Electrophysiological and Behavioral Responses of Adult Anoplophora glabripennis (Motschulsky) to Volatile Components of Host-Plant

Electrophysiological and behavioral responses of adult A. glabripennis (Motsch.) to volatiles from ashleaf maple(Acer negundo L.) were investigated to identify semiochemicals involved in host location. Measurable electroantennogram (EAG)responses were elicited to all compounds tested, the most effective antennal stimulants were trans-2-hexen-1-al,decyl aldehyde andtrans-2-hexen-1-ol.These profiles were similar between males and females. In Y-tube olfactometer bioassays, above three com-pounds with certain concentration, trans-2-hexen-1-al (1%), trans-2-hexen-1-ol (1%) and decyl aldehyde (10%), were significantlyattractive to the adults in laboratory. The results show that either EAG or olfactory responding to a particular volatile compound aremarkedly influenced by the concentration.     

杨树BAG基因的鉴定及表达模式分析

【目的】杨树是我国人工林的重要组成部分,也是公认的模式木本植物。植物BAG蛋白作为保守的分子伴侣,在生长发育和抗逆性中起到关键作用。研究杨树BAG蛋白家族的进化与表达模式,鉴定BAG基因的生物学功能对于林木遗传改良具有重要的指导意义。【方法】以拟南芥7个BAG蛋白为诱饵,搜索毛果杨、水稻和小立碗藓在线数据库(https://phytozome.jgi.doe.gov)获得这3个物种同源的BAG蛋白。利用生物信息学构建毛果杨、拟南芥、水稻和小立碗藓BAG蛋白的系统进化树,分析这些蛋白的生化特性及进化关系。结合杨树芯片(http://bar.utoronto.ca)数据,利用qRT-PCR检测杨树BAG基因的组织和逆境(旱和热胁迫)表达模式。【结果】毛果杨包含14个BAG基因,按照国际命名法(以染色体位置进行排序),将其命名为PtrBAG1—PtrBAG14。系统进化树表明杨树、拟南芥、水稻和小立碗藓BAG蛋白相对保守,大体可以分为2个亚家族。第1个亚家族中,大部分BAG蛋白N端含有UBL结构域,可能作为分子桥梁参与降解某些蛋白;第2个亚家族的大部分BAG蛋白含有IQ结构域,意味着这些蛋白可能与Ca²⁺信号相关。杨树BAG基因在不同逆境处理(热胁迫和干旱胁迫)条件下有不同的表达模式。热处理诱导所有BAGs基因表达发生变化,其中BAG1、BAG4、BAG6、BAG7和BAG8表达被激活,而另9个BAG基因的表达被抑制;特别是,热诱导BAG4和BAG6表达上调超过90倍。干旱胁迫条件下,大部分BAG表达变化幅度很小。组织表达模式分析表明,大部分杨树BAG基因在根、叶、芽、小苗、雌花序、雄花序和木质部中表达量很低,只有BAG2和BAG12在木质部中大量表达。【结论】杨树BAG家族共有14个成员,大体分为2个亚家族,在进化上与本文选用的陆生植物拟南芥和水稻BAG蛋白有更高的相似性。杨树14个BAG基因可能都参与了热胁迫调控,但不同成员在抗热过程中起不同作用。相比而言,大部分杨树BAG基因可能并不参与抗旱。值得指出的是,杨树BAG4和BAG6可能在热胁迫中作用最明显,而BAG2和BAG12可能参与木材形成。     

光肩星天牛对干旱胁迫下复叶槭挥发物的嗅觉反应

对干旱胁迫下3a生复叶槭的挥发物进行了鉴定。当复叶槭受到干旱胁迫时，9种化合物释放量升高(包括：丁醇、戊醇、反—2—己烯—1—醛、顺—3—己烯—1—醇、戊醛、戊酸、己醛、己酸、苯乙酮)，而长叶烯释放量降低：复叶槭复水后苯乙酮升高，但其他挥发物释放量降低。通过GC—EAD检测了光肩星天牛对其中某些化合物的触角电位反应，并使用诱捕器和人工合成单体进行了田间生测实验。丁醇、戊醇和顺—3—己烯—1—醇能引起光肩星天牛的触角反应，这一结果在田间实验中得到了证实。这表明干旱胁迫在光肩星天牛选择寄主植物方面起着重要作用。     

