Defoliation,nitrogen, and competition: effects on plant growth and resource allocation of Cleistogenes squarrosa and Artemisia frigida

Two species, Artemisia frigida Willd. (C₃, semishrub, and dominant on overgrazed sites) and Cleistogenes squarrosa (Trin.) Keng (C₄, perennial bunchgrass, and dominant or codominant on moderately grazed sites) were studied to determine the effects of defoliation, nitrogen (N) availability, competition, and their interactions on growth, biomass, and N allocation in a greenhouse experiment. The main treatments were: two nitrogen levels (N0 = 0 mg N pot^–1, N1 = 60 mg N pot^–1), two defoliation intensities (removing 60% of total aboveground biomass and no defoliation), and three competitive replacement series (monocultures of each species and mixtures at 0.5:0.5). Our results were inconsistent with our hypothesis on the adaptive mechanisms of A. frigida regarding the interactive effects of herbivory, N, and competition in determining its dominant position on overgrazed sites. Cleistogenes squarrosa will be replaced by A. frigida on overgrazed sites, although C. squarrosa had higher tolerance to defoliation than did A. frigida. Total biomass and N yield and ¹⁵N recovery of C. squarrosa in mixed culture were consistently lower than in monocultures, whereas those of A. frigida grown in mixtures were consistently higher than in monocultures, suggesting higher competitive ability of A. frigida. Our results suggest that interspecific competitive ability may be of equal or greater importance than herbivory tolerance in determining herbivore‐induced species replacement in semi‐arid Inner Mongolian steppe. In addition, the dominance of A. frigida on overgrazed sites has been attributed to its ability to shift plant‐plant interactions through gap colonization, root niche differentiation, and higher resistance to water stress.     

坡向和坡位对大兴安岭干旱阳坡蒙古栎林温湿度的影响

于2012年5月中旬至10月初,在大兴安岭干旱阳坡的蒙古栎林内,选择不同的坡向和坡位设置观测样地定点测定土壤温度、空气温湿度和土壤含水量。分析结果表明:不同坡向土壤温度由大到小为南坡、西南坡、东南坡,气温由大到小为西南坡、南坡、东南坡,空气湿度和土壤含水量由大到小均为东南坡、西南坡、南坡;南坡空气和土壤温度由大到小为坡上、坡下,土壤含水量坡下大于坡上含水量,空气湿度坡上大于坡下湿度;空气和土壤温湿度受空间位置和季节分布影响差异较大,不同坡向和坡位土壤温湿度差异明显,不同季节空气温湿度波动较大。     

不同产地黄芪活性成分与硒含量比较分析

【目的】研究不同产地黄芪药材中活性成分与硒元素的含量,分析不同产地黄芪之间的差异及黄芪中硒含量与活性成分之间的相关性,为富硒黄芪的种植及资源开发利用提供参考依据。【方法】采用紫外分光光度法测定黄芪总皂苷、总黄酮、总多糖含量,高效液相色谱法(HPLC)测定不同产地黄芪药材中毛蕊异黄酮葡萄糖苷含量,氢化物发生-原子荧光法测定硒的含量,并对各指标进行统计分析。【结果】山西平鲁区黄芪总皂苷含量最高为1.557%,新疆昭苏县黄芪总黄酮含量最高为0.472%,宁夏隆德县黄芪毛蕊异黄酮葡萄糖苷含量最高为0.091%,新疆博湖县总多糖含量和硒含量均是最高,分别为27.617%和0.323 mg/kg;硒含量与总多糖含量呈极显著正相关(P<0.01),聚类分析中黄芪样品可按照不同成分的含量差异分为3类。【结论】22个不同产地黄芪活性成分含量与硒元素的含量有显著差异(P<0.05)。     

内蒙古蒙药药材种植产业高质量发展对策研究

目的：分析内蒙古自治区蒙药药材种植产业发展存在的主要问题,提出建议对策,为政府合理制定蒙药产业政策提供参考依据。方法：运用实地调研方法,提出蒙药产业链条断链、规范化种植程度较低、土地流转费用高等主要问题。结果与结论：通过深入开展蒙药材资源普查,优化蒙药企业营商环境,建设优质道地蒙药种植基地等措施,提升内蒙古蒙药药材种植产业高质量发展水平。     

蒙古高压异常对我国冬季气候的影响分析

基于单位半径球面上,计算了表征蒙古高压特征的4个高压指数(面积指数S、强度指数P、中心经度λc、中心纬度φc),并研究了蒙古高压指数与我国160站气温、降水的同期相关关系。结果表明,蒙古高压特征参数具有明显的阶段性,1951~1965年高压偏强、偏北,1980年后高压偏弱、偏南;蒙古高压面积与强度指数具有25年左右、8~16和3~6年的振荡周期;除西南地区外,蒙古高压面积、强度和中心纬度异常与我国大部分地区冬季气温呈强烈负相关,而经度异常变化对我国冬季气温影响不大;特征指数与降水的同期相关性明显不及其与气温的相关性。     

植筋胶合木杆件拉压性能试验

将钢筋植入樟子松胶合木端部形成植筋胶合木杆件,研究不同钢筋直径、植入深度、胶层厚度等因素对植筋胶合木杆件拉压性能的影响。采用自行设计的14组84个植筋胶合木杆件,通过传统的两端对拉试验及创新的钢螺帽辅助受压试验,分析其荷载-位移关系曲线、极限承载力、破坏形态与破坏机理。结果表明:随钢筋直径增加,受拉试件极限承载力提高了4.1%~17.13%,受压试件极限承载力提高了25.35%~39.10%,钢筋直径对受压杆件极限承载力影响较大;随植入深度增加,受拉试件极限承载力提高了35.69%~70.21%,受压试件极限承载力提高了34.14%~41.12%,植入深度对杆件受拉及受压极限承载力均产生显著影响;胶层厚度对杆件受力性能影响较小,考虑经济性因素,同时方便试件加工制作,合理的胶层厚度选为2~4 mm。     

内蒙古典型草原放牧绵羊体增重与放牧率之间的关系

实验于１９９０－１９９３年在中国科学院内蒙古草原生态系统定位研究站进行。实验设计为不同放牧率下的划区轮牧，包括１．３３、２．６７、４．００、５．３３和６．６７羊／ｈｍ＾２（１９９０年为１．３３、２．００、２．６７、３．３３和４．００羊／ｈｍ＾２）５个放牧率等级和３个轮牧小区，轮牧周期为４５天或４６天，工放牧１３８天。结果表明，整个暖季放牧期间，相邻３种放牧率间体重差异很少达显著性水平，间隔２个放牧     

陕西延安蒙古牛群体的染色体研究

分析了１５头（１０♂５♀）蒙古牛的核型，Ｃ带、Ｇ带和Ａｇ－ＮＯＲｓ．结果发现，蒙古牛的核型，Ｃ带和Ｇ带与普通牛（Ｂｏｓｔａｕｒｕｓ）相同，其公平核型为６０，ｘｙ母牛为６０，ｘｘ．ｙ染色体为一小的中着丝粒染色体，认为蒙古牛为普通牛型黄牛．观察统计了５９６个细胞的Ａｇ－ＮＯＲｓ数目，每细胞平均Ａｇ—ＮＯＲｓ数为５．８１８±０．５１３，变化范围为３～１０个．     

黄羊毛皮DNA的提取

黄羊为国家二级保护野生动物。应用黄羊外耳耳尖微小毛皮块提取14只黄羊的DNA，给出了部分试剂的配制和预处理、实验方法和操作、DNA提取物的测量等。