Abstract:Objective To investigate the effect of Mycobacterium bovis PtpA protein on NF-κB signaling pathway which is related to immune response, and reveal the role of PtpA protein in the body's response to immunity.Method The PtpA gene eukaryotic expression vector FLAG-PtpA was transfected into HEK293T for SDS-PAGE analysis and Western blot detection. After activation of NF-κB signaling pathway, the effects of PtpA protein on NF-κB signaling pathway were investigated by dual luciferase assay and qPCR.Result The eukaryotic expression vector FLAG-PtpA of PtpA gene was successfully constructed, transfected into HEK293T and analyzed by SDS-PAGE. The specific molecular band was visible with relative molecular mass of 22 000. Western blot results showed that the expression product specifically bound to the primary antibody, demonstrating that the protein was a PtpA protein. In the double luciferase assay, the ratios of the relative fluorescence intensities of firefly luciferase and Renilla luciferase in the test group and the control group were significantly different from 2 to 24 h after transfection (P<0.05). The relative fluorescence values of firefly luciferase and Renilla luciferase in the control group were 2.93 times higher than those in the experimental group 2 h after transfection, indicating that PtpA protein had a significant inhibitory effect on the early activation of NF-κB signaling pathway. qPCR results showed that the expression levels of IL-6, GM-CSF, BIRC-2 and BIRC-3 in the control group were 3.93, 3.42, 2.17 and 2.30 times respectively of those in the test group 2 h after transfection(P<0.01), and were 4.26, 3.93, 2.36 and 2.50 times respectively of those in the test group 4 h after transfection(P<0.01). These results indicated that PtpA protein had a significant inhibitory effect on NF-κB signaling pathway-associated cytokines (IL-6, GM-CSF, BIRC-2 and BIRC-3) in the early stage of immunization.Conclusion qPCR results are consistent with the results of dual luciferase assay, indicating that the effect of M. bovis PtpA on NF-κB signaling pathway mainly occurs in the early stage. This study provides a theoretical basis for the follow-up study of effective tuberculosis prevention and control drugs.

Abstract:Objective To study the effect of nitrogen application rate on yield and quality of low-gluten rice (Oryza sativa). Method Five nitrogen treatments were set under field cultivation conditions. The nitrogen application amounts of N0 (Control), N1, N2, N3 and N4 treatments were 0, 90, 135, 180 and 225 kg·hm^-2 respectively. Low-gluten rice ‘ER22’ was used as material. The effects of different nitrogen levels on the yield, grain protein contents and proportion, and grain quality of ‘ER22’ were analyzed. Result Within the range of 0-180 kg·hm^-2 for nitrogen application, the number of effective panicles, seed setting rate, number of solid grains and rice yield increased with the increase of nitrogen application amount. Under N4 treatment, the seed setting rate and number of solid grains decreased leading to rice yield decline. The contents of total protein and each protein component of ‘ER22’ grain increased with the increase of nitrogen application amount during 0-35 d after flowering. Grain albumin and globulin contents in N2, N3 and N4 treatments at 35 d after flowering were not significantly different, while prolamin contents of N2, N3 and N4 treatments were significantly different. There was no significant difference of gluten content under N3 and N4 treatments. The taste quality of ‘ER22’ grain was good under N1 and N2 treatments. The processing quality was the best under N3 treatment. The overall quality of rice decreased under N4 treatment. Conclusion The suitable nitrogen application amounts for producing high-yield and high-quality low-gluten rice ‘ER22’ range from 135 kg·hm^-2 to 180 kg·hm^-2.

Abstract:Objective To map the quantitative trait loci (QTL) associated with low nitrogen tolerance in rice (Oryza sativa), provide a basis for future fine mapping, cloning and functional characterization of related genes and offer theoretical references for breeding of low nitrogen tolerant rice. Method A set of chromosomal segment substitution lines which was constructed by crossing Koshihikari (recurrent parent) and Nona Bokra (donor parent) were used as test materials. Low nitrogen stress treatment was applied at rice seedling stage. The relative loss ratios of eight phenotypes including rice plant height, root length, root fresh weight, root dry weight, shoot fresh weight, shoot dry weight, total fresh weight and total dry weight were analyzed, and QTL mapping was performed. Result Two loci related to low nitrogen tolerance of rice were successfully mapped. These two QTLs were qRL1-1 and qRFW2-1 which were related to root length and root fresh weight respectively under low nitrogen stress. qRL1-1 was closed to the M1-29 marker on chromosome 1 with a LOD score of 2.89 and explained about 11.23% of total phenotypic variance. qRFW2-1 was closed to the M2-225 marker on chromosome 2 with a LOD score of 2.53 and explained about 9.90% of total phenotypic variance. No loci was found for other six phenotypic indexes. Conclusion QTLs related to root length and root fresh weight under low nitrogen stress are mapped, which lays the foundation for further genetic fine mapping and cloning of the underlying genes.