2-取代酰氨基-5-(α-龙脑烯醛基)-1,3,4-噻二唑化合物的合成及抑菌活性

以α-蒎烯为原料,先经环氧化和催化异构得到α-龙脑烯醛,再与氨基硫脲反应得到α-龙脑烯醛基缩氨基硫脲,然后环合生成α-龙脑烯醛基噻二唑,最后将其与一系列酰氯发生N-酰化反应,合成得到12个未见文献报道的2-取代酰氨基-5-(α-龙脑烯醛基)-1,3,4-噻二唑化合物(6a~6l)。通过FT-IR、~1H NMR、~(13) C NMR和ESI-MS对12个目标产物进行结构表征,并对目标产物的抑菌活性进行了测试。抑菌活性测试表明:在50 mg/L质量浓度下,目标化合物对5种供试病菌均有不同程度的抑制活性,部分目标化合物的抑菌活性与商品抑菌剂嘧菌酯相近,甚至超过嘧菌酯,其中目标化合物6j对小麦赤霉病菌(Fusarium graminearum)的抑菌率达94.4%,6h对苹果轮纹病菌(Physalospora piricola)的抑菌率达97.7%。     

微波辅助萃取-固相微萃取联用技术分析桑叶挥发性成分

用微波辅助萃取-固相微萃取联用技术,结合气相色谱-质谱法对桑叶挥发性成分进行了鉴定,并用面积归一化法测定其相对含量.共鉴定出化合物45种,包括酮、醇、酸、烷烃、烯烃、甾醇、醛、酯及杂环化合物等,其中酮类化合物占总色谱馏出峰面积的 6.56%;醇类化合物占 33.32%;酸类占 13.71%;烃类占 23.44%.主要化合物有: 3,7,11,15-四甲基-2-十六醇(24.05%)、1-乙酰基-4-异丙基-二环[3.1.0]己烷 (16.27%)、5-(2-异丁烯基)-4,6,6-三甲基-3-环己烯酸(8.35%)、3,7,11,15-四甲基-2-十六碳烯-1-醇(5.67%).该技术可以简便、快捷、准确地进行桑叶挥发性成分的分析鉴定.     

基于GC-MS流苏树种子挥发性成分分析

为研究流苏树种子的成分,探讨不同溶剂提取流苏树种子成分的差异。本研究分别采用石油醚、二氯甲烷和丙酮提取流苏树种子成分,以GC-MS联用技术对其化学成分进行分析。结果显示:石油醚提取物含有10种烷烃类、16种酯类和1种酰胺类化合物,占色谱总流出峰面积的91.36%,其中十六烷酸甲酯(10.83%)、反式-13-十八碳烯酸甲酯(60.67%)和6-十八碳烯酸甲酯(11.29%)含量较高;二氯甲烷提取物含有10种烷烃类、4种酯类、2种酸类和3种烯烃类化合物,占色谱总流出峰面积的80.85%,其中1,2-二甲基环戊烷(8.21%)、十六烷酸(14.51%)、(Z,Z)-9,12-十八碳二烯酸(35.93%)等化合物含量较高;丙酮提取物含有10种烷烃类、11种酯类和2种烯烃类化合物,占色谱总流出峰面积的98.23%,其中十六烷酸甲酯(14.07%)、(Z,Z)-9,12-十八碳二烯酸甲酯(44.65%)、(E)-9-十八碳烯酸甲酯(12.27%)和十八酸甲酯(15.62%)含量较高。石油醚和丙酮提取酯类的效果优于二氯甲烷,在提取酸类和烷烃类化合物时,二氯甲烷效果更佳。不同的溶剂提取流苏树种子成分的组成和含量存在一定的差异。     

