Application of exogenous glutamine in promoting cadmium accumulation in draba alpine
By spraying exogenous glutamine solution onto the leaves of Aster tataricus, the limitations of Aster tataricus in the remediation of cadmium-contaminated soil were overcome, the cadmium accumulation capacity and biomass were improved, and the phytoremediation efficiency was enhanced.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- GUANGXI ZHUANG AUTONOMOUS REGION ACAD OF AGRI SCI
- Filing Date
- 2025-04-28
- Publication Date
- 2026-07-14
AI Technical Summary
Existing phytoremediation technologies for heavy metal contaminated soils have long remediation cycles, limited accumulation capacity, and are susceptible to extreme environmental factors. Improving the remediation efficiency of heavy metal contaminated soils has become an important issue, especially since the application of Aster tataricus in cadmium pollution remediation has limitations.
By spraying exogenous glutamine solution at a concentration of 0.5-20 mg/L onto the leaves of Aster tataricus during its growth period, once every 3 days for a total of 6 times, cadmium accumulation in Aster tataricus can be promoted, thereby enhancing its stress resistance and growth capacity.
It significantly increases the amount of cadmium absorbed by the roots of Aster tataricus, improves biomass and photosynthesis, enhances the ability to accumulate cadmium, strengthens phytoremediation efficiency, and reduces the cadmium content in the environment.
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Figure CN120391435B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of heavy metal pollution remediation technology, specifically involving the application of exogenous glutamine in promoting cadmium accumulation in Aster tataricus. Background Technology
[0002] Heavy metals originate from both natural and anthropogenic sources. Natural sources primarily include bedrock weathering, while human activities such as mining, metal smelting, fertilizer application, and wastewater irrigation are the main causes of the continuous increase of heavy metals in water and soil environments (Xu et al., 2023). Guangxi is a renowned "non-ferrous metal" region in my country, with abundant mineral resources. However, due to the disorderly development of enterprises and the indiscriminate discharge of waste, severe heavy metal pollution has occurred in the mining areas, particularly with significant exceedances of elements such as arsenic (As), cadmium (Cd), lead (Pb), and mercury (Hg) (Li Zhaoyi et al., 2024). Because Cd is not biodegradable in environmental media, and heavy metal Cd pollution is characterized by its long-term, cumulative, hidden, and irreversible nature, remediation of heavy metal Cd pollution is difficult, posing a significant potential safety risk to agricultural product quality and human health (Diaconu et al., 2020). Therefore, effective and economical remediation technologies are urgently needed to treat Cd-contaminated soil.
[0003] Currently, the remediation of Cd-contaminated soil can be mainly carried out through physical, chemical, and biological methods (Yang Guodong et al., 2020). Phytoremediation, a type of bioremediation method, directly utilizes green plants to isolate, remove, and degrade organic and inorganic pollutants in soil and water (Pratush et al., 2018; Gomes et al., 2016). Generally, plants can remove heavy metals through phytoextraction, phytostabilization, rhizosphere remediation, or phytofiltration (Ashrafet et al., 2019). Phytoremediation technology is characterized by low remediation cost, high effectiveness, no secondary pollution, and high ecological and aesthetic value after reclamation. It can achieve permanent clean remediation of contaminated soil and is therefore recognized as a green and environmentally friendly in-situ remediation technology (Ali et al., 2013; Zhang Jiangguang et al., 2023).
[0004] *Aster subulatus* Michx., also known as scissor-leaved aster, white chrysanthemum, wild aster, nine-dragon arrow, and awl-shaped aster, is a plant belonging to the genus *Aster* in the family Asteraceae. It grows in moist, saline soils and is distributed in Guangxi, Jiangsu, Zhejiang, Jiangxi, Hunan, and Fujian provinces. *Aster subulatus* possesses advantages such as a well-developed root system, large biomass, stable physiological traits, and tolerance to heavy metal pollution stress. Previous research by our project team found that *Aster subulatus* exhibits strong tolerance and accumulation capacity for Cd, confirming it as a Cd hyperaccumulator and a potential pioneer species for phytoremediation of Cd-contaminated soils in Guangxi (Chen et al., 2023). Although phytoremediation has shown significant advantages in the remediation of heavy metal-contaminated environments, it still has some limitations in practical applications, such as long remediation cycles, relatively limited accumulation capacity, susceptibility to extreme environmental factors, and the disposal of residual heavy metal-containing biomass after remediation. Therefore, how to enhance the advantages of phytoremediation and improve its efficiency has become an important topic of concern for scholars both domestically and internationally. To improve the efficiency of hyperaccumulating phytoremediation, scientists have developed various enhancement technologies, including agronomic enhancement, biotechnology enhancement, and chemical-assisted enhancement.
