基于K均值聚类的厚壁组织区域自动提取

桉树是我国南方的速生丰产林,区域提取是定量分析各种组织抑制桉树茎生根原因的重要前提。为此,介绍了基于K均值聚类的在桉树茎切片图像中自适应提取厚壁组织区域的图像处理技术。将桉树茎切片彩色图像转换为CIEL*a*b*彩色空间,用K均值聚类分析算法对描述颜色的a*和b*通道进行聚类分析,提取细胞厚壁,然后填充其中白色的细胞腔,构成完整的厚壁组织区域。实验结果表明,在CIEL*a*b*空间使用该算法可以获得较准确的实验结果。     

东北地区农机化发展的措施与建议

农业机械化是农业现代化的基础和手段,没有农业机械化,就没有农业现代化.为此,针对东北地区农业机械化发展的现状和存在的主要问题,提出了东北地区农业机械化发展的措施与建议,旨在为农业现代化建设和新农村建设提供参考.     

Construction of mouse ESC line stably expressing Pdx1 by Tet-On system

AIM To construct the mouse embryonic stem cell （ESC） line with stable pancreatic and duodenal homeobox 1 （Pdx1） expression by Tet-On system, which may lay a foundation for further research on the differentiation of Pdx1⁺ definitive endoderm cells into pancreatic cells. METHODS The Pdx1-overexpressing lentiviral vector with green fluorescent protein marker and puromycin resistance was constructed by Tet-On system and was used to infect the mouse ESC. The cells were divided into 3 groups： blank control group （ESC group）, empty lentivirus control group （PDX1^- ESC group） and Pdx1 lentivirus transfection group （PDX1⁺ ESC group）. Flow cytometry was used to detect the transfected cells after screening by doxycycline （DOX）. The function of Tet-On system and the expression of Pdx1 gene were detected. The transfected cells in PDX1^- ESC group and PDX1⁺ ESC group were sorted by flow cytometry, and constructed ESC line with stable expression of Pdx1 and negative control ESC line were verified. RESULTS （1） The positive rates of transfected cells in PDX1^- ESC group and PDX1⁺ ESC group were 90.72% and 94.01% after screening by DOX, respectively. The positive rates of transfected cells in PDX1^- ESC group and PDX1⁺ ESC group was 97.84% and 98.13% after sorting by flow cytometry, respectively. （2） With DOX, green fluorescence was observed in PDX1^- ESC group and PDX1⁺ ESC group. The mRNA and protein expression of Pdx1 was significantly increased in PDX1⁺ ESC group （P<0.05）. Without DOX, no green fluorescence was observed in the cells of the 3 groups, and no significant difference in the mRNA and protein expression of Pdx1 was observed （P>0.05）. （3） After 3 months of cryopreservation, the cell lines still survived in resuscitation culture and were regulated by DOX. CONCLUSION Using Tet-On system, the mouse ESC line with inducible Pdx1 expression were successfully established and could be used as an effective cell model to research the differentiation of Pdx1⁺ definitive endoderm cells into pancreatic cells.     

Expression of cathepsin C and tumor necrosis factor-α in human coronary artery and their relationships with coronary heart disease

AIM To explore the possible mechanism of cathepsin C （CTSC） and tumor necrosis factor-α （TNF-α） in coronary heart disease （CHD） by detecting the protein expression of CTSC and TNF-α in human coronary artery tissue. METHODS The coronary artery tissues from 52 cases of CHD and 25 cases of accidental death without any heart disease in the Forensic Judicial Expertise Center of Guizhou Medical University from October 2018 to December 2019 were collected as CHD group and control group, respectively. The coronary artery stenosis and intimal plaque formation were examined by histopathology, the protein expression of CTSC and TNF-α was determined by Western blot, and the intracellular expression of CTSC and TNF-α was analyzed by immunohistochemical staining. RESULTS The results of HE staining showed that the intima of coronary artery in control group was smooth, and no thickening or stenosis was observed. In CHD group, the intima thickened irregularly, atherosclerotic plaques formed, the intima became thinner and the lumen showed eccentric stenosis in varying degrees （P<0.05）. The results of Western blot showed that the expression of CTSC and TNF-α in CHD group was significantly higher than that in control group （P<0.05）. Immunohistochemical staining showed that both CTSC and TNF-α were expressed in the cytoplasm of foam cells, and their positive expression was significantly higher than that in control group （P<0.05）. The results of Pearson moment correlation analysis showed that there was positive correlation between the expression of CTSC and TNF-α in CHD （r²=0.743, P<0.05）. CONCLUSION The up-regulated expression of CTSC in coronary artery tissue may promote the expression of TNF-α and affect the occurrence and development of CHD.     

