Question
I am working on a project involving evaluating vase life of a numerous varieties of roses. I've found that, in the red variety, bent neck was shown on day 3 vase life. I worked with the same red variety a few months previously and didn't find any or very few instances of this quality defect in red roses. Bent neck didn't occur until after day 6 or 7 vase life. I am so surprised that, this time, bent neck is observed so soon in the vases. I hope that you might be able to give me some insight on why this happens. Below, please find a list of things that I did on my first trial, and the second trial.
In the first trial:
- no fungicide was applied on the red roses
- changed water in the vases every other day
- water contained 50ppm chlorine
In the second trial:
- the roses were sprayed with DECREE 50 WDG Fungicide in the greenhouse
- does not change water; only top up the vase with tap water when water level is below the mid-height of the vases
- water does not contain chlorine
I wonder if any of the changes I made for the second trial could have caused more bent neck. (G.A.)
Answer
It seems almost certain that the difference in behavior of the roses is related to the change in the vase solution that you are using for the second trial (no 'chlorine', meaning, I assume, hypochlorite). Bent neck is the result of a failure in water relations (water can't move up the stem to replace what's lost from the leaves). The reason that this normally occurs is that the stems are blocked with bacteria that grow in the exudates from the cut stem. Including hypochlorite in the water prevents the growth of the bacteria so that the conducting tubes in the stem remain open and are able to replace water lost from the leaves.
– Michael Reid