油橄榄叶挥发油的质谱分析及其对陈齿爪鳃金龟的诱虫活性

采用水蒸气蒸馏法提取油橄榄树叶的挥发油,利用GC-MS分析了其组成成分,并利用"Y"型嗅觉仪测试陈齿爪鳃金龟对油橄榄树叶挥发油的趋向反应。结果表明,油橄榄树叶挥发性物质中含有58个化合物,其中萜烯类化合物主要有β-石竹烯(14.29%)、α-芹子烯(13.13%)、β-芹子烯(10.15%)和α-石竹烯(6.60%),脂肪族化合物主要为3-己烯-1-醇(5.03%)、橙花叔醇(6.72%)、壬醛(2.27%)和苯乙醛(5.61%)等。陈齿爪鳃金龟雌、雄虫对油橄榄树叶挥发物都表现出明显的趋向反应,在较高测试浓度(100、10μL.mL-1)下,雌虫对油橄榄树叶挥发性物质的趋向反应显著大于雄虫。     

香辛料精油成分对生鲜食品中有害菌杀灭活性研究

采用平板稀释法和菌块转移法研究了百里香酚、丁香酚、肉桂醛、茴香脑、水杨醛、柠檬醛、香兰素7种食用植物精油组分对大肠杆菌、金黄色葡萄球菌、沙门氏菌、单增李斯特菌、副溶血性弧菌等生鲜食品常见5种有害菌的杀灭活性。实验结果表明,水杨醛对5种有害菌的综合杀灭能力最强,然后依次是百里香酚、肉桂醛、茴香脑、丁香酚、柠檬醛、香兰素。通过正交试验将水杨醛、肉桂醛、百里香酚、茴香脑复配,得到最佳组合是为:水杨醛、肉桂醛、百里香酚、茴香脑的质量比为2∶5∶20∶5,其杀灭所有供试菌的最低质量浓度为0.25 mg/L,仅为杀菌效果最好的单一水杨醛浓度的1/2。通过对香辛料精油成分杀菌作用协同效应分析得出,复配的香辛精油对单增李斯特菌的杀灭表现出很强的协同增效作用效果,对金黄色葡萄球菌、大肠杆菌和副溶血性弧菌的杀灭表现出相加作用,而对沙门氏菌则表现出无关作用。     

大花栀子果实的化学成分研究

对茜草科植物大花栀子果实进行化学成分研究,分离得到8个化合物.经理化数据对照和波谱分析,鉴定化合物的结构为:(4R) - 4 - 羟基 - 2,6,6 - 三甲基 - 1 - 环己烯 - 1 - 甲酸(1)、西红花酸(2)、西红花苷 - 4(3)、西红花苷 - 3(4)、西红花苷 - 2(5)、西红花苷 - 1(6)、京尼平苷(7)和京尼平 -1 - β - D - 龙胆二糖苷(8).经检索,其中化合物2 ～ 6为首次从该植物中分离得到.     

Storage lipid dynamics in somatic embryos of Norway spruce (Picea abies): histochemical and quantitative analyses

Adequate storage compounds are a prerequisite for successful development during the later stages of somatic embryogenesis; however, the critical amount of reserves below which somatic embryos fail to mature and germinate has not been determined. We analyzed storage lipids during Norway spruce (Picea abies (L.) Karst.) somatic embryogenesis. As maturation progressed, lipids, which were stored as lipid bodies in the cytoplasm, were localized first in suspensor cells of the early embryos, and later in the embryonic root pole, superficial layers of the hypocotyl and in cotyledons. The concentration of total lipids exhibited marked variation, with values peaking during cotyledon development and then decreasing during maturation. Linoleic (18:2), oleic (18:1), palmitic (16:0) and 5,9-octadecenic (5,9-18:2) acids were the most abundant fatty acids in embryos. As embryos developed, linoleic acid concentration increased slightly, whereas oleic acid concentration decreased. Oleic acid was the most prominent component of the fatty acid spectrum in isolated dormant zygotic embryos and megagametophytes. Addition of 5% polyethylene glycol to the medium during somatic embryo maturation caused a shift in the fatty acid spectrum toward that of zygotic embryos. During maturation, changes in the exogenous carbohydrate supply had no significant effect on total lipid concentration in mature embryos. A marked decrease in lipid concentration was detected during desiccation, indicating the importance of adequate lipid reserves during this developmental stage. The lipid content of zygotic embryos differed considerably with harvest year and location, suggesting that zygotic embryo data cannot be an indicator of somatic embryo quality.     

