CC BY
10DOI 10.24412/2709-1201-2024-286-294
EFFECT OF NANOPARTICLES ON THE EARLY BURLAT CHERRY FLOWER
FERTILIZATION
LAMIYA ISMAYILOVA
Doctoral student of the institute of Ecology, NASA of Azerbaijan, Baku, Azerbaijan
ISMAT AHMADOV
Associate professor of Department of Chemical Physics of nanomaterials, Baku State University, Baku, AZ1148, Z.Khalilov str.23, Azerbaijan
HIJRAN AHMADOVA
Doctoral student of the institute of Ecology, NASA of Azerbaijan, Baku, Azerbaijan
JEYRAN SULTANOVA
Azerbaijan State Oil and Industry University, Baku, Azerbaijan
SEVIL HUSEYNOVA
Azerbaijan Architecture and Construction University, Baku, Azerbaijan
Abstract: Along with attempts to use nanomaterial, including nanoparticles, as mineral fertilizers in the agricultural industry, they have begun to use them as a physical factor to increase the productivity ofplants and their resistance to stress factors. Experiments show that it can spread in the environment in different ways and can accumulate in the organs of plants. The effect of nanoparticles on plants is observed by their morphological, physiological, and biochemical effects. In this study, the effects of SiO2 and Fe3O4 nanoparticles on flower fertilization in Early Burlat cherry trees in one season, their accumulation in cherry fruit, and some toxic effects of their fruits were investigated. Since the Early Burlat cherry type is widely used in intensive horticulture, it is suitable for industrial cultivation and is highly productive, so experiments were conducted on this type of tree. The experiments were conducted in the experimental area of the "Fruit and Tea Cultivation" Scientific Research Institute located in the Zardabi settlement of the Guba region (Republic of Azerbaijan) in the season of2023. Cherry trees were sprayed with solutions of 0.5 g/l SiO2 and Fe3O4 nanoparticles in deionized water during early flowering and full flowering. It was clear from the results of the experiments that nanoparticles have a positive effect on the number of flowers formed from flower buds, the fertilization offlowers and the formation offruits. Diffusion and accumulation of nanoparticles in cherry fruits was investigated by EPR method and it was determined that nanoparticles are accumulated in cherry fruit. Toxicological experiments conducted on white rats showed no toxic effects in the blood of rats fed with fruit juice containing nanoparticles.
Keywords: Nanoparticles, cherry tree, fertilization of flowers, fruits, localization of nanoparticles
Introduction
Recently, the use of nanoparticles in the agricultural industry in order to increase the productivity of plants and their resistance to various biotic and abiotic stresses has given promising results. Now, using metal-based, carbon-containing nanoparticles as nanofertilizers, insecticides, and stimulating factors, they have succeeded in creating a number of positive physiological and morphological changes in plant development and productivity. Si, SiO, Fe, Fe2O3, Fe3O4 nanoparticles can also be attributed to these nanoparticles. Experiments have shown that Si nanoparticles, due to their unique properties, are important in increasing the stress resistance and productivity of agricultural plants (Alsaeedi et al., 2019a,b). Si nanoparticles have a positive effect
on the development of plants, create important changes in their physiology and morphology, create structural changes by forming double layers in the epidermal cell wall. (Strout et al., 2013; Suriyaprabha et al., 2014). By strengthening the cell wall, Si nanoparticles prevent fungal, bacterial and nematode infections, support plant growth and increase productivity. Si nanoparticles reduce evaporation by reducing the permeability of the nozzles, thus increasing drought resistance. (Rastogi et al., 2019). Flower performance was significantly improved when Marigold (Tagetes erecta L.) leaves were sprayed with Si nanoparticles at a concentration of 200 mg L-1. Si nanoparticles had an enhancing effect on the biometrics, physiology and properties of flowers. The authors attributed this effect to the accumulation of Si nanoparticles in plant leaves. It has been found that the number of flowers, flower diameter, fresh and dry weight of flowers increase, the flowering period and the days required for the appearance of the first flower buds shorten as the concentration of Si nanoparticles increases in the leaves (Eman and Nevien, 2021). Soaking the bulbs of Oriental Lilies plants in an Ag nanoparticle solution stimulated plant growth, as manifested by enhanced accumulation of leaf and bulb biomass, showed a higher leaf greenness index, formed more flowers, and flowered longer and accelerated flowering (Piotr Salachna et al., 2019). When onion plants (Allium cepa L.) were treated with ZnO nanoparticles at a concentration of 20 and 30 pg/ml, it was found that the plants grew better and bloomed 12-14 days earlier than the control. The authors concluded that ZnO nanoparticles can shorten the flowering period of onions by 12-14 days and even produce healthy seeds (Laware and Shilpa Raskar, 2014)
