Osmotic potential and carbohydrate contents in the corolla of the rose cv. Madelon.
Marissen, N.;
Acta Horticulturae Year: 1991 Issue: No. 298 Pages: 145-152 Ref: 1 ref.
1991
บทคัดย่อ
Roses (Rosa hybrida, cv. Madelon) at normal harvest maturity were placed in water at 5 deg C for 4 h and then transferred to deionized water containing 1 mg AgNO3/litre in conditioned rooms (20 deg , 60% RH, 12 h light/day). For measurement of the osmotic value, petals were frozen at -20 deg , defrosted after a minimum of 2 days and the sap pressed out at 600 kPa for 5 s. The osmotic value of the sap was determined by cryoscopy. Starch, glucose, fructose and sucrose contents were also measured. Flowers opening on the plant were used as a control. During opening on the plant the osmotic potential increased during the first week, whereas during opening in water there was no increase during the first 4 days but on the 7th day the osmotic value appeared to be as high as in flowers which opened on the plant. Starch content decreased rapidly during vase life but remained almost level on the plant. During opening on the plant, glucose, fructose and sucrose contents increased, whereas in water only the fructose content increased and was always lower than on the plant. A further experiment was carried out to investigate possible competition between inner and outer petals. The outer petals were removed at the beginning of vase life to leave 0, 1-5, 6-10, 11-15 or 16-20 petals remaining. After 6 days, the area and sugar contents of the 10 innermost petals were measured. The area and sugar contents of inner petals increased when fewer outer petals were present during vase life, indicating competition between inner and outer petals for sugars during flower development.