WO2001060155A1

WO2001060155A1 - Preservative for ornamental cut flowers

Info

Publication number: WO2001060155A1
Application number: PCT/ES2001/000041
Authority: WO
Inventors: Félix ROMOJARO ALMELA; María SERRANO MULA; María Concepción MARTINEZ MADRID; María Teresa PRETEL PRETEL; Pedro Fernandez Parra
Original assignee: Consejo Superior De Investigaciones Cientificas; Universidad Miguel Hernandez-Otri
Priority date: 2000-02-21
Filing date: 2001-02-08
Publication date: 2001-08-23
Also published as: ES2159268B1; AU3177101A; ES2159268A1

Abstract

The invention concerns a preservative for ornamental cut flowers in the form of a mixture of compounds containing commercial sugar, citric acid, sodium citrate, germicide, ethylene synthesis inhibitor and humectant, which is prepared to be diluted in a liter of water and to preserve the cut carnations therein. The useful commercial life of the cut flowers is thereby considerably enhanced. The main advantages provided by said composition in comparison with commercially available compounds is that it exhibits greater effectiveness in retarding senescence or aging off the cut flower and the fact that it does not contain compounds that may pollute the environment or be harmful to the health of humans or animals.

Description

Title: Preservative for cut ornamental flower.

Technical Sector:

Conservation of ornamental flowers, especially carnation.

State of the Art:

The senescence of the ornamental flower accelerates when it is separated from the plant, which determines that in a few days the flower loses its commercial value. The longevity of the flower is considered as the time it retains its decorative qualities; that is, the time it takes for clear symptoms of wilting to appear, which, for example, in the case of carnation are curl and necrosis of the petals. This senescence process is genetically programmed and controlled by the ethylene hormone, the changes related to it being produced by the expression of specific genes (Van Alvorst, AC and Bovy, AG 1995. The role of ethylene in the senescence of carnation flowers, a review Plant Growth Regulation 16: 43-53.).

In addition, at the beginning of the senescence of certain species of cut ornamental flower there is a slight increase in weight during the first days after harvesting and subsequently it descends very steeply. Coinciding with the onset of fresh weight loss, the ethylene production rate also begins to increase. This ethylene production is autocatalytic, which means that the ethylene produced stimulates its own synthesis (Woodson, WR and Lawton, KA 1988. Ethylene-induced gene expression in carnation petáis. Relationship to autocatalytic ethylene production and senescence. Plant Physiol. 87: 498-503), which sharply increases the rate of ethylene production to a maximum, which then drops in the last two days of senescence. In climacteric flowers it is this hormone that initiates and regulates the processes that ultimately lead to its programmed death. Therefore, the first symptoms of aging are detected when ethylene production begins, which also coincides with the decrease in fresh weight. Due to the importance of ethylene in the senescence of climacteric flowers, numerous studies have been carried out using inhibitors of the two key enzymes involved in the biosynthesis of the hormone (ACC synthetase and ACC oxidase) or their hormonal action, compounds that can inhibit ethylene production and delay senescence (Halevy, AH 1987. Recent advances in postharvest physiology of carnations Acta Horticulturae, 216 243-254, Wang, H. and Woodson, WR 1989.

Reversible inhibition of ethylene action and interruption of carnation petal senescence by norbornadiene Plant Physiology 89 434-438, Serrano, M., Romojaro, F., Casas,

J.L., Del Rio, J. and Acosta, M. 1990. Acton and mechanisme of -aminoisobutyric acid as a retardant of cut carnation senescence Scientia Horticulturae 4 127-134, Van

Alvorst, A.C. and Bovy, A.G. 1995. The role of ethylene in the senescence of carnation flowers, a review Plant Growth Regulation 16 43-53)

However, many of these inhibitors are very useful for studies on physiology of senescence in the laboratory, but their practical application is scarce, since some are toxic and even carcinogenic and others, which are not harmful to health or the environment. They have very high prices, which limits their use in post-harvesting of flowers. This situation has led us to study the possibilities of delaying senescence with a potential for practical application, testing compounds that can actually be used in this sector of the Agriculture

