In vitro regeneration and the change of anatomical appearance in Poncirus trifoliata RAFIN.

탱자(Poncirus trifoliata RAFIN.)의 기내 재분화 및 조직학적 특성

In this study, the induction regeneration of callus from immature embryo in trifoliata orange (Poncirus trifoliata RAFIN.) were accomplished. The embryogenic calli were induced from the immature embryo derived from seed when the calli were irradiated for 16hr at about 2,000 Lux in $\frac{1}{2}$ MS medium supplemented with 3% sucrose, and 44.4$\mu$M BA. Regeneration to whole plants was the most successful in MS medium containing 5.0$\mu$M BA. The yellowish callus was developed at 2 to 3 weeks of culture and the callus was changed from yellow to green at 5 to 6 weeks culture. In vitro regeneration was directly induced from embryogenic callus in MS medium containing 3% sucrose and 5.0$\mu$M BA. Multishoot was formed at 16 weeks culture. Moreover, when the root-formed plantlet was transplanted to soil, they grew to a whole plant. The compact cultured-cells were observed by light microscope after 4 weeks of cultivation and the embryogenic clumps were formed about the 5 weeks. At the same time, the neighboring cells were liquefied. In addition, differentiation of leaf and stem from the callus was observed after 12 weeks. The developed oil sacs and the profacicular cambium of the immature leaf were observed after 18 weeks. Therefore, we can see the considerable changes of cell arrangements according to the developmental stages of calli from trifoliata orange.

본 연구에서는 탱자의 미성숙배로부터 캘러스 유도와 재분화에 관하여 연구하였다. 탱자 배발생 캘러스들은 3% sucrose와 44.4 $\mu\textrm{m}$ BA로 처리된 $\frac{1}{2}$MS배지에서 광조사(2,000 1x, 16h)시에 미성숙종자의 배로부터 유도되었으며 식물체 재분화는 MS배지에 5.0 $\mu\textrm{m}$ BA를 첨가하였을 때 가장 양호하였다. 탱자는 배양2~3주경에 담황색의 캘러스가 유도되었으며 배양5~6주경부터는 딱딱한 녹색의 캘러스로 변하였다. 기내 재분화는 3% sucrose와 5.0 $\mu\textrm{m}$ BA가 첨가된 MS배지에서 배발생 캘러스로부터 직접 유도되었다. 또한 배양 12주 후에 Multishoot가 재분화되었으며, 배양 16주 후에 뿌리가 형성되었다. 또한 뿌리가 형성된 식물체들은 토양으로 옮겨져 완전한 식물체로 잘 자랐다. 광학 현미경 관찰시 탱자에서는 배양4주경에 하얀색의 조밀한 배양된 세포들이 나타났다. 배양6주경부터는 세포들이 신장되면서 배발생 돌기가 나타났으며 주변의 세포들은 액포화 되었다. 또한 배양12주경에는 미성숙 잎에서 발달된 유낭과 전형성층을 관찰하였다.