Leaf pigments are critical indicators of plant photosynthesis,stress,and physiological conditions.Inversion of radiative transfer models(RTMs)is a promising method for robustly retrieving leaf biochem-ical traits from...Leaf pigments are critical indicators of plant photosynthesis,stress,and physiological conditions.Inversion of radiative transfer models(RTMs)is a promising method for robustly retrieving leaf biochem-ical traits from canopy observations,and adding prior information has been effective in alleviating the“ill-posed”problem,a major challenge in model inversion.Canopy structure parameters,such as leaf area index(LAI)and average leaf inclination angle(ALA),can serve as prior information for leaf pigment retrie-val.Using canopy spectra simulated from the PROSAIL model,we estimated the effects of uncertainty in LAI and ALA used as prior information for lookup table-based inversions of leaf chlorophyll(C _(ab))and car-otenoid(C_(ar)).The retrieval accuracies of the two pigments were increased by use of the priors of LAI(RMSE of C_(ab) from 7.67 to 6.32μg cm^(-2),C_(ar) from 2.41 to 2.28μg cm^(-2))and ALA(RMSE of C_(ab) from 7.67 to 5.72μg cm^(-2),C_(ar) from 2.41 to 2.23μg cm^(-2)).However,this improvement deteriorated with an increase of additive and multiplicative uncertainties,and when 40% and 20% noise was added to LAI and ALA respectively,these priors ceased to increase retrieval accuracy.Validation using an experimental winter wheat dataset also showed that compared with C_(ar),the estimation accuracy of C_(ab) increased more or deteriorated less with uncertainty in prior canopy structure.This study demonstrates possible limita-tions of using prior information in RTM inversions for retrieval of leaf biochemistry,when large uncer-tainties are present.展开更多
[Objectives] To determine the optimum conditions and antioxidant activity of Myrica ruba leaf pigment,and provide reference for further development and use of Myrica ruba leaves. [Methods]Pigment of Myrica ruba leaves...[Objectives] To determine the optimum conditions and antioxidant activity of Myrica ruba leaf pigment,and provide reference for further development and use of Myrica ruba leaves. [Methods]Pigment of Myrica ruba leaves was extracted by ethanol extraction method. Absorbance was measured at wavelength of 300 nm. Effects of ethanol volume fraction,solid-to-liquid ratio,temperature,and extraction time were studied. L_9( 3~3) orthogonal experiment was carried out to optimize the extraction process,and DPPH scavenging ability was measured.[Results]The optimum extraction process of Myrica ruba leaf pigment was as follows: the ethanol volume fraction was 50%; the solid-to-liquid ratio was 1: 60( w/v),extraction temperature 70℃; extraction time was 60 min; after the concentration of purified Myrica ruba leaf pigment reached 0. 4455 mg/mL,the DPPH scavenging ability was basically the same as the same concentration Vc.[Conclusions] The experiment indicates that the optimized extraction process has a high yield rate,and Myrica ruba leaf pigment has high anti-oxidant activity.展开更多
The changes in the activity of amylase and amylase-isoenzyme and the degradation of starch and pigment of tobacco leaf during flue-curing were studied by using the electric- heated flue-curing barn designed and made...The changes in the activity of amylase and amylase-isoenzyme and the degradation of starch and pigment of tobacco leaf during flue-curing were studied by using the electric- heated flue-curing barn designed and made by the Henan Agricultural University. The temperature and humidity of the barn were controlled automatically. The results indicated that starch in tobacco leaf decreased rapidly and leveled off after 48 h of curring, in the meantime, the content of soluble sugar increased accordingly and reached a peak at the stage of color-fixing. Both of them had a rapid-changing stage in the first 36 hours of yellowing. The changes of starch and soluble sugar contents had highly significant negative-correlation at 1 % level (rNC89 = -0.8962**, rYY85 = -0.9704**). The activity of amylase increased with the proceeding of curing and reached a peak after 36 hours of curing, then decreased. But the activity of amylase kept at a high level when the humidity of curing-environment was very low, even if the tobacco leaf had been dried. The rapid degradation of starch showed a significantly negative correlation with the increase of activity of amylase at 5 % level (rNC89 = -0.8495*, rYY85 = -0.7839*). The degradation of starch and pigment had the same regulation and had highly significant correlation at 1 % level (rNC89= 0.9649**, rYY85= 0.9428**). There were mainly three amylase-isoenzyme bands -A, B, C respectively, in tobacco leaf during flue curing. They were identified as α-AMY, β-AMY, R-AMY, and the activity of β-AMY was the highest. The changes in amylase activity and contents of starch and pigment were affected by the tobacco leaf moisture and environmental humidity during curing.展开更多
