Optimalization of Flurprimidol Concentration for Improvement of Acclimatization Rate and In Vitro Growth Inhibition in Bioreactor Culture of Strawberry Plantlets via Bioreactor Culture

This study was conducted to improve the acclimatization rate of in vitro strawberry plantlets through bioreactor culture using the growth retardant flurprimidol. Different concentrations [0 (Control), 0.1, 0.5, 1.0, and $2.0mg{\cdot}L^{-1}$] of flurprimidol were added during bioreactor culture. After six weeks of treatments, various growth characteristics were investigated and in vitro plantlets were acclimated in the greenhouse. The growth rate of treated plantlets was much lower than that of control, and as the treatment concentration increased, the growth rate was much decreased. Shoots of plantlets treated with flurprimidol were shorter (2.2-3.7 cm) than those of control (7.9 cm). The number of roots per treated plant was around 11.6-34.2, compared with 51.8 in the control. Root length was also lower (0.88-3.08 cm) than control (4.36 cm). However, the number of new shoots and leaves increased in all treatments except for $2.0mg{\cdot}L^{-1}$ concentration. The root was partially decayed in $1.0mg{\cdot}L^{-1}$ concentration and was completely decayed in $2.0mg{\cdot}L^{-1}$. The survival rate in $0.1mg{\cdot}L^{-1}$ and $0.5mg{\cdot}L^{-1}$ concentrations was 100% and 23.3% respectively. After four weeks of acclimatization, the plantlets restarted growth, and growth characteristics of shoots and roots recovered to the levels of control, except for fresh weight. Based on our results, a concentration of $0.1mg{\cdot}L^{-1}$ flurprimidol is appropriate for improvement of acclimatization rate of in vitro strawberry plantlets in bioreactor culture.

딸기 조직배양묘의 생물반응기 배양 시 Flurprimidol 처리농도에 따른 기내 생장억제 및 순화율 향상

본 실험은 생물반응기를 이용한 딸기 조직배양묘 대량증식 시 flurprimidol 을 처리하여 순화율을 향상시키고자 실시하였다. Flurprimidol 을 0, 0.1, 0.5, 1.0 및 $2.0mg{\cdot}L^{-1}$의 농도로 6주동안 처리하여 생육조사한 결과, flurprimidol을 첨가한 처리구의 생장량이 대조에 비해 감소하였고, 처리농도가 증가할수록 생장억제효과가 크게 나타났다. 초장은 대조가 7.9cm인 것에 비해 flurprimidol 처리는 2.2-3.7cm 범위로 매우 짧아졌다. 뿌리수는 대조가 51.8개/주에 비해 flurprimidol 처리가 11.6-34.2개/주 범위로 감소하였다. 뿌리길이는 대조가 4.36cm에 비해 flurprimidol 처리는 0.88-3.08cm 범위로 크게 짧아졌다. 그러나 액아수는 flurprimidol $2.0mg{\cdot}L^{-1}$ 처리를 제외하고 모든 처리구에서 대조의 8.6개/주에 비해 많이 발생하였을 뿐만 아니라 액아수가 증가할수록 그에 따라 잎수도 증가하였다. Flurprimidol $1.0mg{\cdot}L^{-1}$ 처리 시 뿌리가 부패하여 지하부 발달이 불량하였다. Flurprimidol $1.0mg{\cdot}L^{-1}$와 $2.0mg{\cdot}L^{-1}$ 처리를 제외한 모든 처리의 순화율은 100%로 대조에 비해 23.3% 향상되었다. 순화 4주 후, flurprimidol $0.1mg{\cdot}L^{-1}$ 처리는 생체중을 제외한 지상부 및 지하부 생육이 대조와 비슷하게 회복되었다. 따라서 생물반응기를 이용한 딸기의 조직배양묘 대량 증식 시 순화율 향상을 위한 적정 flurprimidol 농도는 $0.1mg{\cdot}L^{-1}$였다.