Abstract
Nowadays, the applications of nanotechnology are increasing in various fields such as information technology, energy, the medical sector, and agriculture. Nanotechnology has proved its ability to solve problems in agriculture and related industries. Establishing the impact of nanoparticles on various ecosystems has become a primary research topic, but studies on forest ecosystems and trees are quite limited. This study examined the effects of silver nanoparticles on the germination parameters of oriental beech seeds and established their toxic threshold values. Silver nanoparticles were applied at concentrations of 200, 400, 600, 800, and 1000 mg/L to oriental beech (Fagus orientalis) seeds collected from 10 different populations in order to identify the germination rate, germination percentage, seedling height, root collar diameter, plumula length, radicle thickness, and radicle length parameters. The results revealed that silver nanoparticles have a negative effect on germination and seedling parameters of oriental beech seeds, and that this effect is clearly seen in the germination rate at 20 mg/L levels and in seedling characters starting from 60 mg/L dose, causing a decrease of 13% in germination rate, 24% in germination percentage, 40% in plumula length, and 30% in radicle length. The Kahramanmaras-Andirin population was found to be the most affected by nanoparticles, while the Bursa-Inegol and Ordu-Akkus populations were the least affected.
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Effects of Silver Nanoparticles on Germination and Seedling Characteristics of Oriental Beech (Fagus orientalis) Seeds
Halil Barış Özel,a Hakan Şevik,b Yafes Yıldız,a and Hatice Çobanoğlu c,*
Nowadays, the applications of nanotechnology are increasing in various fields such as information technology, energy, the medical sector, and agriculture. Nanotechnology has proved its ability to solve problems in agriculture and related industries. Establishing the impact of nanoparticles on various ecosystems has become a primary research topic, but studies on forest ecosystems and trees are quite limited. This study examined the effects of silver nanoparticles on the germination parameters of oriental beech seeds and established their toxic threshold values. Silver nanoparticles were applied at concentrations of 200, 400, 600, 800, and 1000 mg/L to oriental beech (Fagus orientalis) seeds collected from 10 different populations in order to identify the germination rate, germination percentage, seedling height, root collar diameter, plumula length, radicle thickness, and radicle length parameters. The results revealed that silver nanoparticles have a negative effect on germination and seedling parameters of oriental beech seeds, and that this effect is clearly seen in the germination rate at 20 mg/L levels and in seedling characters starting from 60 mg/L dose, causing a decrease of 13% in germination rate, 24% in germination percentage, 40% in plumula length, and 30% in radicle length. The Kahramanmaras-Andirin population was found to be the most affected by nanoparticles, while the Bursa-Inegol and Ordu-Akkus populations were the least affected.
DOI: 10.15376/biores.19.2.2135-2148
Keywords: Ag; Nanoparticle; Fagus orientalis; Germination
Contact information: a: Department of Forest Engineering, Bartın University, Bartın, Türkiye; b: Department of Environmental Engineering, Kastamonu University, Kastamonu, Türkiye; c: Department of Forest Engineering, Düzce University, Düzce, Türkiye;
* Corresponding author: haticecobannoglu@gmail.com
INTRODUCTION
Rapid industrial developments have created the need for raw material supply required for production, and the extraction and use of underground mines caused by this have led to an increase in the concentrations of many elements in receiving environments such as soil, water, and air (Aricak et al. 2019; Key et al. 2023). These developments in the industrial field have caused significant changes in population projections and balances in the ecosystem. Urbanization due to the concentration of the population in urban areas (Dogan et al. 2022; Zeren Cetin et al. 2023) and global climate change due to changes in the composition of the atmosphere (Tekin et al. 2022; Varol et al. 2022a,b) have become irreversible problems (Koc et al. 2023).
In addition to these problems, environmental pollution is the most significant problem caused by technological and industrial developments (Kuzmina et al. 2023). Pollution, caused by heavy metals used as raw materials in industry, is seen as the most important problem threatening human and environmental health worldwide (Sulhan et al. 2022; Yayla et al. 2022). This is because heavy metals are elements, many of which can be toxic, carcinogenic, and fatal to humans even at low concentrations, and even those, which are necessary as nutritional elements, are unhealthy at high concentrations (Ucun Ozel et al. 2020; Karacocuk et al. 2022). The elements remain intact in nature for a long time, making them even more hazardous (Cesur et al. 2022). The concentrations of heavy metals are constantly increasing due to anthropogenic factors (Cobanoglu et al. 2023a).