Wood properties of trembling aspen and paper birch after 5 years of exposure to elevated concentrations of CO(2) and O(3)

We investigated the interactive effects of elevated concentrations of carbon dioxide ([CO(2)]) and ozone ([O(3)]) on radial growth, wood chemistry and structure of five 5-year-old trembling aspen (Populus tremuloides Michx.) clones and the wood chemistry of paper birch (Betula papyrifera Marsh.). Material for the study was collected from the Aspen FACE (free-air CO(2) enrichment) experiment in Rhinelander, WI, where the saplings had been exposed to four treatments: control, elevated [CO(2)] (560 ppm), elevated [O(3)] (1.5 x ambient) and their combination for five growing seasons. Wood properties of both species were altered in response to exposure to the treatments. In aspen, elevated [CO(2)] decreased uronic acids (constituents of, e.g., hemicellulose) and tended to increase stem diameter. In response to elevated [O(3)] exposure, acid-soluble lignin concentration decreased and vessel lumen diameter tended to decrease. Elevated [O(3)] increased the concentration of acetone-soluble extractives in paper birch, but tended to decrease the concentration of these compounds in aspen. In paper birch, elevated [CO(2)] decreased and elevated [O(3)] increased starch concentration. The responses of wood properties to 5 years of fumigation differed from those previously reported after 3 years of fumigation.     

Intra- and inter-provenance variability in phloem phenols of Picea abies and relationship to a bark beetle-associated fungus

One hundred Norway spruce (Picea abies (L.) Karst.) clones (three ramets per clone) were analyzed for phloem phenol composition and concentration before and 10 days after wound inoculation with sterile malt agar. Fifty clones (Experiment 1) belonged to the same provenance, whereas the remaining clones (Experiment 2) belonged to five provenances from three geographic areas. In Experiment 2, two additional ramets from the same clones were mass inoculated with Ceratocystis polonica (Siem.) C. Moreau to quantify the resistance of each clone. Tree response to wound inoculations was characterized by increased catechin concentration in both experiments, accompanied by increases in astringin and decreases in piceid in Experiment 1. In both experiments, we observed a diverse group of phenolic compounds whose concentrations increased (catechin, astringin) or did not vary (taxifolin glucoside) in response to wound inoculations, whereas concentrations of a homogeneous group of stilbene compounds decreased (piceid) or did not vary (isorhapontin, unidentified stilbene). In Experiment 2, provenances from the alpine and Hercynian-Carpatic areas differed from provenances from the Baltic area with respect to the relative importance of these two groups of compounds, further indicating that the two groupings of phenolic compounds structure the Norway spruce populations. Eighty days after mass inoculation, the percentage of healthy sapwood, which was taken as a measure of tree resistance, indicated that clones from the Baltic area were less resistant to mass inoculations than clones from the alpine and Hercynian-Carpatic areas. We conclude that the degree of resistance of Norway spruce trees to mass inoculations with a bark beetle-associated fungus can be predicted based on the diversity of constitutive phloem phenols and the ability to induce phenol synthesis in response to wounding.     