The most effective way to delay the senescence of the cut climacteric flower is by means of inhibitors of ethylene biosynthesis. In this sense, it is important to note that in recent years, cultivars of this type of flower that do not produce ethylene have been obtained during senescence, as in the case of the Killer carnation (Serrano et al, 1990 b), Sandrosa, Sandra and Chinera [Mayak, S. and Tirosh, T. 1993. Unusual ethylene-related behavior in senescing flowers of the carnation Sandrosa Physiol Plant, 88 420 -426, Wu, MJ, Zacarías, L. and Reid, MS 1991. Variation in the senescence of carnation (Dianthus caryophyllus L) cultivars II Compaπson of sensitivity to exogenous ethylene and of ethylene binding Scientia Hortic 48 109-116] These cultivars of Carnations have a longevity much higher than that presented by the climatic cultivars, So we could conclude that they would be much more suitable for use as an ornamental flower, since they also have a very good flower size and stem length and thickness. However, the Killer carnation is cultivated very little because it has a high sensitivity to thrips, which considerably reduces the production of the plantations and also the carnations infected by thrips usually have an accelerated senescence [Serrano, M., Riquelme, F .and Romojaro, F. 1991.a. Activation of ethylene metabolism in carnations infected by thrips (Frankliniella occidentalis). Rev. Agroquím. Tecnol. Aliment, 31: 3-59-365].

On the other hand, to increase the longevity of the cut climacteric flower, in addition to inhibiting ethylene biosynthesis, it is also necessary to maintain an adequate water supply to the flower, so the preservative solution must have compounds that prevent the proliferation of microorganisms , which would plug the conductive vessels, as well as provide the flower with a nutritious source that meets its metabolic needs.

All the designed solutions have a common base that we call nutritive solution (SN) and that consists of citric-citrate buffer, pH 4, which also contains sucrose as a carbon source, to maintain an energy contribution to the flower, and Triton X-100, as a surfactant and humectant [Serrano, M., Rosauro, J., Del Rio, JA and Acosta, M. 1987. Conservation of the cut carnation flower (Dianthus caryophyllus, L. Cv. Arthur). I. Use of conservative solutions. Annals of Biology 14 (General Biology, 3): 39-44].

The SN is already effective by delaying the senescence of carnations, since the longevity of carnations maintained in it was 11.5 days, 2 days longer than that of control carnations maintained in distilled water. This effect is due to the two components of the SN. Citrus-citrate buffer maintains a pH that limits or prevents microbial growth and inhibits the activity of certain oxidizing enzymes that, together with microorganisms, could clog the xylem's conductive vessels and therefore, contributes to maintaining an adequate water balance in the cut flower [Degrés, C. And Paulin, A. 1981. interests of l'emploi of solutions nutritives to l'issue d'une conservation refrigerator of durée variable d'oeillet Scania. Rev. Gen. Froid, 71 (4): 187-189]. The sucrose, also helps maintain the water balance in the cut flower, causing the stomata to close (thus preventing the initial loss of water), and also, it favors the retention of water and solutes by the cells, preserving the integrity of the membrane through energy metabolism dependent processes (De Stigter, 1980)

However, the SN fails to completely eliminate microbial contamination, which is a problem during the handling, marketing and subsequent maintenance of flowers at the consumer's home. To try to eliminate this problem, different germicidal compounds were tested, finding that quaternary ammoniums were those who presented the best benefits

To block the synthesis of ethylene, responsible for the senescence of climacteric flowers, various compounds have been used that act on the enzymes involved in the biosynthesis of this plant hormone or on the hormonal receptor responsible, after binding with ethylene, of its physiological action

The knowledge of the biosynthetic route that leads to the production of ethylene in plants, has allowed the use of inhibitors in two clear stages of it, limiting or suppressing the synthesis of ethylene and therefore its senescent action

The first of these stages is the passage of S-adenosylmethionine to the laminocyclopropane-carboxylic acid (ACC), which is catalyzed by the enzyme ACC synthetase. Of the different inhibitors that have been used to block its action, aminoetoxivilglycine (AVG) and aminoxyacetic acid (AOA) stand out

The second stage on which one can act is the conversion of ACC into ethylene and which is regulated by the enzyme ACC-oxidase. Its action can be inhibited with Co ²⁺ and Ni ²⁺ ions as well as other compounds such as dinitrophenol and acid. amino isobutyric Although all these compounds have a high effectiveness, their practical applications are very limited due essentially to their toxicity to the consumer and also because of their high cost, so their use has been restricted to research.

