rus
Issue #1/2021
V.N.Zelenkov, V.V.Latushkin, V.V.Potapov, V.V.Karpachov, V.M.Kosolapov, V.T.Sinegovskaya, M.I.Ivanova, A.A.Lapin, P.A.Vernik
Peculiarities of the concentration effect of hydrothermal nanosilica in the pre-sowing treatment of plant seeds upon indicators of biomass and sprouts height in the dark growth mode
Peculiarities of the concentration effect of hydrothermal nanosilica in the pre-sowing treatment of plant seeds upon indicators of biomass and sprouts height in the dark growth mode
DOI: 10.22184/1993-8578.2021.14.1.44.60
The research presents the results of screening studies of 14 agricultural plants with different biological and useful economic properties (17 genotypes, including different species, varieties, and hybrids) to assess the effect of hydrothermal nanosilica on biomass and sprout height in the dark growth germination. Four main types of plant response were revealed in the studied concentration range (0.05, 0.01, 0.005, 0.001 and 0.0005%). These dependencies are characteristic both of the biomass sprout indicator and of the sprout height. The essential role of genetic and epigenetic factors in the formation of the plant response when using hydrothermal nanosilica in seed germination is pointed out.
The research presents the results of screening studies of 14 agricultural plants with different biological and useful economic properties (17 genotypes, including different species, varieties, and hybrids) to assess the effect of hydrothermal nanosilica on biomass and sprout height in the dark growth germination. Four main types of plant response were revealed in the studied concentration range (0.05, 0.01, 0.005, 0.001 and 0.0005%). These dependencies are characteristic both of the biomass sprout indicator and of the sprout height. The essential role of genetic and epigenetic factors in the formation of the plant response when using hydrothermal nanosilica in seed germination is pointed out.
Теги: concentration dependence of biomass and height of sprouts genotypes hydrothermal nanocilica seeds of crops sprouts biomass биомасса ростков генотипы гидротермальный нанокремнезем концентрационная зависимость показателей биомассы и высоты ростк семена сельскохозяйственных культур
PECULIARITIES OF THE CONCENTRATION EFFECT OF HYDROTHERMAL NANOSILICA IN THE PRE-SOWING TREATMENT OF PLANT SEEDS UPON INDICATORS OF BIOMASS AND SPROUTS HEIGHT IN THE DARK GROWTH MODE
The research presents the results of screening studies of 14 agricultural plants with different biological and useful economic properties (17 genotypes, including different species, varieties, and hybrids) to assess the effect of hydrothermal nanosilica on biomass and sprout height in the dark growth germination. Four main types of plant response were revealed in the studied concentration range (0.05, 0.01, 0.005, 0.001 and 0.0005%). These dependencies are characteristic both of the biomass sprout indicator and of the sprout height. The essential role of genetic and epigenetic factors in the formation of the plant response when using hydrothermal nanosilica in seed germination is pointed out.
INTRODUCTION
In recent decades the development of environmentally friendly and nature-like technologies of using mineral resources for crop production and biotechnology has been widely studied. One of the prospective fields to improve the plants properties in open and protected ground is the use of appropriate groups of plant growth regulators, in particular, hydrothermal nanodispersed silica [1–2]. An earlier cycle of long-term research in obtaining silica nanoparticles from natural geothermal waters from the wells of the Mutnovskaya GeoPP (Kamchatka) revealed the biologically active properties of the nanosize forms of silica (HNS) that contribute to increasing the agricultural plants and animals productivity [3–5].
