Method for stimulation of seeds

Abstract

Method for the stimulation of seeds of dicotyledonous plants, wherein the seeds are primed in a solution containing nonionic nanoparticles of a metal selected from: silver (Ag), gold (Au), copper (Cu) and platinum (Pt) at a concentration from 0.05 ppm to 50 ppm to obtain 40-60% by weight of water content, and then dried at room temperature to obtain 10-40% by weight of water content. The invention also relates to the use of a solution of nonionic nanoparticles of a metal selected from: silver, gold, copper and platinum to stimulate seeds of dicotyledonous plants.

Claims

1. A method for the stimulation of seeds of sugar beet comprising priming sugar beet seeds in a solution containing metal nanoparticles and subsequently drying said seeds, wherein the seeds are primed in a nanocolloidal metal solution containing nonionic nanoparticles selected from the group consisting of silver (Ag), gold (Au) and platinum (Pt), wherein the nanoparticles are produced using a physical method, wherein said nanoparticles are at a concentration of 0.05 ppm to 50 ppm, wherein after priming the seeds have a water content of 40-60% by weight, wherein the primed seeds are dried at room temperature to obtain a water content of 10-40% by weight.

2. The method according to claim 1, wherein a nonionic nanocolloidal metal solution in deionised water is applied.

3. The method according to claim 2, wherein seeds are preliminarily rinsed with water and the seeds are dried until a water content of 10-40% by weight is obtained.

Description

DETAILED DESCRIPTION

(1) The seeds should be subjected to a stage of preliminary rinsing in water in order to remove germination inhibitors and potential pathogens present on the surface of the seeds. In case of application of the preliminary rinsing stage, the seeds are subsequently dried to obtain a water content from 10 to 40% by weight.

(2) As seeds of dicotyledonous plants, the seeds of the following plants are used: winter oilseed crops resistant to cold, such as canola; sown in early spring and sensitive to cold to a limited extent, such as: sugar beet, peppers; long germinating seeds of vegetables, such as: carrot, celery.

(3) Preferably, the stage of priming in a solution containing metal nanoparticles is conducted within a period of 1-24 hours, adapted to the plant species.

(4) The invention also comprises the use of a colloidal solution of nonionic nanoparticles of a metal selected from: silver, gold, copper and platinum to stimulate the seeds.

(5) In the method according to the invention, nanocolloidal metal solutions, in which metal nanoparticles do not have an ionic form, are used. However, these are solutions with a highly dispersed metallic phase, obtained with the use of a physical method, e.g. Bredig's method based on spraying pure metals in a voltaic arc or with the use of Bredig's method, wherein Bredig's method was indicated as an example, because in the method according to the invention, nonionic nanoparticles produced with the use of any physical method can be used. As a result, metal nanoparticles free from any impurities, of a purity exceeding 99.9%, are obtained. In contrast, metal particles in ionic form are obtained using chemical methods, which usually leave impurities on the surface of the particles. A physical method can be used to produce nanoparticles in the form of very small clusters suspended in pure, demineralised water. The percentage of metal particles in such solutions in higher than in the case of ionic solutions, and their active surface is also larger.

(6) As a result of priming, nonionic nanoparticles of the above-mentioned metals penetrate into the seeds and remain there, in contrast to the application of ions of the same metals on the surface of grains, as in the above-described methods. Nanoparticles, unlike ions, do not have an electric charge. Thanks to this, they can easier cross a polarised cell membrane, do not require special protein ion channels and can engage in plant metabolism, e.g. they can constitute a catalyst for enzymatic reactions. In contrast, water is a carrier and facilitates the movement of nanoparticles in the tissues of the plant.

(7) Seeds prepared in this manner germinate considerably faster than seeds not subjected to prior priming in a water solution of colloidal nanoparticles, and additionally, germination is very even, which means that all seeds germinate at the same time, which is extremely important in the cultivation of e.g. sugar beet, canola, etc.

(8) It is known that the seeds of e.g. sugar beet, which after 96 h of germination under optimum conditions have a germination capacity at a level of not less than 95%, are considered to be of high quality. In the case of application of the method according to the invention, this reproducible effect is achieved, and it is also possible to achieve this effect as early as after 72 h.

