Application of melatonin to reduction of negative influence of herbicide on plants

Abstract

The invention discloses application of melatonin to reduction of negative effects of herbicides on plants. The melatonin can relieve elongation reduction, dry weight reduction, chlorophyll reduction and lipid peroxidation caused by fluroxypyr-mepthyl and reduce accumulation of fluroxypyr-mepthyl in rice. The melatonin can be used for reducing threats of crops polluted by fluroxypyr-mepthyl to human health.

Description

Technical Field

[0001] The present invention relates to the field of crop cultivation technology, and more specifically, to the application of melatonin in reducing the negative impact of herbicides on plants. Background Art

[0002] Flupyr 2-ethylhexyl (FLUME) is a systemic, post-emergence organic heterocyclic herbicide that is widely used to control broadleaf weeds on cereal crops. The distribution of flupyr 2-ethylhexyl after application is affected by plant absorption, soil leaching, adsorption, abiotic and biotic degradation, etc. It is suitable for controlling broadleaf weeds in wheat, barley, corn, grapes, orchards, pastures, woodlands, lawns, etc.; such as cleavers, Polygonum convolvulus, Purslane, Solanum nigrum, field bindweed, Polygonum, Amaranthus, etc.

[0003] The degradation of isooctyl clofopyralid in soil mainly includes photolysis, hydrolysis and microbial degradation, among which soil organic carbon content and microorganisms play a leading role in the degradation of isooctyl clofopyralid. After isooctyl clofopyralid in soil is absorbed by plants, its conduction and transportation efficiency in plants is low, while its hydrolysis product, isooctyl clofopyralid, can be quickly conducted and dispersed to various parts of plants. However, there are few studies on how isooctyl clofopyralid degrades after entering plants and the factors that affect its degradation in plants, and there are no reports on the degradation and metabolism mechanism of isooctyl clofopyralid in rice.

[0004] In China, more than thousands of tons of clofopyralid are used in the production of cereal crops every year. Therefore, with the large-scale use of clofopyralid in agricultural production, it has caused pollution to ecosystems such as soil, lakes and groundwater. After being absorbed by crops, it poses a potential threat to cash crops and agricultural production including rice. At the same time, clofopyralid has caused a human poisoning death. Therefore, consuming water sources or crops contaminated by clofopyralid will pose a potential threat to human health. Summary of the invention

[0005] The purpose of the present invention is to overcome the deficiencies of the prior art and provide an application of melatonin (MT) in reducing the negative effects of herbicides on plants.

[0006] One object of the present invention is to provide the use of melatonin in reducing the negative effects of clofopyralid on plants.

[0007] Another object of the present invention is to provide the use of melatonin in improving the resistance of plants to clofopyralid ethyl ester.

[0008] In order to achieve the above object, the present invention is implemented by the following technical solutions:

[0009] Melatonin (MT) is one of the hormones secreted by the pineal gland in the brain. Melatonin belongs to the indole heterocyclic compound, and its chemical name is N-acetyl-5-methoxytryptamine, also known as pineal hormone, melatonin, and melatonin.

[0010] The present invention claims the use of melatonin in reducing the negative effects of clofopyralid 2-ethylhexyl on plants.

[0011] Preferably, the plant is a grass plant.

[0012] More preferably, the grass plant is rice.

[0013] Preferably, the negative effect is growth inhibition.

[0014] Preferably, the negative impact is a reduction in dry weight.

[0015] Preferably, the negative impact is a reduction in chlorophyll.

[0016] The present invention also claims the use of melatonin in improving the resistance of plants to clofopyralid 2-ethylhexyl.

[0017] Preferably, the plant is a grass plant.

[0018] Preferably, the grass plant is rice.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The invention discloses the application of melatonin in reducing the negative effects of lofluanid 2-ethylhexyl on plants. Melatonin can alleviate the reduction of elongation, dry weight, chlorophyll, lipid peroxidation and accumulation of lofluanid 2-ethylhexyl in rice caused by lofluanid 2-ethylhexyl. Melatonin can be used to reduce the threat to human health caused by crops contaminated by lofluanid 2-ethylhexyl. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1Figure 2 Effects of melatonin on the growth of rice seedlings under FLUME stress: 10-day-old rice seedlings were treated with 0, 0.02, 0.05, 0.08, 0.11 and 0.14 mg / L of clofopyralid 2-ethylhexyl ester for 6 days; A is the phenotype of rice seedlings treated with FLUME for 6 days, from left to right: CK, CK+MT 200mg / L, FLUME 0.02mg / L, FLUME0.02mg / L+MT 200mg / L, FLUME 0.05mg / L, FLUME 0.05mg / L+MT 200mg / L, FLUME 0.08mg / L, FLUME 0.08mg / L+MT 200mg / L, 0.11mg / L, FLUME 0.11mg / L+MT 200 mg / L, 0.14 mg / L, and FLUME0.14 mg / L+MT 200 mg / L; B is the elongation of rice roots and aerial parts; C is the dry weight of rice roots and aerial parts; D is the total chlorophyll (Chl) concentration of rice leaves; E is the malondialdehyde (MDA) concentration of rice roots and aerial parts; The vertical bars represent the standard deviation of three biological replicates.