Chemical and biological mechanisms of governing the nanoparticles influence on growth and plant development began to be studied not long ago following receipt of the data that corroborate effectiveness of bio-nanotechnologies in agricultural science [6–8]. The studies at the primary stages of ontogenesis play a special role, in particular, on germinating seeds when genetically determined plant parameters are laid with due account of the epigenetic factor and emergence of a new factor of influence – hydrothermal silica nanoparticles [9]. In particular, cultivation of plants in the systems with a controlled microclimate and ability to model the limiting productivity factors has both scientific and practical applications [10–11]. For practical purposes, knowledge of the mechanisms of interaction between nanoparticles and plant cells can be used to develop technological methods of their use in varietal technologies of pre-sowing treatment in open and protected ground crop production. Development of technologies to improve product quality and obtain functional food products is also promising [12–14].
The work [15] shows the effect of hydrothermal nanosilica of various concentrations on seed germination (in terms of germination and germination energy) of a number of agricultural plants differing in biological and useful economic characteristics. This work is a continuation of the research devoted to a study of the hydrothermal nanosilica seed treatment effect on plant development in the initial period of seed germination in the dark mode with primary heterotrophic nutrition.
The purpose of this study was a screening experimental assessment of the response of different agricultural crops seeds to their pre-sowing treatment with hydrothermal silica nanoparticles in a single scale of nanoparticle concentrations in the laboratory dark growth in terms of "weight of 100 sprouts" and "sprout height".
MATERIALS AND RESEARCH METHODS
Germination was carried out in a synergotron chamber – an experimental model of the ISR 1.01 model (developed by the Institute for Development Strategies). In accordance with the purpose of the experimental work, the biomass and height of sprouts obtained from the seeds of 14 agricultural crops for various purposes (vegetables, oilseeds, fodder, medicinal), differing in biological characteristics, genetic nature, chemical and physicochemical composition and structure of seeds and their peels, were studied. In total, 17 genotypes were studied, including different species, varieties and hybrids. The duration of germination of plant seeds in the experiment was maintained according to a period required to determine the germination rate in accordance with GOST 12038-84 "Seeds of agricultural crops. Methods for determining germination ability": radish – 6 days, rapeseed, meadow clover, soybeans, alfalfa – 7 days, tomato, beetroot, meadow fescue and festulolium, salad – 10, bent grass – 14, coriander – 15 days. Sugar beet seeds were germinated according to GOST 22617.2-94 "Sugar beet seeds.
Methods for determining germination, single sprout and good quality" within 10 days. For the new agricultural crop called Abyssinian nougat, GOST has not yet been developed for germination, therefore, the duration of germination and sowing properties in the experiment were determined on the 7th day by analogy with other rapidly germinating agricultural crops.
The germination technique complies with the specified state standards with the following changes which include replacement of filter paper with a mineral wool substrate placed on the synergotron chamber shelves. The germination temperature was 23–24 °С, the repetition was three times. Watering was carried out with distilled water as the substrate dries up. Before sowing, the control groups of seeds were soaked in distilled water for 2 h, and the experimental groups of seeds were soaked in a distillate into which a diluted hydrothermal sol of nanoparticles was introduced so as to ensure their concentration in an aqueous medium of 0.05, 0.01, 0.005, 0.001, 0.0005 wt. %. The exception was soybean seeds, as they were soaked for 15 minutes, since during the work it was found that a further increase in duration of soaking does not lead to an increase in the amount of the aqueous solution with the preparation absorbed by the seeds, and integrity of the soybean seeds is disturbed and they are easily injured when sowing. The working solution of the indicated concentrations was prepared immediately before seed treatment (not exceeding 30 minutes) from 2.5% aqueous HNS sol. The initial medium was a hydrothermal sol containing 37.5 wt.% Silica nanoparticles obtained by the technology of ultrafiltration membrane concentration at NPF Nanosilika LLC (Petropavlovsk-Kamchatsky).
For more details on the characteristics of the initial concentrate of HNS see [15]. Since the purpose of this work was to compare the effects of the influence of hydrothermal nanosilica on various agricultural crops (17 genotypes) and for comparison and analysis of the experimental results, all data were recalculated into relative values (change (increase)) in the weight and sprout height in % relative to the control by each crop (i.e., the option without treatment with HNS).