Abstract:Objective To study the material expression, yield potential and heterosis of transgenic Bt maize(Zea may), and provide references for genetic modification of transgene materials.Method The Reid group elite line PH6WC, the bred inbred lines J1490, J1495 and 4DH10, as well as the introduced line PH1CPS were used as female parents. The Non-Reid based transgenic Bt materials, including 6DH85, J1401, 6DH222, 8DH273 and 8DH279, as well as the self-selected lines J9D207, J1628 and J1688 were used as male parents. Totally 40(5×8) cross combinations according to the NCⅡ design were assembled. The insect-resistant performance and yield potential of transgenic Bt materials were studied.Result Part of the Bt genes were deleted or silenced in transgene materials obtained through backcrossing pedigree method, and no corresponding protein was successfully expressed in the filial generations. The cross combination of transgenic Bt materials could partially avoid yield loss due to pest. Comparing to the control variety, combination 4DH10×8DH279 had the best performance with 31.10% yield increase. For combination J1495×J1401, although it contained the Bt gene and it displayed obvious yield increase (65.77% at the highest) compared with the combination without Bt gene of the same male parent, however, it only had 10.04% yield increase compared with the control variety.Conclusion High-yield and insect-resistant maize varieties can be bred through combining transgene breeding with conventional breeding as well as tracking and testing.

Abstract:Objective A pot experiment was conducted to study Cd accumulation and translocation capacities of 11 maize (Zea Mays) varieties and to screen these varieties, so as to provide a theoretical basis for discovering maize varieties with high Cd accumulation.Method Eleven maize varieties were cultured in soil with 2.5 mg·kg^-1 Cd for 50 d. The dry biomass and Cd content were measured. We used variance analysis and principal component analysis to study the differences in dry biomass, Cd accumulation and translocation capacities of 11 maize varieties.Result There were significant differences in the dry biomass of root and shoot, Cd content, Cd accumulation coefficient and translocation coefficient among 11 maize varieties (P<0.05). The Cd contents of Huacainuo 3 and Guanghongnuo 8 shoots were 26.66 and 20.25 mg·kg^-1 respectively, accumulation coefficients were 10.66 and 8.10 respectively, and translocation coefficients were 1.46 and 2.16 respectively, which were significantly higher than those of other varieties (P<0.05). Principal component analysis showed that the Cd accumulation and translocation capacities of Huacainuo 3 and Guanghongnuo 8 were stronger compared with other varieties (P<0.01).Conclusion Huacainuo 3 and Guanghongnuo 8 have relatively high capacity in Cd accumulation and translocation, and belong to the varieties with high Cd accumulation. They have great potential to remediate to Cd contaminated soil.

Abstract:Objective To compare anti-fungal effects of aqueous extracts of different plants on Fusarium oxysporum f. sp. cubense race4 (FOC4), the causal agent of banana wilt, and further clarify the releasing approaches of anti-fungal compounds from leek (Allium tuberosum Rottler) and Ageratum conyzoides L.Method Mycelial growth rate method and spore germination method were used to examine the inhibitory effects of aqueous extracts from 12 plant species as well as volatiles from leek and A. conyzoides on mycial growth and spore germination of FOC4.Result Aqueous extracts of leek and A. conyzoides showed strong inhibitory effects on FOC4 colony growth, the inhibition rates were 71% and 69% respectively. Dichloromethane extracts and residuals of aqueous extracts from leek leaves showed the inhibition rates of 18.7% and 13.0% respectively, and dichloromethane extraction and residuals of aqueous extracts from leek roots showed the inhibition rates of 39.8% and 22.1% respectively, which suggested that the main active ingredients were low water-soluble organic compounds. The antifungal effects of leaf volatiles showed stronger than those of root volatiles for leek. The volatiles from fresh leek leaves mashed in a sealed glass jar completely inhibited FOC4 colony growth at the concentration of 1.25 g/L, and FOC4 spore germination number was 35 per dish after treated with volatiles from leek roots at the same concentration. The inhibitory effects of aqueous extracts of A. conyzoides fresh leaves on FOC4 were obvious, and the inhibition rates were more than 50% at the concentration of 0.5 g/L. The inhibitory effects of A. conyzoides volatiles on FOC4 was not obvious suggesting that the main antifungal compounds of A. conyzoides were not volatiles.Conclusion Aqueous extracts and volatiles from leek have strong inhibitory effects on FOC4, and leek volatiles show higher inhibitory effect. Aqueous extracts of A. conyzoides can inhibit FOC4 growth，but the inhibitory effects of its volatiles were not obvious.