Cardiovascular effects of Sida cordifolia leaves extract in rats

The cardiovascular activity of the aqueous fraction of the hydroalcoholic extract of Sida cordifolia leaves (AFSC) was evaluated. In normotensive non-anaesthetized rats was observed that AFSC (5, 10, 20, 30 and 40 mg/kg, i.v.) induced hypotension (6 +/- 2%; 8 +/- 2%; 11 +/- 2%; 19 +/- 3% and 33 +/- 3%, respectively) and bradycardia (0.3 +/- 3%; 13 +/- 4%; 38 +/- 6%; 64 +/- 7% and 80 +/- 5%, respectively). Hypotensive response was completely abolished after atropine (2 mg/kg; i.v.) but potentialized after hexamethonium (20 mg/kg; i.v.) (12 +/- 2%; 21 +/- 5%; 28 +/- 3%; 32 +/- 2% and 32 +/- 3%, respectively), while bradycardic response was completely abolished after atropine (2 mg/kg; i.v.) and attenuated with hexamethonium (20 mg/kg; i.v.) (1 +/- 0.3%; 5 +/- 1%; 7 +/- 1%; 7 +/- 1% and 10 +/- 1%, respectively). In hexamethonium treated rats, L-NAME significantly attenuated the hypotensive response (9 +/- 2%; 14 +/- 1%; 16 +/- 1%; 16 +/- 2% and 22 +/- 3%, respectively). In normotensive anaesthetized and vagotomized rats, hypotensive and bradycardic responses were significantly attenuated (0.5 +/- 0.2%; 1 +/- 0.4%; 3 +/- 0.6%; 4 +/- 0.8% and 6 +/- 1%, respectively, n = 6, and 7 +/- 2%; 12 +/- 5%; 15 +/- 2%, 17 +/- 2% and 25 +/- 3%, respectively). The anaesthesia with sodium thiopental did not affect the AFSC-induced responses when compared with those induced in non-anaesthetized rats (data not showed). In conclusion, the results obtained so far show that AFSC produce hypotension and bradycardia, mainly due to a direct stimulation of the endothelial vascular muscarinic receptor and indirect cardiac muscarinic activation, respectively.     

Oxidation of hardwood kraft-lignin to phenolic derivatives with oxygen as oxidant

 A hardwood kraft lignin was oxidized in alkaline medium to obtain phenolic compounds (syringaldehyde, vanillin and its acids). To avoid lignin condensation, the lignin was precipitated from a black liquor with a calcium salt dissolved in a water soluble alcohol. Oxygen was the oxidant employed, and copper (II) and cobalt (II) salts were used as catalysts. Effect of temperature, reaction time, oxygen pressure, alkali concentration and catalyst on yield and product distribution were studied. In all the range of variables lignin conversion and aldehyde yield remains low and the more important effect on aldehyde yield was due to the alkali concentration, which must be fixed at about 2 N. The precipitation method did not significantly increase the aldehyde yield, in contrast with the results of nitrobenzene and CuO oxidations. In catalyzed oxidations, no increase in phenolic aldehydes was observed and, with some catalyst, the conversion into phenolic derivatives was reduced. Lignin conversion into low molecular weight products is responsible for the low phenolic product yield and the type of catalyst could lead the oxidation into phenolic products or into low molecular weight acids. Received 23 November 1998     

Organic and inorganic sulfur transport in the xylem sap and the sulfur budget of Picea abies trees

