THE EFFECT OF SUPPLEMENTARY LIGHTING ON FLOWERING AND CARBOHYDRATE CONTENT OF TWO ROSE CULTIVARS

Rosa hybrida ‘Frisco’ and ‘Madelon’ plants were grown during winter in natural light (NL) and two supplementary lighting time regimes: NL + 6 hours, NL+12 hours per day (PAR 90-110 μmol m^–² s‾¹, depending on the height of the plants). The additional lighting started from 15^th September and it was continued until 30^th of March during 4 years of culture.
The roses were grown in the prepared soil in double row.
Flowers were collected all year around, and cut 80–90 cm above the soil level.
The analyses of the carbohydrates were performed on the first five leaflet leaves below the bud and flower peduncle.
The supplementary lighting had the significant effect on the flowers number of both tested cultivars during the winter periods.
The harvested stems were longer and their number was higher in 12 hours additional light compared with the natural and 6 hours light (‘Frisco’). The cv.’Madelon’ showed lower demand to supplementary light; its productivity was the same for 6 or 12 hours of additional light.
The total carbohydrates content in dry weight in the leaves was smaller than in peduncles.
The amount of glucose fructose and sucrose in the leaves of ‘Madelon’ was significantly higher than in ‘Frisco’, whereas, they were higher in peduncles of cv. ’Frisco’ in natural light than with the supplementary one.
The status of the tested fructose, sucrose, glucose and starch is discussed.

VI International Symposium on Protected Cultivation in Mild Winter Climate: Product and Process Innovation

H. Wiśniewska-Grzeszkiewicz, J. Treder

Rosa sp., supplemental lighting, flower numbers, quality, fructose, glucose, sucrose, starch

https://doi.org/10.17660/ActaHortic.2003.614.72