Abstract:Objective To investigate the effects of sand, vermiculite, sawdust, kitchen paper on the eclosion rate of Megalurothrips usitatus.Method Sand, sawdust and vermiculite, all with three moisture levels, and kitchen paper were used as growth substrates for M. usitatus pupation in laboratory experiments. The number of emerged insects were observed and recorded daily.Result The highest eclosion rate (54.33%) was observed for M. usitatus in kitchen paper, followed by 44.67% in sand with 5% water content, and the lowest eclosion rate was recorded in vermiculite treatment. The shortest pupa developmental period (5.29 d) was observed for M. usitatus in sand with 5% water content, followed by 6.01 d in sand with 7% water content. The highest male-female ratio (0.60) was observed for M. usitatus in vermiculite with 30% water content, followed by 0.48 in vermiculite with 25% water content.Conclusion Kitchen paper is the most suitable pupation substrate for M. usitatus under current laboratory conditions.

Abstract:Objective To understand the emission of air pollutants from open burning of rice straw in Guangdong province，and provide certain reference for utilization of rice straw resources and control of air pollutant.Method Based on the statistical data of rice yield, the ratio of straw to grain, combustion ratio and efficiency of rice straw in Guangdong province from 1990 to 2016, we calculated rice straw yield and air pollutant emission from open burning of rice straw using the emission factor method. The temporal and spatial distribution characteristics of air pollutant emission were analyzed using the ArcGIS 10.2 software.Result From 1990 to 2016, the total amount of rice straw resources in Guangdong Province showed a trend of “decline-rise-decline-rise”, which decreased from 16.87 million tons in 1990 to 10.87 million tons in 2016 with an average annual decrease rate of 1.7%. During the period, the amounts of PM，BC，OC，SO₂，NO_x，NH₄，CO and CO₂ emissions decreased by 8 800，200，5 200，1 100，800，2 900，106 500 and 2 585 800 tons，respectively. Their decrease rates were 48.09%, 50.00%, 48.60%, 50.00%, 50.00%, 48.33%, 48.45% and 48.45%，respectively. The spatial distribution of total amount of pollutant emission from open burning of rice straw was unbalanced in different regions of Guangdong province. In 1990, the amounts of PM pollutant emissions were greater than 1 000 t in Maoming, Yangjiang, Zhaoqing, Guangzhou, Huizhou, Heyuan, Shanwei Jieyang and Chaozhou. In 2000, the PM pollutant emissions were above 1 000 t in most cities of Guangdong province. From 2010 to 2016, except for Jieyang, PM pollutant emissions were below 1 000 t.Conclusion From 1990 to 2000, except for some counties in northern Guangdong, the pollutant emission intensity are high in most cities of Guangdong province. The high value areas of pollutant emission before 2010 are mainly concentrated in Zhanjiang, Maoming, Yangjiang, Zhaoqing, Meizhou, Huizhou, Jieyang and Chaozhou. In 2016，the high intensity of pollutant emission was only concentrated in a small number of counties in western and eastern Guangdong.

