Stem node survival in green house
The 4-month-old in vitro shoots placed in the darkness were transferred into fluorescent light condition at 15–20 lmol m-2 s-1 and regime of 16/8-h (light/dark) (Fig. 1g2). Temperature was maintained at 25 ± 3 C. After 2 months, these shoots were cut into single nodes and cultivated in fern fibers in the greenhouse (under the natural light with PPFD less than 200 lmol m-2 s-1 using sunshade nets, at 16–25 C, and 60–90 % relative humidity) for 12 months (Fig. 1h, i). SPAD values of the shoots and single nodes were determined by the Minolta Chlorophyll meter SPAD-502 (Minolta Co., Ltd, Osaka 541, Japan) after 4 months in the darkness, 2 months under fluorescent lamp and 12 months in the green house.