Technical Field

The invention relates to an environmentally friendly, sustainable, low-cost, high-efficiency, and non-harmful method for reducing heavy metal accumulation and eliminating heavy metal toxicity in plants. The method of the invention uses a choline compound, which is biodegradable and has an important role in plant growth.

State of the Art

From a chemical point of view, the term "heavy metal" is used for transition metals with an atomic weight of more than 20 g/mol and a density of more than 5 g/cm ³ . When evaluated biologically, the term "heavy" is used for metals and metalloids that create toxic effects for plants and animals even at low concentrations. Heavy metals accumulate in soils and waters, causing great dangers in terms of environment and living healthy, and they negatively affect the whole ecosystem by causing biological accumulation since they can pass from low nutrition steps to high steps in the food chain. Therefore, the accumulation of heavy metals in plants leads to the deterioration of food safety through agricultural products and poses a threat to human health. In addition, the negative effects of heavy metals on plants result in the complete destruction of natural vegetation in areas contaminated by heavy metals over time.

The World Health Organization (WHO) has described 13 heavy metals that pose a threat to human and environmental health as arsenic, cadmium, cobalt, chromium, copper, mercury, manganese, nickel, lead, tin, and titanium. Cadmium (Cd), which is among these heavy metals, stands out as one of the most important environmental threats in today's conditions with the increasing industrialization rate. Although cadmium heavy metal has very large harmful effects even at very low concentrations, it negatively affects growth and development in plants and causes permanent damage. For example, cadmium can easily replace magnesium in the chloroplast structure and thus negatively affects chlorophyll synthesis. It also prevents iron (Fe) intake, which is necessary for the process of cadmium photosynthesis, and therefore causes metabolic problems. In the state of the art, many metabolic and physiological anomalies caused by cadmium heavy metal-induced cadmium stress in plants are caused by the increased amount of reactive oxygen species (ROS) at the cellular level. With oxidative stress caused by reactive oxygen species, cellular homeostasis in plants is disrupted and this poses a threat to cells. Because excessive ROS accumulation causes cell death due to oxidative processes such as membrane lipid peroxidation, protein oxidation, enzyme inhibition, and DNA and RNA damage.

There are various applications for reducing the heavy metal intake of plants and eliminating heavy metal toxicity in the current state of the art. In order to minimize the ecological effects of heavy metals, various physical and chemical cleaning methods such as washing the soil, filling the wastes by opening holes, solidification, stabilization, membrane technologies, oxidation, ion exchange, sedimentation, and flocculation have been developed. However, these approaches require high cost and labor, cause irreversible changes in soil properties and lead to deterioration in natural soil microflora. In addition, the said chemical cleaning methods bring about the problem of secondary pollution.

Although the methods of reducing heavy metal accumulation in plants in the existing art and eliminating heavy metal toxicity are long and difficult methods, they require excessive energy use and pressure application, necessitate the use of costly resin, and have restrictions such as application only at high concentrations. For example, the chemical precipitation and filtration method can provide a limited level of activity at high concentrations and cause waste sludge formation. Electrochemical methods are expensive and can only be used effectively in high concentrations. Resins used in ion-exchange methods are high-cost. The evaporation method, on the other hand, requires a lot of energy and is a costly method, and causes waste sludge formation. The reverse osmosis method requires high pressure and is also as expensive as other methods.

Patent application RU2280974C1 in the state of the art relates to a method for reducing the toxic effect of heavy metals on root crops grown in soil contaminated with heavy metals. In the aforementioned method, 0.01 -0.015% aqueous solution of the diphosphonic complex of copperoxyethylide is sprayed on the plants in the fusion phase so that it is 8-10 L per m ² . Within the scope of the mentioned method, the copper oxyethylidendiphosphonic complex, [diaqua1-oxyethane-1 ,1 -diphosphonate (1)], aqueous solution is applied by spraying during the fraternization phase of the plant.

Although the methods used in the current art to remove heavy metals from agricultural products or soil are tried to be kept away from chemicals, it is not possible to say that complete success is achieved at this point. For example, chemicals such as copperoxyethylidene diphosphonic complexes, metasilicate pentahydrate, sodium tripolyphosphate, or mercaptoacetic acid are frequently used in the methods of reducing the toxic effects of heavy metals in the state of the art. Although the chemicals in question seem to be more harmless than many plant chemicals on the market, the substances in question are also a chemical and it is not possible to talk about the presence of a heavy metal remover with a completely natural content for use in agriculture. As a result, heavy metal removers in the current art bring about a secondary chemical waste problem and pose a great risk to employee health in addition to the secondary waste problem. It should also be noted that in methods using 0.01-0.015% aqueous solution of the copperoxyethylidene diphosphonic complex as a metal remover, 8-10 L of copperoxyethylidene diphosphonic complex per m ² is used and this amount is a maximal ratio for a chemical product used in agriculture.

