Abstract:
This study was undertaken to investigate the effect of Accel™, sucrose and silver
thiosulphate (STS) on the dry weight, accumulation of sucrose and reducing sugars
in cut tuberose (Polianthes tuberosa L) petals at various positions along the spike.
Cut stems of Tuberose were held in optimum treatments that prolonged their vase
life (Hutchinson et al., 2003): continuous holding in 25 mg/L BA equivalent of Accel;
pulsing in 20% sucrose for 24 hrs and subsequently holding in either deionized water
(DIW) or in 25 mg/L BA; pulsing in 2 mM STS for 1 hr and subsequent holding in DIW.
The middle and bottom florets of cut flowers held in DIW were heavier than the top
florets. Pulsing tuberose cut flowers in sucrose or in STS improved the dry weights
of the middle and bottom florets in the 1st 3 days but up to 6 days of top florets.
Florets of cut flowers pulsed in sucrose and subsequently held in Accel were heavier
than those subsequently held in DIW or those held continuously in Accel. Sucrose,
STS and Accel increased floret opening but had varied influence on the accumulation
of sucrose and reducing sugars in petals of florets along the spike. Cut tuberose
stems pulsed in sucrose and subsequently held in either DIW or 25 mg/L BA
equivalent of Accel accumulated the largest amounts of sucrose and reducing
sugars. Pulsing cut tuberose flowers in 10% sucrose and subsequently holding them
in Accel or DIW or pulsing in STS, while having no influence on sucrose levels in
bottom florets, significantly increased levels in top florets for the 1st 3 days before
a sharp decline in petals pulsed in sucrose. The main difference was that while most
of the sucrose accumulated in the middle florets, reducing sugars was concentrated
on the bottom florets along the spike. Unexpectedly, pulsing stems in STS or holding
them in Accel had no significant influence on levels of sucrose or reducing sugars
within the 9 days of testing even though most florets had opened by this time. The
results of the present study suggest that while sucrose had a direct influence on
accumulating of sucrose and reducing sugars in florets, Accel and STS improved vase
life and floret opening in cut tuberose stems either indirectly through substrate
mobilization and increased metabolism or may have played another different role
other than substrate mobilization.