Abstract:Objective The effects of different landscape layout schemes on microclimate of residential area were numerically simulated to obtain the optimal scheme.Method Taking an old residential area in Guangzhou as the research site, we measured key characteristics of the outdoor microclimate under typical humid and hot weather condition. A numerical simulation model was built using ENVI-met software. The accuracy and quality of the model were validated by comparing the simulation results with the measured values. The microclimate characteristics of three landscape layout schemes were simulated and analyzed.Result Comparing with the current landscape condition, after clearing shrubs from the landscape layout, the mean temperature increased 0.1 ℃ and the mean humidity decreased 0.51%, and ventilation near the ground was moderately improved. After removing trees from the landscape layout, the mean temperature increased 0.4 ℃, the mean humidity increased 1.18%, and the overall wind speed evidently increased. After the roof was simply landscaped with green plants, the mean temperature decreased 0.16 ℃, the mean humidity increased 1.17%, and the wind speed did not obviously change.Conclusion ENVI-met model can be used to well predict the diurnal variation trend of temperature and humidity, to effectively evaluate the influence of landscape planning and improvement in old residential areas.

Abstract:Objective The formation mechanism and diffusion pattern of the spatial distribution of Cratoxylum cochinchinense were studied to promote the protection and management of the natural forest and landscape construction and application in Pearl River Delta areas with poor ecological environment.Method We used quadrat survey method and selected C. cochinchinense stands distributed in three different areas (Chashan area and Baiyun mountain in Guangzhou, and Shihua mountain in Taishan). The maps of population spatial distribution and diffusion dynamics were drawn using digital processing with ArcGIS platform. These maps were used for analyzing seed dispersal mode and dispersal dynamics. The function model of diffusion rate (y)-DBH (x) of the C. cochinchinense population was established for predicting population diffusion rate.Result The C. cochinchinense trees always aggregated at the local downwind and showed a distribution trend in sampled areas. The growth in projection area of canopy always increased first and then decreased, and the functions of diffusion rate-DBH were univariate quadratic equations in different sampled areas. The growth of canopy of single C. cochinchinense tree first increased and then decreased, and the function model of diffusion rate(y₀)-DBH(x₀) for single C. cochinchinense tree was: y₀=-0.013 5x₀²+0.310 6x₀+0.111 3 (R²=0.999, P=0.000).Conclusion 1) C. cochinchinense population spread by wind. 2) The diffusion rate of canopy first increased and then decreased. The growth of canopy area increased to the peak when the diffusion rate reached the maximum, and the growth of canopy area was 0 when the diffusion rate was 0. At this time, diffusion of the population was limited. 3) Under artificial management, the diffusion rate of canopy reached the maximum of 1.90 m²/cm when tree DBH was 11.5 cm and the population belonged to the 6th diameter class. At this time thinning should be appropriately done to ensure the maximum benefits. The population diffusion was limited when tree DBH was 23.4 cm and the population belonged to the 12th diameter class. At this time thinning must be done to promote the growth and update of population.

Abstract:Objective Carbon and nutrient storages in different soil layers were studied in a 10-years-old Michelia macclurei plantation, in order to understand the soil carbon sequestration capacity and nutrient status of the M. macclurei plantation.Method Five-point sampling method was used to collect soil samples from 0-20, 20-40, 40-60, 60-80 and 80-100 cm depth layers. Soil pH, contents of organic matter, total N, total P, total K, alkalized N, available P and rapidly available K were determined by routine methods. Carbon and nutrient storages were calculated.Result Soil under M. macclurei plantation was acidic (pH3.54-3.79). Soil carbon content of M. macclurei plantation decreased with the increase of soil depth. There was no significant difference in total P and K contents among different soil layers, while the contents of total N, alkalized N, available P and rapidly available K decreased with the increase of soil depth. Soil carbon storage of M. macclurei plantation in 0-100 cm depth layer was 259.26 t·hm^-2. The storages of soil N, P and K in 0-100 cm depth layer were 21.50, 7.47 and 209.42 t·hm^-2, respectively. Soil carbon, P and K storages of each layer increased with increasing soil depth.Conclusion Soil carbon storage of M. macclurei plantation is higher than the average level over all the nation, indicating that the soil in this stand has higher carbon sink potential and ability of improving the soil. There are more soil carbon, P and K storages in deeper layer than in soil surface, indicating poor carbon sequestration capacity and severe leaching erosion in surface soil. It is suggested that in the future management, attention should be paid to prevent soil erosion and enhance the carbon sequestration capacity of surface soil.

