RU2765577C2 - Method for pre-sowing treatment of spring barley seeds - Google Patents

Abstract

FIELD: agriculture.

SUBSTANCE: invention relates to the field of agriculture for the activation of seed growing and plant protection, when growing grain crops. Tetraethoxysilane Si(OEt)₄ in the amount of 1 vol.% is mixed at intensive stirring with a 0.25-molar solution of hydrochloric acid to form silica with pH~2-3 with the addition of an aqueous solution of mineral additives, while nanoparticles of titanium dioxide are added to silica in the amount of 0.003 g/ml of silica, as well as organic modifiers – polyethylene glycol or glycerin – in the amount of 1 vol.%.

EFFECT: providing, due to the synergetic effect of silica, nanoparticles of titanium dioxide and modifying organic additive, favorable effect on morphological parameters of barley sprouts, on their resistance to damage by phytopathogen – the causative agent of root rot, providing conditions for the development of useful epiphytic bacteria recycling organic and inorganic nitrogen compounds to forms available for plants.

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Description

The invention relates to the field of agriculture for activating the growth of seeds and protecting plants in the cultivation of crops. The method is carried out by processing spring barley seeds in suspensions obtained by mixing silica sol based on tetraethoxysilane with titanium dioxide nanopowder and organic modifiers - glycerin or polyethylene glycol. Laboratory tests have shown the high efficiency of using such suspensions obtained by mixing silica sol based on hydrolyzed tetraethoxysilane (1 vol.% TEOS), titanium dioxide nanopowder (0.003 g TiO ₂ /ml silica sol) with the addition of glycerol or polyethylene glycol (PEG-400) - 1 vol. %.

This method of seed treatment accelerates the development of seedlings and roots of plants at the early stages of their development, favors the development of beneficial epiphytic microorganisms - bacteria that process organic and inorganic nitrogen compounds into forms available to plants, and protects plants from phytopathogens.

There are various ways of pre-sowing treatment of seeds to stimulate them and faster germination. So, the authors [Bulgakova E.V., Nefedeva E.E., Pavlova V.A. Increasing the germination of seeds with a hard seed coat by presowing treatment with acetone // Modern problems of science and education. - 2014. - No. 6.; URL: http://science-education.ru/ru/article/view?id=15475 (date of access: 02/24/2020)] suggest using seed treatment in acetone for plant seeds that have very hard shells that are impermeable to water. As a result of this treatment, cracks appeared on the surface of the seeds and due to this, the germination of seeds increased by 20%. However, it is known that acetone is a toxic substance, and the appearance of cracks in the shell that protects the seeds can adversely affect their resistance to bacterial diseases.

It is known to use nanoparticles of various nature for presowing treatment of plant seeds. For example, seeds of common bean (Phaseolus vulgaris L., cv. Biychanka) and soft spring wheat (Triticum aestivum L., cv. Novosibirskaya 29) were soaked before sowing in suspensions of TiO ₂ nanoparticles obtained by electric explosion, 5 nm in size, having a concentration of 8.9 mg/l for 2 days for beans, and for 1 day for wheat. Additionally, during the growing season, the plants were sprayed twice with suspensions of TiO ₂ nanoparticles: at 18 days of age at concentrations of 8.7 mg/l and at 27 days of age at 9.5 mg/l. The suspensions were subjected to ultrasonic dispersion followed by holding until the turbidity stabilized. In 21-day-old control plants (seeds were soaked in water according to the same scheme) and experimental plants, the height of the stem was measured: in wheat - in the tillering phase, in beans - in the phase of the first true leaf. However, as the results of height measurements showed: in 21-day-old plants, seed soaking and subsequent single treatment of plants with suspensions of titanium and aluminum oxide nanoparticles did not affect the growth rate of bean and wheat plants at the initial stage of their development compared to control plants. The positive effect of presowing seed treatment and subsequent foliar top dressing with aqueous suspensions of nanoparticles was manifested only at later stages of plant development [T.P. Astafurova, Yu.N. Morgalev, A.P. Zotikova, G.S. Verkhoturova, S.I. Mikhailova, A.A. Burenina, T.A. Zaitseva, V.M. Postovalova, L.K. Tsytsareva, G.V. Borovikova Influence of nanoparticles of titanium dioxide and aluminum oxide on the morphological and physiological parameters of plants // Bulletin of the Tomsk State University. Biology. 2011. No. 1 (13), p. 113-122].