The patent document CN103450905A in the state of the art, relates to the plant soil processing agent and the production method of this substance to reduce the heavy metal cadmium in tobacco. Thanks to this article, it is aimed to reduce the content of heavy metal cadmium in the soils of tobacco cultivation areas, to reduce the absorption of cadmium by tobacco, and to protect the physical health of smokers. The method used to obtain the plant soil treatment material of the invention in the patent document includes the process steps of aerating a biological material, filtering the biological material using a 120 mesh sieve to form a biological metal powder, adjusting and drying the moisture of the obtained biological material powder to not exceed 2%, spraying the diluted mercaptoacetic acid evenly to the biological material powder, placing the biological material powder in a microwave oven and removing it after 15-20 minutes.

The patent document CN107384433B relates to a method for repairing soil heavy metal contamination using a soil heavy metal passivator. The composition used in the method includes 30 parts of peanut shells, 15 parts of Korean pine needles, 10 parts of sepiolite, 10 parts of fly ash, 5 parts of chitin, 3 parts of sodium metasilicate pentahydrate, 0.4 parts of sodium tripolyphosphate, 0.1 parts of choline chloride, 1.2 parts of microbial agent and 0.05 parts of unslaked lime. After the fermentation process of the composition used in the method, different processes were carried out for a total of 30 days, for 10 days at 45°C and for 20 days at 40°C. The method of application of the composition used in the method includes, respectively, the process steps of plowing the contaminated soil layer using agricultural machines, breaking down the soil blocks, applying the soil heavy metal passivator, plowing the soil again and ensuring that the soil heavy metal passivator is homogeneously mixed with the soil, and then using the soil heavy metal passivator for agricultural cultivation. Considering the process steps of said application method, it has disadvantages due to reasons such as the application takes a long time, the necessity of fermentation for a certain temperature and time, the cost, time, and workload caused by the use of different organic materials and chemicals.

As a result, it is clear that various chemical compositions are used in the patent documents RU2280974C1 , CN103450905A, and CN107384433B, and costly and time-consuming methods are used in each document. To summarize briefly again, in the method subject to patent application numbered RU2280974C1 , both a chemical such as copperoxyethylidene diphosphonic is used and a high rate of raw material is used that may cause yield problems. The method in the patent document numbered CN103450905A uses mercaptoacetic acid chemical and includes time-consuming pre-processing steps such as filtering and drying. In addition to using chemicals such as unslaked lime in the patent document numbered CN107384433B, sodium metasilicate pentahydrate, and sodium tripolyphosphate, the method includes a long (30-day) fermentation process with different process steps, as well as time-consuming process steps such as plowing the soil twice and ensuring homogeneous mixing.

The limitations and inadequacies of the studies on reducing the heavy metal accumulation in the plants in the state of the art and eliminating the heavy metal toxicity, the fact that a method carried out by simply dissolving a compound in the plant, which is in the plant and easily included in the metabolic processes by the plant, which will reduce the heavy metal accumulation in the plants and ensure that the heavy metal toxicity is removed from the agricultural products, is not included in the current art, in other words, the fact that the use of different chemical substances in the studies in the known state of the art is required, the use of heavy chemical substances in the current art is far from practical, at the same time, the use of heavy chemical substances in the current art is far from practical, and the fact that this intense chemical use causes high costs in addition to the threat to the environment and employee health, and the removal of heavy metal accumulation in the current art from the plants due to the reasons such as the heavy metal accumulation methods have long and arduous steps, in which the heavy metal accumulation in the plants has been reduced and the heavy metal accumulation in the current art is necessary for the health of the human environment, and the method has been developed.

Brief Description and Objects of the Invention The invention discloses a sustainable, low-cost, high-efficiency, and environmentally friendly method for reducing heavy metal accumulation in plants and eliminating heavy metal toxicity. In the method of the invention, the choline compound, which is biodegradable and has an important role in plant growth, promotes the production of the glycine betaine molecule, increases the resistance of the plants to stress conditions, and accelerates the uptake of the necessary nutrients by the plant, is used.