The research of Ismayilova et al. (2023) showed that when the flowers and leaves of an apple tree are sprayed with solutions of SiO2 and Fe3O4 nanoparticles, the efficiency of flower fertilization increases, as a result, the number of fruits increases and the productivity increases. On the other hand, SiO2 and Fe3O4 nanoparticles change the composition and size of the fruit. It is interesting that after the fertilization process of the flowers, during the development of the fruit, the nanoparticles can accumulate in the peel, the pulp, and the seed of the fruit. The results of TEM analysis showed that these nanoparticles can be collected in the fruit of flowers fertilized by nanoparticles. When tomato plants were treated in the form of spraying with MnFe2O4 nanoparticles at concentrations of 10 mg/L, the flowering time and number of fruits were significantly accelerated as the dose increased. After spraying the leaves with 10 and 50 mg/l NM MnFe2O4, the flower formation time was significantly reduced by 13 days and 15 days, respectively, compared to the control. Experiments have shown that a MnFe2O4 nanoparticle concentration of 10 mg/l is optimal for obtaining the best effects. The net rate of leaf photosynthesis, the sucrose content in leaves by 7.5% and 8.8% of tomato also increased after 4 and 7 times of successive applications of the nanoparticle at 10 mg/l concentration (Le Yue et al., 2022). Treatment of Arabidopsis thaliana seedlings with carbon nanoparticles caused early flowering under both long and short day conditions, indicating a photoperiod-dependent effect. Treatment with carbon nanoparticles also improved seed germination, showing an elongated hypocotyl, larger cotyledon area and increased chlorophyll content (Kumar Abhishek et al.,2018).
Thus, it is clear from the literature review that nanoparticles can affect the intensity of flowering, flowering period, and their effective fertilization in flowering plants and create various physiological and biochemical effects in plants. From these data, it is clear that the mechanism of the effect of nanoparticles on the fertilization of flowers, which plays a key role in plant productivity, is not fully understood and this issue remains relevant. Therefore, in our experiments, the effect of two important nanoparticles (SiO2 and Fe3O4) on cherry tree flowering and flower fertilization was studied.
Materials and Methods
1.1 Cherry tree and experimental design.
Cherries of the Early Burlat variety were used in the experiments. The trees of this variety of French origin are semi-erect and strong. The Early Burlat variety is characterized by high productivity, the fruits ripen quickly, and the yield is stable. The collection ends in the second ten
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days of May. The best pollinators are the Georgia and Lapins varieties. Cherry is a plant that requires heat and light. However, extremely high temperatures negatively affect its growth and development. Among the plants of the southern regions, this is the most winter-hardy plant. Depending on the variety, the need for moisture is different. The Antipka cherry varieties are characterized by low humidity, while the cherry and cherry varieties are more demanding. However, excessive humidity and the presence of groundwater on the surface negatively affect cherries.
Cherry grows well on light, waterlogged, sandy soils with a thick arable layer. If the soil density (volumetric weight) is 1.5 g/cm3, the cherry tree cannot develop. Cherry is demanding moisture. The fruits of the Early Burlat variety are round, flat, and large. Its color is dark red and bright. The pulp is firm and very juicy. The average size of the fruit width is 20 mm, fruit height is 19 mm, and weight is 8-8.5 grams. This variety is resistant to cracking and bacterial diseases. The experiments were carried out in experimental gardens of the Research Institute of Fruit and Tea Growing, located in the village of Zardabi, Guba district. An area of 40 m2 was allocated for the experiment. Nine trees were divided into three areas with a distance of 140 cm between each tree. The I-zone is called option A, the II-zone is called B-option, and the III-area is called C-option (Figure 1).
Nanoparticles were applied by spraying to a cherry tree on 04/05/2023 at the stage of flower buds and after full flowering. In option A, three trees were sprayed with a suspended solution of SiO2 (silicon dioxide) nanoparticles dissolved in distilled water. To do this, 0.5 g of nanoparticle powder was mixed with 1 liter of distilled water and processed in an ultrasonic device for 15 minutes. On average, each tree was exposed to a 0.5 g/L nanoparticle solution. The trees in option B were the control zone. In this option, no nanoparticles were sprayed onto the trees, only that amount of distilled water was sprayed. In option B, the trees were sprayed with a suspension solution in which Fe3O4 nanoparticles 20-30 nm in size were dissolved. In this case, 0.5 g of nanoparticles were dissolved in 1 liter of distilled water and treated in an ultrasonic apparatus for 15 minutes before spraying. In this variant, on average, each tree was exposed to a nanoparticle solution with a concentration of 0.5 g/L.