Abstract:Objective To identify the off-flavor compounds of liquid by-product from processing purple potato granules using freeze-thaw method, and study the enzymatic deodorization effect.Method Changes of volatile components in partially processed samples, liquid by-product and γ-amylase hydrolysate were analyzed using head space solid phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS).Result Significant differences were found in the sensory flavor and volatile components during the process of freeze-thaw separation of purple potato granules. We identified 16(mainly aldehydes and alcohols), 27(mainly aldehydes, alcohols and phenols), 18(mainly aldehydes and terpenes), 33(mainly alcohols and phenols) and 39 (mainly aldehydes, alcohols, ketones and phenols) kinds of volatile compounds from fresh potato chips, steamed potato, thawed and mashed potato, separation liquid and γ-amylase hydrolysate, respectively. The key substance from fresh potato chips was 1-octen-3-ol leading to the earthy smell of separation liquid. The main substances formed in steaming process were cis-3-nonen-1-ol and indole leading to sour smell and irritant odor of separation liquid respectively. γ-Amylase hydrolysis effectively removed the three odorants in separation liquid and increased the contents of aroma components including benzadehyde, aldehyde, decyl aldehyde, lauryl aldehyde, damascene, carvacrol and heterocyclic compounds such as pyrazines, benzothiazole.Conclusion γ-Amylase hydrolysis can effectively remove the off-flavor of liquid by-product from purple potato granules.

Abstract:Objective To design an agricultural variable nozzle based on magnetorheological fluid, and realize variable spraying in agricultural protection area.Method Mechanical structure of the variable nozzle was designed based on the theory of magnetorheological effect. Structural parameters were optimized through software simulation. Nozzle flow rate was measured under different coil voltage and volume of magnetorheological fluid injected in the nozzle cavity. Effect of coil voltage and volume of magnetorheological fluid injected in the nozzle on flow rate were analyzed.Result When the pressure of the diaphragm pump kept at 0.3 MPa constantly, the nozzle flow rate decreased with the volume of magnetorheological fluid in the nozzle cavity increased from 0 to 2.5 mL. The reduction in flow rate was the least (14.29%) at the coil voltage of 24 V, while the reduction in flow rate was the largest (28.57%) at the coil voltage of 0 V. When the volume of magnetorheological fluid maintained at 1.5 mL and coil voltage increased from 0 to 28 V, the nozzle flow rate increased by 25.00%.Conclusion The variable nozzle based on magnetorheological fluid can realize variable flow rate control by controlling the external magnetic field, and therefore the designed variable nozzle can be used in precise variable agricultural spraying.

Abstract:Objective The change of flight speed in constant flow spraying process of traditional plant protection UAVs causes nonuniform pesticide application, and the common control algorithms cannot meet the requirements of the real-time and stability that UAVs variable spray system needs. To solve these problems, we designed a self-adaptive variable spray system of UAV based on neural network PID.Method The flight speed of UAV was measured by wind pressure transmitter. According to the flight speed, we used pulse width modulation (PWM) for self-adaptive variable spray. At the same time, we measured the actual spray flow with the flow sensor and adjusted the spray flow with PID control algorithm based on BP neural network. We used MATLAB to construct PID control algorithm with BP neural network and compared with PID, fuzzy PID and neural PID control algorithms. In the field experiment, we compared and analyzed the effects of constant spray and variable spray based on changing flight speed. We used water-sensitive paper to obtain the distribution of droplet deposition, and then evaluated the uniformity of deposition distribution from the whole area, flight direction, and spray bar direction respectively.Result The simulation result of algorithms indicated that comparing with PID, fuzzy PID and neuron PID, the rise time of step response for BP neural network PID was 28.57%, 84.73% and 31.03% shorter respectively, the average error of sinusoidal tracking was 63.01%, 87.03% and 0.58% lower respectively, the average error of square wave tracking was 74.00%, 79.53% and 6.80% lower respectively. Additionally, the BP neural network PID had strong robustness, 0 static error, and lower overshoot (1.20%). The comparison of the spray tests showed that this system can automatically adjust the spray flow according to flight speed. The average deviation between the actual flow and the set flow was 8.43%. Based on the testing results of the water sensitive paper, variable spray decreased the coefficient of variation of droplet deposition in the whole area by 26.25% and in the spray bar direction by 18.79% on average compared with constant spray.Conclusion The research results can provide a basis for the application of variable spray technology in precision agricultural aviation.

