EFFECTS OF SUGAR AND TEMPERATURE ON THE G ROWTH OF MINIATURE BULBS OFLILIUM-JAPONICUM THUNB CULTURED ON A ROTARY SHAKER

We investigated conditions which promote bulb enlargement of Lilium ja ponicum Thunb. cultured on a horizontal rotary shaker before transplan ting in the soil. Sucrose, maltose or glucose was added to the liquid Murashige Skoog's (MS) medium, and their utilization by the bulbs was monitored. Sucrose was hydrolyzed into glucose and fructose, which res ulted in an increase in osmotic pressure and subsequent suppression of bulb growth. Little maltose was absorbed by the bulbs, and therefore it was useless for bulb growth. A 3% glucose medium was optimum for bu lb growth. Bulb growth, as measured by fresh weight increase, in the s haking medium kept at 20 degrees C was better than that kept at 25 deg rees C. However, cumulative absorption by the bulbs of NH4+, NO3- and glucose from the medium at 25 degrees C was almost equal to that at 20 degrees C. It suggested that the consumption of sugar at 25 degrees C was greater than that at 20 degrees C. More bulbs which were cultured in the MS medium with glucose, chilled at 0 degrees C, potted, and pl anted in the greenhouse sprouted and bolted at 20 degrees C than did t hose kept at 25 degrees C. The chilling period for maximum sprouting a nd bolting was three months.