Abstract:Objective To exploit major resistance genes of rice (Oryza sativa L.) to bacterial leaf streak (BLS), and provide a basis for enriching rice disease resistant gene resources and breeding resistant cultivars.Method Constructing a mapping population, we conducted genetic analyses of BLS resistance genes in Oryzae rufipogon Griff ‘DY19’ using the bulk segregant analysis method, and preliminarily mapped the BLS resistance gene bls2 through SSR molecular markers.Result The ratio of resistant and susceptible individual plants in F₂ population was in accordance with the theoretical segregation ratio of 1∶3, which showed that the resistance gene to BLS in O. rufipogon ‘DY19’ was consistent with single gene genetic pattern and controlled by one pair of main recessive gene bls2. This gene was mapped in a 4 cM region between molecular markers SL03 (23 474 851 bp) and SL04 (24 484 154 bp) on the second chromosome. This locus was a new disease resistance locus.Conclusion The BLS resistance in O. rufipogon ‘DY19’ is controlled by one pair of new major recessive gene bls2. It can provide a reference for further fine mapping.

Abstract:Objective To create double recessive sweet-waxy corn inbred lines, identify the effects of double recessive sweet-waxy genes on quality traits, and provide a reference and basis for sweet-waxy corn breeding.Method The double recessive sweet-waxy corn materials with wxwxsh₂sh₂ genotype were screened by molecular marker that linked with waxy corn recessive gene wx in F₂ populations obtained from one elite sweet corn line (M01) and three waxy corn lines (L33, L35 and L38). Then these materials were self-pollinated continuously, and 11 pure double recessive sweet-waxy corn inbred lines with wxwxsh₂sh₂ genotype were obtained in F₄ populations. Their soluble sugar content, total starch content and pericarp thickness were measured and compared with the corresponding sweet corn parent and waxy corn parent.Result The primer phi061, which was tightly linked to wx gene, amplified clear and codominant bands between sweet corn parent and waxy corn parent and was selected as the foreground selection marker of waxy gene. The average content of soluble sugar was 12.27% for double recessive sweet-waxy corn inbred lines, which was 2.55% higher than that sweet corn parent and far higher than that waxy corn parent. The average total starch content was 19.73%, which was 3.77% lower than that sweet corn parent, and far lower than that waxy corn parent. The pericarp thicknesses of crown and abgerminal regions of double recessive maize lines were in the interval of their corresponding parents.Conclusion It is a feasible way to create rapidly the double recessive sweet-waxy corn lines by molecular marker assisted selection. Their average content of soluble sugar is higher than that of sweet corn parent, the average content of starch is lower than that of sweet parent, and the average pericarp thickness is between their parents.

Abstract:Objective To explore the drip nitrogen fertigation strategy that is beneficial for carbon pool management in latosolic red soil.Method Pot experiments imitating the fertigation system were conducted. The effects of three drip irrigation methods and five nitrogen treatments on the contents of organic carbon and active organic carbon, carbon pool management index and enzyme activity in soil were investigated.Result Compared with N0-CDI(The amount of nitrogen applied to soil was 0, combined with conventional drip irrigation), N2-ADI (The amount of drip nitrogen fertigation was 0.18 g·kg^-1, combined with alternate drip irrigation) increased soil organic carbon content by 55.2%, soil active organic carbon content by 111.8% and carbon pool management index by 90.5%. Meanwhile, the organic carbon content, active organic carbon content and carbon pool management index significantly correlated with catalase, urease and invertase activities in soil.Conclusion The drip nitrogen fertigation of 0.18 g·kg^-1 combined with alternate drip irrigation is the optimal drip nitrogen fertigation strategy for carbon storage management in latosolic red soil.

