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.     

Two new eremophilane Sesquiterpenoides from Ligularia dictyoneura

Abstract

Two new eremophilane sesquiterpenoides, 6α,9α-dihydroxyeremophilenolide (1), and 1β,10β-dihydroxyeremophilenolide (2), along with ten known eremophilane sesquiterpenoides (3–12) were isolated from the aerial parts of Ligularia dictyoneura (Franch.) Hand.-Mazz. Their structures were elucidated by means of extensive spectroscopic analysis. Compounds 3–6 were assessed for their cytotoxicity against five human cancer cell lines (HL-60, SMMC-7721, A-549, MCF-7 and SW-480), and the result showed that they had no activity.     

A new efficient synthesis of GR24 and dimethyl A-ring analogues, germinating agents for seeds of the parasitic weeds Striga and Orobanche spp.

An efficient and high yielding preparation for the synthetic germination stimulant GR24 (5) and its A-ring dimethyl-substituted analogues 30-32 has been described. The first step involves a Stobbe condensation of benzaldehydes 9-11 with dimethyl succinate. Subsequent transposition of the ester and reduction of the double bond provides the building blocks 15-17 for an intramolecular Friedel-Crafts acylation. ABC-lactones 22-25 are prepared from γ-keto esters 18-21 by saponification, subsequent reduction with sodium borohydride followed by acid-catalyzed lactonization. Coupling of the lactones with the D-ring is accomplished by formylation and subsequent treatment with bromobutenolide 8 to give GR24 and its dimethyl analogues. Bioassays with Striga hermonthica seeds reveal that the dimethyl analogues are slightly less active than GR24 itself.     

Flavonoids from Carthamus tinctorius

Two new flavonoids,(2S)-4′,5-dihydroxyl-6,7-di-O-β-D-glucopyranosyl flavanone(1) and 6-hydroxykaempferol 6,7-di-O-β-D-glucopyranoside(2),were isolated from Carthamus tinctorius.Their structures were elucidated by spectroscopic means including 2D NMR,ESIMS and CD.     

成都市维管植物杂草分布区类型研究

在实地调查的基础上,分析了成都市维管杂草科和属的区系特征.结果表明,成都市维管杂草有75科218属310种,其中外来入侵杂草28种.科的分布区类型分别属于6种类型和4种变型,以热带亚热带成分为主,属的分布区类型隶属于14种类型和9个变型,其热带亚热带分布与温带成分基本相等,表现出从热带亚热带向温带过渡的性质.世界分布的...     

杂草生物治理研究进展

综述了国内外以昆虫、病原微生物、动物、植物、微生物代谢物治理杂草的研究概况，指出杂草生物治理具有对环境安全、持效性强、经济效益高等优点，是实施杂草治理可持续发展的根本出路，具有十分重要的生态、环保和经济意义。     

加拿大一枝黄花挥发油成分及其抗菌活性

为研究加拿大一枝黄花挥发油的化学成分及其抗菌活性,采用水蒸气蒸馏法从上海江湾机场9月所产加拿大一枝黄花中提取挥发油,并用GC-MS技术结合计算机检索对其化学成分进行分析鉴定,用色谱峰面积归一化法计算各组分的相对质量百分数.现共鉴定了加拿大一枝黄花挥发油的28个成分,是总挥发油的85.88%,其主要成分为大香叶烯D(Germacrane D),D-柠檬烯(D-Limonene).另采用平板打孔法,测试了加拿大一枝黄花挥发油的抗菌活性.结果表明,加拿大一枝黄花挥发油对大肠杆菌和枯草芽孢杆菌具有显著的抑制作用,对金黄色葡萄球菌作用不明显.大香叶烯D(Germacrene D)是其主要的抗菌活性成分.     

温度胁迫对菊科杂草生理指标的影响及其适应

设置4,24,44 ℃温度梯度,处理大蓟 （Cirsium souliei）、加拿大飞蓬（Erigeron canadensis L.）、清明菜（Herba Gnaphalii Affinis）、白蒿（Herba Artemisiae Scoparia）、苦荬菜（Ixeris chinesis(Thunb.) Nakal）、马兰（Baphicacanthus cusia）、天名精（Carpesium abrotanoides L.）、黄鹌菜（Youngia japonica (Linn.)DC.）、泥胡菜（Hemistepta lyrata Bunge）和小蓟（Herba Cephalanoploris）等10种菊科杂草,并测定其叶片中丙二醛含量、脯氨酸、可溶性糖和过氧化物酶活性.结果表明：10种菊科杂草对高温耐受能力由大到小分别为马兰、泥胡菜、黄鹌菜、清明菜、小蓟、大蓟、加拿大飞蓬、天名精、白蒿和苦卖菜;对低温耐受能力由大到小分别为天名精、加拿大飞蓬、马兰、白蒿、大蓟、泥胡菜、苦卖菜、小蓟、黄鹌菜和清明菜.     

菜王星防除春油菜地阔叶杂草效果评价

采用菜王星药剂防除春油菜地阔叶杂草，结果表明：苗期使用３０．０、３７．５、４５．０、５２．５ａｉｇ／ｈｍ＾２，总草鲜重防效分别为４６．７％，５７．１％，６８．２％和７７．０％，其中对薄蒴草的防效最高，为９６．９％，对巨荬菜的防效最低，为６４．５％，该药品对油菜安全、高效、增产效果明显。     

A New Ecdysteroid from Rhaponticum uniflorum

The root of Rhaponticum uniflorum (L.) DC. was used in China as a chinese traditional medicine for the treatment of fever and intoxications1. Since the 1980s this plant have been studied and some phytoecdysteroids and other compounds were isolated2-4. We report here the isolation and structural elucidation of a new ecdysteroid 2, 3, 20, 22-diacetonide ajugasterone (1), as well as the isolation of three known ecdysteroids, ecdysterone (2), ajugasterone C (3), ajugasterone C-20, 22-monoacetoni…