辽西地区引种野杏数量性状研究

以辽西地区26个野杏无性系为试材,采用变异性分析、方差分析以及主成分分析等方法,研究了其25个数量性状的变异特点,以期为野杏无性系的遗传多样性研究和良种选育提供重要参考依据。结果表明:19个数量性状呈正态分布;25个野杏无性系数量性状变异系数均值23%,其中22个数量性状的变异系数在10%以上,小枝长度变异系数最大,达64%,单果质量、单核质量、单仁质量的变异系数分别为24%、21%和18%,表明野杏无性系数量性状变异程度丰富,选择潜力较大。野杏无性系果实性状重复力普遍偏高,核仁主要性状重复力次之,树体主要数量性状重复力较二者偏低,均达到极显著水平;果核仁性状的重复力除单果质量、单核质量和仁厚分别为0.634、0.756和0.624外,其它指标皆在0.909以上,其中仁长重复力最高,达0.973。主成分分析结果表明,前6个主成分累积贡献率达83.50%,能够反映野杏无性系数量性状的大部分信息;其中第1主成分主要反映野杏果核仁等经济性状。     

盐碱胁迫对芸豆幼苗生长及根际土壤化学性质的影响

以耐盐碱芸豆品种'HYD'和盐碱敏感型芸豆品种'JW'为试验材料,采用盆栽方法,用Na2CO3、NaHCO32种碱性盐按照摩尔比1∶9进行混合模拟盐碱生境,按照混合后占土壤中的质量百分比0(T0)、0.1％(T1)、0.2％(T2)、0.3％(T3)、0.4％(T4)、0.5％(T5)、0.6％(T6)浓度设计7个梯度,探讨了不同盐碱浓度处理对芸豆幼苗生长和根际土壤化学性质的影响,以期为耐盐碱芸豆品种的筛选提供参考依据.结果 表明:2个芸豆品种株高、茎粗和单株地上鲜干质量和地下鲜干质量与根长、根表面积、根体积均随盐碱浓度增高表现出先增高后降低的趋势,其中在T1处理下达到最高值,'HYD'株高较对照增加7.33％,'JW'根体积较对照增加36.05％,且'HYD'较'JW,对不同盐碱胁迫浓度的变化响应更为明显.土壤pH和电导率均随着盐碱浓度升高呈现逐渐升高的趋势,'HYD'和'JW'根际土壤有机质、碱解氮、速效磷、速效钾含量均呈现先增高后下降的趋势,其中T6处理下显著降低,'HYD'速效磷含量较对照降低14.30％,'JW'速效钾含量较对照显著降低17.98％,并且在各盐碱浓度处理下,'HYD'均高于'JW',表现出对盐碱胁迫较强的适应能力.综合分析表明,芸豆幼苗根系通过对Na+的积累与限制作用,土壤中矿质离子含量增加,提高植物对有效养分吸收以适应盐碱胁迫,故芸豆幼苗生长和根际土壤化学性质均呈现低浓度盐碱胁迫处理在一定程度上促进,高浓度盐碱胁迫处理表现为抑制.     

