The aims were to investigate the effect of salt stress on key enzyme activity of nitrogen metabolism and the concentration of nitrate nitrogen and ammonium nitrogen response to salt stress.Two rice cultivars,Mudanjian...The aims were to investigate the effect of salt stress on key enzyme activity of nitrogen metabolism and the concentration of nitrate nitrogen and ammonium nitrogen response to salt stress.Two rice cultivars,Mudanjiang 30(sensitive cultivar)and Longdao 5(salt-tolerant cultivar),were treated with different salt concentrations(CK 0%,S10.075%,S20.15%,S30.225%and S40.3%).The results showed that the activities of nitrate reductase(NR),glutamine synthase(GS),glutamate synthase(GOGAT)and glutamate dehydrogenase(GDH)in the functional leaves and roots of rice in cold region presented a single peak curve change and the peak occurred in the heading stage;compared with those of the CK,the activities of NR,GS and GOGAT of rice in cold region decreased,but the activity of GDH increased in the heading stage under salt stress.The variation for key enzyme activity of nitrogen metabolism was the highest under S4 treatment.The activities of NR,GS and GOGAT in the functional leaves significantly decreased compared with those in roots;the concentrations of nitrate nitrogen and ammonium nitrogen in the functional leaves and roots of rice in cold region presented a single peak curve change and the peak occurred in the heading stage;compared with that of the CK,the concentration of nitrate nitrogen decreased in leaves and roots,the concentration of ammonium nitrogen decreased and the concentration of ammonium nitrogen in roots increased under salt stress.The variations for the activities of NR,GS and GOGAT in the functional leaves and roots of Longdao 5 were less than those of Mudanjiang 30 under the same concentration of salt stress.展开更多
This paper mainly focused on the growth law, model construction and visualization of a soybean root. A pot experiment was conducted in the laboratory to collect root system data and measure soybean root＇s length, dia...This paper mainly focused on the growth law, model construction and visualization of a soybean root. A pot experiment was conducted in the laboratory to collect root system data and measure soybean root＇s length, diameter and number by excavating in different periods. On the basis of an in-depth analysis of root structure geometry, we analyzed the collected experimental data with logistic equations, and got the growth of soybean root equation, according to its morphological structure characteristics of self-similarity, and discussed the virtual modeling method on the soybean root based on L-system and in Visual c＋＋ Using OpenGL technology to achieve a soybean root system topology model and visualization simulation.展开更多
The rice Dongfu 159 was used for the potting experiment to simulate soil cadmium(Cd)stress,and four silicon preparations,Si-50-G and Si-60-G at a concentration of 0.20%and Si-T-G and Si-E-G at a concentration of 0.50%...The rice Dongfu 159 was used for the potting experiment to simulate soil cadmium(Cd)stress,and four silicon preparations,Si-50-G and Si-60-G at a concentration of 0.20%and Si-T-G and Si-E-G at a concentration of 0.50%,were applied at the tillering stage and booting stage of rice,respectively.The cadmium content,root vitality,root malondialdehyde(MDA)content,and antioxidant enzyme activity of each part of rice plants were determined,in order to provide a theoretical reference for exploring the mechanism of silicon fertilizer on the mitigation of Cd-stressed plants.The results showed that under the condition of cadmium stress,silicon application could significantly increase the root vitality and antioxidant enzyme activity,reduce the content of MDA,and reduce the accumulation of cadmium in various parts of rice.The treatment of Si-T-G applied at the tillering stage was the most effective in increasing the root vitality of rice,which was significantly increased by 63.00%compared with the CK.The treatment of Si-50-G applied at the stage of booting was the most effective in reducing MDA content of rice roots,which was significantly reduced by 30.16%compared with the CK.The treatment of Si-60-G applied at the stage of booting was the most effective in increasing the root superoxide