[0022] Figure 2 Effects of melatonin on rice under clofopyralid stress; A is the SOD activity in the root and aboveground parts, B is the POD activity in the root and aboveground parts, C is the GST activity in the root and aboveground parts, D is the ACE activity in the root and aboveground parts; E is the GT activity in the root and aboveground parts.

[0023] Figure 3 The effect of melatonin on the accumulation of clofopyralid in the roots and aboveground parts of rice under clofopyralid stress. DETAILED DESCRIPTION

[0024] The present invention is further described in detail below in conjunction with the accompanying drawings and specific examples of the specification. The examples are only used to explain the present invention and are not used to limit the scope of the present invention. The test methods used in the following examples are conventional methods unless otherwise specified; the materials and reagents used are reagents and materials that can be obtained from commercial channels unless otherwise specified.

[0025] Example 1 Cultivation of rice and melatonin treatment

[0026] 1. Seed disinfection

[0027] Use 3% hydrogen peroxide solution to disinfect the surface of rice seeds, and then rinse them repeatedly with distilled water 3 to 5 times after 15 minutes.

[0028] 2. Germination

[0029] Place the sterilized rice seeds in a petri dish lined with neutral filter paper and add an appropriate amount of distilled water for germination;

[0030] 3. Seedling cultivation

[0031] After germination, rice seeds with roughly the same germination degree were selected and evenly dotted on a mesh floating plate and placed in a modified 1 / 2 strength Hoagland rice nutrient solution at a day / night temperature of 30 / 25°C, a photoperiod of 14 h, and a light intensity of 200 μmol / m 2 s, cultured in a constant temperature incubator under a relative humidity of 70% for about five days, selected rice seedlings with the same growth trend and transplanted them into small pots containing rice nutrient solution, with 20 seedlings per pot, and acclimated and cultured for 1 to 2 days,

[0032] 4. Melatonin treatment

[0033] After acclimation and cultivation, the rice seedlings were divided into 2 groups (18 pots in each group), one of which was added with gradient concentrations of clofopyralid (0, 0.02, 0.05, 0.08, 0.11 and 0.14 mg / L, 3 pots for each concentration) of clofopyralid, and the other group was used as the control group, and gradient concentrations of clofopyralid (0, 0.02, 0.05, 0.08, 0.11 and 0.14 mg / L, 3 pots for each concentration) and melatonin (200 mg / L) were added to the rice nutrient solution. The rice nutrient solution was changed every 2 days.

[0034] Example 2 Effects of melatonin treatment on physiological indicators

[0035] 1. Experimental Methods

[0036] After the rice of Example 1 was treated for 6 days, the phenotype of the rice before and after the addition of melatonin was recorded by photographing, and the elongation, dry weight, malondialdehyde (MDA) content of the root and aboveground part of the rice seedlings and the chlorophyll content of the leaves were measured.

[0037] Among them, the detection methods of chlorophyll and malondialdehyde (MDA) are from Chen, ZJ, Qiao, Y., Zhang, N., Yang, H., Liu, J. 2023. Acetyltransferase OsACE2 acts as a regulator to reduce the environmental risk of oxyfluorfen to rice production. Science of The Total Environment, 867, 161599.

[0038] 2. Experimental Results

[0039] The results are as follows Figure 1 As shown in the results, the physiological indicators of rice seedlings after adding melatonin were better than those of rice seedlings under the stress of flupyralid 2-ethylhexyl ester. Among them, when the FLUME concentration was 0.08 mg / L, exogenous melatonin had the best effect on improving rice stress resistance. Compared with rice seedlings under FLUME stress alone, exogenous MT increased the elongation of the roots of rice seedlings by 6% and the elongation of the aboveground parts by 24%; the dry weight of the roots increased by 22% and the dry weight of the aboveground parts increased by 11%; the chlorophyll content of the leaves increased by 9% ( Figure 1 After application of exogenous MT, the MDA content in the roots and shoots of rice seedlings also decreased by 42% and 48%, respectively ( Figure 1 E), that is, under FLUME stress, exogenous MT improved the growth of rice seedlings and reduced phytotoxicity.

[0040] Example 3 Effect of melatonin treatment on enzyme activity

[0041] 1. Experimental Methods

[0042] After the rice of Example 1 was treated for 6 days, the activities of five enzymes, namely superoxide dismutase (SOD), peroxidase (POD), glutathione S-transferase (GST), acetyl-CoA (ACE) and glycosyltransferase (GT), were measured in the roots and aboveground parts of the rice seedlings.