RESULTS AND THEIR DISCUSSION
The treatment of seeds with a nanosized silica solution in the experiment made it possible to increase the biomass of sprouts at the end of the germination period for different crops from 8.8% to 53.5% (Fig.1). The indicator is calculated based on the most effective HNS concentration for each crop: 0.05% HNS – festulolium, table beet, 0.01% – bent grass, fescue, 0.005% – clover, coriander, nougat, 0.001% – tomato, sugar beet, soy, alfalfa, rapeseed and 0.0005% – radish, lettuce. On average, the increase for 17 genotypes was 21.7%. Data on the efficiency of HNS for the mass of 100 sprouts when using other concentrations are given below.
Thus, the contribution of the genetic factor to form the biological effects of nanosilica is very significant. Different varieties of the same crop can respond to varying degrees to treatment with the HNS which confirms the need to develop a varietal agricultural technology and a variety (hybrid) passport. Thus, in the present experiment, the increase of biomass differed by more than twice as compared with the control samples in different varieties of rape, alfalfa, and clover. The role (significance) of the epigenetic factor of exposure to nanoparticles is also high, in particular, the manifestation of the effects of changing the mass of 100 sprouts depending on the concentration of HNS in the same variety or hybrid.
In the methodological and practical aspects it is necessary to study the concentration dependences of the HNS biological effects. Table 1 shows data of HNS concentrations when the experiment revealed the maximum and minimum increase of biomass in comparison with the control sample. The difference in one crop sprout biomass growth at various concentrations of HNS was 8.4-53.5% for different genotypes. It should be noted that the biggest difference in the effectiveness of HNS impact concentrations was manifested in the VIK-2 bent (53.5%) and Mars clover (29.5%). For these crop plants the maximum increase in biomass was also noted (by 53.5% and 38.1%, respectively). Consequently, in these crop plants the maximum increase in biomass occurs as a result of the HNS treatment of seeds with a particular concentration, while other concentrations give a lesser effect. In other cases, the effectiveness of different HNS concentrations does not differ so much.
To assess the accuracy of the HNS effect concentration dependences in greater detail, we have constructed graphs of responses of the sprout mass indexes for each plant species in the experiment. Screening of seeds of various crops and varieties according to the response of sprout biomass indexes to treatment with HNS of different concentrations (0.05, 0.01, 0.005, 0.001 and 0.0005%) showed the existence of several types of such response reactions.
Figs.2–4 show four generalized groups of crops, differing in the geometric form of the response – the display on the dependence curve of the mass index of 100 sprouts to control samples depending on the concentration of HNS aqueous sols during pre-sowing seed treatment.
Inclusion of different plants in groups was carried out by visualizing these diagrams reflecting the response forms of seeds (sprouts) of the corresponding crops. Note that the identified four types of reactions can also be traced by the germination energy and seed germination indexes presented in the publication [15]. However, there is no complete coincidence. This is probably due to the fact that the combination of the manifestation of biochemical (specificity and activity of enzymes), biophysical (seed structure), chemical (chemical composition of seed nutrients) and physiological factors (germination features) form the characteristic "mass of 100 sprouts" feature on the diagrams, which gives additional significant differences (change the ranking of the significant factors) along with the genome specificities.
Group 1. The maximum increase due to the HNS application is observed in the area of low and moderate concentrations of nanoparticles in terms of the mass of 100 sprouts: sugar beet (hybrid Smena F1), radish (Yubileiny variety), soybean (Alena variety), tomato (Volgogradsky 5/95 variety), lucerne (varieties Selena and Pastbishnaya 88), rape (varieties Ratnik and Antares) – see Fig.2.
Group 2. The maximum increase due to the HNS application mainly in the range of high and moderately high concentrations of nanoparticles in terms of mass of 100 sprouts: table beet (Demetra variety), coriander (Yantar variety), festulolium (Allegro variety), fescue (Kvarta variety) – see Fig.3.