The authors of a number of works note that the effects of the impact of silicon dioxide nanoparticles on the germination of plant seeds were concentration dependent. So, the authors [Siddiqui, M. N. Role of nano-SiO2 in germination of tomato (Lycopersicum esculentum seeds Mill.). / MH Siddiqui, MH Al-Whaibi // Saudi Biol. sci. - 2014. Vol. 21. P. 13-17] found that low concentrations of silicon nanoparticles increased the germination of tomato seeds, while high concentrations suppressed them. The increase in germination of corn seeds treated with SiO ₂ nanoparticles, as noted in [R. Suriyaprabha [et al.] Silica nanoparticles for increased silica availability in maize (Zea mays L) seeds under hydroponic conditions // Curr Nanosci. 2012. 8. P. 902-908], was due to greater availability of nutrients and changes in the pH of the nutrient medium, however, SiO ₂ nanoparticles slowed down the germination of bean seeds at low concentrations (0.2%), while higher concentrations inhibited growth seedling roots. Soybean seed germination improved when treated with silicon dioxide and titanium nanoparticles due to an increase in nitrate reductase activity [Lu [et al.] Research on the effect of nanometer materials ongermination and growth enhancement of Glycine max and its mechanism // Soybean Sci. -2002. Vol. 21. P. 68-172], as well as due to a better supply of water and nutrients [L. Zheng [et al. Effect of nano-TiO ₂ on strength of naturally aged seeds and growth of spinach // Biol. trace element. Res. 2005 Vol. 104(1). P. 83-91].

To improve the resistance of wheat plants to phytopathogens, pre-sowing treatment of seeds with a fungicidal composition (RF patent No. 2656965), including tebuconazole, prochloraz, kresoximmethyl, and auxiliary components, has been proposed. At the same time, the fungicidal composition is presented in the form of a wort emulsion. The invention provides an expansion of the spectrum of phytopathogens that can be controlled. However, in this case, strong biocidal additives are used, which can increase an undesirable burden on the environment.

From the above examples, a number of which could be continued, it follows that in each specific case, for each plant species under certain conditions, it is necessary to study the effects of the composition of nanoparticles, their concentration, and also the technological features of seed treatment.

A known method of pre-sowing treatment of barley seeds according to the patent of Russian Federation No. 2618143, which includes a physico-chemical effect on the seeds, which is carried out using tetraethoxysilane Si(OEt) ₄ in an amount of from 10 to 30 wt. %, which is pre-hydrolyzed in a water-alcohol solution with a lack of water in the presence of alkali to form silica sol with a pH of ~ 7-8, as well as with the addition of a solution of the necessary mineral additives. In this method, the sol-gel technology is used, due to which a coating is formed on the surface of the seeds, the structure of which is a silica or polysiloxane matrix, into which minerals useful for the plant can be additionally introduced. This facilitates the germination of seeds and the growth of plants at the initial stage of their development, increases their competitiveness with respect to weed seeds and protects the seeds of cultivated plants from harmful effects.

This technical solution, as the closest to the declared technical essence and the achieved result, is accepted as its prototype. This method has shown itself well in laboratory studies on seeds of cereals and vegetables at the stage of early plant development.

At the same time, this method makes it possible to provide favorable conditions only at the stage of development of spring barley plants.

The objective of the claimed invention is to create a technology for pre-sowing treatment of barley seeds, which would be able to provide favorable conditions not only for the development of spring barley plants, but also for the further growth of plants, as well as increase their resistance to phytopathogens.

The essence of the claimed technical solution is expressed in the following set of essential features sufficient to solve the technical problem indicated by the applicant and obtain the technical result provided by the invention.

According to the invention, the method of pre-sowing treatment of barley seeds, including chemical treatment of barley seeds, which is carried out using tetraethoxysilane Si(OEt) ₄ , is characterized by the fact that tetraethoxysilane Si(OEt) ₄ in the amount of 1 vol. % is mixed with vigorous stirring with a 0.25-molar solution of hydrochloric acid, with the formation of silica sol with pH ~ 2-3 with the addition of an aqueous solution of the necessary mineral additives, while titanium dioxide nanoparticles are added to the silica sol in an amount of 0.003 g/ml of silica sol and organic modifiers - polyethylene glycol or glycerin in the amount of 1 vol. %.

