Now 'Sylvia' proteas last even longer
 Researchers
found a simple solution that can double the shelf life of proteas and can
especially benefit the export market. One of the biggest challenges of the
protea industry is to deliver quality products overseas.
For more than 40 years researchers have battled to find a solution to the
problem of post-harvest leaf blackening in proteas. Now Iain Stephens, a
postgraduate student in the Department of Horticultural Science at Stellenbosch
University has, under the guidance of Prof Gerard Jacobs and Dr Deirdre Holcroft,
found a solution that is amazingly simple and affordable.
An analysis of individual sugars (sucrose, glucose and fructose), and their
movement between the leaves and the flower of 'Sylvia' (Protea eximia x Protea
susannae) after harvesting, was the solution to post-harvest blackening,
explains Iain.
The results showed that, of the three sugars, glucose appeared to be the
carbohydrate that determined the longevity of both leaves and flowerheads. It
was this that prompted Iain to test glucose as a holding solution specifically
for 'Sylvia' proteas. Sucrose is the standard holding solution for most
cutflowers, he explained, but it has not worked particularly well with 'Sylvia'.
Experiments showed a holding solution of 2,5% glucose (25g glucose to one
litre of water) significantly and dramatically reduced leaf blackening, reports
Iain. 'Sylvia' proteas kept in lower glucose concentrations blackened rapidly
and vase life was about ten days.
Held at the higher concentration, the proteas showed minimal blackening even
after 20 days. The trials were terminated because of flowerhead collapse after
20 days and not leaf blackening, the first time that has even been recorded,
explained Iain.
'Sylvia' cut proteas rank highly in cut protea exports - currently about 330
000 stems are exported annually. It is an important cultivar to the protea
export industry, he emphasized. The protea industry faces many challenges in
delivering quality products to foreign markets, explained
Iain. This breakthrough should go a long way to ensuring better landed quality
of 'Sylvia'.
by Karin Theron, University of Stellenbosch
|
