危机干扰下旅游共生网络韧性变化及机制——以武陵山片区为例

旅游共生网络韧性是提升旅游业抗风险能力的关键。结合共生理论与韧性理论,建立"干扰-响应-状态"旅游共生网络韧性研究框架,引入共生力度指标优化生长性、层级性、匹配性、连通性和传输性等网络韧性指标的测度方法,基于此分析了危机干扰下武陵山片区旅游共生网络韧性变化及机制。结果表明:(1)旅游共生网络韧性表现出复杂的时空变化特征,节点的共生力度呈差异性增强变化,生长性呈波动增强变化,层级性和匹配性呈摆动变化,连通性和传输性呈非线性非同步增强变化;(2)旅游共生网络对干扰具有不同响应特征,表现为不同时期节点共生力度和节点失效对连通性和传输性的差异影响,以及网络抗干扰能力不同程度的恢复变化;(3)危机干扰下旅游共生网络韧性表现出波动变化特征,结构与要素间呈复杂交互作用机制。要素的协调作用和有序发展,是提升旅游共生网络韧性的重要途径。研究对促进区域旅游业韧性发展具有重要意义。     

桂林岩溶石山常绿落叶阔叶混交林乔木层优势物种生态位研究

采用样方法对不同资源位群落进行调查,通过冗余分析（RDA）结合Monte Carlo随机置换检验筛选出对桂林岩溶石山常绿落叶阔叶混交林乔木层优势物种分布影响显著的土壤资源轴（土壤有机质、土壤水溶钙、土壤速效氮、土壤全氮、土壤pH值和土壤厚度）。利用Levins生态位宽度指数和Pianka生态位重叠指数对桂林岩溶石山常绿落叶阔叶混交林乔木层14个优势物种在土壤有机质、土壤水溶钙、土壤速效氮、土壤全氮、土壤pH值和土壤厚度6个土壤资源轴上的生态位特征进行研究。结果表明：（1）在土壤有机质和土壤水溶钙资源轴上,生态位宽度最大值为常绿物种檵木（0.89、0.94）;在土壤pH值资源轴上,生态位宽度最大值为常绿物种粗糠柴（0.96）;在土壤速效氮、土壤全氮和土壤厚度资源轴上,生态位宽度最大值为落叶物种南酸枣（0.87、0.99、0.97）。（2）14个优势物种在6个土壤资源轴上,生态位重叠均值由大到小依次为土壤厚度 > 土壤全氮 > 土壤水溶钙 > 土壤速效氮 > 土壤pH值 > 土壤有机质,且均表现为常绿物种与常绿物种形成的种对生态位重叠均值（0.84） > 常绿物种与落叶物种（0.74） > 落叶物种与落叶物种（0.66）。（3）综合6个土壤资源轴,生态位重叠值≥0.5的种对高达480对,占总种对数的87.91%,暗示桂林岩溶石山常绿落叶阔叶混交林乔木层优势物种在资源匮乏且资源异质性高的特殊生境中存在激烈竞争,且乔木层种间关系相对不稳定。     

西藏的捕食线虫真菌

从采自西藏海拔在３６４０～４３００米地区的１２５份土样中共检测到食线虫真菌４个属,共２８种。其中纤细梗虫霉Ｓｔｙｌｏｐａｇｅ　ａｒａｅａ ,滑丝梗虫霉Ｓｔｙｌｏｐｏｇｅ　ｌｅｉｏｈｙｐｈａ和印度单顶孢Ｍｏｎａｃｒｏｓｐｏｒｉｕｍ　 ｉｎｄｉｃｕｍ为中国新记录。     

基于N蛋白单克隆抗体的小反刍兽疫病毒抗体检测胶体金试纸条的研制

本研究旨在建立一种简便、快捷、可直观检测小反刍兽疫病毒(peste des petits ruminants virus,PPRV)抗体的检测方法。将pET-32a-N重组质粒转化至大肠杆菌(Escherichia coli) Rosetta(DE3)感受态细胞中进行诱导表达,以纯化的PPRVN蛋白免疫8周龄BALB/c小鼠,取其脾细胞与SP2/0骨髓瘤细胞进行融合,间接酶联免疫吸附试验(enzyme-linked immunosorbent assays, ELISA)筛选及亚克隆,获得了抗PPRV N蛋白的单克隆抗体。将PPRV N蛋白分别作为金标抗原及检测线(T线)包被抗原、单克隆抗体作为质控线(C线)包被抗体,组装成检测PPRVN蛋白抗体的胶体金免疫层析试纸条。结果显示：成功获得1株能稳定分泌抗N蛋白抗体的杂交瘤细胞株,命名为1F1;间接ELISA检测1F1腹水效价为1:128000;亚类鉴定结果为IgG1,轻链为kappa链。Westernblotting结果显示,1F1能与PPRV N蛋白特异性结合;间接免疫荧光(indirect immunofluorescent ass...     