Temporal changes in inorganic and organic sulfur compounds (sulfate, glutathione, cysteine, methionine) were analyzed in xylem sap of 40-year-old Norway spruce (Picea abies (L.) Karst.) trees growing on acidic soils at a healthy and a declining stand in the Fichtelgebirge (North Bavaria, Germany). Studies were carried out (1) to quantify glutathione (GSH) transport in the xylem of spruce, (2) to study the significance of reduced sulfur versus sulfate (SO(4) (2-)) transport in the xylem, and (3) to compare total sulfur (S) transport in the xylem with the amount of foliar uptake of SO(2) in an air-polluted environment. Glutathione was the main reduced S compound in the xylem ranging in concentration from 0.5 to 5 &mgr;mol l(-1). Concentrations of inorganic SO(4) (2-) in the xylem sap were up to 50 times higher than those of GSH ranging from 60 to 230 &mgr;mol l(-1). During the growing season, concentrations of all S compounds in the xylem were highest in May (up to 246 &mgr;mol l(-1)) and decreased during summer and fall (up to 21 &mgr;mol l(-1)). On average, SO(4) (2-) concentrations in xylem sap were 30% higher at the declining site compared with the healthy site. Diurnal changes in organic S compounds were significant for GSH and cysteine with high concentrations during the night and low concentrations during the day. Diurnal changes in inorganic concentrations were not significant. Xylem sap concentrations of SO(4) (2-) and cysteine were twice as high and GSH concentrations were tenfold higher in surface roots than in branches. At both sites, transport of organic S was low (up to 3% of total S) compared to transport of SO(4) (2-). Annual transport of total S in the xylem (SO(4) (2-) was the main component) ranged from 60 to 197 mmol tree(-1) year(-1) at the healthy site and from 123 to 239 mmol tree(-1) year(-1) at the declining site. Although gaseous uptake of SO(2) was estimated to be similar at both sites (38 mmol tree(-1) year(-1); Horn et al. 1989), the ratio between annual gaseous uptake of SO(2) and transport of S in the xylem was 1:4 and 1:5 at the healthy and declining sites, respectively.     

Chemical composition and anti-inflammatory activity of <Emphasis Type="Italic">Boswellia ovalifoliolata</Emphasis> essential oils from leaf and bark

We isolated the essential oils from Boswellia ovalifoliolata N.P.Balakr and A.N.Henry using hydrodistillation, identified the obtained compounds using gas chromatography–mass spectrometry (GC–MS) and Fourier transform-infrared spectroscopy (FT-IR), and studied the photophysical and electrochemical properties using UV–visible and fluorescence spectroscopy and cyclic voltammetry. On the basis of GC–MS spectra, 38 compounds were identified in the essential oil from leaves and 26 in the oil from bark. The bark oil contained 13.44% β-Farnesene (sesquiterpene), 10.45% caryophyllene oxide (sesquiterpene) and 6.6% spathulenol, (2Z,6E)-(sesquiterpene alcohol); the leaf oil contained 11.1% spathulenol (sesquiterpene alcohol), 9.0% caryophyllene oxide (sesquiterpenoids) and 6.3% decyl acetate (ester). FT-IR spectra confirmed the presence of aliphatic aldehydes and ketones, carboxylic acid, alcohols, esters and ethers in both oil types. UV–visible absorption spectra showed maximum absorbance at 245, 290 and 402 nm for bark oil, and 250, 285 and 325 nm for leaf. Bark oil showed strong emission with maximum emission wavelength at 456 nm was higher than that of leaf oil at 414 nm. The essential oil had significant anti-inflammatory activity, and the reduction potential of the leaf oil was ?0.44 and ?0.56 eV for bark.     

泡桐(原变种)果实中抑菌性苯丙素苷成分的研究

研究了泡桐(原变种)果实的化学成分。采用Sephadex LH-20柱色谱及薄层色谱等方法进行分离,从其70%丙酮提取物水溶性部分分离得到4种苯丙素苷化合物,经波谱分析及理化性质分析,化合物分别鉴定为:毛蕊花苷(1)、异毛蕊花苷(2)、campneoside II(3)和isocampneoside II(4)。化合物1和2首次从该植物中得到。抑菌活性试验结果表明,泡桐(原变种)果实中分离得到的苯丙素苷化合物、丙酮提取物、乙酸乙酯溶及水溶性部分具有较高的抑菌活性,其中,对革兰氏阳性菌中表皮葡萄球菌的抑制能力最强。     

Effects of elevated concentrations of atmospheric CO2 and tropospheric O3 on leaf litter production and chemistry in trembling aspen and paper birch communities