[0005] Glutamine plays an important role in plants, especially in responding to environmental stress and adverse conditions. The functions of glutamine in plant stress resistance are as follows: (1) Detoxification of free ammonia: When the ammonia content in plants is too high, glutamine, as a storage and transport form of ammonia, can convert excess ammonia into glutamine or asparagine, thereby detoxifying free ammonia; (2) Nitrogen transport form: Glutamine and asparagine are not only detoxification products of ammonia but also nitrogen transport forms in plants, which are crucial for nitrogen metabolism and distribution in plants under adverse conditions; (3) Antioxidant effect: Glutamine participates in the synthesis of glutathione, an important antioxidant that helps plants resist oxidative stress, thereby improving plant stress resistance. In summary, the main functions of glutamine in plant stress resistance are detoxification of free ammonia, serving as a nitrogen transport form, and participating in antioxidant effects. These functions collectively help plants maintain normal physiological functions when facing environmental stress and adverse conditions.
[0006] There are currently no reports on using exogenous glutamine to promote the remediation of heavy metal pollution by hyperaccumulating plants.
[0007] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention
[0008] The purpose of this invention is to provide the application of exogenous glutamine in promoting the accumulation of cadmium in Aster tataricus.
[0009] To achieve the above objectives, the present invention provides the following technical solution:
[0010] The first objective of this invention is to provide the application of exogenous glutamine in promoting the accumulation of heavy metals in hyperaccumulating plants.
[0011] A second objective of this invention is to provide a heavy metal remediation agent, wherein the heavy metal remediation agent comprises the aforementioned glutamine.
[0012] More specifically, the heavy metal remediation agent is composed of glutamine and deionized water.
[0013] More specifically, the concentration of glutamine in the heavy metal remediation agent is 0.5-20 mg / L.
[0014] A third objective of this invention is to provide the application of the aforementioned heavy metal remediation agent in promoting the accumulation of heavy metals in hyperaccumulating plants.
[0015] More specifically, the hyperaccumulating plant includes *Aster tataricus*; the heavy metal includes cadmium.
[0016] The fourth objective of this invention is to provide the application of the exogenous glutamine or the heavy metal remediation agent in improving the stress resistance and promoting the growth of Aster tataricus in areas contaminated with heavy metals.
[0017] The fifth objective of this invention is to provide the application of the exogenous glutamine or the heavy metal remediation agent in increasing the chlorophyll and carotenoid content of Aster tataricus in areas contaminated with heavy metals.
[0018] The sixth objective of this invention is to provide a method for promoting the remediation of heavy metal pollution by using exogenous glutamine in Aster tataricus. Specifically, during the growth period of Aster tataricus, a glutamine solution is sprayed on the leaves every 3 days for a total of 6 times; and Aster tataricus is harvested 10 days after the end of the foliar spraying.
[0019] More specifically, the glutamine solution has a concentration of 0.5-20 mg / L.
[0020] Compared with the prior art, the present invention has the following beneficial effects:
[0021] This invention investigates the effects of foliar application of glutamine solution on the growth and accumulation of cadmium in the hyperaccumulating plant *Aster tataricus* during its growth period. The results showed that spraying *Aster tataricus* with glutamine solution significantly increased the amount of cadmium absorbed by the roots, improved its biomass and photosynthesis, and increased the overall cadmium accumulation by the plant. This provides technical support for enhancing the remediation of hyperaccumulating plants. Attached Figure Description
[0022] Figure 1 Biomass (plant height, fresh weight, dry weight) of Aster tataricus under different treatments;
[0023] Figure 2 Chlorophyll content of Aster tataricus under different treatments;
[0024] Figure 3 The cadmium content in *Aster tataricus* leaves under different treatments;
[0025] Figure 4 The accumulation of cadmium in *Aster tataricus* under different treatments. Detailed Implementation
[0026] The technical solution of this invention patent will be clearly and completely described below. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this invention.