The claimed set of essential features ensures the achievement of a technical result, which consists in the fact that presowing treatment of seeds in silica sols enriched with mineral additives and additional titanium dioxide nanoparticles contributes to protection against phytopathogens, but does not always provide high germination rates of spring barley. Therefore, to mitigate the action of the active photocatalyst titanium dioxide in silica sol, additional modifying additives, glycerol or polyethylene glycol, were additionally added. At the same time, the synergistic effect of silica sol, titanium dioxide nanoparticles and a modifying organic additive - glycerol or polyethylene glycol, has a beneficial effect both on the morphological parameters of barley seedlings and on their resistance to damage by a phytopathogen - the causative agent of root rot (Cochliobolus sativus (S. Ito & Kurib.) Drechsler ex Dastur) and provides conditions for the development of beneficial epiphytic bacteria that process organic and inorganic nitrogen compounds into forms available to plants.

The claimed method is implemented as follows.

For seed treatment, silica sols were prepared based on tetraethyl ester of orthosilicic acid - tetraethoxysilane (TEOS) hydrolyzed in an acidic medium, which differed in the variants of modifying additives (dopants): titanium dioxide nanopowder, glycerin and polyethylene glycol PEG-400. Hydrochloric acid HCl in the form of a 0.25 M aqueous solution and distilled water are also used as sol precursors. As plant nutritional supplements of macro- and microelements, an aqueous solution containing the following compounds - micro and macroelements (see Table 1) is introduced into silica sol. The procedure for preparing the sols consisted in successive mixing of an aqueous solution of macro- and microelements, TEOS, 0.25 M HCl solution, and modifying additives of glycerol or PEG-400. as a result, silica sols with pH ~ 2-3 were obtained, the compositions of which are presented in table. one.

The obtained silica sols are kept for 1 day before further use. For pre-sowing treatment of seeds, seeds of spring barley of two varieties were selected - "Leningradsky" and "Ataman". Pre-sowing treatment of seeds was carried out as a result of mixing for 10 minutes by simply shaking barley seeds in containers with water (control), as well as with the original silica sol (experiment 1); and with suspensions based on this silica sol: with the addition of titanium dioxide nanopowder (0.003 g TiO ₂ /ml silica sol) - experiment No. 2; with the addition of titanium dioxide nanopowder (0.003 g TiO ₂ /ml silica sol) and glycerin - experiment No. 3; with the addition of titanium dioxide nanopowder (0.003 g TiO ₂ /ml silica sol) and PEG-400 - experiment No. 4.

As titanium dioxide nanopowder, commercial photocatalytic nanopowder TYu ₂ P25 (Degussa®) was used, which contains anatase and rutile in a ratio of about 1/3, the average size of anatase and rutile nanoparticles is ~85 and 25 nm, respectively [T. Ohno., K. Sarukawa, K. Tokieda, M. Matsumura Hi. catal. 2001 Vol. 203. No 1. P. 82-86]. Titanium dioxide powder was mixed with silica sol in a ratio of 0.003 g TiO2 per ₁ ml of silica sol, and the obtained mixtures were subjected to ultrasonic dispersion for 10 min. The seeds were dried at room temperature in air and then at 30°C for 60 min in an oven. Seed drying modes corresponded to those specified in GOST 12038. Treated seeds were stored at room temperature before sowing. Repetition of experience - 400 seeds for each variant of experience.

The study of the biological activity of the tested substances consisted in determining their effect on the morphological parameters of seedling growth. Barley seeds were germinated in Petri dishes with a diameter of 10 cm on filter paper moistened with 10 ml of an aqueous solution of the test substance. In the control variants, the seeds were germinated in distilled water. On the 3rd day, the length of the sprouts and roots of the seedlings was measured. All experiments were repeated three times.

The assessment of the effect of presowing treatment of barley seeds with prepared silica sol and suspensions on the numerical composition of epiphytic microorganisms was carried out as follows. Samples of pretreated dry seeds (10 g each) were placed in flasks with 100 ml of sodium phosphate buffer solution (pH 7.2). The flasks were sonicated for 18 min. The duration of exposure to ultrasound was chosen on the basis of the results of preliminary experiments to determine the dependence of the number of microorganism cells washed off the surface of seeds on the time period of ultrasonic exposure. Further, using the generally accepted method of serial dilutions, which consists in seeding 0.1 ml (or 1 ml) of aqueous suspensions - swabs from the corresponding dilutions into solid and liquid nutrient media, followed by their cultivation in a thermostat at 28°C, the number of microorganisms was determined.