Group 3. The maximum increase is observed mainly in the area of average HNS concentrations in terms of the mass of 100 shoots: bent grass (variety VIK-2), clover (variety Pavlovsky 16), nougat (variety Lipchanin) – see Fig.4.
Group 4. It is characterized by the presence of two pronounced maxima and minima in terms of the mass of 100 shoots: – clover (Mars variety), lettuce (Dubachek MS variety) – see Fig.5 In the experiment, in addition to the mass index of 100 sprouts, the plants were counted according to the height of sprouts at the end of the germination period. The increase in height in comparison with the control sample ranged for different cultures from 2.1 to 51.3% (see Fig.6).
The index is calculated on the basis of the most effective concentration of HNS for each crop: 0.05% HNS – festulolium, fescue, beetroot, tomato, coriander, 0.01% – lettuce, Antares rape, clover Mars, 0.005% – bent grass, sugar beet, alfalfa, Pavlovsky 16 clover, 0.001% – soybeans, nougat, radish, rape Ratnik. On average, the increase for 17 genotypes comprised 13.3%. The data on the efficiency of HNS in terms of the height of sprouts when using other concentrations are given below.
Table 2 shows the data on the HNS concentration when the maximum and minimum increase in height compared to the control sample was observed experimentally. The incremental difference in the height of sprouts of one crop at different HNS concentrations was 2.1–50.1% for different genotypes.
Comparison of the weight gain of 100 sprouts and the sprouts height showed that these indexes are not always directly dependent. For example, for soybeans in the 0.001% HNS variant, the weight gain of 100 sprouts was 51.3% compared to the control, and the height gain was 29.2%. In the variant 0.01% HNS for the same crop, the indexes were 4% and 20.8%, respectively. Thus, the height and mass of a sprout, although interrelated, are independent parameters and are formed individually in ontogenesis.
The genotypes studied in the experiment were subdivided according to four main types of plant response to different HNS concentrations in accordance with the parameter "sprout height" (similar to how it was done above for the biomass of 100 sprouts):
Group 1. The maximum increase resulting from application of HNS is observed in the region of low and moderate concentrations of nanoparticles in terms of sprout height: soybeans (Alena variety), nougat (Lipchanin variety), radish (Yubileyny variety), rape (Ratnik variety), alfalfa (Pastbishchnaya 88 variety).
Group 2. The maximum increase resulting from application of HNS mainly in the range of high and moderately high concentrations of nanoparticles in terms of sprout height: sugar beet (hybrid Smena F1), alfalfa (Selena variety), clover.
Group 3. The maximum increase is observed mainly in the area of average concentrations of HNS in terms of sprout height: table beet (Demetra variety), coriander (Yantar variety), rape (Antares variety), bent grass (VIK-2 variety).
Group 4. It is characterized by the presence of two pronounced maxima and minima in terms of sprout height: festulolium (Allegro variety), fescue (Kvarta variety).
The distribution of genotypes by sprout biomass and sprout height are not identical, which indicates the complex individual characteristics of the formation of these properties.
CONCLUSIONS
The study continues a series of works on assessing the effect of hydrothermal nanosilica on the level and direction of plant metabolism at different stages of ontogenesis and changes in the their useful economic properties. Treatment of seeds with a solution of nanosized silica in the experiment made it possible to increase the biomass of sprouts at the end of the germination period for different crops from 8.8 to 53.5% and plant height from 2.1 to 51.3%. On average, for 17 genotypes of agricultural plants, the gain in biomass was 21.7%, sprout height 13.3%.
