GB2325137A - Plant propagation material storage and distribution system - Google Patents

Abstract

A system, suitable for use in the storage and distribution of plant propagation material, which comprises plant propagation material 4, a water soluble or water dispersible first layer 1 and, disposed between the plant propagation material 4 and the first layer 1, a second layer 2 which shields the plant propagation material 4 from direct contact with the first layer 1. The plant propagation material is preferably seeds. The water soluble first layer 1 preferably comprises a polyvinyl alcohol and the second layer 2 preferably comprises a series of circles containing particulate titanium dioxide.

Description

STORAGE SYSTEM The present invention relates to systems suitable for the storage, transportation and distribution of plant propagation material.

Plant propagation material includes propagules, plant parts, plant tissues and plant organs which are capable of growing or regenerating into a plant, for example seeds, spores, somatic embryos, callus material, cells or cell aggregates, microcuttings, cuttings, bulbs, tubers, corms, rhizomes, stolon and fruit. Today the seed business is highly competitive. The performance of the seeds has a direct effect on competitive position and profitability. It is desirable to sow seeds in a manner which will achieve close to 100% germination. Anything less than 100% germination increases costs and reduces profits. The failed areas often need to be re-sown. This can be very labour intensive and therefore expensive. It is an aim of the present invention to provide a means of storing, transporting and planting plant propagation material, including propagules such as seeds, which results in a high degree of sowing precision and/or emergence or germination.

Damage to seeds is a major cause of low emergence or germination rates. It is known that seeds, especially small and/or delicate seeds, are subject to mechanical damage during handling and transportation. Seeds can be so badly damaged that they are unable to grow and develop into healthy plants. It is an aim of the present invention to provide a means of storing, transporting and distributing plant propagation material including propagules, such as seeds, which reduces mechanical and physiological damage.

Seeds, if they are small, may be pelleted with, for example, clay mixtures which facilitates sowing of the seeds and facilitates handling (DE-A-2551579). The seeds can, however, b damaged during this pelleting process.

This reduces the percentage of seeds which are able to germinate and/or develop into healthy plants.

It is an aim of the present invention to provide a means of storing, transporting and distributing plant propagation material; particularly propagules such as seeds which facilitates handling and planting of the plant propagation material.

At present, pre-germinated seeds such as those described in US-A-5585536 and US-A-5522907 will only survive for a limited period of time between germination and planting.

This time period depends on the nature of the seed and the storage conditions. It is a further aim of the present invention to provide a means of storing pre-germinated seeds for longer periods of time and/or reducing the percentage of pre-germinated seeds which fail to develop into healthy plants.

The use of polyvinyl alconol (PVOH) in seed tapes is known.

A seed tape is a water soluble tape on which seeds can be placed at regular intervals. Because PVOH has moisture absorbing properties, seed tapes of this material need to be made immediately before planting so that the germination ability of the seeds is not impaired. This is essential if seeds are pre-germinated as the seeds' ability to take up or imbibe moisture from the film causes the seeds to develop prematurely. Seed tapes, in the past, have only been suitable for use with relatively large seed.

Typically seed tapes have been used when the seed is larger than 1 mm diameter.

The present invention seeks to overcome one or more of the problems associated with seed tapes by providing water soluble or water dispersible systems useful for the storage, transportation and distribution of plant propagation material, including propagules, preferably seeds.

The present invention accordingly provides a system, suitable for use for the storage and distribution of plant propagation material, including propagules, preferably seeds, which comprises the plant propagation material, a water soluble or water dispersible first layer and, disposed between the plant propagation material and the first layer, a second layer which shields the plant propagation material from direct contact with the first layer. The second layer preferably controls, eg. reduces or prevents, transmission of water from the first layer to the plant propagation material.

The system according to the present invention preferably also comprises a third layer, which is water soluble or water dispersible and is disposed on the side of the plant propagation material remote from the first layer. When the third layer is present a fourth layer, which shields the plant propagation material from direct contact with the third layer is preferably disposed between the plant propagation material and the third layer. The fourth layer preferably controls, eg. reduces or prevents, transmission of water from the third layer to the plant propagation material.

The second and fourth layers, when present, may be disposed as, eg. films of material in a laminated construction. The films may be continuous or discontinuous.

The second and fourth layers, when present1 are preferably discontinuous and are preferably confined to the area surrounding the plant propagation material, for example as a circle or square having a diameter or diagonal dimension of 0.5 to 20 mm, preferably 5 to 20 mm with the plant propagation material disposed approximately in the middle.

They may also be, in effect, combined in one or more layers surrounding the plant propagation material, for example combined in one or more. layers surrounding each propagule.

