Effects of illumination on nutrient absorption from the liquid-shaking medium by enlarging miniature lily bulbs (Lilium japonicum Thunb.).

摘要

The effects of illuminating the liquid-shaking culture on the absorption of nutrients by enlarging miniature bulbs of L. japonicum were investigated. When bulbs (0.3-0.4 g fresh weight (FW)) were cultured for 165 days under light or dark conditionsin 3 types of liquid media containing 3 or 6% glucose or sucrose, light promoted enlargement. A medium with 3% glucose in the light was optimum for bulb enlargement; FW was～5.3 g by the end of the experiment. Cumulative absorption of sugars, NH4+, NO3-and K+ by bulbs exposed to light and sucrose was significantly higher than those grown in the dark. Light and sucrose had no effect on Ca2+ and Mg2+ absorption. The gain in bulb FW in the light almost equalled that of sugar absorption by the bulb, whichsuggests that bulb enlargement was not related to photosynthesis but to promotion of sugar absorption from the medium. Illuminating the liquid-shaking culture enabled the production of 5-g bulbs (about 9 cm in circumference) in 5-6 months.