Screening of seeds of different agricultural crops and varieties according to the reaction of biomass and sprout height to the treatment with HNS of different concentrations (0.05, 0.01, 0.005, 0.001 and 0.0005%) showed existence of several types of such response reactions. Four main types of reaction of plant seed germination in the dark to the effect of hydrothermal silica nanoparticles in the concentration range from 0.0005% to 0.05% were revealed. The difference in the gain of the sprouts biomass of the same crop in comparison with the control at different HNS concentrations was 8.4–53.5% for different genotypes, according to the increment in the sprouts height – 2.1–50.1%. Thus, the genetic factor contribution to the formation of the biological effects of nanosilica is very significant.
Different varieties of the same crop can respond to varying degrees to treatment with the HNS, which confirms the need to develop varietal agricultural techniques and a passport of a variety (hybrid), including establishing the responsiveness of specific genotypes to different doses of hydrothermal nanosilica. Comparison of the weight gains of 100 sprouts and the sprouts height showed that these indexes are not always directly related. Thus, the height and mass of the sprout, although interrelated, are independent parameters and are formed individually in ontogeny.
The data obtained in the study can be useful for understanding the mechanisms of the effect of nanoparticles at the stage of seed germination with heterotrophic nutrition, as well as for subsequent use in the development of biotechnologies for pre-sowing seed treatment in open and protected ground crop production, and for obtaining new kinds of food products – seed sprouts and microgreens with a high content of biologically active substances. ■
The research presents the results of screening studies of 14 agricultural plants with different biological and useful economic properties (17 genotypes, including different species, varieties, and hybrids) to assess the effect of hydrothermal nanosilica on biomass and sprout height in the dark growth germination. Four main types of plant response were revealed in the studied concentration range (0.05, 0.01, 0.005, 0.001 and 0.0005%). These dependencies are characteristic both of the biomass sprout indicator and of the sprout height. The essential role of genetic and epigenetic factors in the formation of the plant response when using hydrothermal nanosilica in seed germination is pointed out.
INTRODUCTION
In recent decades the development of environmentally friendly and nature-like technologies of using mineral resources for crop production and biotechnology has been widely studied. One of the prospective fields to improve the plants properties in open and protected ground is the use of appropriate groups of plant growth regulators, in particular, hydrothermal nanodispersed silica [1–2]. An earlier cycle of long-term research in obtaining silica nanoparticles from natural geothermal waters from the wells of the Mutnovskaya GeoPP (Kamchatka) revealed the biologically active properties of the nanosize forms of silica (HNS) that contribute to increasing the agricultural plants and animals productivity [3–5].
Chemical and biological mechanisms of governing the nanoparticles influence on growth and plant development began to be studied not long ago following receipt of the data that corroborate effectiveness of bio-nanotechnologies in agricultural science [6–8]. The studies at the primary stages of ontogenesis play a special role, in particular, on germinating seeds when genetically determined plant parameters are laid with due account of the epigenetic factor and emergence of a new factor of influence – hydrothermal silica nanoparticles [9]. In particular, cultivation of plants in the systems with a controlled microclimate and ability to model the limiting productivity factors has both scientific and practical applications [10–11]. For practical purposes, knowledge of the mechanisms of interaction between nanoparticles and plant cells can be used to develop technological methods of their use in varietal technologies of pre-sowing treatment in open and protected ground crop production. Development of technologies to improve product quality and obtain functional food products is also promising [12–14].
The work [15] shows the effect of hydrothermal nanosilica of various concentrations on seed germination (in terms of germination and germination energy) of a number of agricultural plants differing in biological and useful economic characteristics. This work is a continuation of the research devoted to a study of the hydrothermal nanosilica seed treatment effect on plant development in the initial period of seed germination in the dark mode with primary heterotrophic nutrition.
The purpose of this study was a screening experimental assessment of the response of different agricultural crops seeds to their pre-sowing treatment with hydrothermal silica nanoparticles in a single scale of nanoparticle concentrations in the laboratory dark growth in terms of "weight of 100 sprouts" and "sprout height".