2.2 Nanoparticles and preparation their solutions.
SiO2 and Fe3O4 nanoparticles used in the experiments were purchased from Skyspring Nanomaterials.Inc, Houston TX, USA. The sizes of powdered SiO2 and Fe3O4 nanoparticles were in the range of 20-30 nm. Nanoparticles were dissolved in deionized water at the rate of 0.5 g/l to obtain a dispersed solution. Before application, in order to avoid agglomeration of nanoparticles, the dispersed solution was processed in an ultrasonic sonicator (QSONiCA sonicator) for 15 minutes. The flowers of the trees were sprayed with a spray method in a short time interval.
2.3 EPR method
Absorption and localization of Fe3O4 nanoparticles in cherry fruits were detected by the EPR method. First, the EPR spectrum of the solution of Fe3O4 nanoparticles was recorded on a Bruker ESP300E (Bruker, Germany) device, and the accumulation of these nanoparticles in plant fruits was determined based on the change in the EPR signal. Samples were taken from the pulp of cherry fruits grown in options B and C, and sections were prepared and dried in a vacuum device. EPR signals of Fe3O4 nanoparticles in dried samples were recorded.
Results
3.1 Phenology observations
This is the first study investigating the effects of different nanoparticles and methods of their application on the fertilization and flowering of the "Early Burlat' cherry tree. In the experiments, "Early Burlat" cherry trees planted in the open field in the form of seedlings in 2016 were used. The trees at the time of the experiment were 7-year-old trees in the 2023 season. Phenology observations
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were made during the fruiting vegetation period of cherry trees. During this period, tree development, budding, leaf formation, flowering and fruiting stages were observed. The period from awakening of generative organs and flower buds to fruit harvesting was observed. Observations have shown that flower buds begin to wake up in the second decade of April, the initial awakening of buds occurs on April 20. The first flowering is observed a week after the awakening of the shoots. A week after the first flowering, the trees are in full bloom, and on May 5, the flowering of the trees and the fertilization of the flowers ends. Starting from this period, the process of formation and growth of fruits begins. The fruits of ""Early Burlat" cherry trees fully ripen at the end of May and the first ten days of June, and harvesting begins from this period. Table 1 shows the results of phenology observations made on trees belonging to the ""Early Burlat" cherry variety in the study area in 2023.
3.2 Pomology observations
As we mentioned, the main goal of the experiments was to investigate the rate of fertilization of flowers in Early Burlat cherry trees treated with nanoparticles, the efficiency of the fertilization process, and how the number of fruits changes as a result. Therefore, 3 trees were selected for each option (options A, B, C) as shown in the methodology, and 3 branches of each tree were sprayed with nanoparticles. Branches of trees selected from option A were sprayed with a solution of SiO2 nanoparticles, branches of trees selected from option C were sprayed with a solution of Fe3O4 nanoparticles. The branches of trees selected from option B were sprayed only with distilled water. The first spraying was carried out at the stage of formation of flower buds on the branch, and the second spraying was carried out at the stage of complete flowering. After the second spraying, it was determined how many flowers were successfully fertilized and produced fruit. The results of the experiment are given in Table 2.
From the results of the experiments, it was clear that spraying with both nanoparticles, both SiO2 and Fe3O4, affects the process of turning flowers into fruits of "Early Burlat" cherry trees. Thus, the number of flower buds on 3 branches in control option B was 179 on average, 144 turned into full flowers, and 92 fruits were obtained from these flowers. Thus, 68.8% of the flowers were effectively fertilized and were able to turn into fruits. In variant A, in which one branch from each of the 3 trees was sprayed with SiO2 nanoparticles, the average number of flower buds was 156, of which 152 turned into full flowers, and 118 fruits were obtained from these flowers. Thus, 77.8% of the flowers were effectively fertilized and were able to turn into fruits. In option C, one branch from each of the 3 trees was sprayed with Fe3O4 nanoparticles, the average number of flower buds was 208, 184 turned into full flowers, and 151 fruits were obtained from these flowers. Thus, 84.7% of the flowers were effectively fertilized and were able to turn into fruits.
