Using Flowering Times and Leaf Numbers to Model the Phases of Photoperiod Sensitivity in Antirrhinum majus L

• Published in: Annals of botany 2003-11, Vol.92 (5), p.689-696
• Main Authors: ADAMS, S. R., MUNIR, M., VALDÉS, V. M., LANGTON, F. A., JACKSON, S. D.
• Format: Article
• Language: English
• Subjects: Antirrhinum - classification; Antirrhinum - genetics; Antirrhinum - physiology; Antirrhinum - radiation effects; Flowering; Flowers; Flowers - physiology; Horticulture; Hybrid Vigor; Inflorescences; juvenility; Key words:Antirrhinum majus; leaf number; Leaves; Memory interference; Modeling; Models, Biological; Photoperiod; Plant Leaves - physiology; Plants; reciprocal transfer; Seedling emergence; snapdragon
• ISSN: 0305-7364; 1095-8290
• DOI: 10.1093/aob/mcg194

A model has been developed that can be used to determine the phases of sensitivity to photoperiod for seedlings subjected to reciprocal transfers at regular intervals between long (LD) and short day (SD) conditions. The novel feature of this approach is that it enables the simultaneous analysis of the time to flower and number of leaves below the inflorescence. A range of antirrhinum cultivars were grown, all of which were shown to be quantitative long‐day plants. Seedlings were effectively insensitive to photoperiod when very young (juvenile). However, after the end of the juvenile phase, SD delayed flowering and increased the number of leaves below the inflorescence. Plants transferred from LD to SD showed a sudden hastening of flowering and a decrease in leaf number once sufficient LD had been received for flower commitment. Photoperiod had little effect on the rate of flower development. The analysis clearly identified major cultivar differences in the length of the juvenile phase and the photoperiod‐sensitive inductive phase in both LD and SD.