MATERIALS AND RESEARCH METHODS
Germination was carried out in a synergotron chamber – an experimental model of the ISR 1.01 model (developed by the Institute for Development Strategies). In accordance with the purpose of the experimental work, the biomass and height of sprouts obtained from the seeds of 14 agricultural crops for various purposes (vegetables, oilseeds, fodder, medicinal), differing in biological characteristics, genetic nature, chemical and physicochemical composition and structure of seeds and their peels, were studied. In total, 17 genotypes were studied, including different species, varieties and hybrids. The duration of germination of plant seeds in the experiment was maintained according to a period required to determine the germination rate in accordance with GOST 12038-84 "Seeds of agricultural crops. Methods for determining germination ability": radish – 6 days, rapeseed, meadow clover, soybeans, alfalfa – 7 days, tomato, beetroot, meadow fescue and festulolium, salad – 10, bent grass – 14, coriander – 15 days. Sugar beet seeds were germinated according to GOST 22617.2-94 "Sugar beet seeds.
Methods for determining germination, single sprout and good quality" within 10 days. For the new agricultural crop called Abyssinian nougat, GOST has not yet been developed for germination, therefore, the duration of germination and sowing properties in the experiment were determined on the 7th day by analogy with other rapidly germinating agricultural crops.
The germination technique complies with the specified state standards with the following changes which include replacement of filter paper with a mineral wool substrate placed on the synergotron chamber shelves. The germination temperature was 23–24 °С, the repetition was three times. Watering was carried out with distilled water as the substrate dries up. Before sowing, the control groups of seeds were soaked in distilled water for 2 h, and the experimental groups of seeds were soaked in a distillate into which a diluted hydrothermal sol of nanoparticles was introduced so as to ensure their concentration in an aqueous medium of 0.05, 0.01, 0.005, 0.001, 0.0005 wt. %. The exception was soybean seeds, as they were soaked for 15 minutes, since during the work it was found that a further increase in duration of soaking does not lead to an increase in the amount of the aqueous solution with the preparation absorbed by the seeds, and integrity of the soybean seeds is disturbed and they are easily injured when sowing. The working solution of the indicated concentrations was prepared immediately before seed treatment (not exceeding 30 minutes) from 2.5% aqueous HNS sol. The initial medium was a hydrothermal sol containing 37.5 wt.% Silica nanoparticles obtained by the technology of ultrafiltration membrane concentration at NPF Nanosilika LLC (Petropavlovsk-Kamchatsky).
For more details on the characteristics of the initial concentrate of HNS see [15]. Since the purpose of this work was to compare the effects of the influence of hydrothermal nanosilica on various agricultural crops (17 genotypes) and for comparison and analysis of the experimental results, all data were recalculated into relative values (change (increase)) in the weight and sprout height in % relative to the control by each crop (i.e., the option without treatment with HNS).
RESULTS AND THEIR DISCUSSION
The treatment of seeds with a nanosized silica solution in the experiment made it possible to increase the biomass of sprouts at the end of the germination period for different crops from 8.8% to 53.5% (Fig.1). The indicator is calculated based on the most effective HNS concentration for each crop: 0.05% HNS – festulolium, table beet, 0.01% – bent grass, fescue, 0.005% – clover, coriander, nougat, 0.001% – tomato, sugar beet, soy, alfalfa, rapeseed and 0.0005% – radish, lettuce. On average, the increase for 17 genotypes was 21.7%. Data on the efficiency of HNS for the mass of 100 sprouts when using other concentrations are given below.
Thus, the contribution of the genetic factor to form the biological effects of nanosilica is very significant. Different varieties of the same crop can respond to varying degrees to treatment with the HNS which confirms the need to develop a varietal agricultural technology and a variety (hybrid) passport. Thus, in the present experiment, the increase of biomass differed by more than twice as compared with the control samples in different varieties of rape, alfalfa, and clover. The role (significance) of the epigenetic factor of exposure to nanoparticles is also high, in particular, the manifestation of the effects of changing the mass of 100 sprouts depending on the concentration of HNS in the same variety or hybrid.