Recent technological developments have taken the threat of heavy metal pollution to a new level. Silver nanoparticles, as well as magnetic field sensors, infrared (IR) detectors, photoconductors, light-emitting diodes, sun-selective coatings, various sensors, solar cells, and photo detectors are commonly used (Afsheen et al. 2020). Nanoparticle pollution is a more advanced type of pollution that contains all concerns of heavy metal pollution. Particularly in the chip and information technologies, nanoparticles are used in the development of products obtained from natural elements and minerals during the production of devices, which have domestic and industrial use. Nanoparticle pollution is explained as a level of pollution formed by the particles that emerge during production and damage all biological life cycles by slowly bringing them to the non-operating and unanalysable level of functionality (Cañas et al. 2008).
Nanotechnology is being applied in various fields including information technology, energy, the medical sector, and agriculture (Sadak et al. 2008). Nanoparticle pollution affects all living systems. It damages biological functions in animal, plant, and human societies. However, despite these hazardous effects, the use of nanoparticles and the products containing them is rapidly increasing due to the advancement of nanotechnologies in the sector of new material use. Along with the effects of global warming in recent years, nanoparticles, which enter the atmosphere and rapidly spread in the environment, continue to cause serious harm to life by reaching even the most remote and inaccessible parts of the globe. The number of studies conducted on nanoparticle pollution formations as well as their harms can be described as insufficient (Ozdemir 2023). Some of the most important effects of nanoparticles are observed in forests. Identifying the effects of nanoparticles on forest ecosystems and forest elements is of great importance in terms of revealing the extent of the danger as well as taking the necessary precautions. This study aimed to identify the effects of silver (Ag) nanoparticles, which are increasingly spreading in nature and causing nanoparticle pollution, at different doses on the germination parameters of the seeds of oriental beech (Fagus orientalis). The hypothesis of the study can be explained as “Ag nanoparticles affect the germination ability and seedling characters of beech seeds”. Oriental beech is one of the important primary forest tree species in Türkiye, and it was collected from different locations. Oriental beech is an important wood raw material and its seeds are very important for wildlife due to their high nutrient content (Ayaz et al. 2011; Hrivnak et al. 2023).
EXPERIMENTAL
Materials and Method
The seeds that were used were collected from natural beech forests of Türkiye. Information regarding the populations from which the seeds were collected is given in Table 1 and Fig. 1.
Fig. 1. Locations of populations
The seeds were subjected to health tests, and the oriental beech seeds, which showed no problems in the parts of embryo and endosperm and had normal and healthy developmental performance, were used in germination tests.
Table 1. Populations from which the Seeds Were Collected
One of the primary aims of the study was to reveal the effects of Ag nanoparticles on the germination parameters of oriental beech seeds and to determine their toxic threshold values. For this purpose, 5 different nanoparticle concentrations at the doses of 20, 40, 60, 80, and 100 were prepared under sterile and hygienic conditions in the laboratory environment and kept in sterile concentration bottles to be applied to the collected seeds.
For germination tests, the oriental beech seeds, to which five different doses of concentrations were applied, were placed in disposable sterile petri dishes prepared with quantitative filter papers. Five repetitions were performed for each dose, and including 30 healthy seeds for each repetition, nanoparticles were applied to 150 seeds in total. A total of 900 seeds, including the control group, were used during germination tests. Germination tests were carried out in a 3M ClimaCell brand germination cabinet. In the germination cabinet, the temperature of the germination environment was set as 20 °C, relative humidity as 70%, and exposure time as 12 h.
Germination was monitored by applying 10 mL of nanoparticle solution daily to the oriental beech seeds placed in 100 mL petri dishes in a way not to touch each other. On the 7th day of the applications, the number of seeds germinated was counted in order to calculate the germination rate (GR). The application continued for 35 days, and at the end of the 35th day, seedling length (SeedL), root collar diameter (RCD), plumula length (PlL), radicle length (RadL), and radicle thickness (RadT) were measured using a digital micro-compass in all germinated seeds. The seeds, which had not been germinated, were cut and checked whether they were healthy or not, and the germination percentage (GP) was calculated by dividing the total germinated seeds to the total healthy seeds. Similarly, the germination rate was found by dividing the number of seeds, germinated on the 7th day, to the number of healthy seeds. The obtained data were evaluated with the help of the SPSS 22.0 package program, and analysis of variance and Duncan test were applied to the data.
