Posted by: HortAlaska | May 16, 2018

Vase Life of Peonies – add sugar or not?

The dynamics of starch and sugar utilisation in cut peony (Paeonia lactiflora Pall.) stems during storage and vase life E.F. Waltona,∗, H.L. Boldinghb, G.F. McLarenc, M.H. Williamsa,1, R. Jackman 2010. Post Harvest Biology and Technology 58:142 – 146. Peony carbs vase life.

This article published in 2010 from NZ scientists examines the quantities of carbohydrates in fresh cut peony stems stored up to 8 weeks at 0C and compared them with flowers still attached to the plant. The idea was to determine if there was sufficient carbs in the cut stems to promote max. vase life or should they try to increase carb production in the field or add carbs to the vase water  to extend vase life

They used ‘Sarah Bernhardt’ peonies. Fresh cut stems that had not been stored (control) opened in about 4.9 days and remained at the full bloom stage for an additional 9.1 days. Field flowers had a similar vase life. Flower buds stored 8 weeks opened much more rapidly in 1.9 days and remained at the full bloom stage for 7.1 days. At the beginning of vase life trials, non structural carbs made up 27% of bud dry weight and during flower opening, carb concentrations declined to only trace amounts. The biggest decrease occurs just as the petals begin to unfurl. At the same time total sugars increased and peaked when flowers had fully opened, then gradually decreased as the flower senesced. The main sugars were fructose and glucose.

Flowers still in the field showed that the amount of sugar moving into a stem  during flower opening was about 3.2 g or about 14.3% of dry weight of the whole stem or 42% of the dry weight of the open flower. It would follow, then, that adding sugars to the vase water of fresh cut stems might extend vase life by improving carbohydrate levels in the flowers and stems. However, when comparing the flowering sequence between flowers in the field and fresh cut flowers, there is no difference in the number of days flowers take to open or in the total vase life. The authors conclude that even though there is a big influx of carbs into the stem and flower, carbs are not a limiting factor in vase life.

They propose, instead, that the big difference is in what happens to the starches. In  cold storage, starches are hydrolyzed (broken down into simpler sugars)  in the tissues within the first two weeks, something that does not occur in field or fresh cut flowers. This resulting massive availability of sugars leads to very rapid flower opening in stored flowers and shorter vase life. So how do you slow starch hydrolysis in storage?

 

 


Responses

  1. Very interesting conclusion. I am interested to see any replication of this and to see a followup study on the starch issue. How do you slow the starch hydrolization?

    Like


Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

Categories

%d bloggers like this: