Determination of acetolactate synthase activity and protein content of oilseed rape(Brassica napus L.)leaves using visibleear-infrared spectroscopy

摘要

A new acetolactate synthase(ALS)-inhibiting herbicide,propyl 4-(2-(4,6-dimethoxy-pyrimidin-2-yloxy)benzylamino)benzoate(ZJ0273),was applied to oilseed rape(Brassica napus L.)leaves in different leaf positions.Visibleear-infrared(Vis/NIR)spectroscopy was investigated for fast and non-destructive determination of ALS activity and protein content in rapeseed leaves.Partial least squares(PLS)analysis was the calibration method with comparison of different spectral preprocessing by Savitzky-Golay(SG)smoothing,standard normal variate(SNV),first and second derivative.The best PLS models were obtained by first-derivative spectra for ALS,whereas original spectra for soluble,non-soluble and total protein contents.Simultaneously,certain latent variables(LVs)were used as the inputs of back-propagation neural network(BPNN)and least squares-support vector machine(LS-SVM)models.All LS-SVM models outperformed PLS models and BPNN models.The correlation coefficient(r),root mean square error of prediction(RMSEP)and bias in validation set by LS-SVM were 0.998,0.715 and 0.079 for ALS,0.999,33.084 and 1.178 for soluble protein,0.997,42.773 and 6.244 for non-soluble protein,0.999,59.562 and 7.437 for total protein,respectively.The results indicated that Vis/NIR spectroscopy combined with LS-SVM could be successfully applied for the determination of ALS activity and protein content of rapeseed leaves.The results would be helpful for further on field analysis of using Vis/NIR spectroscopy to monitor the growing status and physiological properties of oilseed rape.