarized are as follows: 1. In culture establishment stage, ratio of culture establishment was 96.7% and the best resuit was obtained using MS medium supplemented with 1.0mg/l BA and 0.2mg/l IBA. 2. In shoot multitication stage, both shoot multiplication and growth were achieved in average 5.6cm. These results were obtained on in MS medium supplemented with 1.0mg/l BA and 0.2mg/l IBA. 3. In roothing stage, phloroglucinol(PG) acted as IBA synergist in root initiation. The most faverable combinations for root development was half-strength MS medium supplemented with 162mg/l PG and 0.2mg/l IBA, and ratio of rooting was 58.0%. 4. In Vitro formed plantlets were transplanted to paper pots in greenhouse with 85% of relative humidity. 96% of survival rate was obtained from artificial soil mix having same volume of sand, vermiculite, peat, and soil.

• Journal of Plant Biotechnology
• /
• 제30권2호
• /
• pp.155-160
• /
• 2003

Grapevine leafroll-associated virus 3(GLRaV-3) is one of the most severe pathogens for viral diseases found in Korea. This study was conducted to establish the virus-free stock production system for the virus disease control. The effects of thermotherapy, merestem culture and chemotheratpy to eliminate the GLRaV-3 in gratevines were tested. Thermotherapy at 37$\pm$2$^{\circ}C$ for 6∼8 weeks combined with 0.5∼1.0mm size of meristem culture method was the most effective for virus elimination. Thermotherapy alone was not effective. In chemotheratpy, DHT and Amantadine (20, 40mg/L) treatment in medium was more effective than Ribavirin to eliminate the GLRaV-3 in grapevine. However, Ribavirin spraying to potted was not available for virus elimination. Therefore, virus-free stock production system using the thermotherapy combined with shoot apical meristem culture was the most effective in grapevine.