基金supported by the National Natural Science Foundation of China (41975044)the Open Research Fund of the State Laboratory of Information Engineering in Surveying,Mapping,Remote Sensing,Wuhan University (20R02)+2 种基金the Fundamental Research Funds for the Central Universities,China University of Geosciences (Wuhan)(111-G1323520290)funded by SNSA (Dnr 96/16)the EU-Aid funded CASSECS Project。
文摘Leaf pigments are critical indicators of plant photosynthesis,stress,and physiological conditions.Inversion of radiative transfer models(RTMs)is a promising method for robustly retrieving leaf biochem-ical traits from canopy observations,and adding prior information has been effective in alleviating the“ill-posed”problem,a major challenge in model inversion.Canopy structure parameters,such as leaf area index(LAI)and average leaf inclination angle(ALA),can serve as prior information for leaf pigment retrie-val.Using canopy spectra simulated from the PROSAIL model,we estimated the effects of uncertainty in LAI and ALA used as prior information for lookup table-based inversions of leaf chlorophyll(C _(ab))and car-otenoid(C_(ar)).The retrieval accuracies of the two pigments were increased by use of the priors of LAI(RMSE of C_(ab) from 7.67 to 6.32μg cm^(-2),C_(ar) from 2.41 to 2.28μg cm^(-2))and ALA(RMSE of C_(ab) from 7.67 to 5.72μg cm^(-2),C_(ar) from 2.41 to 2.23μg cm^(-2)).However,this improvement deteriorated with an increase of additive and multiplicative uncertainties,and when 40% and 20% noise was added to LAI and ALA respectively,these priors ceased to increase retrieval accuracy.Validation using an experimental winter wheat dataset also showed that compared with C_(ar),the estimation accuracy of C_(ab) increased more or deteriorated less with uncertainty in prior canopy structure.This study demonstrates possible limita-tions of using prior information in RTM inversions for retrieval of leaf biochemistry,when large uncer-tainties are present.
基金Supported by Student’s Platform for Innovation and Entrepreneurship Training Program of Guangxi Zhuang Autonomous Region,China in 2016(201610599033)Innovation and Entrepreneurship Ethnical Medicine Teaching Team Program of Guangxi Zhuang Autonomous Region,China(Gui Jiao Gao Jiao[2015]93&Gui Jiao Gao Jiao[2016]6)
文摘[Objectives] To determine the optimum conditions and antioxidant activity of Myrica ruba leaf pigment,and provide reference for further development and use of Myrica ruba leaves. [Methods]Pigment of Myrica ruba leaves was extracted by ethanol extraction method. Absorbance was measured at wavelength of 300 nm. Effects of ethanol volume fraction,solid-to-liquid ratio,temperature,and extraction time were studied. L_9( 3~3) orthogonal experiment was carried out to optimize the extraction process,and DPPH scavenging ability was measured.[Results]The optimum extraction process of Myrica ruba leaf pigment was as follows: the ethanol volume fraction was 50%; the solid-to-liquid ratio was 1: 60( w/v),extraction temperature 70℃; extraction time was 60 min; after the concentration of purified Myrica ruba leaf pigment reached 0. 4455 mg/mL,the DPPH scavenging ability was basically the same as the same concentration Vc.[Conclusions] The experiment indicates that the optimized extraction process has a high yield rate,and Myrica ruba leaf pigment has high anti-oxidant activity.
文摘The changes in the activity of amylase and amylase-isoenzyme and the degradation of starch and pigment of tobacco leaf during flue-curing were studied by using the electric- heated flue-curing barn designed and made by the Henan Agricultural University. The temperature and humidity of the barn were controlled automatically. The results indicated that starch in tobacco leaf decreased rapidly and leveled off after 48 h of curring, in the meantime, the content of soluble sugar increased accordingly and reached a peak at the stage of color-fixing. Both of them had a rapid-changing stage in the first 36 hours of yellowing. The changes of starch and soluble sugar contents had highly significant negative-correlation at 1 % level (rNC89 = -0.8962**, rYY85 = -0.9704**). The activity of amylase increased with the proceeding of curing and reached a peak after 36 hours of curing, then decreased. But the activity of amylase kept at a high level when the humidity of curing-environment was very low, even if the tobacco leaf had been dried. The rapid degradation of starch showed a significantly negative correlation with the increase of activity of amylase at 5 % level (rNC89 = -0.8495*, rYY85 = -0.7839*). The degradation of starch and pigment had the same regulation and had highly significant correlation at 1 % level (rNC89= 0.9649**, rYY85= 0.9428**). There were mainly three amylase-isoenzyme bands -A, B, C respectively, in tobacco leaf during flue curing. They were identified as α-AMY, β-AMY, R-AMY, and the activity of β-AMY was the highest. The changes in amylase activity and contents of starch and pigment were affected by the tobacco leaf moisture and environmental humidity during curing.
