Springer Online Journal Archives 1860-2000
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Abstract Tulip bulbs cv. Apeldoorn are dry-stored at 5°C for 12 weeks to ensure sufficient elongation of the flower stalk, when subsequently planted at higher temperatures (17–20°C). To investigate whether free polyamines are involved in this process, flower stalk internodes were analyzed during dry-storage and after planting of the bulbs. During dry-storage for 12 weeks at 5°C (cooled) and 17°C (non-cooled), the free putrescine, spermidine and spermine amounts per flower stalk increased. The putrescine amount increased at 5°C significantly more than at 17°C, whereas the opposite was found for the spermine amount. These differences developed early during dry-storage and disappeared rapidly at subsequent higher temperatures. After planting, the lower- and uppermost flower stalk internodes of the pre-cooled bulbs elongated much faster than those of the non-cooled ones. In the pre-cooled bulbs, the free polyamine amounts per internode increased with time after planting, but the time course of these changes was different. In the non-cooled bulbs, the free polyamine amounts increased to a much lesser extent or remained more or less constant. It is argued that the observed changes in the free polyamine contents are probably not required for the cold-induced extension growth of tulips cv. Apeldoorn.
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