Foliar Emergence from Bulblets of Lilium longiflorum Thunb. as Related to in Vitro Generation Temperatures1

Abstract

Abstract Bulblets of Lilium longiflorum generated in vitro in the dark at 30°C produced leaves more rapidly and more completely after transplanting to vermiculite than those generated in vitro at 25°. The product of temperature × time (days) was equalized by varying the number of days at the 2 temperatures to make treatments comparable. Therefore, the effect of temperature in vitro was not due to a linear relationship between bulblet development and the product of temperature × time. Bulblets formed at 30°C for half of the temperature × time product of the tissue culture period produced leaves after transplanting at rates similar to those of bulblets generated at a constant 30°C. Exposure of bulblets generated in vitro at 25°C to 4° for 2 weeks before planting in vermiculite resulted in leaf production not significantly different from that of chilled or non-chilled bulblets generated in vitro at 30°C. However, chilling significantly increased fresh weight of bulblets produced in vitro at either temperature. The data suggest that temperature during in vitro development affects Easter lily bulblet dormancy as measured by leaf production.