3.3 Accumulation of nanoparticles in fruits
One of the goals of our experiments was to check whether flowers diffuse into cherry fruits after being treated with nanoparticles. Due to the positive effect of spraying nanoparticles on the flowers during the fertilization process, the productivity of cherry trees and the number of fruits were higher than in the control. Therefore, it has been hypothesized that nanoparticles may enter the flower bed during fertilization and remain in the fruits. We have proven this by TEM analysis and EPR method in our previous experiments with apple wood. It was found that the used SiO2 and Fe3O4 nanoparticles can migrate to the flower bed after spraying the flowers and accumulate in the fruits (Ismayilova et al., 2023).We once again confirmed the accumulation of Fe3O4 nanoparticles in cherry fruits by the EPR method. Samples for EPR were taken from fruits, the flowers of which were sprayed with Fe3O4 nanoparticles. EPR signals were taken from the flashy part of cherry fruits taken from the normal control variant, as well as from the flashy part of fruits of trees treated with Fe3O4 nanoparticles. Figure 4 shows the EPR signals. The results showed that these are signals of iron oxide, but it cannot be said that these signals are signals of Fe3O4 nanoparticles. Because the
signals obtained from the variant with the application of Fe3O4 nanoparticles do not differ from the signals of the control variant without the use of Fe3O4 nanoparticles.
3.4 Identification of toxic effects of nanoparticle-containing cherry fruits
Our experiments have shown that when the flowers of apple or cherry trees are sprayed with SiO2 and Fe3O4 nanoparticles, these nanoparticles can be collected in the fruits formed from those flowers. Therefore, it should be clarified what toxicological effects can occur when such fruits are used as food. Taking this into account, we had to investigate the changes in the blood of white experimental rats of the juice obtained from the fruit of the Early Burlat cherry variety to which SiO2 nanoparticles were applied. The experiments were conducted on white rats at the Toxicology Department of the Scientific Research Institute of Azerbaijan Medical University. White rats were fed juice obtained from the fruit of the Early Burlat cherry variety containing SiO2 nanoparticles and, as a control, with juice obtained from the fruits of cherries taken from normally grown trees, as well as without any fruit juice. The white rats used in the experiments were 7-8 months old and weighed about 170 g. 15 white rats were selected and divided into 3 groups with 5 rats in each group. The first group of rats was fed fruit juice containing SiO2 nanoparticles, the rats in the second group were fed juice obtained from the fruits of normally cultivated cherry trees, and the mice of the third group were not given any juice. For 7 days (from 04.07.2023 to 11.07.2023), each rat was given 2 ml of fruit juice once a day. Fruit juices were first diluted with distilled water in a ratio of 1:1. Fruit juices were directly injected through the oral cavity of white rats. After 7 days, the introduction of fruit juices to the rats was stopped. The rats were then anesthetized with Colypsol and sacrificed. First, the supplies used in the experiments were sterilized using sodium hypo chloride (NaClO). 2 ml of blood was taken from each rat, analyzed in an auto hematology analyzer, and total blood parameters were determined. The results of these experiments are given in Tables 3.
The results of our experiments showed that in white rats fed with cherry fruit juice, there was no significant change in blood composition parameters in general. However, there is a noticeable change in some indicators. For example, GRA (in % confidence) was 7.16% in rats that did not receive any cherry fruit juice, while the value of this parameter was 3.0% in rats fed normal juice. In rats that received cherry fruit juice containing SiO2 nanoparticles, its value decreased again and was 1.7%. A slight increase was observed in the value of the RDW-SD parameter. Thus, in rats that did not receive any fruit juice, its value was 28.0, in rats that received juice, its value was 30.5, and in rats that received juice containing SiO2 nanoparticles, its value was 32.1. An increase was also observed in the P-LRC parameter. Thus, in rats that did not receive any fruit juice, its value was 1.7, in rats that received juice, its value was 2.1, and in rats that received juice containing SiO2 nanoparticles, its value was 3.6. The effect of SiO2 nanoparticles on this blood parameter was more serious. Its price has increased more than 2 times. Thus, it can be said that no toxic effect is observed in the blood of white rats fed with the juice of Early Burlat cherry fruit containing SiO2 nanoparticles.
