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741.
Sixty-eight compounds were identified by coupled gas chromatography and mass spectrometry (GC-MS) in the chemosphere of Cannabis sativa L. pollen and entire male and female plants of two cultivated varieties, Northern Lights and Hawaian Indica. Twenty-one and 28 substances, respectively, were present in pollen of the two forms. To conserve the natural composition of volatiles a delicate headspace method was employed. The two varieties represent different chemotypes which distinguish themselves, in the main quantitatively, in the setup of volatiles from pollen and entire male and female plants. Twenty compounds were monoterpenes, including the five major components: β-myrcene (E)-β-ocimene, terpinolene, β-pinene and limonene; 25 were sesquiterpenes, and the other 23 were of mixed biogenetic origin, including 3-methyl-1-butanol and benzylalcohol which occurred only in pollen; two pyrazines occurred only in Northern Lights females. Besides being of interest in natural products chemistry, the results should have relevance for plant systematics and for the pharmaceutical and technical applications of Cannabis . We demonstrate that the pollen has a distinct chemical character in possessing two exclusive volatiles, while lacking seven compounds occurring in males and females of both variants.  © 2005 The Linnean Society of London, Botanical Journal of the Linnean Society , 2005, 147 , 387–397.  相似文献   
742.
Golden hamsters (Mesocricetus auratus) use olfactory cues to assess traits of conspecifics such as kinship, individual identity, and reproductive status. The environment, however, is full of a wide variety of other olfactory information such as signals emitted by some of the hamster’s primary predators. Given this, we hypothesized that hamsters use odors from predators as an indirect sign of increased predation risk in the environment. In addition, based on data that show that wild hamsters are diurnal while laboratory hamsters are nocturnal, we hypothesized that if golden hamsters did respond to the predator odors, perceived predator risk might influence daily activity patterns in hamsters. We tested male and female hamsters over 5 d with scent gland secretion from domestic ferrets (Mustela putorius furo) and compared their behavior to that observed when they were exposed to a clean arena. In response to the predator odor, subjects significantly decreased the amount of time active outside of their burrow, returned to their burrow more quickly, and spent less time near the predator odor than the clean control stimulus. These results strongly support our hypothesis that hamsters, like other species of small mammals, avoid predator odors. The results did not, however, support our second hypothesis that exposure to predator odors during the dark phase of the light cycle would elicit a switch to a more diurnal pattern of activity. More work is needed to understand how environmental cues and internal mechanisms interact to shape activity patterns.  相似文献   
743.
744.
蓝喉蜂虎的捕食行为与食性   总被引:1,自引:0,他引:1  
在我国有分布的7种蜂虎科鸟类中,蓝喉蜂虎(Merops viridis)分布范围最广,但相关野外研究还比较少。2011~2016年,我们以江西省吉安市郊区的一个蓝喉蜂虎种群为研究对象,在观察野外捕食行为的基础上,记录了其食物种类,研究了该鸟的食性。蓝喉蜂虎的食物主要是蜂类、蝶类和蜻蜓类昆虫,其被捕食频次的百分比分别为26.0%、26.3%和38.3%。其中,繁殖前期以蜂类居多,繁殖后期以蜻蜓类居多,数量比例存在显著的季节性差异。这种差异可能是昆虫生活史差异造成的。网络图片资料佐证了其食物种类主要为以上3类昆虫。在吞食食物前,蓝喉蜂虎会对不同类群的昆虫进行不同时长和不同方式的处理。此外,野外研究发现,产卵期蓝喉蜂虎巢室中散布着可能被吞食过带有食物残渣的小型贝类碎片。通过实验筛选营巢河滩地的沙土,发现这些贝壳碎片是外来。这表明,蓝喉蜂虎可能通过取食小型贝类贝壳,在产卵期获取短期额外的钙质补偿。蓝喉蜂虎在其分布区内属不常见鸟类,但其捕食的主要昆虫类群在我国南方比较常见,这说明食物不是限制该鸟分布的原因。蓝喉蜂虎是一个极具观赏价值的美丽小鸟,当前亟需深入研究,为该鸟的保护提供决策依据。  相似文献   
745.
福建省水稻稻米重金属污染的对应分析   总被引:14,自引:0,他引:14  
采用环境统计学方法布点采集福建省闽南、闽中和闽西北38个早晚稻稻谷样本,应用对应分析方法研究影响地区稻作类型的稻米Hg、As、Cd、Pb、Cu 5种重金属污染差异的主要因子,并通过主要因子揭示重金属与地区稻作类型间的关系.结果表明,福建省不同地区水稻稻米5种重金属含量与稻作类型存在较大差异,变异范围较大,其中超标率最高的是Pb,达100%,其次为Hg和Cd,分别为78.95%和50.0%,最低的是Cu,仅2.3%,而As无超标.Pb和Cd是导致地区稻作类型间差异的主要因子.聚类分析表明,38个稻谷样品可聚为7类,不同地区稻作类型,由于与污染源距离不一,受重金属污染的程度呈明显差异,体现不同的污染特征.可以认为,对不同地区稻作类型稻米重金属污染应采取地区控制与品种搭配相结合的策略,才能达到控制和消除稻米重金属污染的目的.  相似文献   
746.
