A-Li Chai

Chinese Academy of Agricultural Sciences, Beijing, Beijing Shi, China

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Publications (5)1.47 Total impact

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    ABSTRACT: Fourier transform infrared spectroscopy (FTIR) technique was applied in the early rapid detection of Plasmodiophora brassicae in root of Chinese cabbage while the symptom had not appeared. The Chinese cabbage root was inoculated with Plasmodiophora brassicae. Chinese cabbage root infected with Plasnmodiophora brassicae and uninfected root samples showed their difference in FTIR spectra. The absorption peaks at 1 227, 1 143 and 1 105 cm-1 were only found in the infected root samples, and combined with the variation in the peak area at these absorption peaks they could be used for early rapid detection for clubroot of Chinese cabbage. In addition, the polymerase chain reaction was used to verify the veracity of Fourier transform infrared spectroscopy (FTIR) technique. The results show that the detection results are consistent with each other, and they could detect the Plasmodiophora brassicae 5 days after inoculation. Results clearly demonstrated that the PTIR technology is a highly sensitive, convenient and quick one for the early rapid detection of clubroot of Chinese cabbage, and provides a new thought and method for the early detection of plant disease.
    Guang pu xue yu guang pu fen xi = Guang pu 06/2013; 33(6). · 0.29 Impact Factor
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    ABSTRACT: Fourier transform infrared (FTIR) attenuated total reflectance (ATR) spectroscopy was used in combination with multivariate statistic analysis for identification of soil-borne fungi that causes severe economic damage to agriculture: Fusarium monili forme, Fusarium semitectum, Fusarium oxysporum, Fusarium solani, Rhizoctonia solani, Sclerotinia sclerotiorum, Pythium aphanidermatum and Phytophthora capsici. The original FTIR spectra were normalized, and the second derivatives were calculated, from which the peak wave numbers showing greatest variability were selected: 2924, 2854, 1745, 1641, 1547, 1466, 1406, 1376, 1306, 1240, 1201, 1152, 1109 and 1028 cm(-1). To discriminate different fungal strains, canonical discriminant analysis and cluster analysis were performed at these characteristic wave numbers. Results showed that the classification accuracies achieved 100% for different species of fungi, and classification accuracies for different fusarium strains achieved 95.56%, demonstrating the high potential of this technique for fungi identification.
    Guang pu xue yu guang pu fen xi = Guang pu 08/2011; 31(8):2094-7. · 0.29 Impact Factor
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    ABSTRACT: Fourier transform infrared spectroscopy (FTIR) technique was applied in the early detection of corynespora spot on cucumber leaves while the symptom had not appeared. The cucumber leaves were inoculated with Corynespora cassiicola. By observing the changes in the FTIR spectra of infected cucumber leaves at various times of post-infection, three sensitive bands, 1 735, 1 545 and 1 240 cm(-1) were selected for the identification of cucumber corynespora leaf spot. According to the peak areas at these sensitive bands, cucumber leaf samples infected with C. cassiicola and control uninfected leaf samples could be classified correctly. Results clearly demonstrated that the FTIR technology is an available one for the early detection of corynespora spot on cucumber leaves while the symptom has not appeared and it provides a new method for the early detection of corynespora spot.
    Guang pu xue yu guang pu fen xi = Guang pu 06/2011; 31(6):1506-9. · 0.29 Impact Factor
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    ABSTRACT: Fourier transform attenuated total reflection infrared spectroscopy (FTIR-ATR) has been a novel technical procedure to identify and classify microorganisms in recent years. In the present study, Fourier transform infrared spectroscopy(FTIR) in combination with an attenuated total reflection (ATR) unit were used to discriminate important plant-destroying fungi. Mycelia of 17 fungal strains belonging to 14 different species were grown on potato dextrose agar (PDA) plants and subjected to FTIR-ATR measurements. High-resolution and well-reproducibility infrared spectra were obtained, and significant spectral differences among these strains were observed in the wavenumber regions of 1800-1485 cm(-1), 1485-1185 cm(-1), and 1185-900 cm(-1). According to the characteristic bands in these regions, cluster analysis was executed to classify the FTIR spectra. The result showed that different fungal strains could be identified correctly, demonstrating the high potential of FTIR-ATR as a tool for fungal strain identification and classification. The method is rapid, inexpensive and reproducible, and requires minimum sample preparation.
    Guang pu xue yu guang pu fen xi = Guang pu 11/2010; 30(11):2941-4. · 0.29 Impact Factor
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    ABSTRACT: Hyperspectral imaging (400-720 nm) and discriminate analysis were investigated for the detection of normal and diseased cucumber leaf samples with powdery mildew (Sphaerotheca fuliginea), angular leaf spot (Pseudomopnas syringae), downy mildew (Pseudoperonospora cubensis), and brown spot (Corynespora cassiicola). A hyperspectral imaging system was es tablished to acquire and pre-process leaf images, as well as to extract leaf spectral properties. Owing to the complexity of the original spectral data, stepwise discriminate and canonical discriminate were executed to reduce the numerous spectral information, in order to decrease the amount of calculation and improve the accuracy. By the stepwise discriminate we selected 12 optimal wavelengths from the original 55 wavelengths, and after the canonical discriminate, the 55 wavelengths were reduced to 2 canonical variables. Then the discriminate models were developed to classify the leaf samples. The result shows that the stepwise discriminate model achieved classification accuracies of 100% and 94% for the training and testing sets, respectively. For the canonical model, the classification accuracies for the training and testing sets were both 100%. These results indicated that it is feasible to identify and classify cucumber diseases using hyperspectral imaging technology and discriminate analysis. The preliminary study, which was done in a closed room with restrictions to avoid interference of the field environment, showed that there is a potential to establish an online field application in cucumber disease detection based on visible spectroscopy.
    Guang pu xue yu guang pu fen xi = Guang pu 05/2010; 30(5):1357-61. · 0.29 Impact Factor

Publication Stats

1.47 Total Impact Points

Institutions

  • 2010–2011
    • Chinese Academy of Agricultural Sciences
      • Institute of Vegetables and Flowers
      Beijing, Beijing Shi, China