Induction mechanism of p-fluorophenoxyacetic acid_Kain Industrial Additive

Background and overview^[1]

Fluorobenzenes have stable chemical properties, are difficult to biodegrade, and are carcinogenic and teratogenic to the human body. The mineralization and degradation of these substances has always been a problem in sewage treatment. p-Fluorophenoxyacetic acid is an important phenoxy plant growth regulator, which can be absorbed through the roots, stems, leaves, flowers and fruits of plants. It is mainly used to prevent flower and fruit drop, inhibit rooting of beans, promote fruit setting, and induce It is a seedless fruit and has the effect of accelerating ripening and increasing yield. This kind of organic matter is one of the more common organic pollutants in agricultural production.

Apply^[2]

Fluorophenoxyacetic acid can activate the insect resistance of rice to rice planthoppers, and can reduce the survival rate of rice planthopper nymphs to less than 10%, which has high economic benefits.

1) Root absorption treatment of p-fluorophenoxyacetic acid reduces the survival rate of rice planthopper nymphs

The concentrations of p-fluorophenoxyacetic acid used are 1mg/L and 10mg/L. The rice used is nutrient solution cultured rice, which is grown as a single plant; the treatment method is to add p-fluorophenoxyacetic acid to the rice nutrient solution to a final concentration of 1mg/L or 10mg/L, and use the nutrient solution without adding p-fluorophenoxyacetic acid as Contrast. After treatment with p-fluorophenoxyacetic acid for 12 hours, a special glass cover (4cm in diameter, 8cm in height, with 48 small holes of 0.8mm in diameter evenly distributed on the tube wall) was placed on each rice stem, and newly hatched brown planthoppers or brown planthoppers were introduced. There are 15 white-backed planthopper nymphs, and the top of the glass cover is sealed with a round sponge. The experiment was conducted in an artificial climate room with a temperature of 28±2°C, a humidity of 70-80%, and 14 hours of light. The number of surviving nymphs of the two planthoppers was recorded every day, and each treatment was repeated 10 times. Starting from the 2nd day after p-fluorophenoxyacetic acid treatment, there was a significant decrease in the nymphal survival rate of both planthoppers. The survival rate of brown planthoppers on the 8th day of rice treated with 1 mg/L of p-fluorophenoxyacetic acid was 35.1%, which was significantly lower than the 90.3% of the control. However, the survival rate of brown planthoppers on the 8th day of rice treated with 10 mg/L of p-fluorophenoxyacetic acid was only 35.1%. The remaining 1.5%; similarly, the survival rate of white-backed planthoppers on the 8th day of rice treated with p-fluorophenoxyacetic acid 1mg/L was 41.3%, which was significantly lower than the 90.5% of the control, while p-fluorophenoxyacetic acid 10mg/L The survival rate of brown planthoppers in treated rice was only 3.1% on the 8th day. The results showed that p-fluorophenoxyacetic acid root absorption treatment significantly improved the direct resistance of rice to rice planthopper nymphs.

2) Spraying p-fluorophenoxyacetic acid on stems and leaves improves rice resistance to rice planthopper nymphs

The concentrations of p-fluorophenoxyacetic acid used are 20mg/L and 100mg/L. The rice used is nutrient solution cultured rice, which is grown as a single plant; the treatment method is to prepare p-fluorophenoxyacetic acid with water at the corresponding concentration (20 mg/L or 100 mg/L), and then use a small sprayer to spray the rice stems and leaves; use tap water as comparison. After the mist droplets on the rice stems and leaves are completely dry, put a special glass cover (4cm in diameter, 8cm in height, 48 small holes with a diameter of 0.8mm evenly distributed on the tube wall) on the rice stems, and insert the newly hatched brown planthopper or white-backed planthopper. There are 15 planthopper nymphs, and the top of the glass cover is sealed with a round sponge. The experiment was conducted in an artificial climate room with a temperature of 28±2°C, a humidity of 70-80%, and 14 hours of light. The number of surviving planthopper nymphs was recorded every day, and each treatment was repeated 10 times. Starting from the 2nd day after p-fluorophenoxyacetic acid treatment, there was a significant decrease in the nymphal survival rate of both planthoppers. The survival rate of brown planthoppers on the 8th day of rice treated with 20 mg/L of p-fluorophenoxyacetic acid was 60.3%, which was significantly lower than the 86.5% of the control. However, the survival rate of brown planthoppers on the 8th day of rice treated with 100 mg/L of p-fluorophenoxyacetic acid was only 60.3%. The remaining 19.2%; similarly, the survival rate of white-backed planthoppers on the 8th day of rice treated with p-fluorophenoxyacetic acid 20mg/L was 66.1%, which was significantly lower than the 81.4% of the control, while p-fluorophenoxyacetic acid 100mg/L The survival rate of brown planthoppers in treated rice was only 23.2% on the 8th day. The results showed that p-fluorophenoxyacetic acid stem and leaf spray treatment significantly increased the direct resistance of rice to rice planthopper nymphs.

