消光系数是作物模型的重要参数,准确获取作物不同位置的消光系数,可以准确模拟作物的冠层光合速率,从而提高作物模型的模拟精度。该研究依据黄瓜(Cucumis sativus L.)和芹菜(Apium graveolens L.)不同位置(群体底部(Bottom of Crop,BC)...消光系数是作物模型的重要参数,准确获取作物不同位置的消光系数,可以准确模拟作物的冠层光合速率,从而提高作物模型的模拟精度。该研究依据黄瓜(Cucumis sativus L.)和芹菜(Apium graveolens L.)不同位置(群体底部(Bottom of Crop,BC)处,1/3群体中部(1/3 Height of Crop,1/3HC)处,2/3群体中部(2/3 Height of Crop,2/3HC)处)的辐射数据,以津盛206和尤文图斯为试验品种,利用11个播期的试验观测数据建立了基于正午时刻消光系数k值的温室作物消光系数模型,确定了模型参数,用相互独立的数据进行模型检验。结果表明:1)关于正午时刻(12时)的k值变化,黄瓜在秋冬茬期间呈现先下降后上升的变化趋势,而春茬呈现相反的趋势,秋冬茬高于春茬,位置越高,k值越大。芹菜在生长季内,k值为先增加后下降的过程,位置越高,k值呈现先下降后上升的变化趋势。2)关于k值日变化,黄瓜和芹菜均呈现先上升后下降的变化趋势,位置越高,k值越大。3)关于作物发育进程中各发育阶段内k值变化,在相同发育阶段内,黄瓜随着高度上升,k值逐渐增大;芹菜呈现先下降后上升的趋势。在相同位置水平下,黄瓜各阶段k值的阶段均值都呈现先下降后上升的变化趋势,芹菜各阶段k值均值逐渐下降。4)时刻k值随正午时刻k值、位置以及时刻t呈线性下降的关系,模型参数与作物类型和位置有关。不同作物(黄瓜和芹菜)k值的模拟值与实测值的均方根误差(Root Mean Square Error,RMSE)分别为0.45和0.06,归一化均方根误差(Normalized Root Mean Square Error,NRMSE)分别为18.34%和13.35%;不同位置(BC处,1/3HC处,2/3HC处)消光系数k值的模拟值与实测值的RMSE分别为0.47、0.36和0.33,NRMSE分别为17.91%、19.69%和23.85%。该模型能够较准确模拟消光系数的日变化过程,可应用于蔬菜生长发育模型构建及仿真模拟。展开更多
Objectives:The purpose of this study was to evaluate the antibrowning functions of hawthorn leaf extract on fresh-cut potato and its possible mechanism.Materials and Methods:Fresh-cut potatoes were treated with differ...Objectives:The purpose of this study was to evaluate the antibrowning functions of hawthorn leaf extract on fresh-cut potato and its possible mechanism.Materials and Methods:Fresh-cut potatoes were treated with different concentrations(0.01%,0.05%,and 0.1%)of hawthorn leaf extract and preserved at 4 C for 8 days.The appears nee and colour of potato slices were evaluated,along with the content of the phenol,malondialdehyde(MDA),and hydrogen peroxide(H2O2)during cold storage.Meanwhile,the activities of polyphenol oxidase(PPO),peroxidase(POD),phenylalanine ammonia-lyase(PAL),lipoxygenase(LOX),catalase(CAT),superoxide dismutase(SOD),and the antioxidant capacity were determ in ed.Furthermore,the composition of hawthorn leaf extract was analyzed by high-performance liquid chromatographytandem mass spectrometry(HPLC-MS/MS).Results:The addition of hawthorn leaf extract effectively delayed the browning process.It not only enhanced the CAT activity and antioxidant capacity but also reduced the LOX activity and accumulation of MDA and H_(2)O_(2).Meanwhile,the activities of PPO,POD,and PAL as well as the content of phe nol were con trolled.Additionally,25 phe nols,34 flavonoids,and 5 proa nthocya nidins were identified through high-performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS),ideluding caffeic acid,quercetin and catechol.Conelusion:Hawthorn leaf extract significantly alleviated the browning of fresh-cut potato.It could serve as a n atural an tibrowning alter native by stabilizing the membra ne and modulating reactive oxygen species and redox reactions.展开更多