Abstract:Objective To perform comparative analysis of acidification characteristics and aluminum speciation of soil samples collected from mining and non-mining areas in Southern China, and provide a theoretical basis for the remediation of soil acidification in Southern China.Method Soil pH, organic matter content, exchangeable acid content, clay contents and cation exchange capacity (CEC) of 31 soil samples in Southern China were measured, and aluminum forms were examined by sequential extraction method. The correlation analysis and principal component analysis were applied to study the distribution of different aluminum species in soil of mining and non-mining areas.Result The contents of exchangeable hydrogen (Ex-H) (2.75 cmol·kg^-1) in mining soil were significantly higher than those in non-mining soil (0.97 cmol·kg^-1). The mining soil had significantly lower pH (H₂O) (3.44), CEC (6.34 cmol·kg^-1), clay content (13.05%), weakly organically bound aluminum (Al_Orw) (3.44 mmol·kg^-1) and organically bound aluminum (Al_Or) (12.96 mmol·kg^-1) contents than those in non-mining soil (4.39, 12.70 cmol·kg^-1, 28.64%, 8.32 and 41.46 mmol·kg^-1), respectively. For both mining and non-mining soil, the correlation analysis showed that exchangeable aluminum (Al_Ex) content had significantly negative correlation with pH (H₂O) (r=-0.577** and -0.671**), and Al_Ex content had significantly positive correlation with exchangeable acid quantum (Ex-Q) (r=0.927** and 0.662**), Ex-H (r=0.976** and 0.555*) and exchangeable aluminum (Ex-Al) contents (r=0.870** and 0.632**), respectively. The principal component analysis (PCA) showed that there were significant differences in soil acidification characteristics between mining and non-mining areas, and there were significant differences in the comprehensive characteristics of soil with different pH levels (pH < 3.50, 3.50≤pH < 4.50, 4.50≤pH < 5.50 and pH≥5.50).Conclusion Compared with non-mining soils, mining soils have stronger acidity and lower content of organically bound aluminum. Non-mining soils have higher pH (H₂O), CEC and clay contents. The acidification characteristics of mining and non-mining soil are significantly different, and the acidification characteristics of soil with different pH gradients are also significantly different. Therefore, it is particularly necessary to improve soil pH and organic matter content in the remediation process of acidified soil of mining area.

Abstract:Objective To obtain the complete mRNA sequence and structure of porcine LPAR3 gene, study the gene promoter activity, and explore the transcriptional regulation of LPAR3 gene in endometrium and the mechanisms which may affect sow farrowing.Method The 5'RACE and 3'RACE techniques were used to obtain the complete LPAR3 mRNA sequence. The potential promoter transcription factor binding sites and CpG islands in the 5' regulatory region were predicted. Recombinant vectors with different length of promoters and dual-luciferase reporter gene were constructed, then were transfected with pRL-TK plasmid into pig endometrial cells, and the promoter activities were detected. RT-qPCR was used to compare the relative expression of LPAR3 gene in Erhualian(ER) and Landrace×Large White (LL) pigs on the 12th day of gestation. Sodium bisulfite modified sequencing was used to compare the methylation status of LPAR3 gene in endometrial tissues of ER and LL pigs on the 12th day of gestation.Result The full length of pig LPAR3 mRNA was 2 127 bp, the 5'UTR and 3'UTR were 202 and 860 bp respectively, and the CDS region was 1 065 bp. The 5' regulatory sequence, including 3 080 bp (-2 430/+650 bp) upstream of the LPAR3 gene, was cloned. The online prediction results of the 5' regulatory region showed that there was no TATA box in the LPAR3 promoter, but there were GC element and binding sites for CPBP and other regulatory factors. Two potential CpG islands were found at -190/-84 and -44/+651 bp. Nine recombinant vectors with 5' deletions of the promoter were constructed and transfected into pig endometrium cells. The dual-luciferase assay showed that the activity of promoter P4 (+454/+80 bp) was the highest, followed by P6 (-123/+80 bp). RT-qPCR results showed that the expression of LPAR3 gene in the endometrium of ER pigs on the 12th day of gestation was higher than that in other tissues, and it was extremely significantly higher than that in the endometrium of LL pigs on the 12th day of gestation. The methylation status of LPAR3 gene was low in the endometrium of two breeds and had no significant difference between two breeds.Conclusion The full length of pig LPAR3 mRNA is 2 127 bp. The endometrial expression level of LAPR3 gene in ER pigs is higher than that in LL pigs on the 12th day of gestation, indicating that LPAR3 gene may be involved in early gestation of pigs and affects litter size.