dismutase(SOD)activity,which was significantly increased by 39.36%compared with the CK.The treatment of Si-60-G applied at the tillering stage was the most effective in increasing the root peroxidase(POD)and catalase(CAT)activities,which were significantly increased by 64.66%and 51.52%,respectively,compared with the CK.The treatment of Si-T-G applied at the tillering stage was the most effective in reducing Cd content of rice roots,stems and grains,which were significantly reduced by 39.53%,61.19%and 43.41%,respectively,compared with the CK,and the treatment of Si-60-G was the most effective in reducing Cd content of leaves,which was significantly reduced by 53.40%compared with the CK.展开更多
Objective: To estimate the presence and the quantity of endotoxin of periodontally involved root surfaces after root surface debridement.Methods: Ninety single rooted teeth with severe bone resorption were selected,wh...Objective: To estimate the presence and the quantity of endotoxin of periodontally involved root surfaces after root surface debridement.Methods: Ninety single rooted teeth with severe bone resorption were selected,which were scheduled for extraction.The teeth were randomly assigned into 3 groups.The teeth in the first group were served as control and they did not receive any debridement.The teeth in the second group were scaled and root planned with Gracey curettes.The teeth in the third group were debrided with the new ultrasonic device VectorTM-system(Dürr Dental).The endotoxin concentrations before and after debridement were assessed by Limulus Amebocyte Lysat(LAL).Results: The concentration of endotoxin of periodontally involved teeth in the control group was 0.825 EU/ml.Scaling and root planning resulted in a significant reduction of the values as follows: Gracey curettes 0.240 EU/ml,VectorTM-system 0.184 EU/ml.Conclusion: Scaling and root planning leads to obvious reduction of the endotoxin on periodontally involved root surfaces and VectorTM-system is comparatively more effective than Gracey curettes.展开更多
针对目前缺乏水稻钵苗多株根系交织于基质形成独立钵体复合体基础模型研究的问题,同时为后续开展水稻钵苗移栽机构栽植过程探究机械-钵体互作规律提供理论基础,本文依据水稻钵苗根系物理机械特性与生长规律,提出了一种基于Matlab根系数...针对目前缺乏水稻钵苗多株根系交织于基质形成独立钵体复合体基础模型研究的问题,同时为后续开展水稻钵苗移栽机构栽植过程探究机械-钵体互作规律提供理论基础,本文依据水稻钵苗根系物理机械特性与生长规律,提出了一种基于Matlab根系数值模拟生长的水稻钵苗钵体复合体离散元模型建立方法。通过破坏性检测对移栽期水稻钵苗根系的几何形态与根系拓扑关系及基质相关参数进行测量与分析,结合钵盘边界因素及根-根、根-钵盘间交互生长特性,建立水稻根系生长规律相关特性函数,并通过Matlab程序设计获取水稻钵苗根系生长拓扑轨迹。利用分割排序法求解完整粒子中心坐标,依托EDEM软件平台分别将所建立的水稻钵苗根-基质离散元几何模型与EdinBurgh Elasto-Plastic Adhesion with Bonding接触力学模型结合,实现水稻钵苗钵体复合体离散元模型的建立。开展水稻钵苗钵体压缩和剪切试验对比研究,结果表明,仿真结果与试验结果趋向保持一致,误差满足相关要求,验证了水稻钵苗钵体复合体离散元模型的可行性。展开更多
基金Supported by the National Key R&D Program of China(2016YFD0300104)。
文摘The aims were to investigate the effect of salt stress on key enzyme activity of nitrogen metabolism and the concentration of nitrate nitrogen and ammonium nitrogen response to salt stress.Two rice cultivars,Mudanjiang 30(sensitive cultivar)and Longdao 5(salt-tolerant cultivar),were treated with different salt concentrations(CK 0%,S10.075%,S20.15%,S30.225%and S40.3%).The results showed that the activities of nitrate reductase(NR),glutamine synthase(GS),glutamate synthase(GOGAT)and glutamate dehydrogenase(GDH)in the functional leaves and roots of rice in cold region presented a single peak curve change and the peak occurred in the heading stage;compared with those of the CK,the activities of NR,GS and GOGAT of rice in cold region decreased,but the activity of GDH increased in the heading stage under salt stress.The variation for key enzyme activity of nitrogen metabolism was the highest under S4 treatment.The activities of NR,GS and GOGAT in the functional leaves significantly decreased compared with those in roots;the concentrations of nitrate nitrogen and ammonium nitrogen in the functional leaves and roots of rice in cold region presented a single peak curve change and the peak occurred in the heading stage;compared with that of the CK,the concentration of nitrate nitrogen decreased in leaves and roots,the concentration of ammonium nitrogen decreased and the concentration of ammonium nitrogen in roots increased under salt stress.The variations for the activities of NR,GS and GOGAT in the functional leaves and roots of Longdao 5 were less than those of Mudanjiang 30 under the same concentration of salt stress.