Another possibility of inhibiting the synthesis of ethylene is to block the hormonal receptor, so that by preventing the union of both compounds, the physiological action of ethylene is avoided, and the onset of senescence processes of the cut flower is significantly delayed.

Some compounds such as 2.5 North American and diazocyclopentadiene that block the hormonal receptor cannot be used in practice because they are highly carcinogenic.

At present, to achieve this action and prolong the useful commercial life of the cut ornamental flower, Ag ⁴ ion is used, applied in the form of a complex with the thiosulfate ion. Preservative solutions present in the market for continuous or pulsation treatments contain this chemical complex.

However, the use of the Ag ⁴ ion is also being questioned, because of its toxicity to the consumer and because the elimination of the solutions used presents a serious problem as it is highly polluting and very aggressive with the environment.

Given this problem, a preservative solution has been designed that had or exceeded the effectiveness of those currently on the market and that did not present toxicity and pollution problems. Description of the invention

Brief description of the invention:

The invention that we intend to patent consists of two preservative solutions for cut ornamental flower that synthesizes ethylene, for continuous and pulsation treatments. In the continuous treatment the cut ornamental flower is kept in the solution during the entire conservation period, not being necessary to add or change it.

The pulsation treatments are carried out by immersing the flower in the preservative solution for a maximum time of 48 hours, to subsequently transfer it to water or to the continuous preservation solution.

Both solutions are formulated based on commercial sugar, citric acid, sodium citrate, germicide, ethylene synthesis inhibitor and humectant. The concentrations of each of the constituents are different for the continuous and pulsating solution.

Detailed description of the invention.

Currently, there are preservative solutions on the market to prolong the useful commercial life of the cut ornamental flower, which have the disadvantage, in the case of the preservation of climacteric flowers, of containing in their formulation compounds with high toxicity for the consumer and aggressive with the environment.

It is precisely the one used to inhibit the synthesis of ethylene, the most directly responsible for the onset of the withering of the climacteric cut flower which has a high toxicity index, either in the form of silver nitrate or silver thiosulfate.

Also, some germicide of the 8-hydroxyquinoline type may also be present, which also has high levels of toxicity.

Although these preservative solutions are only used for flower treatments, in some countries of the European Union there is a reluctance in commercial marketing circuits or the acquisition of flowers treated with preservative solutions containing silver ion. This situation has been aggravated in recent years in the Netherlands and England, as some commercial operators require their suppliers that the flower has not been treated with silver-based compounds.

The preservative solution developed by us presents the innovation of not including in its formulation germicides with toxic action and having replaced the silver ion as an inhibitor of ethylene synthesis with a compound that is required in a very low concentration and is used in agriculture and even in agriculture Some ophthalmic treatments.

The germicide used is a quaternary ammonium polymer that has the characteristic of being a potent bactericide, fungicide and algicide of wide application. From the chemical point of view, the compound is an alkyldimethylenzilamonium chloride (benzalkonium chloride, side chain 13-15).

This compound is currently used for disinfectant treatments in the food, hospital and water treatment industry (industrial, human consumption and swimming pools). These uses, as well as their low acute oral toxicity, for white rats (has an LD 50 of 530 mg / kg), ensure their innocuous character for the formulation of preservatives of cut flower solutions.

The ethylene synthesis inhibitor used in the formulation of the preservative solution object of the patent is boric acid in very low concentrations. This compound acts on the enzyme ACC-synthetase, responsible for the transformation of SAM (S-adenosylmethionine) into ACC (Lamino-1 carboxylic acid cyclopropane) which in turn is transformed into ethylene by the action of the enzyme ACC-oxidase.