An object of the invention is to provide an effective antioxidant method in plant growth to reduce heavy metal deposition in plants and to eliminate heavy metal toxicity. An effective and antioxidant method of plant growth is provided by containing the choline molecule, which is effective in plant growth and also plays an antioxidant role in many plant tissues and can be easily taken from the leaves through stomata.

Another object of the invention is to provide a method that will positively affect the product efficiency in the plants as well as reducing the heavy metal accumulation in the plants and eliminating the heavy metal toxicity. In the method of the invention, the product efficiency is increased by the use of the organic and biodegradable choline compound, which is the leading component of glycine betaine. The choline compound is a vital metabolite in plants and other eukaryotes as it is used to synthesize phosphatidylcholine (Ptd-CHO) from membrane phospholipids. In addition, the restriction of glycine betaine production in cells depends mainly on the presence of the choline compound, and the ratio of glycine betaine is increased by external choline compound administration. Glycine betaine is a very effective chelate agent. It provides support to the plant in coping with the stress of the plants under intense stress and accelerates the intake of nutrients by the plant. Thanks to the choline compound that promotes the production of the glycine betaine molecule, the efficiency in plants is also increased.

In addition, it is intended to provide a sustainable method for reducing heavy metal accumulation in plants of the invention and eliminating heavy metal toxicity. A sustainable method is provided by the use of a completely organic and biodegradable choline compound, the precursor component of glycine betaine, in the method of the invention.

Another object of the invention is to provide an economical method for reducing heavy metal accumulation and eliminating heavy metal toxicity in plants. Providing an economical method for reducing heavy metal accumulation in plants and eliminating heavy metal toxicity is achieved by applying only low doses of choline compound in the form of spraying, with irrigation systems, or by adding it to the plant's nutritional components instead of applications that require extra energy and costs such as chemical precipitation, filtration, electrochemical processes, ion exchange methods, and evaporation method.

Another object of the invention is to provide a method with high efficiency for reducing heavy metal accumulation and eliminating heavy metal toxicity in plants. A method with high efficiency in the invention is provided by the fact that a high rate of heavy metal accumulation reduction and heavy metal toxicity removal can be achieved even in the use of low doses of choline compound.

An object of the invention is to provide a method that is environmentally friendly and does not harm living health in order to reduce heavy metal accumulation in plants and to eliminate heavy metal toxicity. An environmentally friendly and non-harmful method for reducing heavy metal accumulation in plants and eliminating heavy metal toxicity is provided by using the choline compound, an essential nutrient with sustainable and natural content, instead of the agricultural chemicals in the state of the art in the method of the invention. In addition to all these, the necessity of using applications that cause waste sludge formation such as chemical precipitation filtration methods used to reduce heavy metal accumulation in plants and eliminate heavy metal toxicity in the state of the art is eliminated by using choline compound in the method for reducing heavy metal accumulation in plants of the invention and eliminating heavy metal toxicity.

Descriptions of the Figures

Figure 1. Graph showing the cadmium accumulation in tomato seedlings where the method of the invention is applied

Figure 2. Graph showing the change in ascorbic acid content in tomato seedlings where the method of the invention is applied

Figure 3. Graph showing the change in chlorophyll content in tomato seedlings in which the method of the invention is applied

Detailed Description of the Invention

The invention relates to a sustainable, low-cost, high-efficiency, and environmentally friendly method for reducing heavy metal accumulation in plants and eliminating heavy metal toxicity. In the method of the invention, the choline compound, which is biodegradable and has an important role in plant growth, promotes the production of the glycine betaine molecule, increases the resistance of the plants to stress conditions, and accelerates the uptake of the necessary nutrients by the plant, is used. The choline compound is a vital metabolite in plants and other eukaryotes as it is used to synthesize phosphatidylcholine (Ptd-CHO) from membrane phospholipids. In addition, the restriction of glycine betaine production in cells depends mainly on the presence of the choline compound, and the ratio of glycine betaine, which is a very effective chelating agent, is increased by external administration of the choline compound. It helps plants under intense stress to cope with stress and accelerates the intake of necessary nutrients by the plant. Thanks to the choline compound that promotes the production of the glycine betaine molecule, the efficiency in plants is also increased.