Abstract:Objective To explore the etiology of a serious infectious disease occured in Rana nigromaculata tadpoles in a farm of Sichuan Province.Method Pathological examination and virus isolation were carried out for the diseased tadpoles of R. nigromaculata. The isolated pathogen was identified by artificial infection test, transmission electron microscopy, PCR detection and phylogenetic analysis.Result External clinical signs included hemorrhage on body surface and swollen abdomen with yellow ascites. Based on histopathological observation, we found that liver, spleen, kidney, pancreas and other organs had damages with obvious degeneration and necrosis focus, and basophilic inclusions appeared in the cytoplasm of some pathological cells. The tissue homogenates of diseased tadpoles were inoculated into epithelioma papulosum cyprini (EPC) cells under 25 ℃ and caused typical cytopathic effect (CPE) after four days with the TCID₅₀ of 10⁸ mL^-1. In the artificial infection test of virus fluid, the tadpoles showed the symptoms similar to those observed in naturally infective tadpoles and the mortality reached 80%, which suggested that the isolated virus was the determined pathogen of this disease. Transmission electron microscopic observation showed that the virus was regular hexagon with capsule, the diagonal diameter was (135±8) nm, and virus particles arrayed in crystalline or freely in the cytoplasm. PCR examination of the MCP gene showed positive results for samples of diseased tadpoles, aquaculture water source and isolated virus. Phylogenetic analysis based on MCP gene sequences indicated that the sequence of isolated virus had above 99% similarity to ranavirus, and the isolated virus belonged to the FV3-like virus group.Conclusion This study confirmed that ranavirus was the causative agent of this outbreak, and the virus is named as Rana nigromaculata ranavirus (RNRV).

Abstract:Objective To study the control effect of clothianidin on citrus psyllid(Diaphorina citri) under drip irrigation, and provide a new way for controlling Huanglongbing (HLB) spread.Method An indoor simulation drip irrigation experiment was conducted for clothianidin. The distribution of clothianidin in soil and the content in citrus leaves were tested, and the clothianidin efficacy was studied under laboratory condition. The content of clothianidin in citrus leaves was detected and analyzed in field experiment. Result The control effect of single drip irrigation could be as long as four months in greenhouse. The migration distribution of clothianidin was a semicircle with a drop head as a starting point in soil, and the control effects of D. citri were more than 80% when clothianidin contents of citrus leaves were greater than 0.64 mg·kg^-1. Under field condition, the contents of clothianidin in upper leaves were also greater than 0.64 mg·kg^-1 from 7 to 63 days after applying clothianidin.Conclusion Clothianidin application through a drip irrigation system exhibits excellent efficacy against citrus psyllid, which provides an effective measure for prevention and control of HLB.

Abstract:Objective To study phototactic behavior of Diaphorina citri Kuwayama (Asian citrus psyllid)in different light waves, research the microstructure of adult compound eye and its changes under light- and dark-adaptation, and lay a foundation for developing non-chemical prevention and control technology of D. citri.Method Phototactic test instrument was used to test phototactic rate of D. citri adult towards lights with different wavelengths. The scanning electron microscopy and histological sections were used to observe the structures of compound eyes of D. citri adults.Result The phototactic rates of D. citri adults towards different lights were different. The phototactic rate was the biggest for ultraviolet (365-370 nm), which was 66.62%-71.38%, and followed by blue light (470-475 nm, 47.17%-50.88%), green light (520-525 nm, 39.37%-44.26%), yellow light (590-592 nm, 28.18%-31.32%) and red light (620-630 nm, 14.68%-18.33%). The adult compound eyes were located on the antenna bases at both sides of the head, which were in the shape of a half circle, had a smooth surface without the auxiliary structure, and belonged to the typical parallel eyes. The ommatidium was composed of cornea, crystalline cone, retinula cells, basement membrane and pigment cell. The ommatidium was typical hexagonal in the central region of compound eyes and nearly circular near the periphery of compound eyes. Female and male adults of D. citri consisted of 225-254 and 238-252 ommatidias per compound eye, respectively.Conclusion D. citri adults are more tending to ultraviolet, blue light and green light than white light. There is no difference in the structure and morphology of compound eyes between female and male adults of D. citri. This research provides a reference for studying the phototactic mechanism.

Abstract:Objective To alleviate reductions in yield and quality caused by continuous cropping of patchouli (Pogostemon cablin), and explore the application potential of effective microorganisms (EM) in continuous cropping of patchouli.Method We designed five treatment groups (EM were counted by volume faction): Garden soil (control soil), continuous cropping soil, continuous cropping soil + 0.1% EM, continuous cropping soil + 0.8% EM, and continuous cropping soil + 1.6% EM. Pot experiments were conducted to investigate the effects of EM addition on growth characteristics and soil microecology of patchouli cuttings.Result Compared with the treatment of only continuous cropping soil, the root length, plant height, fresh weight, root activity and chlorophyll content of treatment groups with EM addition were significantly higher, the numbers of soil bacteria and actinomycetes increased, the number of fungi decreased, and soil urease, sucrase and polyphenol oxidase activities increased significantly. The 0.8% EM treatment had the most significant effect on the growth characteristics and soil microecology of patchouli cutting seedlings, and plant height, fresh weight, root length, root activity and total chlorophyll content increased by 70.34%, 195.32%, 101.52%, 156.84% and 195.33% respectively. In the 0.8% EM treatment, the numbers of soil bacteria and actinomycetes peaked on the 40th day of cultivation, and soil urease, sucrase and polyphenol oxidase activities also peaked on the 40th day of cultivation, which were 81.46%, 54.26% and 137.90% higher than those in the treatment of only continuous cropping soil.Conclusion EM can effectively alleviate the problem of continuous cropping obstacles of patchouli, and can be used as a good additive in the continuous cropping of patchouli.