Abstract:Objective To design a pre-cutting type and all-in-one sugarcane planter, so as to open furrows, fertilize, discharge seedlings, cover soil and cover film during a single operation.Method The finite element analysis software ANSYS was used for modal analysis of the sugarcane planter. The soil disturbance indexes of three furrow ploughs were obtained through field experiments. The hydraulic transmission system, seeding mechanism, furrow covering device, fertilization mechanism and film covering mechanism were designed. We used field experiments to measure the qualified rates of planting depth and covering soil thickness, planting density, bud injury rate, missing rate, coefficient of variation in stability of fertilization amount and rate of plastic film damage of the sugarcane planter.Result The simulation results showed that the frame was prone to resonance when the excitation frequency was from 134.47 to 514.35 Hz, and the maximum displacement could reach 19.67 mm. The results of field experiment showed that the soil disturbance index of convex furrow plough was 17.05, and the maximum furrow depth was 19.13 cm, which met the standard of sugarcane planting furrow depth. The qualified rate of planting depth was 83%, the qualified rate of covering soil thickness was 91%, the planting density was 135 331 hm^-2, the bud injury rate was 4.7%, the missing rate was 4.5%, the coefficient of variation in stability of fertilization amount was 6.1%, and the rate of plastic film damage was 51%, which all met the design criteria of sugarcane planter.Conclusion This small pre-cutting type and all-in-one sugarcane planting machine meets the design requirements and can significantly improve sugarcane planting efficiency.

Abstract:Objective To study the temperature change rate and temperature difference during the cooling process of cool storage refrigerator.Method CFD simulation software was used to simulate the unsteady flow field in the refrigerator. A three-dimensional coupling model including the internal and external environment of the cooler was established. Distribution of temperature field in the storage room was analyzed during the cooling process of cool storage refrigerator. The flow distribution diagrams of cross and longitudinal sections in the storage room were obtained. Based on the established model, the effects of different fan speed, return duct area and initial temperature of cold strip on the flow field in the storage room were studied.Result The simulation results showed that the refrigerator could reduce the temperature of the storage room from 16 ℃ to 0 ℃ within eight minutes. The temperature in the area directly opposite to the outlet duct was relatively lower, and the temperature distribution in other areas was more uniform. The simulation results were in good agreement with the experimental results. The average absolute error of temperature change in the storage room was 0.68 ℃, and the average absolute error of temperature distribution was 0.29 ℃. The cooling time could be shortened by increasing the fan speed and increasing the return duct area, or by decreasing the initial temperature of the cold strip. The rate of temperature change in the storage room decreased with the cooling time. The temperature difference in the storage room decreased with the increase of the fan speed and increased with the increase of the return duct area and the decrease of the initial value of the cold strip temperature.Conclusion The research results provide references for optimizing cooling parameters of cool storage refrigerator.

Abstract:Objective To explore the influences of hole size of the nest hole wheel seed-metering and the adaptability of Panax notoginseng seeds on seed-filling performance, determine the relationships between P. notoginseng seeds of different grades and the adaptability shapes of seed-metering devices.Method We divided P. notoginseng seeds into four levels, and designed four different types of nest hole sizes. Using the discrete element software EDEM, we simulated the seed-filling process of graded seeds in seed-metering device with different size of nest hole. The seed filling performances of different grade seeds in seed-metering devices with different sizes were analysed, and the adaptability size of seed-metering device for the graded seeds was obtained. The experimental verification was carried out.Result P. notoginseng seeds of all levels have their suitable nest hole wheels. The 5.0-5.5 and 6.5-70 mm grading sections of seeds have the suitable hole sizes of 7.5 and 8.5 mm respectively, and both of 5.5-6.0 and 6.0-6.5 mm grading sections seeds match the hole size of 8.0 mm. When seeds of all gardes are filled in the adaptive seed-metering devices, the qualified indexes are more than 95.83%, the miss-seeding indexes are lower than 2.00% and the redundant-seeding indexes are 2.17%. The linear relationship between the long axis size of seed (l) and aperture (L), and the relationship between the height axis size of seed (h) and hole depth (H) are all established, which are L=0.58l+4.28 and H=0.75h+3.96, respectively.Conclusion The seed-filling performance fully meets the agronomic requirements of P. notoginseng seeding, which provides a theoretical basis for the design of nest hole size of the nest hole wheel seeding device.