Research Progress on Detection Techniques of Fungicide Residues in Chinese Chives

Chinese chive is a kind of medicinal and edible plant,with many diseases,and chemical fungicides are usually used for control.In order to find out the risk of pesticide residues in Chinese chives,this paper summarized relevant literatures published in recent years,and sorted out and analyzed the types of pesticides used and detection techniques of common diseases in Chinese chives.

Detection and Analysis of Pesticide Residues in Chinese Chives and Risk Assessment of Dietary Intake

[Objectives]This study was conducted to understand the status of pesticide residues and dietary intake risk of Chinese chives in Tangshan area. [Methods] Sixty eight kinds of pesticide residues in 415 Chinese chive samples collected from Tangshan area were qualitatively and quantitatively determined by high-performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS) and gas chromatography(GC) in 2020. [Results] The results showed that 41 kinds of pesticide residues were detected in the 415 Chinese chive samples, and the detection rate was 69.4%(288/415), and there was a combination of pesticides in many samples. According to the National Food Safety Standard―Maximum Residue Limits of Pesticides in Food(GB 2763-2019), the residues of 12 pesticides exceeded the maximum residue limits(MRLs), and the unqualified rate was 38.07%(158/415). The highest detection rate of clothianidin was 41.20%(171/415), but there was no MRL in GB 2763-2019. The next was procymidone, the detection rate of which was 35.42%(147/415), and the over-standard rate was 30.12%(125/415). Forbidden and restricted pesticides were detected in some samples. According to the dietary exposure risk assessment, the NEDI/ADI values were all less than 1 and the intake risk was within acceptable range. In Tangshan area, the types of pesticides used in Chinese chive production are complex, and there are risks of multi-residue pollution and use of banned and restricted pesticides and unregistered pesticides. It is suggested that routine monitoring of pesticide residues and management of pesticide use should be strengthened to ensure the quality and safety of agricultural products. [Conclusions] This study provides a theoretical basis for the safe production of Chinese chive and the standardized and rational use of pesticides.

Main Problems and Countermeasures of Chinese Chive Quality and Safety in China

In recent years,the problem of pesticide residues in Chinese chives has attracted widespread attention from society.This paper comprehensively analyzed the production and planting situation,quality and safety status and changes in pesticide standards of Chinese chives,and deeply discussed the main quality and safety problems of Chinese chives and their causes.On this basis,it was proposed to improve the quality and safety level of Chinese chives from three aspects:improving limit standards,promoting green production prevention and control techniques,and strengthening supervision on input products.

Effect of Chitosan with Different Molecular Weights on Postharvest Quality of Chinese Chive Scapes

[Objective] The purpose of this study was to determine the effect of chitosan with different molecular weights on quality and lignification of postharvest Chi- nese chive scapes （Allium tuberosum Rottler ex Sprengel）. [Method] Some physio- logical and biochemical indexes such as weight loss, decay index, opening rate of flowers, chlorophyll and ascorbic acid content, respiration rate, the activities of enzymes, lignin and cellulose content of Chinese chive scapes treated with three kinds of chitosan with different molecular weights were investigated during the room stor- age at 20 ℃ to simulate shelf life. [Result] The results showed that all the treat- ments of chitosan with different molecular weights significantly delayed weight loss, decay index and opening rate of flowers, maintained higher chlorophyll and ascorbic acid content, inhibited respiration rate, reduced the activities of enzymes phenylala- nine ammonia lyase, cinnamyl alcohol dehydrogenase and peroxidase, and retarded lignin and cellulose accumulation during the storage of Chinese chive scapes. However, high molecular weight chitosan has better preservation effect on Chinese chive scapes. [Conclusion] The results suggest that the coating treatment of high molecu- lar weight chitosan may be a promising technique to maintain postharvest quality of Chinese chive scapes.

Comparison of Methods for Ultra-drying of Chinese Chive Seeds

[Objective] This study aimed to identify the ultra-drying method most suitable for the storage of Chinese chive seeds through comparing different ultra-drying meth- ods. [Method] Through setting treatments including freezing, silica gel drying and heating drying at 50℃ as well as two controls, the effects of different drying methods for storing ultra-dried Chinese chive seeds were compared. [Result] There were no significant differences in the germination rate and seedling length between Chinese chive seeds treated with heating drying at 50℃ and those treated with either freezing or get drying at the initial stage of the storage. Storing of Chinese chive seeds previously treated with either heating drying at 50℃, or freezing or gel drying for 0-98 months at 20℃ hadn＇t caused any adverse effect on the germination rate of seeds. And the effect of different storage conditions on seedling length displayed earlier than that on the germination rate. There was no significant difference on seedling length between seeds treated with heating drying at 50℃ and those treated with freezing drying after stored for as long as 98 months, revealing similar efficacy on storing seeds. [Conclusion] Freezing drying requires huge investment and cost for perennial running, and silica gel drying is slow in drying and time-consuming. By contrast, heating drying at 50℃ is an economic and simple method, which can enable the Chinese chive seeds to sustain a longevity of eight years or more.