Abstract:Objective To calculate quickly and precisely forest carbon sequestration in afforestation projects, we selected major broad-leaved tree species in Guangdong, including Cinnamomum camphora, Schima superba and Liquidambar formosana，and established biomass growth model of individual tree. Method All 270 sample trees with 90 sample trees for each tree species were obtained according to 10 diameter classes during the process of modeling. We established four types of biomass growth models for aboveground and underground biomass of three tree species from different origins (natural forest or planted forest) using age as the independent variable. The compatibility issue among growth models of different aboveground components (stem wood, bark, branch, leaf) was solved using optimized models with a set of simultaneous equations and controlled total biomass.Result Comparing trees from different origins including natural forest and planted forest, the biomass upper limits and ages of the maximum growth rate for the same species under the same biomass model were different. The biomass upper limits and ages of the maximum growth rate indicated by different equations for the same tree species under the same origin were largely different. When estimating the aboveground biomass, the optimal types of equations for different tree species were different. Logistic model was used to establish the compatibility model for the simultaneous equations of biomass for aboveground components of three tree species. The R_adj² values from stem wood biomass equations of three species ranged from 0.560 to 0.768, and MPEs ranged from 3.05% to 6.73%. The R_adj² values from bark biomass equations ranged from 0.552 to 0.866, and the MPEs ranged from 2.02% to 6.27%. The R_adj² values from branch biomass equations ranged from 0.309 to 0.706, and the MPEs ranged from 3.01% to 14.33%. The R_adj² values from leaf biomass equations ranged from 0.495 to 0.767, and the MPEs ranged from 4.16% to 7.14%.Conclusion Comparing the parameters and evaluation indexes of four models, the optimal model of aboveground biomass is the Logistic model and the optimal model of underground biomass is the Schumacher model. The proportion of each aboveground component in total aboveground biomass constantly changes with age during the growth process. The compatibility model for the simultaneous equations of biomass for aboveground components of three tree species is established using Logistic model, and the fitting effects of biomass models for stem wood and bark biomass are better than those for branch and leaf. These biomass models could estimate forest carbon combined with carbon coefficient in planted forest for known age in a certain period.

Abstract:Object To evaluate the quality of one-year-old container seedlings of Dalbergia cochinchinensis, and provide a technical basis for its seedling cultivation and plantation development.Method Seedling grading indexes were determined by principal components analysis. We used the mean ±standard deviation and progressive clustering methods to analyze the proportions of seedlings in different grades, grading standards and differences among grades in afforestation effects at early stage of seedlings in Yangjiang, Gaoming of Guangdong and Zhangzhou of Fujian. The suitable grading method and standards were determined.Result The principal component contribution rates of seedling height (H) and ground diameter (D) were 59.85% and 26.02%, respectively. H and D could be used as the grading indexes for one-year-old D. cochinchinensis seedlings, and these traits were significantly different among different graded seedlings. The cumulative variance contribution rate of seedling height and ground diameter was 85.87%. There were no obvious differences in the proportions of seedlings in each grade and grading ranges between two grading methods. Qualified D. cochinchinensis seedlings (Grade Ⅰ and Ⅱ) determined by the mean ±standard deviation method performed well in the early growth period and had higher survival rates (> 90%) at all test sites. Seedling traits and survival rates after planting of 3 and 12 months had highly significant positive correlations with H and D at planting time.Conclusion The mean ±standard deviation method is more feasible for grading of one-year-old D. cochinchinensis seedlings by comprehensively evaluating the proportions of seedlings in different grades, ranges of grading indexes, early afforestation effect and practical seedling cultivation. The grading standards are as follows: Grade Ⅰof H ≥ 119.76 cm and D ≥ 7.66 mm; grade Ⅱ of 69.62 cm ≤ H < 119.76 cm and 5.04 mm ≤ D < 7.66 mm; grade Ⅲ of H < 69.62 cm and D < 5.04 mm.