(9) The use of metal nanoparticles of known biocidal activity further increases the resistance of seeds to the harmful effect of pathogens; however, the effect of stimulation is also present in the case of metals with no attributed biocidal activity, such as gold and platinum. This indicates that the stimulation effect is achieved due to other characteristics of metal nanoparticles than only biocidal activity. This hypothesis was confirmed by the results of the conducted studies. The seeds were stimulated under non-sterile laboratory conditions, sown after stimulation into plastic containers lined with filter paper soaked with deionised water and incubated in an environmental chamber. Under such conditions, the seeds were not exposed to adverse effects of soil contamination under field conditions but to groups of pathogens potentially present on the surface of the seeds, containers, filter paper or in the air.

(10) It should be emphasised that the effect declared in the method according to the invention did not occur when the seeds were stimulated with an Ag solution in ionic form, and the effects obtained in comparison with seeds not stimulated with metal nanoparticles were even worse.

EXAMPLES

(11) The invention has been described based on the examples.

Example 1

(12) Effect of Colloidal Solutions of Nonionic Nanoparticles of Ag, Au, Cu and Pt on the Germination of Sugar Beet Seeds.

(13) Colloidal solutions of nanoparticles: silver (Ag) at an initial concentration of 100 ppm, copper (Cu) at an initial concentration of 100 ppm, gold (Au) at an initial concentration of 50 ppm and platinum (Pt) at an initial concentration of 20 ppm, were obtained using Bredig's method, in a device known from the description of Polish utility model No. RWU.066178.

(14) Aqueous solutions of copper, silver, gold and platinum nanoparticles at concentrations of 0.05 ppm, 0.1 ppm, 0.5 ppm, 1 ppm, 5 ppm, 10 ppm, 20 ppm and 50 ppm were preparedfor this purpose, the initial solutions of the above-mentioned nanoparticles were diluted with deionised water.

(15) The study material comprised dry fruits of sugar beet called seeds in the description of the invention (in the case of sugar beet, the seed material comprises botanical fruits; however, in scientific papers, they are called seeds, while a botanical seed is present in the ligneous pericarp and is covered with a lid), of high vigour (Janosik variety provided by the Sugar Beet Cultivation Plant in Kutno), not stimulated, rinsed with water for 2 h, and subsequently dried to a moisture of 20%. The seeds used in this experiment were not treated with fungicides or other plant protection products. Seeds prepared in this way (approximately 300 units) were primed (in light, at room temperature) in 200 ml of respective solutions of nanoparticles for 4 h, under continuous stirring. Seeds primed in deionised water, not containing nanoparticles, were used as control.

(16) After priming, the seeds were allowed to dry for 48 h, in light, at room temperature, on a solid surface having no sorption properties to avoid the effect of chromatography, which could take place when using e.g. filter paper.

(17) Germination tests were conducted in a Fitotron chamber under optimum conditions for sugar beet (15 C., dark) in technical triplicate (3100 seeds), wherein the % of germinated seeds was controlled every day for 4 consecutive days. The seeds germinated in plastic containers, lined with filter paper, of a field water capacity of 60% (the optimum for sugar beet). It is agreed that a germinated seed is a seed in which the lid of the pericarp was broken by an elongating radicule (visible without microscope/binoculars).

(18) The results were averaged for 3 repetitions and are presented in Table 1 in the form of the % of germinated seeds.

(19) All nanoparticles in each of the applied concentrations caused an increase in the rate and capacity of germination, both after 72 and 96 h of germination, as compared to the control (seeds primed in deionised water).

(20) In the case of using gold nanoparticles at a concentration of 10 ppm and 20 ppm, the effect of stimulation of germination was observed as early as after 48 h of imbibition. The use of nanoparticles of silver and copper also produced a positive effect, as compared to the control, 72 h after conducting the test. The effect of stimulation of germination by all applied solutions of nanoparticles was observed even after 96 h of imbibition.

Example 2

(21) Comparative Test of Nonionic Ag Nanoparticles with Ionic Ag Nanoparticles for the Germination of Sugar Beet Seeds.