One, or preferably both, of the second and fourth layers preferably comprise a substantially water insoluble particulate material. The particulate material in the second and/or fourth layers facilitates the break up and dispersion of the storage system of the invention in the growth medium. The second and fourth layers preferably also control, eg. reduce or prevent, the transmission of light to the plant propagation material. A lightreflective material, eg. particulate titanium dioxide, is preferred. It will be understood that the particulate material is generally substantially inert to water and to the growing medium.

The area of the second and fourth layers preferably comprising water insoluble particulate material, when both are present, surrounding the plant propagation material are preferably unequal. When the area is circular the diameters are preferably different. Such an arrangement facilitates penetration of water to the plant propagation material when the or each water soluble or water dispersible material has been dissolved or dispersed by the application of water.

The water insoluble particulate material is preferably applied in suspension in a liquid medium comprising a binder. The inks which can be applied by conventional printing methods such as flexography or gravure printing are suitable. Gravure printing is preferred as this process gives a high level of control over the density of the ink used. Gravure can be used at high speeds and gives high quality print resolution and a layer of water insoluble particulate material of well defined thickness. Such inks provide a particulate layer which also provides a barrier to light, particularly when titanium dioxide is used as the particulate material.

Suitable water soluble materials include polyvinyl alcohol, polyethylene oxide or modified cellulose. Preferably at least one layer of the system of the invention comprises a polyvinyl alcohol (PVOH). Suitable polyvinyl alcohols include partially hydrolysed polyvinyl acetate; they typically have 88 to 89% hydrolysis (this degree of hydrolysis is typical for cold water soluble PVOH).

Suitable films comprising PVOH include Aquafilm, Hydrolene, Solublon and Monosol. The films are typically 10m to 100jim thick. There are several advantages of using PVOH.

PVOH is bio-degradable; it is broken down by microorganisms. PVOH is also an oxygen barrier; this may help to prolong the life of the propagules. PVOH is also antistatic. This facilitates handling of the system and of the propagules, particularly when the latter are small.

In production of the systems according to the invention the second layer (preferably comprising water insoluble material) may be applied, for example by gravure printing, to a water soluble or water dispersible material and the propagule applied on, for example, the second layer which is preferably in the form of a circle or square at each location where plant propagation material is required. The plant propagation material may be applied as such or, in order to facilitate handling, in the form of a suspension in a liquid. Suitable suspensions include suspensions which comprise a water soluble or water dispersible polymer. The suspension is generally aqueous and dries in situ. The suspension may comprise a water soluble adhesive which is compatible with the films and the plant propagation material. Suitable adhesives include starch, modified cellulose, glucose or other sugars. Preferably the adhesive is a polyvinyl alcohol.

The material in which the plant propagation material is suspended may, when dried, provide a coated plant propagation material which has, in effect, a 'combined' second and fourth layer as described above. The material preferably controls, eg. reduces or prevents, the transmission of water from the first and, when present, the third layer to the plant propagation material. The material may comprise a substantially water insoluble particulate material as hereinbefore described for the second and fourth layers. A light reflective material such as titanium dioxide is also preferred.

The suspension used to apply the plant propagation material may comprise a colourant or fluorescent additive.

The presence of such an additive makes it possible to differentiate propagules by colour coding and may also be useful in monitoring application of the plant propagation material during manufacture of the systems of the invention.

A system comprising a first layer as hereinbefore described, a coated plant propagation material as described above and, optionally, a second layer as hereinbefore described, interposed between the first layer and the coated plant propagation material also constitutes a feature of the invention. Such a system is illustrated in Figure 4 of the accompanying drawings.

In the accompanying drawings: Figure 1 shows an overhead view of the first and second layers of a system of the invention showing seeds placed on the second layer.

Figure 2 shows an overhead view of the third and fourth layers of a system of the invention.

Figure 3 shows a side view of a system of the invention.

Figure 4 shows a side view of a system of the invention comprising a coated propagule, a first layer and a second layer optionally interposed between the first layer and the coated propagule.

A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawings.

Referring to the drawings, the system of the invention shown in the drawings comprises a first layer which is a cold water soluble film PVOH(1). A series of particulate titanium dioxide-containing circles (2) are printed on one side of (1). Each circle (2) contains a seed location point marked in the drawing with a cross (3). In Figure 1 a seed (4) is placed at each location point (3). In Figure 2 the third layer (5) is a cold water soluble film PVOH. A series of particulate titanium dioxide-containing circles (6) are printed on one side of (5).

Figure 3 shows a complete system of the invention. The seed (4) is shielded from the water soluble film PVOH layers (1) and (5) by the particulate titanium dioxidecontaining circles (2) and (6).