Abstract:Objective To explore the distribution characteristics and accumulation rules of polycyclic aromatic hydrocarbons (PAHs) in cucurbitacae vegetables，and evaluate the health risks of each cucurbitacae vegetable to people in different age groups and genders in Nanning.Method The samples of Cucumis sativus, Momordica charantia, Luffa cylindrical and Benincasa hispida var. chieh-qua were collected. For each type of vegetable, we collected roots of 30 plants, 1 kg stems, 1 kg leaves, 1 kg petioles and 20 fruits. The vegetables were pretreated by ultrasonic extraction and solid phase extraction. The contents of 16 different PAHs in different parts of vegetables were detected by high performance liquid chromatography (HPLC).Result Sixteen types of PAHs were all detected in four kinds of cucurbitacae vegetables, the contents of total PAHs ranged from 88.44 to 1 229.85 μg.kg^-1. The order of detected PAHs amounts in cucurbitacae vegetables was 5-ring PAHs > 6-ring PAHs > 2-ring PAHs > 4-ring PAHs > 3-ring PAHs. The cancer risk levels of diverse population groups in Nanning by ingesting fruit from cucurbitacae vegetables were in the range of 1.48×10^-6 and 7.87×10^-5. The cancer risk levels caused by ingesting only edible portions were in the range of 2.23×10^-7 and 3.35×10^-6.Conclusion Comparing different organs of the same cucurbitacae vegetables, leaves had the highest PAH contents for all four vegetables, C. sativus pulp had the lowest PAHs content, M. charantia and L. cylindrical flesh had the lowest PAHs contents, B. hispida var. chieh-qua petious had the lowest PAHs content. Comparing leaves of different cucurbitacae vegetables, PAHs content was the highest in B. hispida var. chieh-qua while the lowest in M. charantia. Under the current consumption amount of vegetables, potential carcinogenic risks exist for Nanning residents by ingesting fruits of cucurbitacae vegetables.

Abstract:Objective To optimize the medium composition and fermentation conditions of Penicillium citrinum PA-33 to improve its antibacterial activity. Method Single factor experiments were used to determine the optimum basic medium, carbon sources, nitrogen sources and inorganic salts. The optimum formulation of fermentation medium was determined by response surface methodology. On the basis of single factor tests of fermentation conditions, the optimal combination of fermentation conditions was optimized by ternary quadratic rotation unitized design and frequency analysis method. Result The optimal medium composition were: Potato juice 219.91 g·L^-1, mannitol 34.11 g·L^-1 and soybean powder 6.25 g·L^-1. The optimal fermentation conditions were: Liquid volume 50 mL, inoculation concentration 3.5% (φ), culture temperature 28 ℃, rotation speed 150 r·min^-1 and fermentation for 12 d. The inhibition zone diameter of fermentation broth after optimization on Escherichia coli reached 28.99 mm, increased by 10.26 mm compared with 18.73 mm under the original conditions. Conclusion Response surface methodology, ternary quadratic rotation unitized design and frequency analysis method significantly enhance the antibacterial activity of fermentation broth of Penicillium citrinum PA-33, and this study provides a basis for isolation of antibacterial active substances and industrial production of this strain.

Abstract:Objective To provide a basis for immobilization of industrial enzymes such as lipase using macroporous resin for adsorption and epoxy crosslinker for crosslinking.Method The immobilization of lipase was performed through adsorption using macroporous resin as the carrier and epoxy crosslinker as the crosslinking agent. We investigated the effects of different factors on adsorption-crosslinking immobilization, and used response surface design to optimize the immobilization conditions. The immobilized enzyme was prepared and its stability was investigated.Result Macroporous resin HPD750 was selected as the carrier, and poly (ethylene glycol) diglycidyl ether was selected as the crosslinker. The optimal conditions of lipase immobilization were as follows: Adsorption temperature 45 ℃, enzyme addition amount 60 mg·g^-1, crosslinking temperature 30 ℃, crosslinking time 12.5 h, pH6.36, and comcentration of crosslinking agent 0.7%. Under these optimized conditions, the immobilized lipase activity was 565.31 U·g^-1 and the recycled rate of lipase activity was 32.16%. Compared with free lipase, the immobilized lipase exhibited obviously better thermal stability and pH stability. The immobilized lipase was of good operation stability and remained 34.86% of the original activity after repeated usage for 10 times. The immobilized lipase also exhibited good storage stability and remained 64.81% of the original activity after storage at 4 ℃ for 30 days.Conclusion Using macroporous resin HPD750 as the carrier and poly (ethylene glycol) diglycidyl ether as the crosslinker, the immobilized enzyme has significantly improved thermal stability and pH stability, and it also exhibits good operation stability and storage stability.