Effect of Different Environmental Conditions on Algicidal Effect of Water-soluble Extracts of Chinese Chive

[Objective] The paper was to study the algicidal effect of water-soluble extracts of Chinese chive under different environmental conditions, so as to provide reference for further study and development of new algicidal substances. [Method] The effects of water-soluble extracts of Chinese chive on the growth of Microcystis aeruginosa under different pH, light and aeration conditions were compared and studied. [Result] The growth inhibition rate of water-soluble extracts of Chinese chive on M. aeruginosa was greater than 90% under different pH conditions. With the growth of M. aeruginosa, the culture liquid with different initial pH was finally tended to 9-9.5. The growth inhibition rate of water-soluble extracts of Chinese chive on algae cell increased with the prolongation of culture time within the light intensity range of 1 000-4 000 lx. The inhibition effect of water-soluble extracts of Chinese chive on M. aeruginosa under low light intensity（1 000 lx）was better than that under high light intensity, the best light intensity for growth was not conducive to the exertion of allelopathic effect. Meanwhile, aeration condition was more conducive to the inhibition effect of water-soluble extracts of Chinese chive on the growth of M. aeruginosa. [Conclusion] pH, light and aeration conditions all affected the inhibition effect of water-soluble extracts of Chinese chive treated by high temperature on M. aeruginosa. Understanding the effect of these environmental factors on algicidal effect of allelochemicals could provide reference for further study and development of new algicidal substances.

Effect of Different Organic Fertilizers on Chinese Chives(Allium tuberosum) Growth and Yield

[Objeclive] This study was conducted to select suitable organic fertilizer for Chinese chives, so as to improve yield and benefit of Chinese chives. [Method] Pot experiments were carried out to investigate effects of 3 organic fertilizers peanut cake fertilizer, chicken manure and mushroom residue on growth and yield of Chi- nese Chives. [Result] The 3 organic fertilizer treatments had better effects on plant height, stem diameter and leaf width than the CK. Treatment 1 showed the best effect on growth and development of Chinese chives, treatment 2 exhibited the sec- ond best effect, and treatment 3 showed the poorest effect. Treatment 1 showed the highest yield and economic benefit, of 65.514 t/hm^2 and 175.556×10^4 Yuardhm2, respectively, treatment 2 showed the second highest effects, and treatment 3 showed the lowest yield and economic benefit. [Conclusion] Selecting peanut cake fertilizer for production of Chinese chives could significantly improve yield and eco- nomic benefit of Chinese chives.

6-Benzylaminopurine treatment maintains the quality of Chinese chive(Allium tuberosum Rottler ex Spreng.) by enhancing antioxidant enzyme activity

Chinese chive usually develops an off-flavor after a short storage time. To explore effective ways to maintain the postharvest quality of Chinese chive, the effect of exogenous application of 6-benzylaminopurine（6-BA） on postharvest quality and antioxidant activity of chive was evaluated, and the mechanism of the physiological responses of chive to 6-BA treatment was explored. Chives were sprayed for 10 min with 100, 300, or 500 mg L–1 6-BA or with alkaline solution as the control, then stored at（2±1）°C with a relative humidity（RH） of 80–85%. We found that 300 mg L–1 6-BA significantly delayed yellowing and chlorophyll degradation, maintained the total phenolic and flavonoid content, and improved the activities of antioxidant enzymes, including superoxide dismutase（SOD）, catalase（CAT） and peroxidase（POD）. In conclusion, we identified exogenous application of 6-BA as an effective method for maintaining postharvest quality of Chinese chive. In addition, our finding that the activities of antioxidant enzymes increase in response to exogenous 6-BA provides new insights into the mechanism of cytokinin-based postharvest fresh-keeping.

Evaluation of renoprotective effect of Chinese chive extracts on adenine-induced chronic renal failure

The renoprotective effects of Chinese chive water and ethanol extracts(CCWE and CCEE)on adenineinduced chronic renal failure(CRF)mice were evaluated in this study.Results showed that the renal pathological damages and the enhancement of serum creatinine and blood urea nitrogen of CRF mice could be significantly alleviated by the treatment of CCWE,but not CCEE.When the concentration of CCWE reached 200 mg/kg/day,the area of renal pathological damage was decreased to the 48.1%of model group,and the levels of serum creatinine and blood urea nitrogen were decreased to the 87.7%and 83.9%of model group,respectively.Meanwhile,it could be found that renal oxidative stress and inflammation of CRF mice were remarkably inhibited by CCWE.These results indicated CCWE could improve the kidney function of CRF mice via enhancing antioxidant ability and inhibiting inflammation,and was the main renoprotective fraction of Chinese chive.