(22) Similarly as in Example 1, a colloidal solution of nonionic silver particles at an initial concentration of 100 ppm and ionic Ag particles at an initial concentration of 200 ppm were suitably diluted with deionised water. Colloidal solutions of nonionic silver nanoparticles were obtained using Bredig's method, in a device known from the description of Polish utility model No. RWU.066178, while the source of ionic Ag particles was a commercially available solution of the composition.

(23) The study material comprised dry fruits of sugar beet of the same type and was prepared in a similar manner as described in Example 1. The results are presented in Table 2.

(24) It should be emphasised that in the case of application of an Ag solution in ionic form, no stimulation effect was observed after 32 h, and on the contrary, it was observed that the application of Ag solutions in ionic form produced worse results in comparison to seeds stimulated with a solution of Ag nanoparticles in nonionic form, and was worse even in comparison to the controlled, non-stimulated group.

Example 3

(25) Effect of Colloidal Nonionic Solutions of Ag Nanoparticles on the Germination of Pepper Seeds.

(26) Colloidal solutions of silver (Ag) nanoparticles at an initial concentration of 100 ppm, obtained using Bredig's method, were diluted with deionised water to concentrations of 1 ppm and 20 ppm.

(27) The study material comprised dry seeds of peppers of varieties: Variety a, Variety b and Variety c. The seeds were primed in a solution of Ag nanoparticles and deionised water (control), respectively for 1 h, in light, at room temperature, on a solid surface having no sorption properties to avoid the effect of chromatography, which could take place when using e.g. filter paper (in the same manner as described in Example 1 for sugar beet seeds). Subsequently, the seeds were subjected to slow drying. Seeds prepared in this way were germinated at 20 C., in a Fitotron chamber, in technical triplicate (3100 seeds), wherein the % of germinated seeds was controlled every day for 7 consecutive days. The seeds germinated in plastic containers, lined with filter paper, of a field water capacity of 60%.

(28) The use of solutions of Ag nanoparticles at a concentration of 1 and 20 ppm significantly improved the germination of most tested pepper varieties. The results are presented in Table 3.

(29) TABLE-US-00001 TABLE 1 Effect of colloidal solutions of nonionic Ag, Au, Cu and Pt nanoparticles on the germination of sugar beet seeds % of germinated seeds after a Concentration defined period of imbibition Type of solution (ppm) 24 h 48 h 72 h 96 h Control (H.sub.2O) 0 0 57 85 nano-Ag 0.05 0 2 78 94 0.1 0 0 57 92 0.5 0 0 55 95 1 0 0 74 100 5 0 0 75 98 10 0 0 69 94 20 0 0 70 95 50 0 0 51 92 nano-Cu 0.05 0 1 77 95 0.1 0 0 66 96 0.5 0 0 50 94 1 0 0 70 91 5 0 0 80 94 10 0 0 79 98 20 0 0 86 98 50 0 0 49 95 nano-Au 0.05 0 0 60 97 0.1 0 0 50 94 0.5 0 0 84 98 1 0 1 90 99 5 0 1 89 97 10 0 7 96 98 20 0 13 95 97 50 0 0 57 93 nano-Pt 0.05 0 2 75 95 0.1 0 1 78 97 0.5 0 0 53 91 1 0 1 88 100 5 0 2 86 96 10 0 3 92 98 20 0 2 93 97

(30) TABLE-US-00002 TABLE 2 Comparative test of nonionic Ag nanoparticles with ionic Ag nanoparticles for the germination of sugar beet seeds. % of germinated seeds after a Type of Concentration defined period of imbibition solution ppm 24 h 48 h 72 h 96 h Control (H.sub.2O) 0 0 57 85 nano-Ag 1 0 0 74 100 20 0 0 70 95 Ionic Ag 1 0 0 35 59 20 0 0 52 96

(31) TABLE-US-00003 TABLE 3 Effect of colloidal nonionic solutions of Ag nanoparticles on the germination of pepper seeds. % of germinated seeds after 7 days of imbibition Type of treatment Variety a Variety b Variety c Control (H.sub.2O) 75 75 75 nano-Ag (1 ppm) 85 80 80 nano-Ag (20 ppm) 85 85 85