The Influence of Storage Conditions on the Biochemical Composition and Morphology of Dahlia Tubers

Abstract

The aim of this study was to assess by means of biometric measurements and FT-IR and FT-Raman spectroscopic techniques the influence of storage conditions on the morphology and biochemical composition of Dahlia tubers. Investigated samples belong to ‘Kennemerland’ and ‘Red Pygmy’ cultivars of the Dahlia hybrida species, which were preserved over winter at 5-8 °C, 30-40% air humidity in different substrates: sand, sand and sawdust, peat and sawdust. The biometric parameters revealed that the peat and sawdust substrate is the most appropriate one for tubers storage, whereas the sand substrate is the least suitable one. The inulin signature was evidenced in all tuber samples as well as the changes of biochemical composition induced by different storage conditions. The analysis of the FT-IR and FT-Raman spectra demonstrated that the inulin accumulation inside the tubers is favourably influenced by the sand storage, and depends on the cultivar type. Moreover, it was established that the peat and sawdust substrate favours the polyacetylene formation inside the tubers probably because it facilitates the occurrence and development of pathogens inside the tuber. It was also found that the polyacetylene concentration increased, which is associated with the plant response to the pathogen invasion, depends on the cultivar type.