Abstract
Shoots of balloon flower (Platycodon grandiflorum A. DC.) derived from in vitro germinated seeds were cultured on MS medium containing $0.1\;\cal{mg/L}$ NAA under various photosynthetic photon flux (PPF) 33, 66, and $99\;{\mu}mol\;m^{-2}s^{-1}$ with or without membrane filter. Number of air exchanges per hour (NAEH) of the culture vessel with membrane filter on the lid was $4.9 h^{-1}$ and that without membrane filter was $0.1 h^{-1}$ Plantlets grown in $4.9 h^{-1}$ NAEH showed greater growth than in $0.1 h^{-1}$ NAEH. According to increase of PPF, plantlets growth decreased in $0.1 h^{-1}$ NAEH while it increased in $4.9 h^{-1}$ NAEH. At the same PPF, fresh weight and sugar content in plantlets in $4.9 h^{-1}$ NAEH were above 1.9, 2.0 times higher than those in $0.1 h^{-1}$ NAEH, respectively. Also they were enhanced in $4.9 h^{-1}$ NAEH by increase of PPF whereas no significance in $0.1 h^{-1}$ NAEH. The percentage of water content of plantlets in $4.9 h^{-1}$ NAEH was $4.2\~5.5\%$ lower than those in $0.1 h^{-1}$ and no difference in PPF. The content of total chlorophyll in plantlets in $4.9 h^{-1}$ NAEH was higher $0.27\~0.79\;\cal{mg/g}$ F.W. than that in $0.1 h^{-1}$ NAEH. By increase of PPF, it was decreased in $0.1 h^{-1}$ NAEH while had no significant difference in $4.9 h^{-1}$ NAEH. Guard and subsidiary cells of leaves in $4.9 h^{-1}$ NAEH were more developed than in $0.1 h^{-1}$ NAEH. Especially, in $99\;{\mu}mol\;m^{-2}s^{-1}$ leaves in $0.1 h^{-1}$ NAEH had undeveloped subsidiary cells and wide open stomata whereas those in $4.9 h^{-1}$ NAEH had well-developed subsidiary cells.
기내 배양환경을 조절하여 건전한 유식물체를 획득하기 위해 도라지를 무균발아시켜 shoot부분을 NAA $0.1\;\cal{mg/L}$ 가 첨가된 MS 기본배지에 치상한 후 배양용기의 뚜껑위에 membrane filter를 부착하여 환기횟수를 달리하고 광도를 33, 66, 99 ${\mu}mol\;m^{-2}s^{-1}$로 처리하여 생장반응을 조사하였다. Membrane filter 부착구의 환기횟수는 $4.9 h^{-1}$이었으며 미부착구는 $0.1 h^{-1}$이었다. 환기횟수 $4.9 h^{-1}$ 처리구에서 $0.1 h^{-1}$ 처리구에 비해 전반적으로 생장이 양호하였으며 $0.1 h^{-1}$에서는 광도가 증가할수록 생장이 저조한 반면 $4.9 h^{-1}$ 처리구에서는 광도의 증가에 따라 생장이 좋은 경향이었다. 동일한 광도에서 환기횟수 $4.9 h^{-1}$ 처리구는 $0.1 h^{-1}$ 처리구에 비해 생체중은 1.9배, 당 함량은 1.4배 이상 높았으며 환기횟수 $4.9 h^{-1}$ 처리구는 광도의 증가에 따라 생체중과 당 함량이 높아졌으나 $0.1 h^{-1}$ 처리구는 광도에 의한 효과가 인정되지 않았다. 함수율은 환기횟수 $4.9 h^{-1}$ 처리구에서 $0.1 h^{-1}$ 처리구에 비해 $4.2\~5.8\%$가 낮았으나 광도 처리에 의한 차이는 없었다. 동일한 광도에서 총 엽록소 함량은 환기횟수 $4.9 h^{-1}$ 처리구에서 $0.1 h^{-1}$ 처리구에 비해 $ 0.27\~0.79\;\cal{mg/g}$ F.W.가 높았으며 환기횟수 $0.1 h^{-1}$ 처리구는 광도의 증가에 따른 효과가 나타나지 않았으나 환기횟수 $0.1 h^{-1}$ 처리구는 높은 광도에서 감소하였다. 환기횟수 $4.9 h^{-1}$는 $0.1 h^{-1}$에 비해 잎의 공변세포가 크고 주변 부세포가 잘 발달되어 있었다. 특히 PPF $99\;{\mu}mol\;m^{-2}s^{-1}$에서 환기횟수 $0.1 h^{-1}$는 부세포의 발달이 미흡하고 기공이 많이 열려 있는 상태인 반면 환기횟수 $4.9 h^{-1}$는 부세포가 잘 발달된 잎을 지니고 있었다.
