CHANGES IN FREE POLYAMINES IN TULIPA-GESNERIANA FLOWER STALKS DURING DRY-STORAGE AND AFTER PLANTING OF BULBS

Tulip bulbs cv. Apeldoorn are dry-stored at 5-degrees-C for 12 weeks t o ensure sufficient elongation of the flower stalk, when subsequently planted at higher temperatures (17-20-degrees-C). To investigate wheth er free polyamines are involved in this process, flower stalk internod es were analyzed during dry-storage and after planting of the bulbs. D uring dry-storage for 12 weeks at 5-degrees-C (cooled) and 17-degrees- C (non-cooled), the free putrescine, spermidine and spermine amounts p er flower stalk increased. The putrescine amount increased at 5-degree s-C significantly more than at 17-degrees-C, whereas the opposite was found for the spermine amount. These differences developed early durin g dry-storage and disappeared rapidly at subsequent higher temperature s. After planting, the lower- and uppermost flower stalk internodes of the pre-cooled bulbs elongated much faster than those of the non-cool ed ones. In the pre-cooled bulbs, the free polyamine amounts per inter node increased with time after planting, but the time course of these changes was different. In the non-cooled bulbs, the free polyamine amo unts increased to a much lesser extent or remained more or less consta nt. It is argued that the observed changes in the free polyamine conte nts are probably not required for the cold-induced extension growth of tulips cv. Apeldoorn.