The enzyme that blocks boric acid (ACC synthetase) is precisely the one that regulates the formation of ethylene, modulating the amount of ACC available at the cellular level and therefore the amount of ethylene produced. Based on benzalkonium chloride and boric acid, a matrix preservative solution has been formulated for cut ornamental climacteric flower, for continuous and pulsation treatments

The compounds used and their concentration ranges are as follows

• Sucrose between 1% and 20%

• Citric acid between 0.06 and 0.6 grams / liter m Sodium citrate between 0.066 and 0.66 grams / liter m Detergent between 0.01 and 0.1 ml / liter "Boric acid between 0.5 mM and 100 mM m Benzalkonium chloride between 0.01 and 0.5 ml / liter

The use of this formulation in the conservation of carnation cut both in the continuous treatment and in pulsation has allowed to significantly prolong its longevity with respect to preservative solutions used in research or commercial. Another aspect of great economic interest is that with this preservative solution the cost Continuous and pulsation treatment is lower compared to that obtained with commercial solutions existing in the market

Example of embodiment of the invention

Of the different species of ornamental flower the most cultivated in the producing countries is the carnation. It is characterized by being climacteric and having a useful commercial life considered as short-medium that varies, depending on the time of the year, between 5 and 9 days. In order to verify the effectiveness of the preservative solution formulated for continuous and pulsed treatments, it has been tested with different varieties of carnation, finding in all of them an increase in the longevity of the cut flower

Among the possible concentrations and compounds of the preservative solution tested with positive effects, we have selected the following as an example of the embodiment

For continuous treatments Flowing water has been used to which the constituents have been added in the order and concentration indicated below: m Citric acid: 0.6 grams / liter m Sodium citrate: 0.66 grams / liter to Sucrose (commercial sugar) : 5 grams / liter m Benzalkonium chloride: 0.1 milliliter / liter - Triton X-100: 0.1 milliliter / liter

The continuous application of this preservative solution to the cut carnation allows to increase its longevity with respect to water between 75 and 100%, and with respect to commercial preservative solutions, by 20%.

For pulsation treatments:

Compounds in the order and concentration indicated below are added to tap water:

1. Citric acid: 0.6 grams / liter

2. Sodium citrate: 0.66 grams / liter

3. Sucrose (commercial sugar): 100 grams / liter

4. Boric acid: 6.52 grams / liter 5. Benzalcoin chloride: 2 milliliters / liter

6. Octiphenolic ether of deca-ethylene glycol: 0.1 milliliter / liter

The stems of the cut ornamental flower should be submerged over 10 cm and kept between 12 and 48 hours. The flowers are then removed and immersed in running water or in the continuous preservative solution.

With this system the longevity of the carnation has increased with respect to the flower submerged in water between 100 and 120% and commercial solutions, between 30 and 40%. The presence of the germicide allows its use for 32 successive days, not having been detected during that period in the preservative solution development of aerobic mesophilic microorganisms, molds and yeasts.

Claims

1. Preservative for cut ornamental flower characterized in that it contains in its composition formulated solutions based on commercial sugar, citric acid, sodium citrate, germicide, inhibitor of ethylene synthesis and humectant. 2. A preservative according to claim 1 characterized by a formulation based on benzalkonium chloride and boric acid, with the following compounds and concentration ranges: m Sucrose: between 1% and -20% m Citric acid: between 0.06 and 0 , 6 grams / liter Sodium citrate: between 0.066 and 0.66 grams / liter m Detergent: between 0.01 and 0.1 ml / liter m Boric acid: between 0.5 mM and 100 mM m Benzalkonium chloride: between 0 , 01 and 0.5 ml / liter

3. Method of applying a preservative according to claim 1 for continuous treatment of ornamental flower characterized in that the constituents are added to water in the following order and concentration:

• Citric acid: 0.6 grams / liter

• Sodium citrate: 0.66 grams / liter • Sucrose (commercial sugar): 5 grams / liter

• Benzalkonium Chloride: 0.1 milliliter / liter

• Triton X-100: 0.1 milliliter / liter

4. Method of applying a preservative according to claim 1 for treatment in pulsation of ornamental flower characterized in that the constituents are added to water in the following order and concentration:

7. Citric acid: 0.6 grams / liter

8. Sodium citrate: 0.66 grams / liter

9. Sucrose (commercial sugar): 100 grams / liter

10. Boric acid: 6.52 grams / liter 11. Benzalcoin chloride: 2 milliliters / liter

12. Octiphenolic ether of deca-ethylene glycol: 0.1 milliliter / liter with cut stems submerged over 10 cm. For 12 to 48 hours.