The method for reducing heavy metal accumulation in plants and eliminating heavy metal toxicity includes the process step of applying the choline compound to plants by spraying, irrigation, drip irrigation system, adding it to the soil, or adding it to all fertilizer formulations in the form of liquid, granular or foliar fertilizer spray together with the micro and macronutrients needed by the plant. The choline compound described in the invention can be added to plant nutrient components and applied in soilless or soil-based agriculture. The dose of the choline compound applied in the said method is in the range of 0.1-500 millimolar. The method of the invention can be applied to all plants.

An analysis study was conducted to measure the effectiveness of the method for reducing the heavy metal accumulation in the plants of the invention and eliminating the heavy metal toxicity on the cadmium heavy metal. In said study, tomato (Solarium lycopersicum) seedlings were provided and taken to the air conditioning cabinet under controlled conditions to be grown in peat/perlite (1 :1) in pots with a size of 14x12 cm. The conditions in which the plants are kept in the air conditioning cabinet are 24°C/20°C (day/night), 70% relative humidity, 16/8 hours (light/dark) photoperiod regime, and 1200 lux light intensity. Choline compound was applied to 5-week-old tomato seedlings grown under controlled conditions before cadmium (Cd) stress. In the results obtained, the choline compound was determined by biochemical parameters, which were analyzed to reduce the accumulation of tomatoes in tomato seedlings, as well as to inhibit the toxicity of heavy metals. The choline compound significantly reduced the accumulation of Cd in both roots and leaves. In Figure 1 , the column graph showing the cadmium accumulation in tomato seedlings, where the method of the invention is applied, is given. As can be clearly seen from the graph of the milk in Figure 1 , the use of choline compounds significantly reduced the accumulation of cadmium in both root and leaves. In addition, Figure 2 shows the changes in the ascorbic acid content of tomato plants where the method of the invention is applied. It is clear from Figure 2 that the application of the choline compound increases the ascorbic acid content of the plant, thus providing important support for the choline compound in the fight against stress. Figure 3 shows the change in chlorophyll content, which is one of the growth and development parameters, in tomato plants where the method of the invention is applied. When the chlorophyll content is examined, it is seen that the method of the invention increases the chlorophyll content in plants under Cd stress and therefore, the method in question is an important supporter of plant growth and development.

In the method of the invention, thanks to the use of the choline compound, which is thought to be a very important chelating agent in plants, which is the precursor component of glycine betaine, and the use of no agricultural chemicals, etc. other than the choline compound mentioned in the method, a method with sustainable, ecological properties and no harm to the environment and human health, with 100% natural content is provided to reduce heavy metal accumulation in plants and eliminate heavy metal toxicity.

In addition to reducing heavy metal accumulation in plants and eliminating heavy metal toxicity, product efficiency in plants is also positively affected by the method of the invention. The organic and biodegradable choline compound, which is the precursor component of glycine betaine in the method of the invention, is a vital metabolite in plants and other eukaryotes because it is used in the synthesis of phosphatidylcholine (Ptd-CHO), one of the membrane phospholipids. It helps plants to combat the stress of plants that are under intense stress with the application of choline compounds from the outside and accelerates the intake of necessary nutrients by the plant.

The methods developed to reduce the toxicity of heavy metals and the uptake of these metals by plants in the state of the art (washing the soil in areas contaminated by heavy metals, filling the wastes by opening a pit, solidification and stabilization, chemical precipitation and filtration method, electrochemical methods, ion exchange method, evaporation method and reverse osmosis method, etc.) require high cost and labor force and cause efficiency loss problem since they require high energy use. With the method of the invention, reducing heavy metal accumulation in plants and eliminating heavy metal toxicity is achieved with natural methods without the need for high energy and pressure, at a low cost, requiring minimum labor. Since the use of only low-millimeter choline compounds in the method creates a great effect in terms of removing the heavy metals from the plants, applications that will cause economic and industrial efficiency problems such as costly resin uses, or high energy use are also prevented.

Cadmium, which spreads to the environment with various industrial activities and causes permanent damage to plants, easily replaces the magnesium (Mg) in the structure of the chloroplast and also prevents the metabolic activities in plants by preventing the iron (Fe) intake required during photosynthesis. Although methods have been developed to eliminate the uptake of heavy metals by plants and the heavy metal toxicity in agricultural products in the known state of the art, the metabolic activities in plants due to the chemicals used in these methods are suppressed. Thanks to the use of only choline compounds as a component in the method of the invention, both the metabolic activities of the plants can be carried out properly and the plants can develop in an extra healthy way since the need for a second chemical use that damages the plant, and the plant metabolism is eliminated.