Determination of primary metabolites, cell wall components and enzyme activity during flower development in damask rose (Rosa damascena Mill.)

Damask rose is cultivated for its valuable products, such as essential oil, but the biochemical and metabolic changes occur during the flower development are not well understood. In the study, phenological, primary and secondary metabolites, color compounds, carbohydrate metabolism, cell wall components and related enzyme activities were determined at five developmental stages in oil-bearing rose flowers. Significant differences detected in examined phenological features during the flower development. The amount of primary metabolites showed increasing trends, except protein and oil content, during the flower development. Secondary metabolites contents changed depending on the metabolite studied, while organic acid and phenolic contents decreased the amount of essential oil and the number of components increased during flower development. While the amounts of anthocyanin and other color compounds were high until III development, they decreased at later stages of flower development. Changes in colorimetric parameters (L*, a*, b*, c*, hº) followed change of color components during the flower development. Carbohydrate metabolism showed significant differences; while fructose, glucose, soluble sugars, total carbohydrates and starch contents were high, the sucrose levels were low at the later stages of flower developmental. Although ADF, NDF and hemicellulose contents did not change during flower development, pectin content increased and cellulose content decreased. Activity of all cell wall enzymes (β-galactosidase, β-glucosidase, endoglucanase, pectin lyase, pectin methyl esterase and polygalacturonase) increased until the fourth period, but their activity decreased significantly at the fifth period of flower development. Principal coordinate analysis and correlation analysis were carried out to identify relationships between the examined parameters, out of 741 correlations, 80 was positive and 55 was negatively correlated with each other. Principal coordinate analysis explained 85.1% total variation and divided development stages into four clusters. In conclusion, occurrence of significant biochemical changes was detected at third and fourth stages of damask rose flower development.