Autumn daffodil (Sternbergia lutea) is a wild bulbous plant with tremendous ornamental value. Knowledge of the changes that occur during dormancy would be helpful to improve breeding strategies for this geophyte, its artificial cultivation for application in landscaping, and its commercialization. In a Mediterranean climate, the plant enters dormancy in June (stage 1, S1), dormancy proper, which lasts for two months [July and August; stage 2 (S2)], while September and October [stage 3 (S3), i.e., autumn] represent the exit from dormancy and the start of flowering. In this research, the biochemical changes in four tissues of bulbs (outer scales, inner scales, basal plate and bud) in the three stages (S1-S3), as well as in the leaves and roots of plants in two stages (S1, S3), were assessed. The total soluble protein, proline, phenolic and hydrogen peroxide (H2O2) contents in almost all tissues of the bulb increased from S1 to September (the first month of stage 3), but then decreased in October (the second month of stage 3). In contrast, total soluble carbohydrate content and superoxide dismutase (SOD) activity decreased during S2 but increased in S3. Malondialdehyde (MDA) content and peroxidase (POD) activity increased in S1-S3. In leaves and roots, proline, H2O2, and MDA content, as well as POD and SOD activity, were highest in S1. In contrast, total soluble carbohydrate and total soluble protein contents were highest in S3. The findings of this experiment will help to better understand autumn daffodil bulb dormancy from a biochemical perspective, allowing for more effective management of commercial bulb propagation and production, as well as transportation.