чашки Петри. Стаканы выдерживали трое суток в помещении с температурой 24°С. Затем для равномерного распределения мицелия в плошках песок тщательно перемешивали и увлажняли. В каждый стакан высевали по 12 семян ячменя. Стаканы помещали в световой комнате под лампы дневного света, с режимом 16 часов день, 8 часов ночь. Учет проводили на 8-е сутки. Определяли массу выживших растений, визуально оценивали степень поражения каждого растения, давали оценку поражения в баллах по шкале Гоймана [Гойман Э. Инфекционные болезни растений / Пер. с нем. И.Г. Семенковой; Под ред. проф. М.С. Лунина. М.: Изд-во иностр. лит., 1954. 608 с.].Evaluation of the impact of presowing seed treatment of spring barley on resistance to root rot pathogen Cochliobolus sativus (S. Ito & Kurib.) Drechsler ex Dastur was carried out according to the following well-known method [Guidelines for studying the resistance of cereal crops to root rot. L. VASKHNIL, VIR, 1976]. Sterile sand moistened to 50–60% of the total moisture capacity was used for the experiments. The mycelium of Cochliobolus sativus (S. Ito & Kurib.) Drechsler ex Dastur was added to 500 ml plastic beakers;

Petri dishes. The glasses were kept for three days in a room with a temperature of 24°C. Then, to evenly distribute the mycelium in the bowls, the sand was thoroughly mixed and moistened. 12 barley seeds were sown in each glass. The glasses were placed in a light room under fluorescent lamps, with a mode of 16 hours a day, 8 hours a night. Accounting was carried out on the 8th day. The mass of surviving plants was determined, the degree of damage to each plant was visually assessed, the damage was assessed in points on the Goiman scale [Goiman E. Infectious plant diseases / Per. with him. I.G. Semenkova; Ed. prof. M.S. Lunin. M.: Izd-vo inostr. lit., 1954. 608 p.].

The results of the study of the effect of presowing treatment of spring barley seeds on the morphological characteristics of its seedlings are presented in Table 2.

As can be seen from Table 2, both the original silica sol and silica sol with the addition of titanium dioxide nanoparticles do not significantly increase the length of barley seedlings and roots. In contrast to these results, a significant increase in both the length of seedlings and the length of roots was recorded for variants Nos. 3 and 4, where organic modifiers glycerol or PEG-400 were additionally added to the suspension. Based on this information, the following experiments to determine the number of beneficial bacteria on the surface of barley seeds (see Table 3) and the resistance of its seedlings to a phytopathogen (the causative agent of root rot Cochliobolus sativus (S. Ito & Kurib.) Drechsler ex Dastur) (see Table 3). Table 4) was carried out only for the initial silica sol and for suspensions with additions of glycerol and PEG-400.

As can be seen from Table. 3, pre-sowing treatment in suspensions of compositions 3 and 4 containing a mixture of silica sol, titanium dioxide nanoparticles and additives of glycerol or polyethylene glycol significantly increased the number of beneficial bacteria that convert nitrogen compounds into a form easily absorbed by plants. This fact will improve the physiological state of spring barley plants and, ultimately, increase its yield.

The data in table 4 indicate an increase in the resistance of barley plants to the phytopathogen - the causative agent of root rot when using the proposed suspensions with the addition of titanium dioxide and glycerol or polyethylene glycol.

Claims (1)

A method for presowing treatment of barley seeds, including a chemical treatment of barley seeds, which is carried out using tetraethoxysilane Si(OEt) ₄ , characterized in that tetraethoxysilane Si(OEt) ₄ in an amount of 1 vol.% is mixed with vigorous stirring with 0.25 molar hydrochloric acid solution to form silica sol with pH ~ 2-3 with the addition of an aqueous solution of mineral additives, while titanium dioxide nanoparticles are added to silica sol in the amount of 0.003 g/ml silica sol and organic modifiers - polyethylene glycol or glycerin - in the amount of 1 vol.%.