PHYSIOLOGICAL MARKERS FOR LILY BULB MATURITY

Abstract

The aim of this study was to find physiological markers for lily bulb maturity. This would provide a tool for the grower to determine the optimal time for lifting. The following physiological parameters were measured in daughter sprouts at two week intervals from week number 34 to 52: the abscisic acid (ABA) content, sucrose content, osmotic potential and respiratory activity. As experimental objects the cultivars Connecticut King (Asiatic hybrids; dormant at lifting), 'Star Gazer' (Oriental hybrids; dormant at lifting) and Snow Queen (longiflorums; non-dormant) were used. In each cultivar one or more parameters were found that changed considerably towards the moment of lifting. The most dramatic changes were observed in the parameters ABA- content, sucrose-content and osmotic potential in the cultivar Connecticut King'. The same trend was observed in Star Gazer', but to smaller extent. These results enable us to assess correlations of these parameters with the flower quality of the bulbs that were lifted at the same moments and stored below 0°C for flower production in the autumn of 1998. In 'Snow Queen only the sucrose content showed an increase with sprout development. Respiratory activity decreased towards the time of lifting in all cultivars. A correlation was found between the process of dormancy and the ABA content. Only in the dormant cultivars ('Connecticut King' and 'Star Gazer') the ABA content increased with sprout development and the increase in ABA level preceded the cessation in sprout growth.