ISHS Acta Horticulturae 543: VII International Symposium on Postharvest Physiology of Ornamental Plants
EFFECTS OF PRE-HARVEST LIGHT INTENSITY AND TEMPERATURE ON CARBOHYDRATE LEVELS AND VASE LIFE OF CUT ROSES |
| Author: | N. Marissen |
| Abstract:
In post-harvest physiology it is often assumed that a high concentration of carbohydrates in the harvested cut flowers is a prerequisite for a long vase life. For roses it is known that a sugar supply in the vase solution increases vase life, probably because the sugars are used as substrate for respiration, maintenance, synthesis and osmoregulation, and thus senescence is delayed. Sugars from the vase solution are transported via the leaves into the flower bud. In roses, the leaves can act as a storage pool for carbohydrates, which are transported to the flower bud during vase life. In two subsequent experiments the effects of respectively light level and growth temperature on vase life and carbohydrate level of different rose varieties have been investigated. The level of supplementary lighting causes great differences in carbohydrate contents of leaves and flower buds at the moment of cutting. The vase life however, was roughly the same for most varieties. In the next winter season the same crop was grown at different temperatures, all temperatures with an equal level of supplementary lighting. Now, there were small differences in vase life, in which the roses grown at 20 oC lasted significantly longer than roses grown at 16 oC. Carbohydrate contents in the leaves did not show big differences: sucrose levels in 16 oC-grown leaves were 10 % higher than in 20 oC-grown leaves. Starch levels were low, and 16 oC-grown leaves had half the amount of starch (6 mg/gDW) of 20 oC-grown leaves. It can be concluded that the relation between vase life and carbohydrate pool in leaves or flower bud is absent, and also that differences in vase life due to the levels of supplementary lighting and growth temperature are small. | |
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