Discussion
In fruit trees, the normal development of generative organs, the flowering process and the successful fertilization of flowers are the keys to reproductive success and are important for high productivity. Great progress has been made in the last few years to understand the cellular and molecular mechanisms of flower fertilization and the factors influencing this process using model plants. It should be noted that the mechanisms of double fertilization in flowers are very complex and a large number of factors affect the regulation of this process. In recent years, significant progress has been made in studying the molecular mechanisms of flower fertilization in flowering plants. In particular, several attempts have been made to prevent fusion of gamete nuclei (karyogamy) and polyspermy. After the two male gametes freely enter the embryo sac, they find themselves in a very complex microenvironment consisting of degenerated synergid, pollen tube components, and extracellular fluids. The osmolarity, pH, and composition of this microenvironment surrounding the gametes are not fully known. Experiments have shown that the
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amount of total calcium detected in synergids is high, as well as the amount of chlorotetracycline (CTC) or anti monate deposits. (Chaubal and Reger 1990, 1992a, b, 1993; Huang and Russell, 1992b). Perhaps, after the synergid is degenerated and participates in the microenvironment for gamete fusion, the formation of freely bound calcium occurs. However, no information is provided on the amount of free calcium. It can be said that the composition of the microenvironment is probably very important for the ability of gametes to unite.
The effect of nanoparticles on the fertilization process in flowers has been little investigated and experiments are needed in this field. It can be assumed that the positive effect of nanoparticles on flower fertilization is related to changing the microenvironment surrounding the gametes. Nanoparticles can change the osmolarity, pH and composition of the microenvironment.
Conclusion
One of the promising aspects of the application of nanotechnology in agricultural practice is the clarification of the effect of nanoparticles on plant productivity. The productivity of flowering plants depends on the effective fertilization of their flowers. In the presented research, the effect of SiO2 and Fe3O4 nanoparticles on the fertilization of cherry blossoms was studied. It was found that both nanoparticles have a positive effect on the fertilization of flowers, and as a result, the number of fruits is greater than in the control variant. Nanoparticles can accumulate in cherry fruit. No significant changes were observed in the blood of white experimental rats fed cherry juice, and thus it can be concluded that the administration of these nanoparticles does not pose any toxic risk.
Table 1. Phenology observations of the "Early Burlat" cherry for the 2023 season
Observation days Phenology changes
22.03.2023 Awakening of flower buds
15.04.2023 First flowering
25.04.2023 Full bloom
05.05.2023 End of flowering
06.06.2023 Fruit ripening period and harvesting
Table 2. Pomology observations of the "Early Burlat"cherry for the 2023 season
Branches Options Number of Number of Number of Percentage of
flower buds flower fruits flowers turning into fruit
1 A (SiO2) 165 160 125 78,1 %
2 A (SiO2) 156 153 109 71,2 %
3 A (SiO2) 148 144 121 84,03 %
1 B control 260 206 112 54,4 %
2 B control 156 125 86 68,8 %
3 B control 121 101 78 77,2 %
1 C (Fe3 O4) 278 256 180 70,3 %
2 C (Fe3 O4) 196 155 140 90,3 %
3 C (Fe3 O4) 151 141 132 93,6 %
Table 3. Changes in blood composition parameters of white rats
Blood composition Rats that did not Rats receiving Rats receiving fruit
parameters receive fruit juice normal fruit juice juice containing SiO2 nanoparticles
WBS 109 /L 6.05 5.50 5.51
LYM 109 /L 5.57 5.22 5.14
MID 109 /L 0.35 0.19 0.39
GRA 109 /L 0.12 0.08 0.08
LYM % 86.2 91.2 93.0
MID % 7.1 5.7 5.2
GRA % 7.16 3.0 1.7
RBC 109 /L 6.39 6.03 7.27
HGB g/L 107 98 130
HCT % 32.0 29.3 39.6
MCV fL 49.8 52.8 54.3
MCH pg 16.7 17.4 17.2
MCHC g/L 334 330 327
RDW-SD fL 28.0 30.5 32.1
RDW-CV % 12.0 12.3 12.7
PLT 109 /L 971 855 765
MPV fL 5.4 5.3 5.8
PDW % 9.4 9.7 9.7
PCT % 0.529 0.465 0.442
P-LRC % 1.7 2.1 3.6
Figure 1. The experimental Early Burlat cherry trees in the flowering stage
Figure 2. The powder and TEM images of experimental nanoparticles.
Figure 3. The "Early Burlat" cherry tree, flowers and fruits
Figure 4 EPR signals of the "Early Burlat"cherry fruit from the control variant (A) and from which has sprayed with Fe3O4 nanoparticles (B) in the flowers period
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