title: [Rapid diagnostics of early phosphorus deficiency in mini-cucumber plants under protected cultivation by near infrared spectroscopy].
abstract: The morphological symptom of phosphorus deficiency at early stage is similar to the appearance of leaf aging process in preliminary phase, so that visual diagnostics of phosphorus deficiency in mini-cucumber plants at early stage is practically impossible. Near infrared reflectance spectra contain information about differences in compositions of leaf tissues between phosphorus-deficient plants and healthy plants. In the present paper, near infrared reflectance spectroscopy was used to provide diagnostic information on phosphorus deficiency of mini-cucumber plants grown under non-soil conditions. Near infrared spectra was collected from 90 leaves of mini-cucumber plants. Raw cucumber spectra was preprocessed by SNV and divided into 27 intervals. The top 10 principal components (PCs) were extracted as the input of BP-ANN classifiers by principal component analysis (PCA) while the values of nutrient deficient were used as the output variables of BP-ANN and three layers BP-ANN discrimination model was built. The best experiment results were based on the top 3 principal components of No. 7 interval when the spectra was divided into 27 intervals and identification rates of the ANN model are 100% in both training set and the prediction set. The overall results show that NIR spectroscopy combined with BP-ANN can be efficiently utilized for rapid and early diagnostics of phosphorus deficiency in mini-cucumber plants.
authors.affiliation: School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, China. stoneboy_2007@vip.sohu.com
authors.forename: Ji-yong
authors.initials: JY
authors.lastname: Shi
authors.forename: Xiao-bo
authors.initials: XB
authors.lastname: Zou
authors.forename: Jie-wen
authors.initials: JW
authors.lastname: Zhao
authors.forename: Han-ping
authors.initials: HP
authors.lastname: Mao
authors.forename: Kai-liang
authors.initials: KL
authors.lastname: Wang
authors.forename: Zheng-wei
authors.initials: ZW
authors.lastname: Chen
authors.forename: Xiao-wei
authors.initials: XW
authors.lastname: Huang
mesh_terms: D018553:Cucumis sativus / Q000737:chemistry*; D008962:Models, Theoretical; D010758:Phosphorus / Q000032:analysis* / Q000172:deficiency; D018515:Plant Leaves; D025341:Principal Component Analysis; D019265:Spectroscopy, Near-Infrared
chemical_list: D010758:Phosphorus