In the methodological and practical aspects it is necessary to study the concentration dependences of the HNS biological effects. Table 1 shows data of HNS concentrations when the experiment revealed the maximum and minimum increase of biomass in comparison with the control sample. The difference in one crop sprout biomass growth at various concentrations of HNS was 8.4-53.5% for different genotypes. It should be noted that the biggest difference in the effectiveness of HNS impact concentrations was manifested in the VIK-2 bent (53.5%) and Mars clover (29.5%). For these crop plants the maximum increase in biomass was also noted (by 53.5% and 38.1%, respectively). Consequently, in these crop plants the maximum increase in biomass occurs as a result of the HNS treatment of seeds with a particular concentration, while other concentrations give a lesser effect. In other cases, the effectiveness of different HNS concentrations does not differ so much.
To assess the accuracy of the HNS effect concentration dependences in greater detail, we have constructed graphs of responses of the sprout mass indexes for each plant species in the experiment. Screening of seeds of various crops and varieties according to the response of sprout biomass indexes to treatment with HNS of different concentrations (0.05, 0.01, 0.005, 0.001 and 0.0005%) showed the existence of several types of such response reactions.
Figs.2–4 show four generalized groups of crops, differing in the geometric form of the response – the display on the dependence curve of the mass index of 100 sprouts to control samples depending on the concentration of HNS aqueous sols during pre-sowing seed treatment.
Inclusion of different plants in groups was carried out by visualizing these diagrams reflecting the response forms of seeds (sprouts) of the corresponding crops. Note that the identified four types of reactions can also be traced by the germination energy and seed germination indexes presented in the publication [15]. However, there is no complete coincidence. This is probably due to the fact that the combination of the manifestation of biochemical (specificity and activity of enzymes), biophysical (seed structure), chemical (chemical composition of seed nutrients) and physiological factors (germination features) form the characteristic "mass of 100 sprouts" feature on the diagrams, which gives additional significant differences (change the ranking of the significant factors) along with the genome specificities.
Group 1. The maximum increase due to the HNS application is observed in the area of low and moderate concentrations of nanoparticles in terms of the mass of 100 sprouts: sugar beet (hybrid Smena F1), radish (Yubileiny variety), soybean (Alena variety), tomato (Volgogradsky 5/95 variety), lucerne (varieties Selena and Pastbishnaya 88), rape (varieties Ratnik and Antares) – see Fig.2.
Group 2. The maximum increase due to the HNS application mainly in the range of high and moderately high concentrations of nanoparticles in terms of mass of 100 sprouts: table beet (Demetra variety), coriander (Yantar variety), festulolium (Allegro variety), fescue (Kvarta variety) – see Fig.3.
Group 3. The maximum increase is observed mainly in the area of average HNS concentrations in terms of the mass of 100 shoots: bent grass (variety VIK-2), clover (variety Pavlovsky 16), nougat (variety Lipchanin) – see Fig.4.
Group 4. It is characterized by the presence of two pronounced maxima and minima in terms of the mass of 100 shoots: – clover (Mars variety), lettuce (Dubachek MS variety) – see Fig.5 In the experiment, in addition to the mass index of 100 sprouts, the plants were counted according to the height of sprouts at the end of the germination period. The increase in height in comparison with the control sample ranged for different cultures from 2.1 to 51.3% (see Fig.6).
The index is calculated on the basis of the most effective concentration of HNS for each crop: 0.05% HNS – festulolium, fescue, beetroot, tomato, coriander, 0.01% – lettuce, Antares rape, clover Mars, 0.005% – bent grass, sugar beet, alfalfa, Pavlovsky 16 clover, 0.001% – soybeans, nougat, radish, rape Ratnik. On average, the increase for 17 genotypes comprised 13.3%. The data on the efficiency of HNS in terms of the height of sprouts when using other concentrations are given below.