747.
Objectives: The aims of this study were to: (1) investigate patients' views on euthanasia and physician-assisted suicide (PAS), and (2) examine the impact of question wording and patients' own definitions on their responses. Design: Cross-sectional survey of consecutive patients with cancer. Setting: Newcastle (Australia) Mater Hospital Outpatients Clinic. Participants: Patients over 18 years of age, attending the clinic for follow-up consultation or treatment by a medical oncologist, radiation oncologist or haematologist. Main Outcome Measures: Face-to-face patient interviews were conducted examining attitudes to euthanasia and PAS. Results: 236 patients with cancer (24% participation rate; 87% consent rate) were interviewed. Though the majority of participants supported the idea of euthanasia, patient views varied significantly according to question wording and their own understanding of the definition of euthanasia. Conclusions: Researchers need to be circumspect about framing and interpreting questions about support of 'euthanasia', as the term can mean different things to different people, and response may depend upon the specifics of the question asked.  相似文献   
748.
花生壳粉生物吸附水溶液中阴离子染料的研究   总被引:1,自引:1,他引:0  
An untried,low cost, locally available biosorbent for its anionic dye removal capacity from aqueous solution was investigated. Powder prepared from peanut hull had been used for hiosorption of three anionic dyes, amaranth (Am), sunset yellow (SY) and fast green FCF (FG). The effects of various experimental parameters (e.g.initial pH and dye concentration, sorbent dosage, particle size, ion strength, contact time etc.) were examined and optimal experimental conditions were decided. At initial pH 2.0, three dyes studied could be removed effectively.When the dye concentration was 50 mg" L-1 the percentages of dyes sorbed was 95.5 % in Am, 91.3 % in SY and 94.98 % in FG, respectively. The ratios of dyes sorbed had neared maximum values in all three dyes whensorbent dose of 5.0 g·L^-1 and the sorbent particle size in 80—100 mesh was used. The increasing the ion strength of solution caused the decrease in biosorption percentages of dyes. The equilibrium values arrived at about 36 hour for all three dyes. The isothermal data of biosorption followed the Langmuir and Freundlich models. The biosorption processes conformed the pseudo-first-order rate kinetics. The results indicated that powdered peanut hull was an attractive candidate for removing anionic dyes from dye wastewater.  相似文献   
749.
柯丽娜  庞琳  王权明  韩增林  王辉 《生态学报》2018,38(15):5498-5508
以大连市长兴岛附近海域为研究区域,收集1995年、2000年Landsat TM遥感影像及2005年、2010年、2016年高分辨率遥感影像,分析20年来研究区围填海的动态空间分布及景观格局变化特征,建立面向对象的围填海存量资源分类提取方法,并构建围填海存量资源指数,对长兴岛围填海存量资源状况进行分析,得出以下结论:(1)长兴岛附近海域围填海年动态变化在2010—2016年间幅度最大;长兴岛东南部为围填海动态变化的主要区域。(2)整个区域在监测期内表现出多种围填海小型斑块被整合,大型斑块积极向外扩展的发展态势,区域内景观表现出多样性和复杂性增加而优势度减小的趋势。(3)长兴岛附近海域围填海总体利用效率较低,填而未建区域面积最大,其次为围而未填区域及低效工业城镇用海类型,围填海存量资源总面积达到22008.5 hm~2。  相似文献   
750.
三种乔木落叶分解过程中跳虫群落结构的演替   总被引:9,自引:3,他引:9  
柯欣  赵立军  尹文英 《昆虫学报》2001,44(2):221-226
1993到1995年,用落叶袋法研究跳虫群落在青冈Cyclobalanopsis glauca、马尾松Pinus massoniana和麻栎Quercus acutissima 3种乔木落叶分解过程中的演替变化。青冈落叶分解经淋洗、养分固定和养分活化3个阶段,马尾松和麻栎没有出现阶段性变化。青冈落叶中跳虫个体数和多样性指数均高于马尾松和麻栎落叶中的相应值。跳虫在落叶分解过程中的集聚型分为3组:A组为落叶分解前期集聚的种类,B组为后期的种类,C组为中期或全过程的种类。3种乔木在A组中共有的种类为鳞Tomocerus sp.、等节Isotoma sp. 和杭州刺齿Homidia hangzhouensis;B组共有种类为八眼符Folsomia octoculata、拟裸长角Pseudosinella sp. 和类符Folsomina onychiurina;C组没有共有种类。  相似文献   
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