This study was conducted to develop a seed propagation protocol of Hemerocallis taxa native to the Korean Peninsula. In this study, the seed dormancy types were classified. The germination traits of H. thunbergii, H. dumortieri, H. hakuunensis, and H. hongdoensis were also characterized. The initial embryo to seed length ratio (E:S ratio) in seeds of the four Hemerocallis species was between 0.80 and 0.90 at harvest, however, the E:S ratio did not increase until just before germination. Thus, seeds of the four Hemerocallis species had no morphological dormancy (MD), and at least 84% of seeds of all tested species germinated at 25/15℃ under light within 30 days. The lower the incubation temperature, the lower the germination rate of seeds of the four Hemerocallis species. However, the temperature range for germination was expanded due to old stratification. Gibberellin treatment increased the germination rate or germination speed at a relatively low temperature of 15/6℃. However, this treatment did not improve the germination rate as much as the temperature at 25/15℃. Under 15/5℃ of incubation, cold stratification increased the final germination percentage and rate/speed and expanded the temperature range for germination from high to low (25/15℃ → 15/6℃). This indicates that the seeds have a conditional dormancy (CD) that germinates in a narrow temperature range. In conclusions, the four Hemerocallis seeds exhibited nondeep physiological dormancy.
Natural uranium-contaminated soil in Korea Atomic Energy Research Institute (KAERI) was generated by decommissioning of the natural uranium conversion facility in 2010. Some of the contaminated soil was expected to be clearance level, however the disposal cost burden is increasing because it is not classified in advance. In this study, pre-classification method is presented according to the ratio of naturally occurring radioactive material (NORM) and contaminated uranium in the soil. To verify the validity of the method, the verification of the uranium radioactivity concentration estimation method through γ-ray analysis results corrected by self-absorption using MCNP6.2, and the validity of the pre-classification method according to the net peak area ratio were evaluated. Estimating concentration for 238U and 235U with γ-ray analysis using HPGe (GC3018) and MCNP6.2 was verified by -spectrometry. The analysis results of different methods were within the deviation range. Clearance screening factors (CSFs) were derived through MCNP6.2, and net peak area ratio were calculated at 295.21 keV, 351.92 keV(214Pb), 609.31 keV, 1120.28 keV, 1764.49 keV(214Bi) of to the 92.59 keV. CSFs for contaminated soil and natural soil were compared with U/Pb ratio. CSFs and radioactivity concentrations were measured, and the deviation from the 60 minute measurement results was compared in natural soil. Pre-classification is possible using by CSFs measured for more than 5 minutes to the average concentration of 214Pb or 214Bi in contaminated soil. In this study, the pre-classification method of clearance determination in contaminated soil was evaluated, and it was relatively accurate in a shorter measurement time than the method using the concentrations. This method is expected to be used as a simple pre-classification method through additional research.
본 연구는 국내 자생하는 진달래속(Rhododendron) 종들의 종자 휴면유형 분류 및 발아특성 구명을 목표로 하였다. 진달래속 종들의 배는 형태적휴면(MD)이 없는 완전히 발달된 직선(linear) 형태였으며, 만병초 및 꼬리진달래 종자는 탈리 시점에 이미 휴면이 없는 것으로 밝혀졌다. 반면에 털진달래 종자는 population 수준에서 부분적으로 생리적휴면(PD)을 가지고 있는 것으로 나타났다. 털진달래의 이러한 생리적휴면 (PD)은 외생 지베렐린(GA3) 1,000mg・L-1 처리를 통해 타파될 수 있었다. 그러나 4℃에서의 저온층적처리는 털진달래 종자 휴면 타파에 효과가 없는 것으로 나타났다. 종합적으로 판단 했을 때, 진달래속(Rhododendron) 종들의 적정 발아 환경조 건은 광조건・25/15℃(만병초), 암조건・20/10℃(꼬리진달래), 광 조건・25/15℃(털진달래)로 확인된다. 진달래속(Rhododendron) 에서의 종간 차이(interspecific variation)로 인해 모든 종이 종자 휴면유형 또는 발아특성에서 구별이 되었다. 본 연구는 국내 자생하는 진달래속(Rhododendron) 종들의 생리・생태 특성을 이해하는 데 이용될 수 있을 것이다.