Chemical diversity of the essential oils of twenty populations of Tanacetum polycephalum Sch. Bip. from Iran

Chemical diversity of the essential oils of twenty wild populations of Tanacetum polycephalum Sch. Bip., was investigated. The aerial parts of T. polycephalum were collected at full flowering stage from West Azerbaijan Province of Iran, air-dried; hydrodistilled to produce essential oils. The essential oils were analyzed by GC-FID and GC-MS. A total of forty compounds were identified accounting for 96.4–99.9% of the total oils. The most principal compounds were cis-thujone (0–82.3%), trans-thujone (0–79.8%), camphor (1.3–75.0%), 1,8-cineole (4.5–43.3%), borneol (1.0–36.2%) and bornyl acetate (0–26.8%). Hierarchical cluster analysis based on the percentages (>0.5%) of the essential oils components was carried out to determine the chemical diversity among the populations studied. The cluster analysis resulted in the identification of four main chemotypes namely: ‘camphor + 1,8-cineole’, ‘mixed’, ‘cis-thujone’ and ‘trans-thujone’.     

基于近红外反射光谱的外来入侵植物的辨识

提出了一种利用可见一近红外反射光谱技术对婆婆纳、波斯婆婆纳、直立婆婆纳等3种入侵植物和本地杂草宝盖草的植物辨别方法,可以对外表相似度极高的这4种植物进行有效鉴别.研究在对光谱曲线进行预处理和聚类分析后,随机采用30×4个样本作为建模样本,其余的20×4个样本作为预测样本,应用独立软模式法SIMCA(soft independent models of class analogy)进行分类,在显著性水平为5%下,其预测分辨率为78.75%,去除婆婆纳后的预测分辨率为90%.根据变量建模能力(modeling power)值,找到敏感波段496～521,589～626和789～926 nm,并将相应的波段的光谱值作为最小二乘的支持向量机LS-SVM(least squares support vector machine)的输入,进行建模预测,并以预测结果作为目标函数值,进行遗传算法GA(genetic algorithm)优化,结果发现,预测分辨率达95.35%,辨识效果好,能快速正确区分外来入侵植物.     

凉山州主要外来杂草种类及危害

外来杂草已对凉山州的农作物生产、果园、草坪、环境和生物多样性等造成了严重危害。本文论述了凉山州主要外来杂草的种类及其危害。     

川西北草地应用2,4—滴丁酯的除莠效应

选用2,4—滴丁酯除莠剂,在川西北荒芜人工草地上,按一定浓度配药喷雾,对处理后不同时间的草地随机取样,选取6个样方进行莠草杀灭效果实测。结果表明:该除草剂对八种典型莠草有显著防除效果;且在喷药后一定时间内,随时间的延长,除莠效果进一步提高。鉴于川西北草地莠草现状及化学除莠效益,建议大面积推广使用这种高效、低毒、低残毒除莠剂。     

Gene flow from transgenic oilseed rape (Brassica napus L.) to cruciferous weeds under mentor pollen inducement

The alien gene flow between genetically modified glyphosate-resistant rapeseed variety Q3 (Brassica napus L.) and four cruciferous weeds was studied under mentor pollen inducement. The results showed that when Thlaspi arvense L., Capsella bursa-pastoris (L.) Medic, Cardamine hirsute L. and Rorippa palustris (L.) Besser were pollinated with mentor pollen, the mixed Q3 and the weed, pollen grains aggregated largely and germinated quickly, and the numbers of pollen tubes penetrating into the style and the ovary were greatly increased as compared with corresponding self-pollination groups. Twenty four to forty eight hours after pollination, several pollen tubes were observed to penetrate into the ovule via micropyle in each mentor combination. However, when the mentor progenies were analyzed by PCR, all of them showed negative for the Q3 herbicide-resistant gene. Collectively, these results indicated that crossing between T. arvense, C. bursa-pastoris, C. hirsuta, R. palustris (as female) and Q3 (as male) was highly incompatible and the herbicide-resistant gene could not flow from Q3 to these four weeds.     

