テッポウユリ

Experiments were carried out to make clear influences of light and temperature conditions towards bolting and emergence of scaly leaf in lily scale bulblets during the scaling, especially the first 6 months after the beginning of scaling. Easter lily ‘Hinomoto’ was scaled in peatmoss nursery beds of various depths, 0, 0-3 and 3-12 cm, under the conditions of 25 and 15℃ constant temperature in a phytotron, Biotron Institute, Kyushu University, and under natural outdoor environment. Scales set at depths of 0 and 0-3 cm became to be exposed daily to sun light. When scaled under light condition, bulblets showed a much earlier expansion of their scaly leaves as compared to the slow bolting (stem leaf expansion) in others. Such a rapid emergence of scaly leaves was observed with a still larger frequency as compared to the bolting in darkness. The lower the scaling temperature became, the more remarkable the situation was to appear. Bolting was more frequent at 25℃ than that at 15℃ about 5 months after the beginning of scaling. During the following 3 months bolting did not increase at 25℃, but increased at 15℃, with the result that bolting at 15℃ became more frequent than that at 25℃. In darkness, most bulblets showed more frequent bolting than scaly leaf emergence at any temperatures. This bolting was accelerated when scale bulblets were transferred into the high temperature conditions. One month after the beginning of scaling in darkness at 25 and 15℃, scales with bulblets were transplanted and kept scaling in darkness at 25, 20, 15, 10 and 5℃ for the following 5 months. At 25, 20 and 15℃, the lower the temperature was, the higher the bolting was. When scaled at 25℃ for the first one month, the bolting ratio was higher than that when scaled at 15℃. At 10 and 5℃, however, no leaf expanded regardless of the scaling temperatures of the first one month. One month after the acceleration of leaf expansion at 25℃, only scaly leaves emerged on these bulblets. The scaly leaf ratio was higher when scaled at 15℃ than at 25℃ of the first one month. The results are as follows: The light which is irradiated on scales during the scaling acts to promote the emergence of scaly leaves to suppress bolting. Such effect of light is accelerated by low temperature. Primary growth response of scale bulblets in darkness is to bolt, being induced by low temperature. Scale bulblets developed at higher temperature are induced more easily than those at lower ones. After the induction of bolting, the elongation of the stem is accelerated by high temperature.