Abstract
This experiment was conducted to study the effect of $CO_2$(0, 2, 500, 5, 000, 10, 000ppm) enrichment by enabling ventilation on micropropagation of multi-shoot and on the saponin contents in vitro in Korean ginseng (Panax ginseng C. A. Meyer). Embryo was cultured in Murashige and Skoog medium added 3mg/ l of Indolbutyric acid, Benzyladenin and Gibberellic acid $(GA_3)$, respectively. $CO_2$, enrichment had little effects on the number of adventitious buds and shoots originated from adventitious buds. The ratio of differentiated shoots to adventitious buds were about 50% in $CO_2$, enrichment treatment. The shoots originated from adventitious bud showed more rapid growth and had larger leaf area than the shoots originated from the leaf primordia did. The number of shoot primordia was the highest in 2, 500ppm of $CO_2$ enrichment treatment. On the contrary, 10,000ppm of $CO_2$, enrichment made smaller the number of shoot primordia and ratio of shoots to shoot primordia. The range of shoots differentiated was from shoot primordia were 15. 4 to 23. 9. The rate of dry weight of cultured shoots showed lowest (7. 5%) in control and highest (8. 59%) in 2, 500ppm of $CO_2$, enrichment. Rate of in vitro flower in control was 7.6% and that in 2500ppm of $CO_2$ was about twice (15.7-16.3%) as much as in control. Flower number per a embryo cultured was about 1.2-1.3. In the multi-shoots with callus enriched by 2, 500ppm of $CO_2$, the contents of crude saponin and ginsenosides in multi-shoots alone were higher than in multi-shoots with callus. The characteristics of ginsenosides in multi-shoots were especially the higher content of ginsenoside Rd, Re, and $Rg_1$.
인삼 조직배양에 있어 multi-shoot 대량번식을 통한 이차대사산물의 이용가능성을 조사코자 강제통기방식에 의해 $CO_2$를 기내에 공급하여 배배양하였던 바 multi-shoot 분화특성 및 사포닌 함량에 미치는 $CO_2$의 효과는 다음과 같다. 부정아 수와 부정아 유래의 신초수는 무처리와 $CO_2$ 2처리구간에 차이가 적었고 분화율은 50%내외이었고 부정아에서 분화한 신초는 경엽의 전개가 빠르고 생장량이 높은것이 특징이었다. 한 개의 자엽에서 분화되는 shoot primordium의 수는 대체로 15.4개-23.9개로 $CO_2$ 2, 500ppm처리구가 가장 양호하였고 $CO_2$ 10, 000ppm의 고농도는 오히려 shoot primordium수 뿐만 아니라 신초 분화율도 저하시켰다. 무처리의 건물율은 7,50%이었던데 반하여 $CO_2$ 2, 500ppm처리구는 건물율이 8.59%로 여타 $CO_2$ 처리구에 비하여 가장 높았다. 기내개화율은 무처리가 7.6%이었으나 $CO_2$, 2, 500-5, 000ppm처리구는 16.3-15.7%로 무처리에 비하여 2배 가량 높았다. 그러나 1개의 치상 배에서 얻어지는 개화수는 1.2-1.3개로 $CO_2$ 처리농도에 따른 차이가 없었다. 조사포닌 함량은 $CO_2$ 2, 500ppm처리구의 경우, 캘러스와 신초가 혼재되어 있는 소식물체는 5.80%이었던데 비하여 multi-shoot가 8.32%로 높았고 ginsenoside함량은 multi-shoot의 경우, ginsenosid Rd, Re 그리고$Rg_1$이 특히 많았다.