文摘消光系数是作物模型的重要参数,准确获取作物不同位置的消光系数,可以准确模拟作物的冠层光合速率,从而提高作物模型的模拟精度。该研究依据黄瓜(Cucumis sativus L.)和芹菜(Apium graveolens L.)不同位置(群体底部(Bottom of Crop,BC)处,1/3群体中部(1/3 Height of Crop,1/3HC)处,2/3群体中部(2/3 Height of Crop,2/3HC)处)的辐射数据,以津盛206和尤文图斯为试验品种,利用11个播期的试验观测数据建立了基于正午时刻消光系数k值的温室作物消光系数模型,确定了模型参数,用相互独立的数据进行模型检验。结果表明:1)关于正午时刻(12时)的k值变化,黄瓜在秋冬茬期间呈现先下降后上升的变化趋势,而春茬呈现相反的趋势,秋冬茬高于春茬,位置越高,k值越大。芹菜在生长季内,k值为先增加后下降的过程,位置越高,k值呈现先下降后上升的变化趋势。2)关于k值日变化,黄瓜和芹菜均呈现先上升后下降的变化趋势,位置越高,k值越大。3)关于作物发育进程中各发育阶段内k值变化,在相同发育阶段内,黄瓜随着高度上升,k值逐渐增大;芹菜呈现先下降后上升的趋势。在相同位置水平下,黄瓜各阶段k值的阶段均值都呈现先下降后上升的变化趋势,芹菜各阶段k值均值逐渐下降。4)时刻k值随正午时刻k值、位置以及时刻t呈线性下降的关系,模型参数与作物类型和位置有关。不同作物(黄瓜和芹菜)k值的模拟值与实测值的均方根误差(Root Mean Square Error,RMSE)分别为0.45和0.06,归一化均方根误差(Normalized Root Mean Square Error,NRMSE)分别为18.34%和13.35%;不同位置(BC处,1/3HC处,2/3HC处)消光系数k值的模拟值与实测值的RMSE分别为0.47、0.36和0.33,NRMSE分别为17.91%、19.69%和23.85%。该模型能够较准确模拟消光系数的日变化过程,可应用于蔬菜生长发育模型构建及仿真模拟。
基金sustained by the National Natural Science Foundation of China(No.32001765)the Open Project Program of the State Key Laboratory of Food Nutrition and Safety,China(SKLFNS-KF-202016).
文摘Objectives:The purpose of this study was to evaluate the antibrowning functions of hawthorn leaf extract on fresh-cut potato and its possible mechanism.Materials and Methods:Fresh-cut potatoes were treated with different concentrations(0.01%,0.05%,and 0.1%)of hawthorn leaf extract and preserved at 4 C for 8 days.The appears nee and colour of potato slices were evaluated,along with the content of the phenol,malondialdehyde(MDA),and hydrogen peroxide(H2O2)during cold storage.Meanwhile,the activities of polyphenol oxidase(PPO),peroxidase(POD),phenylalanine ammonia-lyase(PAL),lipoxygenase(LOX),catalase(CAT),superoxide dismutase(SOD),and the antioxidant capacity were determ in ed.Furthermore,the composition of hawthorn leaf extract was analyzed by high-performance liquid chromatographytandem mass spectrometry(HPLC-MS/MS).Results:The addition of hawthorn leaf extract effectively delayed the browning process.It not only enhanced the CAT activity and antioxidant capacity but also reduced the LOX activity and accumulation of MDA and H_(2)O_(2).Meanwhile,the activities of PPO,POD,and PAL as well as the content of phe nol were con trolled.Additionally,25 phe nols,34 flavonoids,and 5 proa nthocya nidins were identified through high-performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS),ideluding caffeic acid,quercetin and catechol.Conelusion:Hawthorn leaf extract significantly alleviated the browning of fresh-cut potato.It could serve as a n atural an tibrowning alter native by stabilizing the membra ne and modulating reactive oxygen species and redox reactions.
