DORMANCY RELEASE OF MICROPROPAGATED BULBLETS OF LILIUM-SPECIOSUM AFTER LONG CULTURE IN SOIL

Micropropagated Lilium speciosum Thumb. bulblets were cold-treated at 2C for various periods before being planted in soil. About 20% of noncold-treated bulblets and 100% of bulblets cold-treated for 6 weeks sprouted within 10 weeks after planting. Intermediate lengths of cold treatment resulted in intermediate percentages of emergence. The remaining 80% of the noncold-treated bulblets sprouted synchronously from 25 to 33 weeks after planting. In these bulblets, the number of scales increased before sprouting. A sample of bulblets that had received a short cold treatment (2 or 3 weeks) also showed biphasic emergence, with the second period between 25 and 33 weeks. When the cold treatment was interrupted by 3 weeks at 17C, the percentage of emergence during the first period was reduced and the timing of the second period advanced.