Abstract

This study was carried out to determine optimal medium conditions for mass propagation by bioreactor culture of ever-bearing strawberry (Fragaria ${\times}$ ananassa D.). Two different type of nitride were that mixed $NH_4NO_3$ and $KNO_3$ or added $KNO_3$ only. And nitride concentrations were at the 4 levels of $1/2{\times}$, $1{\times}$, $2{\times}$ and $3{\times}$ that was included $NH_4NO_3$ and $KNO_3$. Sucrose content ranged at 3 levels of $10g{\cdot}L^{-1}$, $20g{\cdot}L^{-1}$ and $30g{\cdot}L^{-1}$ and medium pH were at the 3 levels of 4.6, 5.6 and 6.6. In bioreactor culture, medium that are included $NH_4NO_3$ and $KNO_3$ together in MS medium was suitable for mass propagation. Medium EC rose rapidly when the nitride concentration was increased. For that reason, plantlet growth was inhibited. Shoots of nitride $1/2{\times}$ concentration was 10.8 ea and $1/2{\times}$ concentration was suitable for shoot propagation. Fresh weight of sucrose $30g{\cdot}L^{-1}$ was 3,101 mg which was heaviest and aerial and ground part were higher than the other concentration. Shoots were increased in proportion to the increasing concentration of sucrose. In the pH condition, from pH 5.6 to 6.8 were appropriate for the optimum growth of aerial and ground part of plant. From the results, in bioreactor culture for mass propagation, MS medium was suitable $1/2{\times}$ concentration that was included $NH_4NO_3$ and $KNO_3$ together, and added $30g{\cdot}L^{-1}$ of sucrose, and then adjusted pH between 5.6 and 6.6.

본 실험은 사계성 딸기의 무병묘 대량생산을 위한 bioreactor 배양 시 배지조건을 구명하기 위해 실시하였다. 배지조건은 MS배지 내 질소질 종류 2처리 ($NH_4NO_3-KNO_3$혼합, $KNO_3$ 단독), MS배지 내 질소농도 4처리 (1/2배, 1배, 2배, 3배), sucrose농도 3처리 ($10g{\cdot}L^{-1}$, $20g{\cdot}L^{-1}$, $30g{\cdot}L^{-1}$)와 배지 pH 3처리 (pH 4.6, 5.6, 6.6) 등을 실험하였다. 사계성 딸기의 bioreactor 배양 시 MS배지 내에 $NH_4NO_3$와 $KNO_3$를 혼합처리한 배지가 생육량이 많았다. 질소농도가 높아질수록 배지 EC가 급격히 높아지고, 그에 따라 유식물체 생육이 억제되었다. 질소질 1/2배에서 생육량이 많고 신초가 10.8개로 가장 많이 발생하였다. Bioreactor 배양 시 sucrose농도는 $30g{\cdot}L^{-1}$에서 생체중이 3,101 mg으로 가장 무거웠고, 지상부와 지하부 생육량 모두 다른 농도에 비해 많았다. 또한 sucrose농도가 높아질수록 신초수도 증가되는 경향을 보였다. 배지 pH는 5.6-6.6 범위에서 지상부와 지하부 생육량이 모두 많았다. 따라서 사계성 딸기 조직배양묘의 bioreactor를 이용한 대량증식 및 뿌리발달에 알맞은 배지 조건은 MS 무기염을 기본으로 하여 배지 내 질소질은 $NH_4NO_3$와 $KNO_3$ 혼합, 농도는 1/2배, sucrose농도는 $30g{\cdot}L^{-1}$과 배지 pH는 5.6-6.6 범위가 가장 적당하였다.

Keywords

• Fragaria ${\times}$ ananassa;
• medium pH;
• nitride;
• shoot propagation;
• sucrose concentration