Abstract:Objective The development trend of agricultural small UAV (ASUAV) is having a capability with autonomous flight, working route planning and optimization, precise control and variable operation. This study provides the optimized selection of flight heading, take-off and landing location, turning mode and flight point coordinate solution for ASUAV before autonomous flight operation under the condition of whole-area coverage.Method Turning mode strategy of ASUAV was studied based on autonomous flight at constant speed under constraint of the minimum turning radius. The path planning method under arbitrary convex polygons was analyzed and designed. An integerized route planning scheme was proposed based on the slight change of working width. Path planning and optimal selection under the condition of whole region-coverage were achieved in the structured farmland area.Result The whole-area coverage path planning method based on the optimal turning mode of ASUAV was applicable to the farmland with arbitrary convex polygon structure. GUI program could optimize flight route with the highest efficiency while calculating flight point coordinates of ground boundary. An irregular convex hexagonal field with an area of about 2.7 hm² was randomly planned in the field. The simulation results showed that when ASUAV was flying parallel to the longest side of the field, the invalid distance was the shortest with about 540 m, and the efficiency was the highest which was close to 90%.Conclusion The optimized turning mode, take-off and landing location, flight heading and route inflection point coordinates can realize the full area coverage. This result can provide a reference for ASUAV autonomous flight operation.

Abstract:Objective In order to solve the problem of the missed sowing and the uniform adjustment for sowing amount by the driven wheel existing in traditional mechanical rice direct seeder, and realize automatic and precise adjustment to the sowing amount of rice direct seeder.Method A traditional mechanical rice direct seeder, commonly used in the Southern Jiangsu area, was modified by incorporating an automatic seeding control system based on the PID speed control algorithm. During sowing, the working speed of implement was obtained by the designed speedometer. The theoretical rotational speed of sorting shaft was obtained according to sowing control strategy combining the set target sowing amount with the operational speed. The measured feedback speed of seeding axis closed the control loop of the DC motor using a PID speed regulation algorithm and an encoder, which could be adjusted on-line to achieve accurate seeding.Result The speed adjustment time of seeding motor without load was less than 0.63 s and the maximum overshoot was 8.21%. The longest time for the motors to be recharged was 0.32 s when a load of 12.5 N·m was applied to the device. For the target sowing amount, the maximum value of speed control error was less than 7.21%, speed error was less than 5.21%, and sowing amount error in field was less than 4.92%. When field speed of vehicle varied in step, the seeding speed responded in time and the vehicle had a higher seeding synchronization. The seeding adjustment performance was significantly improved using the automatic release meter compared with the conventional direct seeder.Conclusion The automation transformation of this system is easy, which focuses on improving the adjustment mechanism of sowing amount, improves the sowing performance of traditional seeder, and has a high adaptability to traditional rice direct seeder machine.

Abstract:Objective To monitor the health status of fruit trees and predict the yield of sweet pomelo (Citrus maxima), a detection model of chlorophyll content in C. maxima leaves was established in a C. maxima orchard of Nankang, Ganzhou.Method The leaf spectrum and SPAD value of C. maxima were measured using Field Spec4 portable earth spectrometer and SPAD-502 chlorophyll meter. The hyperspectral nondestructive detection model of chlorophyll content was constructed by single variable regression, stepwise regression and partial least squares (PLS) method, and the accuracy was examined.Result The reflectances of original spectrum at 553 nm and the first order spectra at 692 and 752 nm had the highest correlation with chlorophyll content. These three bands were sensitive bands of spectral reflectance of C. maxima leaves. When the number of principal components was four, PLS had the highest level of precision. PLS model had higher accuracy, fitting degree and determination coefficient (r²=0.869) compared with the single variable and stepwise regression models, and PLS model had the lowest root mean square error (RMSE) being 3.013 and the lowest relative error (RE) being 6.82%. Comparing and analyzing the estimation models of original spectrum, first derivative spectrum and PLS fitting, PLS model was superior to the two traditional models in terms of sample precision and prediction ability.Conclusion PLS model is suitable for the estimation of chlorophyll content by hyperspectral data，and the best nondestructive detection model for the chlorophyll content of C. maxima.