STUDIES ON SOME FACTORS AFFECTING THE VASE LIFE AND QUALITY OF THE CUT FOWERS OF CARNATION (Dianthus caryophyl/us L.) AND ROSE (Rosa hybrida L.).

Two experiments were carried out on                                          "White Sim" standard
carnation and "Dallas" roses, in order to study the effects of ethanol, as an
anti-ethylene agent, in comparison to silver salts on the vase life and quality of
the cut flowers in the presence or absence of external ethylene source. The
experiments were conducted at the Dept. of Plant Production, College of Agric.,
King Saud University, Saudi Arabia durin; the two successive seasons 1995
and 1996. Within each season, carnation experiment was conducted twice on
1^st of March and 1⁵¹ of April, and, rose experiment on 1⁵¹ of May and 1⁵¹ of June
in each year. Flowers were placed in eiher deionized distilled water, 4%
ethanol, 6% ethanol, 1 mM silver nitrate, and 1 mM silver thiosulfate (STS)
solutions containing zero or 50 ppm ethephon. Flowers were placed inside fully
controlled growth chambers under standard conditions of 20°C, 16 hours of
2000 lux fluorescent light, 60 - 70 % relative humidity, and continuous air
circulation of low velocity. Data were collected on vase life, fresh weight gain,
and average daily solution uptake of the flower.
The results showed that, in the absence of ethephon from the solution, all
chemicals improved vase life and quality of both carnation and roses compared
with the 01 water. In the absence of etbephon, silver nitrate solution gave best
results of vase life, maximum weight ga n, and solution uptake for both
carnation and roses. STS solution rankec second, followed by 6% ethanol,
while 4% ethanol' ranked fourth in descending order for all previous
measurements.
The results also showed that the presence of ethephon in the solution
reduced vase life and quality of both carnation and roses, and it was observed
that carnation was more affected by ethephon than roses. In the presence of
50 ppm ethephon in the solution, all chemic" Is improved vase life of cut roses
in comparison with 01 water containing ethe-ohon, while STS and 6% ethanol
were the only two chemicals that improvec vase life of cut carnation. In
addition, in the presence of ethephon in Ihe solution, STS was the best
chemical, followed by 6% ethanol for both "White Sim" carnation and "Dallas"
roses.
In this respect, it was concluded that in the absence of external ethylene,
at least a part of cut carnation and rose senescence is caused by the effect of
internal ethylene produced by the flower issue. Ethanol is a promising
chemical that could be used in flower preservative solutions as an anti-ethylene
agent, but further studies are needed before giving recommendations for
optimum concentration that could be used for cifferent cut flowers.