[0043] 2. Experimental Results

[0044] The results are as follows Figure 2 As shown, the results showed that the activities of SOD, POD, GST, ACE and GT in rice seedlings increased after the addition of melatonin. Among them, the improvement effect was best when the FLUME concentration was 0.08 mg / L. Among them, the SOD activity in the roots and aboveground parts of rice seedlings after the addition of MT was 1.1 times and 1.2 times that of the SOD activity under FLUME stress alone. The POD activity in the roots and aboveground parts of rice seedlings after exogenous MT was 1.2 times and 1.3 times that of the POD activity under FLUME stress alone. The GST activity in the roots and aboveground parts of rice seedlings after exogenous MT was 1.6 times and 2.6 times that of the GST activity under FLUME stress alone. The ACE activity in the roots and aboveground parts of rice seedlings after exogenous MT was 1.2 times and 1.3 times that of the ACE activity under FLUME stress alone. The GT activities in the roots and aerial parts of rice seedlings after exogenous MT were 1.4 and 1.3 times of those under FLUME stress.

[0045] In summary, exogenous MT application can enhance the antioxidant and detoxification defense enzyme activities of rice seedlings by reducing excessive ROS and FLUME, and reduce the oxidative damage caused by FLUME to rice seedlings.

[0046] The enzyme activity determination method comes from: Chen, ZJ, Lv, Y., Zhai, XY, Yang, H., 2021. Comprehensive analyses of degradative enzymes associated with mesotrione-degraded process in rice for declining environmental risks. Sci. Total Environ. 758, 143618.756

[0047] Chen,ZJ,Qiao,YX,Zhang,N.,Liu,JT,Yang,H.,2021.Insight intometabolism pathways of pesticide fomesafen in rice:Reducing cropping and environmental risks.Environ.Pollut.283,117128.

[0048] Su,

[0049] Example 4 Effect of melatonin treatment on FLUME accumulation

[0050] 1. Experimental Methods

[0051] After the rice of Example 1 was treated for 6 days, the accumulation of FLUME in the root and aerial part of the rice seedlings was determined. The specific method is: weigh 3g of the root or aerial part, add 5mL of deionized water and 10mL of acetonitrile in turn, adjust the pH to 2-3 with formic acid, shake and extract for 1h, add a certain amount of sodium chloride, vortex for 5min, centrifuge at 4000rpm for 5min, take 8mL of supernatant, put it into a 50mL round-bottom flask, evaporate it to nearly dryness, add 1mL of acetonitrile to make up the volume, transfer the solution after making up the volume to a 2mL centrifuge tube with 50mg PSA and 50mg C18, vortex for 1min, centrifuge at 4000rpm for 10min, pass the membrane, put it into the injection bottle and wait for the machine.

[0052] HPLC conditions: mobile phase: acetonitrile: 0.05% phosphoric acid aqueous solution = 75:25 (volume ratio), flow rate: 1 mL / min, wavelength: 220 nm, column temperature: 30° C., column: XDB-C18.

[0053] 2. Experimental Results

[0054] The results are as follows Figure 3 As shown, the results showed that the accumulation of FLUME in rice seedlings decreased after the addition of melatonin. After 6 days of treatment with 0.14 mg / L FLUME, the accumulation of FLUME in the roots and aboveground parts of rice was the highest. The concentration of FLUME in the roots was 0.78 mg / kg, and the concentration in the aboveground parts was 0.59 mg / kg. However, exogenous MT treatment effectively reduced the accumulation of FLUME after 6 days of FLUME exposure. The accumulation of FLUME in the roots of rice seedlings treated with exogenous MT was 86% of that treated with 0.14 mg / L FLUME alone, and the accumulation of FLUME in the aboveground parts of rice seedlings treated with exogenous MT was 89% of that treated with 0.14 mg / L FLUME alone.

[0055] In summary, exogenous MT can alleviate oxidative stress-related cell damage, increase the activities of antioxidant and detoxification enzymes, and improve the developmental performance of rice seedlings. MT also significantly reduced the accumulation of FLUME in the aerial parts and roots of rice seedlings.

Claims

1. Application of melatonin in reducing the negative effects of clofopyralidone-2-ethylhexyl on plants.

2. The use according to claim 1, characterized in that: The plant is a grass plant.

3. The use according to claim 2, characterized in that: The grass plant is rice.

4. The use according to claim 1, characterized in that: The negative effect is the accumulation of 1-ethylhexyl fluopyr.

5. The use according to claim 1, characterized in that: The negative effect is growth inhibition.

6. The use according to claim 1, characterized in that: The negative effect is a reduction in dry weight.

7. The use according to claim 1, characterized in that: The negative impact is a reduction in protochlorophyll.

8. Application of melatonin in improving the resistance of plants to clofopyralid 2-ethylhexyl ester.

9. The use according to claim 8, characterized in that: The plant is a grass plant.

10. The use according to claim 8, characterized in that: The grass plant is rice.

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