化学除草剂在苗圃地的应用试验

通过对除草剂的应用试验,不同除草剂的单独使用对阔叶杂草的除草能力,从强到弱依次为:百草枯、草甘膦、扑草净、果尔、都尔、乙草胺、高效盖草能、精禾草克;对禾本科杂草的除草能力从强到弱依次为:百草枯、扑草净、高效盖草能、草甘膦、精禾草克、果尔、乙草胺、都尔。不同除草剂的混合使用相对于单一除草剂效果和性能都有了明显的提高,特别是克乙丁试剂无论对阔叶杂草或禾本科杂草除草率都达到了100%;混合除草剂的抑草期也比单一除草剂要长。通过对难除杂草的效果试验,发现加大草甘膦浓度能提高除草效果;克乙丁试剂、草二试剂、扑草净对有害生物—加拿大一枝黄花有较好的除草效果。     

城乡梯度上一年生杂草叶片氮磷含量的变化及其与土壤氮磷的关系

在上海城乡梯度上,选取隶属于禾本科和菊科的3种广布型一年生杂草:狗尾草(Setaria viridis)、稗(Echinochloa crusgalli)和醴肠(Eclipta prostrata),通过测定3种杂草单位质量叶片氮含量、单位质量叶片磷含量及其生境中土壤总氮、总磷的含量,分析城乡梯度上植物叶片氮磷含量的变化及其与土壤氮磷之间的关系.结果表明:1总体上,从中心城区至远郊区,3种一年生杂草的叶片氮含量显著上升,而叶片磷含量无显著变化;2其中,狗尾草与醴肠的叶片氮含量呈显著上升趋势,狗尾草叶片磷含量呈显著上升趋势;3土壤总氮、总磷与植物单位质量叶片氮、叶片磷总量呈显著性负相关(p0.05).综上可知,杂草的叶片氮磷含量对城市化有显著响应,物种间存在差异;土壤氮磷含量的变化是其成因之一.     

Chemical composition,phytotoxic and antifungal properties of Ruta chalepensis L. essential oils

The chemical composition, and phytotoxic and antifungal activities of the essential oils isolated by using hydrodistillation from the aerial parts of Tunisian rue were evaluated. Significant variations were observed among harvest periods. The analysis of the chemical composition by gas chromatography/mass spectrometry showed that 2-undecanone (33.4–49.8%), 2-heptanol acetate (13.5–15.4%) and α-pinene (9.8–11.9%) were the main components. The antifungal ability of rue essential oils was tested by using disc agar diffusion against ten plant pathogenic fungi. A high antifungal activity was observed for the essential oil isolated at flowering developmental phase. Furthermore, rue essential oils showed high level of herbicidal activity against several weeds.     

Two New Eremophilenolides from Ligularia fischeri

Ligulariajischerihasl0ngbeenusedastraditi0naImedicinet0relievec0ugh,invig0ratethecircuIation0fbIo0dandst0ppain'.FromtheplantgrowinginShengnonaiia,Hubei-Chlna,t\v0neweremophiIen0lideshavebeenisolated.Comp0undlwasneedlecrystalsfrompetr0lether(60-9O'C),m.p.=148-l50'C.ItsformulawasdeterminedasC,,H,'O'by"C-NMRandDEPTspectrainaccordancewiththem0lecularionpeakm/z=280inEIMS.Thetypeofcarbonsignals(5xC,3xCH,4xCH,,4xCH,)(Table2)sh0wedithadabicyclicsesquiterpeneskeletonbearingameth0xy.ahemi-…     

种植制度对开封和封丘地区麦田杂草群落结构和生物多样性的影响

2005、2006年4～5月份,对开封和封丘地区的小麦-玉米和小麦-水稻两种种植制度条件下冬小麦麦田杂草群落结构进行调查和统计分析.结果表明,两种种植制度麦田杂草种群相似性系数分别是0.65和0.51.二者相比较,小麦-玉米种植制田间杂草优势集中度较低,生物多样性较高,表现为物种丰度高15%～24%,生物多样性高11%～37%,均匀度与种植制度的关系不显著.