[0027] 1. Materials and Methods
[0028] 1.1 Test Materials
[0029] L-Glutamine (≥99%, CAS: 56-85-9, Shanghai Aladdin Biochemical Technology Co., Ltd.);
[0030] Seeds of Aster tataricus were collected from a lead-zinc mining area about 120km from Yulin City, Guangxi Province.
[0031] 1.2 Pot Experiment
[0032] To simulate cadmium-contaminated soil, the experiment was conducted using sand culture in pots, with 1.5 kg of quartz sand in each pot. *Aster tataricus* was collected from a lead-zinc mining area approximately 120 km from Yulin City, Guangxi Province. The seeds were sterilized with 95% ethanol and then cultured in cadmium-free seedling trays. After a period of time, seedlings with similar growth characteristics (similar plant height, number of leaves, and vigor) were selected as experimental materials, and three seedlings were transplanted into each pot, for a total of 15 pots.
[0033] The experimental environment was as follows: 12-hour light cycle, 25℃ light cycle / 20℃ dark cycle, relative humidity 70%, and light intensity 300 μmol / (m²). 2·s), continuous ventilation was maintained for 24 h. A Hoagland nutrient solution was replenished every 4 days, and the pH value of the nutrient solution was adjusted to about 5.6 with 0.1 mmol / L sodium hydroxide or 0.1 mmol / L hydrochloric acid. One week after planting Aster subulatus, 500 mL of 100 mmol / L Cd solution was added to 12 of the pots, and a sand culture pot without Cd solution (3 pots) was set as the blank control (CK).
[0034] 1.3 Experimental design of foliar spraying
[0035] Based on the above operations, after 3 days, aqueous solutions of glutamine at different concentrations were sprayed. There were a total of 5 treatment groups (Table 1), with the leaf tips dripping water as the limit and completely covering the leaves. A total of 6 sprays were made, once every 3 days. After all treatments were completed, cultivation was continued for 1*0 days and then harvested. The biomass and heavy metal cadmium content of Aster subulatus were measured. Cadmium treatment control group: Foliar spraying with deionized water instead of the glutamine aqueous solution.
[0036] Table 1 Experimental design
[0037]
[0038] 1.4 Sample treatment and analysis
[0039] After the experiment, Aster subulatus was taken out of the pot as a whole plant, washed with tap water, and after rinsing clean and removing the fine sand from the roots, the roots were soaked in 20 mmol / L Na2-EDTA solution for 20 min to remove the cadmium ions adsorbed on the surface, and then repeatedly rinsed clean with deionized water. After air drying the moisture, the fresh weight and plant height of the whole plant were measured. Aster subulatus was divided into two parts: aboveground and underground, placed in an oven at 105 °C for 30 min for fixation, and then adjusted to 70 °C for drying to a constant weight to determine the dry matter weight. The samples were ground with a stainless steel grinder and passed through a 40-mesh sieve. The samples were digested with a H2O2-HNO3 mixed solvent on an intelligent electric digestion instrument. A flame-graphite furnace atomic absorption spectrometer was used to determine the heavy metal content of the sample digestion solution.
[0040] 1.5 Experimental results
[0041] 1.5.1 Effects on biomass
[0042] The results are shown in Figure 1 .
[0043] As Figure 1 -A shows, the plant height of Aster subulatus under the treatment showed Cd < 0.5Gln < 5Gln < 20Gln < CK, among which Cd decreased by 28.4% compared with CK, while the plant heights of 0.5Gln, 5Gln, and 20Gln were all increased compared with Cd.
[0044] ]>As Figure 1As shown in Figure -B, the fresh weight of Aster subulatus showed 0.5 Gln < Cd < 5 Gln < 20 Gln < CK under the treatments; among which, Cd decreased by 37.3% compared with CK, and compared with Cd, 5 Gln and 20 Gln increased by 15.3% and 63.3% respectively.
[0045] As Figure 1 shown in Figure -C, the dry weight of Aster subulatus showed Cd < 0.5 Gln < 5 Gln < CK < 20 Gln under the treatments; among which, Cd decreased by 38.3% compared with CK, and 20 Gln increased by 7.9% compared with CK. And 0.5 Gln, 5 Gln and 20 Gln all increased compared with Cd.