Design and experiment of a Chinese chive harvester

Recognizing the labor intensity of current domestic Chinese chive harvesting and the need for its mechanized harvesting,a self-propelled electric Chinese chive harvester is designed.The machine is composed of a control system,supporting mechanism,cutting parts,conveying and clamping mechanisms,frame,and collection system.It can complete Chinese chive feeding,cutting,transmission,and binning operations at one time.It has a cutting width of 0.25 m and wheelbases of 260 mm and 460 mm.Two 12 V,42 Ah lead-acid batteries were used in series as the power supply.The mechanical properties of Chinese chive were analyzed,and shear and compression tests were carried out to determine that the average value of the maximum shear force on the chives is 129 N.Up to a compressive force of 225 N,Chinese chives are not damaged.According to the physical characteristics of Chinese chives and the requirements of the harvesting operations,design and calculation of the key components of the harvester’s transmission mechanism and the strength of the whole machine frame were completed.An embedded control system and Cortex-M3 microprocessor were used to control the harvester and realize its functions of rolling and harvesting while regulating its speed and protecting its motor.Using the Box-Behnken test design method,the machine’s operating speed,cutter speed,and cutter height were selected as influencing factors,and the lodging rate and loss rate were evaluated as a test.A mathematical regression model of influencing factors and evaluation indexes was established to analyze the influence of these factors and indexes and optimize test parameters.The optimal parameter combination is determined to be:operating speed,1.1 km/h;cutter speed,220 r/min;cutter height 2.0 cm.The parameters were verified from field tests and the results showed that under the optimized parameter combination,the average lodging rate was 3.96% and the average loss rate was 3.23%,indicating that the Chinese chive harvester meets the agronomic requirements of Chinese chive harvesting.This harvester could be modified to harvest other crops such as chrysanthemums and Mongolian Chinese chive.

EFFECT OF SOLARIZATION TO KILL BRADYSIA CELLARUM ON CHINESE CHIVE GROWTH AND SOIL MICROBIAL DIVERSITY

Bradysia cellarum Frey (Diptera: Sciaridae) is an important subterranean pestand is especially damaging to Chinese chive. An effective and moreenvironmentally safe method than pesticides is needed for its control. Theefficacy of B. cellarum control, growth of Chinese chive and soil microbialdiversity were investigated after uae of soil solarization to exterminate thisinsect pest. The results show that on the first day after soil solarization 100%control of B. cellarum was achieved. Growth of Chinese chive was lower insolarized plots than in control plots over the first 10 days after treatment. Chivegrowth in solarized plots increased subsequently to match that in the controlplots. Moreover, the soil microbial community diversity in the treatment groupdecreased initially before gradually recovering. In addition, the abundance ofbeneficial microorganisms in the genus Bacillus and the phyla Proteobacteria,Chloroflexi and Firmicutes increased significantly. Soil solarization is thereforepractical and worthy of promotion in Chinese chive-growing regions.

Preference of Adult Bradysia odoriphaga Yang et Zhang to Different Colors and Trapping Effect of Yellow Sticky Trap

The trapping effects of yellow, blue, green, cyan and white sticky traps on adult Bradysia odoriphaga Yang et Zhang were studied in the field during its peak occurrence period. The results showed that yellow sticky trap received the best trapping effect on adult B. odoriphaga, follow by blue and green sticky traps, while cyan and white sticky traps received worse effects. The yellow sticky trap settled at south position was most attractive to adult B. odoriphaga, which had significant differences with tho^e placed at east and north positions （P 〈 0.05 ） ; the yellow sticky trap at hanging height of 0 cm showed significantly higher attractive- ness than those at heights of 20 and 40 cm.

Design and experiment of a barrel-shaped aeroponic cultivation system

Theoretically,aeroponic cultivation is easy to make plant roots in a better growth environment.In order to give better play to the theoretical advantages of aeroponic cultivation,further optimize the structure of the aeroponic cultivation system,and make the aeroponic cultivation system more scientific and reasonable,a barrel-shaped aeroponic cultivation system is designed.The aeroponic cultivation system is composed of a monitoring and control system,power equipment,nutrient solution storage,and treatment facility,nutrient solution supply pipelines,aeroponic cultivation barrels,and nutrient solution return pipelines.The cultivation system working principle and its technical requirements were analyzed,and its structure for meeting the requirements of large-scale production was determined.A performance test of the barrel-shaped aeroponic cultivation system using cultivated narrow leaved Chinese chives was conducted.The Chinese chives were cultivated to 6 beds of the cultivation barrel.The system supplied nutrient solution every 30 min for 2 min each time.After 5 weeks growth,the length,leaf width,and single weight of Chinese chive ranged from 293-362 mm,4.1-6.7 mm,and 3.48-5.47 g,respectively,the average length,leaf width,and single weight of Chinese chive were 327 mm,5.1 mm,and 4.24 g,respectively,and there were no significant differences in the length,leaf width,and single weight of Chinese chive on 6 beds by One-way ANOVA.The test results showed that all the Chinese chive in each bed of the cultivation barrel grew well and uniform,which indicated that the circulation process of nutrient solution supply and return in the system was normal,the process of nutrient solution atomization in the system was uniform,and the aeroponic cultivation system operated normally and stable and could be applied in production.