WO1991003159A1

WO1991003159A1 - Composition for preserving plants

Info

Publication number: WO1991003159A1
Application number: PCT/AU1990/000383
Authority: WO
Inventors: John Zuccon
Original assignee: Daratech Pty. Ltd.
Priority date: 1989-08-31
Filing date: 1990-08-30
Publication date: 1991-03-21
Also published as: NZ235121A

Abstract

Aqueous solutions for preserving plants by immersing freshly cut stems into the solutions are disclosed. The solution consists of a water soluble dye, an inorganic salt and a mixture of polyols where one of the polyols has at least five hydroxyl groups per molecule. Especially preferred combinations of polyols are glycerol and sorbitol.

Description

COMPOSITION FOR PRESERVING PLANTS

FIELD OF THE INVENTION

This invention relates to compositions for preserving plants, and methods for preserving plants.

BACKGROUND OF THE INVENTION

It has previously been found that the natural appearance and strength of plants and parts thereof may be extended by immersing the roots or freshly cut stems in an aqueous solution which contains glycerol, one or more dyes, one or more, inorganic salts and an organic acid such as citric acid. An example of such treatments is United States Patent Number 4243693 in the name of Nordh and Svensson. For certain plant species such as conifers it has been reported that methanol or ethanol as a further solution additive may confer further useful properties. This is the case in United States Patent Number 4278715 in the name of Romerosier and Webb where combinations of monohydric alcohols and di or tri hydric alcohols are used.

Whilst prior art compositions offer promising performance there are some technical and commercial limitations of such compositions. For example, certain palms when treated with such prior art solutions exhibit bleeding. Bleeding is a phenomenon where the leaves of treated plants exhibit a leaching of dye into water droplets that form on the leaf surface. Water droplets that form as a result of atmospheric condensation in appropriate temperature and humidity regimes. Prior art compositions have also been found to have limitations with certain Australian flora such as Acacia and Eucalyptus. It is an object of the present invention to provide plant preserving compositions that overcome some of the limitations of prior art compositions or at least provide alternative preserving compositions.

SUMMARY OF THE INVENTION

This invention provides in one form an aqueous solution for preserving plants wherein the solution comprises a water soluble dye, an inorganic salt and a polyol wherein at least a portion of the polyol is selected from water soluble polyols having at least five hydroxyl groups present on each polyol molecule.

Preferably the polyol having at least five hydroxyl groups present on each polyol molecule is selected from the group consisting of sorbitol and mannitol, and most preferably the polyol is sorbitol.

Preferably the polyol comprises a combination of polyols.

Preferred combinations of polyols are glycerol and sorbitol; sorbitol and poly (ethylene gly col), and; glycerol, sorbitol and poly (ethylene glycol).

In an alternative form the invention provides a method of treating plants with the solution defined above by immersing freshly cut stems of plants into the preserving solution.

It will be appreciated that whilst the invention is directed towards aqueous solutions in a form suitable for the treatment of plants, for transport and storage reasons it may be desirable to prepare concentrated solutions that have minimum amounts of water present. Before use these concentrated solutions are diluted with appropriate quantities of water.

Species of plants that are particularly suitable to treatment are Acacia and Eucalyptus.

Dyes that are useful for the present invention are water soluble dyes for preserving plants described in the prior art Suitable concentrations are also adequately described in the prior art. Preferred dyes are Edicol Blue, Fast Green, Tartrazine, Amaranth, Erythrosine, Ponceau 4R. These dyes are further identified as follows: Edicol blue Tartrazine Yellow Sunset Yellow Amaranth Red Ponceau 4R Red Erythrosine Fast Green

The types levels and functions of the inorganic salts suitable for the present invention are described in the prior art.

The invention will be further described by reference to preferred embodiments described in the examples below. In these examples all parts are expressed as parts by weight.

EXAMPLE 1

Aqueous solutions were prepared by mixing the constituents set out below.

EXAMPLE 2

Small cuttings of Acacia (Cootamundra) in flower were treated in solutions A-F as follows. A test plant was cut at the stem above the root line, and then recut whilst immersed in water. After recutting, the test plant was immersed in the test solution at 20°C and allowed to stand for 48 hours with the surrounding ambient conditions having a relative humidity of 40% and good atmospheric air circulation.

It was found that all test solutions had preserved the test plants but that plants preserved with solutions A, B and E exuded sap from woody section of the plants, whilst those preserved with solutions C, D and F did not exhibit this defect. It was also noted that preservation was effected most rapidly with Composition D.

EXAMPLE 3

Solutions A-F were evaluated for preserving, green bamboo, palms (Washingtonia) and Eucalyptus (Perriniana). The test method used was as set out in Example 2. When preserved plants were evaluated for bleeding resistance in a humid atmosphere, it was found that plants preserved with solutions B, D and F significantly reduced bleeding which was particularly evident for the palm and bamboo.

These Examples illustrate the benefits of the present invention. It should be noted that whilst the use of sorbitol as the sole polyol leads to non-bleeding compositions, the leaves of plants treated in this way may lack suitable flexibility and in practice a combination of glycerol and sorbitol achieve useful results. It is unknown as to why compositions of the present invention confer the above advantageous properties. However, without limiting the scope of the present invention, it is believed the presence of a polyol that tends to crystallise at ambient temperatures or above introduces sufficient structure into the treated plant to prevent bleeding. It is believed that high molecular weight polyols with molecular weight above about 500 are not appropriate as they result in inadequate transport of sufficient polyol to the leaves of the plants. They may also cause blocking of the passageways within the plant stem. Cost consideration and performance indicate that sorbitol is the preferred polyol with at least five hydroyls. However mono and polysaccharides may also have useful application in the present invention.

Since modifications within the spirit and scope of the invention may be readily effected by persons skilled in the art, it is to be understood that the invention is not limited to the particular embodiment described, by way of example, hereinabove.

Claims

1. A composition for preserving plants comprising solution of a water soluble dye, an inorganic salt and a water soluble polyol wherein at least a portion of the polyol is selected from polyols having at least five hydroxyl groups present in each polyol molecule.

2. A composition as defined in Claim 1 where in the polyol having at least five hydroxyl groups present on each polyol molecule is selected from the group consisting of sorbitol and mannitol.

3. A composition as defined in Claim 2 where the polyol is sorbitol.

4. A composition as defined in Claim 1 wherein a portion of the polyol is selected from molecules having up to four hydroxyl groups per molecule and the remainder of the polyol is selected from molecules having at least five hydroxyl groups per molecule.

5. A composition as defined in claim 4 where in polyols are combinations of glycerol and sorbitol, sorbitol and poly (ethylene gylcol), or sorbitol, glycerol and poly (ethylene glycol).

6. A method of treating plants by immersing a cut stem of a plant into a solution as defined in any one of Claims 1 to 5.

7. A method of treating plants as defined in Claim 6 wherein the plants are from species Acacia, Eucalyptus, Thryptomene, Gypsophilla, Banksia, Boronia, Limonium, Heuadendron, Status and Kanagraroopas.

8. A method of treating plants as defined in Claim 7 where in plants are from species Acacia and Eucalyptus.