[0046] It shows that Cd stress can inhibit the normal growth of Aster subulatus, while exogenous addition of glutamine can, to a certain extent, increase the biomass of Aster subulatus and alleviate the inhibitory effect of cadmium on the growth of Aster subulatus.
[0047] 1.5.2 Effects on chlorophyll content
[0048] The results are shown in Figure 2 .
[0049] As Figure 2 can be seen, the chlorophyll a content of Aster subulatus showed Cd < 20 Gln < 5 Gln < 0.5 Gln < CK under the treatments; among which, Cd decreased by 51.7% compared with CK, and the chlorophyll a contents of 0.5 Gln, 5 Gln and 20 Gln increased by 77.7%, 32.6% and 24.8% respectively compared with Cd.
[0050] The chlorophyll b content of Aster subulatus showed Cd < 20 Gln < 5 Gln < 0.5 Gln < CK under the treatments; among which, Cd decreased by 19.5% compared with CK, and the chlorophyll b contents of 0.5 Gln, 5 Gln and 20 Gln increased by 50.8%, 12.6% and 6.0% respectively compared with Cd.
[0051] The carotenoid content of Aster subulatus showed Cd < 20 Gln < 0.5 Gln < 5 Gln < CK under the treatments; among which, Cd decreased by 67.3% compared with CK, and the carotenoid contents of 0.5 Gln, 5 Gln and 20 Gln increased by 118.1%, 124.9% and 86.1% respectively compared with Cd.
[0052] It shows that exogenous addition of glutamine can alleviate the inhibitory effect of cadmium on the chlorophyll synthesis of Aster subulatus, and adding low - concentration glutamine (0.5 or 5 mg / L) has a better promoting effect on the chlorophyll synthesis of Aster subulatus under cadmium pollution than high - concentration glutamine (20 mg / L).
[0053] 1.5.3 Effects on the cadmium content of Aster subulatus
[0054] See results Figure 3 .
[0055] Depend on Figure 3 It can be seen that, compared with Cd, the cadmium content of Aster tataricus in the 0.5Gln, 5Gln and 20Gln treatment groups increased by 56.4%, 30.9% and 103.7% respectively, mainly due to the increase in cadmium content in the underground parts (roots).
[0056] 1.5.4 Effect on cadmium accumulation in *Aster tataricus* leaves
[0057] See results Figure 4 .
[0058] Depend on Figure 4 It was found that, compared with Cd, the cadmium accumulation in *Aster tataricus* increased by 21.1%, 56.5%, and 157.4% in the 0.5 Gln, 5 Gln, and 20 Gln treatment groups, respectively. This indicates that the addition of glutamine can enhance the cadmium accumulation capacity of *Aster tataricus*, and the addition of 20 mg / L glutamine is even more effective in enhancing the cadmium accumulation capacity of *Aster tataricus*.
[0059] In summary, glutamine can enhance the stress resistance, survival ability, growth and development, and cadmium accumulation capacity of *Aster tataricus* under cadmium stress. Compared with phytoremediation alone, exogenous glutamine can improve the remediation efficiency of *Aster tataricus* for cadmium pollution, thereby reducing the cadmium content in the environment.
[0060] The foregoing description of specific exemplary embodiments of the invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. The scope of the invention is intended to be defined by the claims and their equivalents.
Claims
1. Application of exogenous glutamine in promoting the accumulation of heavy metal cadmium in the hyperaccumulating plant Aster tataricus.
2. The application of exogenous glutamine as described in claim 1 in improving the stress resistance of *Aster tataricus* in areas contaminated with heavy metal cadmium or promoting the growth of *Aster tataricus* in such areas.
3. The application of exogenous glutamine as described in claim 1 in increasing the chlorophyll or carotenoid content of Aster tataricus in areas contaminated with heavy metal cadmium.
4. A method for using exogenous glutamine to promote the remediation of cadmium pollution by *Aster tataricus*, characterized in that, Specifically, during the growth period of Aster tataricus, spray the leaves with glutamine solution every 3 days for a total of 6 times; and harvest Aster tataricus 10 days after the end of the foliar spraying.
5. The method for remediating cadmium pollution using exogenous glutamine as described in claim 4, characterized in that, The concentration of the glutamine solution is 0.5-20 mg / L.