基金Supported by the Scientific Research Project of Heilongjiang Province(11551054)
文摘This paper mainly focused on the growth law, model construction and visualization of a soybean root. A pot experiment was conducted in the laboratory to collect root system data and measure soybean root＇s length, diameter and number by excavating in different periods. On the basis of an in-depth analysis of root structure geometry, we analyzed the collected experimental data with logistic equations, and got the growth of soybean root equation, according to its morphological structure characteristics of self-similarity, and discussed the virtual modeling method on the soybean root based on L-system and in Visual c＋＋ Using OpenGL technology to achieve a soybean root system topology model and visualization simulation.
基金Supported by the National Natural Science Foundation of China(31340032)。
文摘The rice Dongfu 159 was used for the potting experiment to simulate soil cadmium(Cd)stress,and four silicon preparations,Si-50-G and Si-60-G at a concentration of 0.20%and Si-T-G and Si-E-G at a concentration of 0.50%,were applied at the tillering stage and booting stage of rice,respectively.The cadmium content,root vitality,root malondialdehyde(MDA)content,and antioxidant enzyme activity of each part of rice plants were determined,in order to provide a theoretical reference for exploring the mechanism of silicon fertilizer on the mitigation of Cd-stressed plants.The results showed that under the condition of cadmium stress,silicon application could significantly increase the root vitality and antioxidant enzyme activity,reduce the content of MDA,and reduce the accumulation of cadmium in various parts of rice.The treatment of Si-T-G applied at the tillering stage was the most effective in increasing the root vitality of rice,which was significantly increased by 63.00%compared with the CK.The treatment of Si-50-G applied at the stage of booting was the most effective in reducing MDA content of rice roots,which was significantly reduced by 30.16%compared with the CK.The treatment of Si-60-G applied at the stage of booting was the most effective in increasing the root superoxide dismutase(SOD)activity,which was significantly increased by 39.36%compared with the CK.The treatment of Si-60-G applied at the tillering stage was the most effective in increasing the root peroxidase(POD)and catalase(CAT)activities,which were significantly increased by 64.66%and 51.52%,respectively,compared with the CK.The treatment of Si-T-G applied at the tillering stage was the most effective in reducing Cd content of rice roots,stems and grains,which were significantly reduced by 39.53%,61.19%and 43.41%,respectively,compared with the CK,and the treatment of Si-60-G was the most effective in reducing Cd content of leaves,which was significantly reduced by 53.40%compared with the CK.
文摘Objective: To estimate the presence and the quantity of endotoxin of periodontally involved root surfaces after root surface debridement.Methods: Ninety single rooted teeth with severe bone resorption were selected,which were scheduled for extraction.The teeth were randomly assigned into 3 groups.The teeth in the first group were served as control and they did not receive any debridement.The teeth in the second group were scaled and root planned with Gracey curettes.The teeth in the third group were debrided with the new ultrasonic device VectorTM-system(Dürr Dental).The endotoxin concentrations before and after debridement were assessed by Limulus Amebocyte Lysat(LAL).Results: The concentration of endotoxin of periodontally involved teeth in the control group was 0.825 EU/ml.Scaling and root planning resulted in a significant reduction of the values as follows: Gracey curettes 0.240 EU/ml,VectorTM-system 0.184 EU/ml.Conclusion: Scaling and root planning leads to obvious reduction of the endotoxin on periodontally involved root surfaces and VectorTM-system is comparatively more effective than Gracey curettes.
文摘针对目前缺乏水稻钵苗多株根系交织于基质形成独立钵体复合体基础模型研究的问题,同时为后续开展水稻钵苗移栽机构栽植过程探究机械-钵体互作规律提供理论基础,本文依据水稻钵苗根系物理机械特性与生长规律,提出了一种基于Matlab根系数值模拟生长的水稻钵苗钵体复合体离散元模型建立方法。通过破坏性检测对移栽期水稻钵苗根系的几何形态与根系拓扑关系及基质相关参数进行测量与分析,结合钵盘边界因素及根-根、根-钵盘间交互生长特性,建立水稻根系生长规律相关特性函数,并通过Matlab程序设计获取水稻钵苗根系生长拓扑轨迹。利用分割排序法求解完整粒子中心坐标,依托EDEM软件平台分别将所建立的水稻钵苗根-基质离散元几何模型与EdinBurgh Elasto-Plastic Adhesion with Bonding接触力学模型结合,实现水稻钵苗钵体复合体离散元模型的建立。开展水稻钵苗钵体压缩和剪切试验对比研究,结果表明,仿真结果与试验结果趋向保持一致,误差满足相关要求,验证了水稻钵苗钵体复合体离散元模型的可行性。