In Figure 4: the layer 1 comprises a polyvinyl alcohol; the layer 2, which is optional, -comprises a substantially water insoluble particulate material; and 4 is the coated propagule.

In a preferred method for the production of a system of the invention a further water soluble or water dispersible layer carrying a fourth layer, eg. comprising a water insoluble particulate material, is applied to the system produced using a suspension as described above in order to "sandwich" the plant propagation material between the second and fourth layers which preferably comprise water insoluble particulate material. The second and fourth layers are preferably discontinuous so that the water soluble or water dispersible layers can be sealed together, for example by heat sealing.

The systems of the invention may additionally comprise an additive to enhance emergence or germination of the plant propagation material to promote healthy growth of the plants. Such additives may be present in any of the layers or in the liquid medium used to suspend the plant propagation material to facilitate its application.

Additives include pesticides, growth promoters, growth regulators, nutrients and bird repellents. Preferably the system comprises at least one such additive.

The areas on which the second and/or fourth layers are provided are preferably arranged so that the laminated system of the invention can be placed directly over a growth medium with the plant propagation material in predetermined positions. The system may comprise registration points for use with seed trays of predetermined dimensions.

If the systems comprise two water soluble films these may be identical or may be different. Preferably both film(s) comprise a water soluble polymer. Most preferably the films comprise a polyvinyl alcohol as described above.

The systems of the present invention can be used with any suitable plant propagation material. The systems of the invention are particularly suitable for the storage, transportation and distribution of small seeds and/or high value seeds. However, use of the systems of the invention is not restricted to small seeds and/or high value seeds.

By "small seeds" is meant seeds of less than 500 microns.

The seeds may be coated or uncoated. If the seeds are coated, any coating known in the art may be used. Coated seeds may be produced from suspensions as hereinbefore described. Such coatings are applied using known methods.

The coatings may comprise a water insoluble particulate material. It will be understood that when the plant propagation material is large one or both of the first and third layers may be formed to accomodate it.

Plant propagation material especially ungerminated propagules can be stored in the systems of the invention for several months prior to use. Both ungerminated and pre-germinated propagules can be stored and distributed using the systems of the invention.

The systems of the present invention can be used with both ungerminated and pre-germinated propagules.

The systems can be stored in transparent or non-transparent packaging. The systems themselves are generally translucent or transparent. However, if a film is coated with a moisture barrier and/or reflective material the systems may be non-transparent. Germinated propagules should preferably be stored in the absence of light to reduce further growth.

The systems may be stored in damp atmospheres such as greenhouses and garden sheds. They are preferably stored within a water impermeable outer container or envelope.

The present invention also provides a kit for producing the multi-layered systems of the invention containing plant propagation material of the user's choice.

Such a kit may comprise one or two sheets of a laminate comprising a first and a second layer a3 hereinbefore described. The kit optionally comprises plant propagation material e.g propagules, such as seeds. One sheet of laminate may be folded over to encapsulate the plant propagation material, e.g. propagules, or two sheets placed, in registration, one over the other. The laminate constitutes a feature of the invention and preferably comprises regularly spaced areas comprising a substantially water insoluble particulate material.

Claims (14)

1. A system, suitable for use in the storage and distribution of plant propagation material, which comprises plant propagation material, a water soluble or water dispersible first layer and, disposed between the plant propagation material and the first layer, a second layer which shields the plant propagation material from direct contact with the first layer.

2. A system according to claim 1 in which the second layer controls transmission of water from the first layer to the plant propagation material.

3. A system according to claim 1 or 2 in which the second layer comprises a substantially water insoluble particulate material.

4. A system according to claim 1, 2 or 3 which comprises a third layer, which is water soluble or water dispersible, disposed on the side of the plant propagation material remote from the first layer.

5. A system according to any one of the preceding claims which comprises a fourth layer, comprising a substantially water insoluble particulate material, disposed between the plant propagation material and the third layer.

6. A system according to any one of the preceding claims wherein the water soluble or water dispersible material comprises a polyvinyl alcohol.

7. A system according to any one of the preceding claims wherein the water insoluble material is titanium dioxide.

8. A system according to any one of the preceding claims wherein the plant propagation material is a propagule.

9. A system according to claim 8 wherein the propagule is a seed.

10. A laminate comprising a first and a second layer as defined in any one of claims 1 to 3, 6 and 7.

11. A kit comprising a laminate according to claim 10 and, optionally, plant propagation material.

12. A system according to claim 1 substantially as hereinbefore shown in any one of the drawings.

13. A laminate according to claim 10 substantially as hereinbefore described.

14. A kit according to claim 11 substantially as hereinbefore described.