Acceleration of Flowering of Statice (Limonium sinuatum Mill.) by Seed Vernalization

Abstract

Statice (Limonium sinuatumi Mill. =Statice sinuata L.) is one of perennials, and has a low temperature requirement for bolting and flowering. It is generally stated that in perennials and biennials the low temperature requirement is satisfied when growing plants are chilled in winter, but not when germinating seeds are chilled. In this study, the effect of chilling of germinating seeds on bolting and flowering of statice was investigated. Three cultivars, ‘Early Blue’ (early flowering), ‘Midnight Blue’ (medium flowering), and ‘Super Blue’ (late flowering) were used.
1. The statice plants sown in autumn developed flower stalks and formed flower buds in the following spring only when they experienced a certain amount of low temperature in winter.
2. The plants from seeds vernalized by chilling at 2-3°C for 30 days flowered earlier with a smaller number of foliage leaves than those from non-vernalized seeds. The vernalized plants produced a greater number of cut flowers in early crop season, that is, until the following March. Although L. sinuatum is perennial, it proves to be a plant of seed vernalization type.
3. The most effective temperature for seed vernalization was 2°C. The temperature of 5°C had less effect. Early and medium flowering cultivars were vernalized sufficiently by 2°C for 20 days, while late flowering cultivar for 40 days.
4. When the vernalized seedlings were transferred directly to high temperature conditions (constant temperature of 30°C), and grown there for 5 days or more, the vernalization effect was nullified completely. Under field conditions, daily mean temperatures higher than 25°C caused the devernalization.