Abstract
Flower bud initiation and development in Gypsophila paniculata L. ‘Bristol Fairy’ grown under field conditions were observed by means of a scanning electron microscope.
In plants which were exposed to a sufficient amount of chilling during the previous winter, flower bud initiation took place when the stem attained 18cm in length. Subsequently, differentiation of sepals and petals occurred. Stamen primordia in the terminal floret were initiated around April 30. Between May 5 and 10, when the shoots were in the visible bud stage, the pistil primordium appeared in the terminal floret. Following differentiation of floral organs, the style elongated and the petaloid stamens appeared. The petals and petaloid stamens expanded in succession which led to the dehiscing of the sepals, resulting in anthesis of the terminal floret on May 30.
In plants which were exposed to a limited amount of winter chilling, flower bud initiation of the terminal floret was delayed. It did not take place in buds located from middle to basal nodes of the main stem. However, after the apical meristem enlarged, differentiation and development of the floral organs in the terminal floret were unaffected by the amount of exposure to previous chilling.
