H. Lambrechts et al., CHANGES IN FREE POLYAMINES IN TULIPA-GESNERIANA FLOWER STALKS DURING DRY-STORAGE AND AFTER PLANTING OF BULBS, Plant growth regulation, 13(1), 1993, pp. 71-76
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.