外源褪黑素通过诱导SlRR基因表达调控番茄盐碱胁迫响应

以"浙杂205"番茄为试材,通过测定SlRR基因的相对表达量以及番茄幼苗叶片的抗氧化酶系统、活性氧含量、渗透调节物质含量,探讨外源褪黑素是否能有效诱导番茄RR基因的表达以缓解盐碱胁迫对番茄的损伤.结果 表明:与对照相比,单独盐、碱处理下Solyc05g006420.2(SlRR4)、Solyc10g079700.1(SlRR5)、Solyc03g113720.2(SlRR6)、Solyc02g071220.2(SlRR7)、Solyc01g065540.2(SlRR8)、Solyc05g054390.2(SlRR9)、Solyc04g008050.2 (SlRR10)、Solyc12g010330.1(SlRR11)的表达水平显著提高,番茄幼苗的超氧化物歧化酶(SOD)、过氧化物酶(POD)、抗坏血酸过氧化物酶(APX)活性、H2O2含量、O2(*)含量以及脯氨酸(Pro)含量均显著提高;与单独盐、碱处理相比,褪黑素预处理的番茄幼苗SlRR4、SlRR5的表达量显著上调,SOD、POD、APX活性和Pro含量显著提高,而H2O2含量、O2(*)含量显著下降.由此可知,外源褪黑素预处理能够显著诱导SlRR基因的表达以提高抗氧化酶的活性从而减少自由基的产生,提高渗透调节物质含量来维持植物体的渗透平衡,进而缓解盐碱胁迫对番茄的损伤.     

农村居民收入来源对贫困的影响

提高贫困地区农村居民收入是实现减贫、脱贫的重要手段,厘清不同收入来源对贫困的影响效果,对针对性采取措施解决农村贫困问题、防止脱贫户返贫具有重要意义.基于农村居民收入与贫困的理论逻辑分析,利用2010-2018年全国23个未脱贫省份的省际面板数据实证检验农村居民不同收入来源对贫困的影响.结果 表明:农村居民工资性收入、经营净收入和财产净收入对减缓贫困具有显著的促进作用,转移净收入对减缓贫困作用不明显;不同收入来源对减缓贫困的边际贡献依次为经营净收入＞工资性收入＞财产净收入＞转移净收入;不同收入来源对贫困的影响存在明显的地域差异,具体表现为不同地区之间以及同一地区内部之间的差异.基于研究结论提出相关政策建议为促进农村贫困人口全面脱贫提供参考依据.     

化肥减量有机替代对茄子生长及土壤养分的影响

以"新龙长茄"为试材,采用日光温室全膜双垄沟播的栽培方法,研究了不施肥(CK),施100％纯化肥(T1)、75％化肥(T2)、75％化肥+25％有机肥(T3)、50％化肥+50％有机肥(T4)、25％化肥+75％有机肥(T5)、100％有机肥(T6)共7个化肥减量有机替代施肥处理对茄子农艺性状、产量和品质及土壤养分的影响,以期为日光温室茄子生产中合理施肥提供参考依据.结果 表明:施肥可以促进茄子植株生长,明显提高茄子产量和土壤养分含量;与当地常规施肥相比,T1、T2处理对茄子生长、产量和土壤养分的影响均不显著;而化肥减量配施有机肥T4处理可不同程度促进茄子植株生长、提高土壤养分含量,并且可以显著增产33.74％、增加可溶性糖含量63.1％、降低硝酸盐含量35.06％.因此,50％化肥+50％有机肥(T4)的施肥对茄子生长、产量提升和品质改善具有较大的作用.     

中国省域核桃产业竞争力评价

核桃作为中国重要的木本油料产业之一,在发挥生态保护、促进贫困地区经济发展、实现我国乡村振兴战略等方面发挥着重要作用.科学评价中国各省(市、自治区)核桃产业竞争力对明确地区核桃发展劣势、巩固竞争优势、合理制定产业未来发展战略具有重要意义.基于核桃生产及消费相关静态统计年鉴数据,采用熵值法和因子分析法,从基本竞争力、生产竞争力、市场竞争力、技术竞争力4个方面对中国18个主要核桃种植省市区进行核桃产业竞争力综合评价.结果 表明:以云南、新疆、四川、北京、山东为代表的区域,核桃产业竞争力最强,应充分发挥其资源优势,加快科技创新,提高当地核桃产业化程度;以浙江、河南、山西、陕西、河北为代表的区域,核桃产业竞争力较强,应在产业规模的基础上,重点发展第二产业,推动核桃产业转型升级;以重庆、安徽、湖南、湖北、甘肃、贵州、吉林、西藏为代表的区域,核桃产业竞争力最弱,应进一步发挥核桃产业发展潜力,以优质产品取胜.