• 한국작물학회지
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• 제44권3호
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• pp.263-266
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• 1999

Tobacco (Nicotiana tabacum L. ‘KF109’) seeds were primed in polyethylene glycol 6000 (PEG 6000) solutions to determine a) what osmotic potential of the solution would be optimal for priming, i.e., critical potential level for preventing germination, and b) what temperature and duration would be the most effective in priming. The germination was completely prevented below -0.8 MPa of PEG 6000, that indicates a optimum water potential for seed priming. Seeds were primed for 0, 1, 2, 3, 5, 10 and 15 days at 15, 20 and $25^{\circ}C$, respectively, under the-0.8 MPa PEG 6000 solution to find out the most effective temperature and duration for priming. The effectiveness of priming, particularly in germination speed, was observed more distinctly when the primed seeds were germinated at 15$^{\circ}C$ than 2 5$^{\circ}C$. The greatest reduction of the time to 50% germination (T/sob 50/) was when the seeds were primed at $25^{\circ}C$. The reduction rate of the $T_{50}$ was rapid when primed from 1 day to 8 days and then slowed down in the seeds primed for longer than 8 days. The time from 10 to 90% germination ( $T_{10-90}$ increased in the primed seeds for longer than 8 days which showed the reversed effect of synchronous germination. However, $T_{50}$ was reduced continuously in the seeds even primed over 8 days. Thus, the optimum condition for tobacco seeds priming with PEG 6000 solution was -0.8 MPa in osmotic potential of the solution at $25^{\circ}C$ for 8 days.ays.

• 식물조직배양학회지
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• 제27권4호
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• pp.299-307
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• 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.

• 한국균학회지
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• 제15권3호
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• pp.149-157
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• 1987

1. 검정곰팡이 (Aspergillus niger)를 실험균주로 하여 동조적으로 액침배양한 결과 포자의 발아로 부터 균사의 생장, 생식기관의 성숙 및 경자까지의 분화를 재현시킬 수 있었으며 그 다음의 아세트산염 배지에서 농도와 pH가 적절할 때 포자의 형성을 볼 수 있었다. 2. pH 5.5, 6.0, 6.5 및 7.0로 조절하고 각각 농도를 대조구, 20mM, 40mM, 80mM 및 160mM로 조절한 아세트산염 배지에서 검정곰팡이를 $28^{\circ}C$의 온도로 4일간 진탕배양하면서 균체량과 pH변화, 포자개시 시간을 측정하였다. 아세트산염 배지에서 적응이 되면 균체량은 증가하였으며 성장이 진행되면서 PH가 증가하다가 포자가 형성되면 pH는 감소하였다. pH 7.0의 아세트산염 배지에서는 균이 적응할 수 없고 pH 증가가 너무 지나치게 되어 균체량은 점차 감소하였다. 또 포자형성개시 시간은 pH 5.5의 아세트산염 배지에서는 그 농도가 20mM일 때 1일, 40mM일 때 2일, 80mM일 때 3일, 160mM일 때 4일이 소요되었으며 pH 6.0의 아세트산염 배지에서는 그 농도가 40mM일 때 2일만에, 80mM일 때 1일만에, 160mM일 때 4일만에 포자가 형성되었다. 또 pH 6.5의 아세트산염 배지에서는 80mM의 농도일 때 3일만에, 160mM일 때 4일만에 포자가 형성되었고 pH 7.0의 아세트산염 배지에서는 포자가 형성되지 않았다. 모든 pH의 아세트산염 배지에서 대조구에서는 포자가 형성되지 않았다.