遮荫对桂南种植罗汉果净光合速率和品质的影响

通过大田栽培试验,探讨生育后期不同遮荫处理(遮荫率0、30%、50%和70%)对罗汉果净光合速率和罗汉果品质的影响。经过遮荫处理,罗汉果净光合速率日变化曲线由对照组(遮荫率为0)的双峰型转变为单峰型,曲线峰值出现在中午12:00时。遮荫率50%处理的曲线峰值、罗汉果苷Ⅴ含量和干果重比其它遮荫处理和对照组的高。结果表明,在桂南种植的罗汉果,生育后期给予遮荫率50%的处理对增加罗汉果的净光合速率,提高罗汉果苷Ⅴ含量和干果重较为有利。     

Sperm binding, in vitro fertilization, and in vitro embryonic development of bovine oocytes fertilized with spermatozoa incubated with norepinephrine

The final stages of sperm maturation, fertilization, and early embryonic development occur within the oviduct and are essential for successful reproduction in mammals. Norepinephrine was previously identified in native bovine oviductal fluid and its in vitro effects on bull sperm capacitation and the acrosome reaction have been determined. It was unknown how physiological concentrations of norepinephrine influence sperm binding, fertilization, and embryo development. Therefore, the objective of this study was to determine if pre-incubating bovine spermatozoa with physiological concentrations of norepinephrine prior to insemination of bovine oocytes would improve sperm-oocyte binding, fertilization, and embryonic development in vitro. Norepinephrine, in concentrations representing those measured in bovine oviductal fluid, was used to treat bovine spermatozoa prior to insemination. Spermatozoa incubated in norepinephrine were used to inseminate bovine oocytes matured in vitro, and oocytes were evaluated for sperm binding and fertilization. Additional experiments were conducted to evaluate how early in the co-incubation period oocytes were fertilized by spermatozoa pre-incubated with norepinephrine, and to test the developmental competence of those oocytes fertilized with norepinephrine-treated sperm. Sperm binding to the zona pellucida was reduced by pre-incubation with norepinephrine. Rates of fertilization and embryo development did not increase as a result of pre-incubating spermatozoa with norepinephrine, but as early as 4h after insemination, spermatozoa treated with 20 ng/ml norepinephrine fertilized more oocytes than spermatozoa incubated in medium alone. Interestingly, this concentration of norepinephrine was found to capacitate spermatozoa in previous studies. These data suggest that oocytes fertilized by spermatozoa incubated in 20 ng/ml norepinephrine fertilize earlier in vitro than sperm pre-incubated in medium alone, and provide additional support for the role of norepinephrine in sperm capacitation and the acrosome reaction.     

青海祁连瑞香狼毒的光谱差异特征提取

瑞香狼毒是分布在青海省高寒草甸的主要毒害草之一,近年来其迅速蔓延对当地畜牧业危害严重并使草地生态系统日趋退化.在海北州祁连县选取狼毒分布的典型退化草甸,采用2012—2014年狼毒盛花期获取的实测光谱数据,分析狼毒与牧草的光谱差异性.结果表明： 在350~900 nm的可见光 近红外波段,狼毒顶花的光谱反射特征明显异于狼毒叶片和同期牧草等绿色背景,顶花与绿色背景的光谱反射率差异主要体现在红谷和蓝谷.随着盖度的增加,狼毒群落光谱反射率整体升高,在近红外反射峰处狼毒群落与牧草群落光谱反射率具有最大差值,且不同盖度狼毒群落之间的差异性最明显.顶花与绿色背景以及狼毒群落与牧草群落的一阶导数光谱差异均体现在黄边幅值和蓝边幅值.狼毒群落盖度与光谱特征参量的线性回归分析表明,红谷与狼毒群落盖度的相关性最好(R²=0.94),反演狼毒群落盖度的精度最高.盛花期区分狼毒与牧草的主要光谱特征参量为红谷、蓝谷与近红外反射峰,其对应的红、蓝及近红外波段的组合可用于构建狼毒提取的敏感指数.