Human activities are increasing the concentrations of atmospheric carbon dioxide ([CO2]) and tropospheric ozone ([O3]), potentially leading to changes in the quantity and chemical quality of leaf litter inputs to forest soils. Because the quality and quantity of labile and recalcitrant carbon (C) compounds influence forest productivity through changes in soil organic matter content, characterizing changes in leaf litter in response to environmental change is critical to understanding the effects of global change on forests. We assessed the independent and combined effects of elevated [CO2] and elevated [O3] on foliar litter production and chemistry in aspen (Populus tremuloides Michx.) and birch-(Betula papyrifera Marsh.) aspen communities at the Aspen free-air CO2 enrichment (FACE) experiment in Rhinelander, WI. Litter was analyzed for concentrations of C, nitrogen (N), soluble sugars, lipids, lignin, cellulose, hemicellulose and C-based defensive compounds (soluble phenolics and condensed tannins). Concentrations of these chemical compounds in naturally senesced litter were similar in aspen and birch-aspen communities among treatments, except for N, the C:N ratio and lipids. Elevated [CO2] significantly increased C:N (+8.7%), lowered mean litter N concentration (-10.7%) but had no effect on the concentrations of soluble sugars, soluble phenolics and condensed tannins. Elevated [CO2] significantly increased litter biomass production (+33.3%), resulting in significant increases in fluxes of N, soluble sugars, soluble phenolics and condensed tannins to the soil. Elevated [O3] significantly increased litter concentrations of soluble sugars (+78.1%), soluble phenolics (+53.1%) and condensed tannins (+77.2%). There were no significant effects of elevated [CO2] or elevated [O3] on the concentrations of individual C structural carbohydrates (cellulose, hemicellulose and lignin). Elevated [CO2] significantly increased cellulose (+37.4%) input to soil, whereas elevated [O3] significantly reduced hemicellulose and lignin inputs to soil (-22.3 and -31.5%, respectively). The small changes in litter chemistry in response to elevated [CO2] and tropospheric [O3] that we observed, combined with changes in litter biomass production, could significantly alter the inputs of N, soluble sugars, condensed tannins, soluble phenolics, cellulose and lignin to forest soils in the future.     

瑞香狼毒根的超临界萃取物抑菌活性和成分分析

瑞香狼毒(Stellera chamaejasme)为瑞香科(Thymelaeaceae)植物,广泛分布于我国西北、华北等地(刘欣等,2004)。据《神农百草经》记载,瑞香狼毒与大戟科(Euphorbiaceae)植物狼毒大戟(Euphorbia fischeriana)、月腺大戟(E.ebracteolata)同作狼毒入药,其性味苦平,全草有毒,有逐水祛痰、破积杀虫之功效(张慧文等,2006)。瑞香狼毒也是一种     

Gas exchange and dry matter allocation responses to elevation of atmospheric CO(2) concentration in seedlings of three tree species

Photosynthetic rates of 13-month-old Pinus radiata D. Don, Nothofagus fusca (Hook f.) ?rst. and Pseudotsuga menziesii (Mirb.) Franco seedlings grown and measured at elevated atmospheric concentrations of CO(2) (~620 microl l(-1)) were 32 to 55% greater than those of seedlings grown and measured at ambient (~310 microl l(-1)) concentrations of CO(2). Seedlings grown in ambient and elevated concentrations of CO(2) had similar rates of photosynthesis when measured at ~620 microl l(-1) CO(2), but when measured at ~310 microl l(-1) CO(2), the P. radiata and N. fusca seedlings which were grown at elevated CO(2) had lower rates of photosynthesis than the seedlings grown at an ambient concentration of CO(2). Stomatal conductances in general were lower when measured at ~620 microl l(-1) CO(2) than at ~310 microl l(-1) CO(2). Stomatal conductances declined in all species grown at both CO(2) concentrations when the leaf-air water vapor concentration gradient (DeltaW) was increased from 10 to 20 mmol H(2)O mol(-1) air. The percent enhancement in photosynthesis for P. radiata and P. menziesii at elevated CO(2) was greater at 20 mmol than at 10 mmol DeltaW, suggesting that elevated CO(2) may moderate the effects of atmospheric water stress. Dry matter allocation patterns were not significantly different for plants grown in ambient or high CO(2) air.