RESULTS AND DISCUSSION
When examining the results, it was found that the application doses on GR were not statistically significant in all populations, except P7. At the same time, the population-based changes in GR was not statistically significant at all doses, except the control group and 600 mg/L. The lowest GR value was obtained at 1000 mg/L dose of nanoparticle application, while the highest value was obtained at 200 mg/L dose of nanoparticle application, in all populations. However, the GR value was observed to be decreasing as the nanoparticle application increases.
Table 2. Changes in GR Depending on Population and Nanoparticle Application
On the basis of population, the lowest value was obtained in P7, while the highest value was obtained in P9. In the control group, while the lowest value was obtained in P7 (17.8%), the highest was obtained in P9 (21.9%). In P7, it decreased to 15.5% at 200 mg/L dose of nanoparticle application and this number was observed to be gradually decreasing. In P9, GR increased to 22.2% at 200 mg/L dose of nanoparticle application, but decreased to 19.5% at 1000 mg/L dose of nanoparticle application depending on the dose.
Table 3. Changes in GP Depending on Population and Nanoparticle Application
According to the results of variance analysis, the application doses were statistically significant in all populations on GP. Likewise, the population-based changes in GP were found to be statistically significant at all doses. In general, the lowest GP value in all populations was obtained at high dose (1000 mg/L) of nanoparticle application, while the highest GP value was obtained in the control group. The GP value decreased as the nanoparticle concentration increased.
On the basis of population, the lowest value was generally obtained in P7, while the highest value was obtained in P9. In the control group, the lowest value was obtained in P7 (57.6%), while the highest value was obtained in P9 (78.7%). In P7, it decreased to 54.7% at 200 mg/L dose of nanoparticle application, and it contiuend to decrease as the dose increased. In P9, GP decreased to 67.2% at 200 mg/L dose of nanoparticle application, and continued to decrease in the same way.
Table 4. Changes in Seedling Length, Depending on Population and Nanoparticle Application
Taking the results obtained into consideration, it was seen that the application doses were not statistically significant with respect to SeedL in all populations. Likewise, the population-based change in SeedL was not found to be statistically significant at all doses, except the control group. The lowest SeedL value was obtained at 1000 mg/L dose of nanoparticle application in all populations, while the highest value was obtained at 200 mg/L dose of nanoparticle application. The SeedL value was observed to be decreasing as the nanoparticle concentration increases.
Table 5. Changes in RCD Depending on Population and Nanoparticle Application
While the lowest population-based value was obtained in P72, the highest was obtained in P9. In the control group, the lowest value was obtained in P7 (6.3%), while the highest value was obtained in P4, P8, and P9 (7.2%). In P7, SeedL, which increased to 6.8% at 200 mg/L dose of nanoparticle application, began to decrease inversely with the dose increase, and decreased to 6.3% at 1000 mg/L dose of nanoparticle application. In P9, SeedL increased to 7.8% at 200 mg/L dose of application and continued to decrease immediately afterwards depending on the dose increase. When examining the results given in the table, it is apparent that the application doses were not statistically significant in all populations on RCD. At the same time, the population-based changes in RCD were not statistically significant at all doses. Overall, on a population basis, the lowest value was obtained in P10, while the highest value was obtained in P9.
Table 6. Changes in Pumula Length, Depending on Population and Nanoparticle Application
According to the results of variance analysis, the application doses with respect to PlL were statistically significant in all populations. The population-based changes in PlL were not statistically significant at all doses, except the control dose. Generally, in all populations, the lowest PlL value was obtained at the 1000 mg/L dose of nanoparticle application, while the highest value was obtained in the control group. The PlL value was observed to be decreasing as the nanoparticle concentration increased. On a population basis, the lowest value was generally obtained in P7, while the highest value was obtained in P9. In the control group, while the lowest value was obtained in P7 (0.8%), the highest value was obtained in P9 (1.1%).
Table 7. Changes in Radical Thickness, Depending on Population and Nanoparticle Application
The application doses were statistically significant with respect to RadT in all populations, except in P2, P6, and P9. At the same time, the population-based changes in RadT were not statistically significant at all doses, except the control group. Generally, in all populations, the lowest RadT value was obtained at the 1000 mg/L dose of nanoparticle application, while the highest value was obtained in the control group. The RadT value was observed to be decreasing as the nanoparticle concentration increased.
On a population basis, while the lowest value was generally obtained in P7, the highest value was obtained in P4. In the control group, the lowest value was obtained in P7 (1.0%), while the highest value was obtained in P9 (1.3%).
Table 8. Changes in RadL Depending on Population and Nanoparticle Application