3) Fluorophenoxyacetic acid itself has no effect on the survival of rice planthoppers

In order to exclude the possible impact of p-fluorophenoxyacetic acid itself on the survival rate of rice planthopper nymphs, in this example, the stomach poisoning, contact killing and other effects of p-fluorophenoxyacetic acid itself on rice planthopper nymphs at different concentrations were measured. In the experiment to determine the gastric toxicity of p-fluorophenoxyacetic acid on rice planthopper nymphs, p-fluorophenoxyacetic acid at concentrations of 5, 20, and 50 mg/L was added to the planthopper artificial feed. The control was without p-fluorophenoxyacetic acid. Artificial feed of phenoxyacetic acid. Place artificial feed containing different concentrations of p-fluorophenoxyacetic acid (20 μL at each end) wrapped with Parafilm sealing film at both ends of a glass double-pass tube with a diameter of 4 cm and a height of 8 cm. Add 15 newly hatched white-backed flies into the tube. Lice nymphs; artificial feed without p-fluorophenoxyacetic acid was placed as a control.

The glass double-pass tube was placed in an artificial climate box (temperature 28°C, light 12 hours), artificial feed was changed once a day, and the number of surviving nymphs was recorded. The experiment was repeated 10 times. The results show that adding p-fluorophenoxyacetic acid at the test concentration in artificial feed does not affect the survival rate of nymphs of white-backed planthoppers; in feeds containing p-fluorophenoxyacetic acid at 0, 5, 20 and 50 mg/L, the nymphs in the second The survival rates on day 4 were 85.7%, 85.5%, 87.4% and 81.3% respectively; the survival rates on day 4 were 56.2%, 58.6%, 54.3% and 57.6% respectively; indicating that p-fluorophenoxyacetic acid itself has no gastric toxicity to planthoppers effect. In the experiment to determine the contact killing effect of p-fluorophenoxyacetic acid on rice planthopper nymphs, p-fluorophenoxyacetic acid was selected at concentrations of 5, 20, and 50 mg/L, and the control was distilled water without p-fluorophenoxyacetic acid. �The third-instar white-backed planthopper nymphs (1 μL per worm) were anesthetized with carbon dioxide and p-fluorophenoxyacetic acid or distilled water at the corresponding concentration. Then, after waking up, they were raised on 30-day-old rice seedlings, and 15 larvae were raised on each seedling. head; the rice is placed in an artificial climate room with a temperature of 28±2°C, a humidity of 70-80%, and 14 hours of light. Each treatment was repeated 10 times. The survival of planthopper nymphs was observed and recorded 24 and 48 hours after treatment. The results showed that after 24 hours of treatment, the survival rates of planthopper nymphs in the control group and those with p-fluorophenoxyacetic acid concentrations of 5, 20 and 50 mg/L were 93.3%, 92.0%, 93.1% and 92.0% respectively; after 48 hours, the The values ​​were 90.2%, 92.0%, 91.6% and 90.8%, with no significant difference; indicating that p-fluorophenoxyacetic acid itself has no contact killing effect on planthoppers.

Induction mechanism of p-fluorophenoxyacetic acid^[2]

The concentration of p-fluorophenoxyacetic acid used is 5mg/L, and the rice used is nutrient solution cultured rice, which is grown as a single plant; the treatment method is to add p-fluorophenoxyacetic acid to the rice nutrient solution until the final concentration is 5mg/L. L, the nutrient solution without p-fluorophenoxyacetic acid was used as a control, and each treatment was repeated 5 times. The experiment was conducted in an artificial climate room with a temperature of 28±2°C, a humidity of 70-80%, and 14 hours of illumination. The results showed that after treatment with p-fluorophenoxyacetic acid for 72 hours, the contents of 4-hydroxybenzoic acid and γ-aminobutyric acid in rice increased significantly. The amount of 4-hydroxybenzoic acid was 2.12 times that of the control, and the amount of γ-aminobutyric acid was 2.12 times that of the control. The amount was 2.86 times that of the control. 4-Hydroxybenzoic acid is a phenolic acid defense compound, and γ-aminobutyric acid is a non-protein amino acid. It has a direct toxic effect on pests and can affect the peripheral nervous system of insects. Treatment of rice with p-fluorophenoxyacetic acid increases the content of these defense compounds, thereby adversely affecting pests and improving rice resistance to pests.

Content determination^[3]

A method for simultaneous determination of multiple plant growth regulators in exported vegetables. Including steps such as extraction, purification, concentration, and ultra-high performance liquid chromatography-triple quadrupole/complex linear ion hydrazine mass spectrometry (UHPLC-QTRAP) determination. This method can simultaneously determine gibberellin, indole-3-butyric acid, and parabens. Chlorophenoxyacetic acid, abamectin, acetate, atrazine, simazine, 6-benzylaminopurine, 2,4-dichlorophenoxyacetic acid, chlorfenamide, mesoquat, chlormequat , paclobutrazol, uniconazole, abscisic acid, thidiazuron, 17 kinds of plant growth regulators. The method for simultaneous determination of multiple plant growth regulators in exported vegetables provided by the invention has the advantages of simple steps, short time consumption, and high accuracy and precision.

Main reference materials

【1】Research on the rules of photocatalytic degradation of p-fluorophenoxyacetic acid CN201510613527.6 A method to stimulate induced insect resistance in rice

【2】CN201510238783.1 Simultaneous determination method of multiple plant growth regulators in exported vegetables