Table 2 shows the data on the HNS concentration when the maximum and minimum increase in height compared to the control sample was observed experimentally. The incremental difference in the height of sprouts of one crop at different HNS concentrations was 2.1–50.1% for different genotypes.
Comparison of the weight gain of 100 sprouts and the sprouts height showed that these indexes are not always directly dependent. For example, for soybeans in the 0.001% HNS variant, the weight gain of 100 sprouts was 51.3% compared to the control, and the height gain was 29.2%. In the variant 0.01% HNS for the same crop, the indexes were 4% and 20.8%, respectively. Thus, the height and mass of a sprout, although interrelated, are independent parameters and are formed individually in ontogenesis.
The genotypes studied in the experiment were subdivided according to four main types of plant response to different HNS concentrations in accordance with the parameter "sprout height" (similar to how it was done above for the biomass of 100 sprouts):
Group 1. The maximum increase resulting from application of HNS is observed in the region of low and moderate concentrations of nanoparticles in terms of sprout height: soybeans (Alena variety), nougat (Lipchanin variety), radish (Yubileyny variety), rape (Ratnik variety), alfalfa (Pastbishchnaya 88 variety).
Group 2. The maximum increase resulting from application of HNS mainly in the range of high and moderately high concentrations of nanoparticles in terms of sprout height: sugar beet (hybrid Smena F1), alfalfa (Selena variety), clover.
Group 3. The maximum increase is observed mainly in the area of average concentrations of HNS in terms of sprout height: table beet (Demetra variety), coriander (Yantar variety), rape (Antares variety), bent grass (VIK-2 variety).
Group 4. It is characterized by the presence of two pronounced maxima and minima in terms of sprout height: festulolium (Allegro variety), fescue (Kvarta variety).
The distribution of genotypes by sprout biomass and sprout height are not identical, which indicates the complex individual characteristics of the formation of these properties.
CONCLUSIONS
The study continues a series of works on assessing the effect of hydrothermal nanosilica on the level and direction of plant metabolism at different stages of ontogenesis and changes in the their useful economic properties. Treatment of seeds with a solution of nanosized silica in the experiment made it possible to increase the biomass of sprouts at the end of the germination period for different crops from 8.8 to 53.5% and plant height from 2.1 to 51.3%. On average, for 17 genotypes of agricultural plants, the gain in biomass was 21.7%, sprout height 13.3%.
Screening of seeds of different agricultural crops and varieties according to the reaction of biomass and sprout height to the treatment with HNS of different concentrations (0.05, 0.01, 0.005, 0.001 and 0.0005%) showed existence of several types of such response reactions. Four main types of reaction of plant seed germination in the dark to the effect of hydrothermal silica nanoparticles in the concentration range from 0.0005% to 0.05% were revealed. The difference in the gain of the sprouts biomass of the same crop in comparison with the control at different HNS concentrations was 8.4–53.5% for different genotypes, according to the increment in the sprouts height – 2.1–50.1%. Thus, the genetic factor contribution to the formation of the biological effects of nanosilica is very significant.
Different varieties of the same crop can respond to varying degrees to treatment with the HNS, which confirms the need to develop varietal agricultural techniques and a passport of a variety (hybrid), including establishing the responsiveness of specific genotypes to different doses of hydrothermal nanosilica. Comparison of the weight gains of 100 sprouts and the sprouts height showed that these indexes are not always directly related. Thus, the height and mass of the sprout, although interrelated, are independent parameters and are formed individually in ontogeny.
The data obtained in the study can be useful for understanding the mechanisms of the effect of nanoparticles at the stage of seed germination with heterotrophic nutrition, as well as for subsequent use in the development of biotechnologies for pre-sowing seed treatment in open and protected ground crop production, and for obtaining new kinds of food products – seed sprouts and microgreens with a high content of biologically active substances. ■
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