刺五加、短梗五加的花蜜分泌节律、花蜜成分及访花者多样性的比较研究

野外定位观测刺五加（Eleutherococcus senticosus）、短梗五加（E.sessiliflorus）的花蜜分泌节律、访花者的多样性,室内分析其花蜜的主要成分。结果表明,刺五加雄株的花杂在开花1－3（4)d分泌花蜜,雌株在开花5－7,6－8或7－9d分泌花蜜;短梗五加以及刺五加两性株的部分花杂,在开花后有两次分泌花蜜的过程：第1次与花药开裂散粉时间一致,第2次与柱头具可授性的时间一致。而且,刺五加和短梗五加都由动物帮助传粉,花蜜分泌的时间与多数访花者的访花时间一致,在一天之中,散出花粉的花朵分泌花蜜的时间早于接受花粉的花杂,这种时间差异应该是植物控制该 花者流向并导致传粉成功的关键。短梗五加与刺五加之间以及刺五加不同性别的植株之间,花蜜的成分及相对含量各有特点,但都以果糖和葡萄糖为主。在刺五加、短梗五加花朵上记录到的访花昆明分别为50余种和40余种,多数隶属于膜翅目、鳞翅目、鞘翅目和半翅目。其中膜翅目的胡蜂、马蜂、熊蜂,双翅目的食蚜蝇、寄蝇等是刺五加、短梗五加的常见访花者。     

獐牙菜属四种植物花蜜特征的比较

花蜜的分泌特征在种间、种内以及植株内不同花朵间的变异决定了花朵对访花动物的吸引和访花模式, 进而影响传粉效率和植物繁殖成功。然而, 我们对花蜜分泌特征变异性的认识还不够深入, 缺乏野外实验数据。研究选取龙胆科獐牙菜属(Swertia) 4种同域分布的植物, 即獐牙菜(S. bimaculata)、西南獐牙菜(S. cincta)、贵州獐牙菜(S. kouitchensis)和紫红獐牙菜(S. punicea)为研究对象, 开展花蜜特征及其变异性的研究。通过比较种内套袋24 h和自然状况下花朵的3个花蜜特征, 即花蜜体积、糖浓度和含糖量(重量)的异同, 以及同一植株不同花朵间花蜜特征的差异, 试图阐明花蜜特征在种间、种内植株间和个体内的变异性。结果显示獐牙菜属4种植物的花蜜特征有显著差异; 套袋24 h处理和自然状态花朵的花蜜特征大多有显著差异, 仅有獐牙菜和贵州獐牙菜的糖浓度在两种处理间差异不显著; 相邻两朵花的糖浓度都具有显著正相关, 然而, 花蜜体积和糖含量在相邻花朵间的相似性较低; 相邻两朵花花蜜特征的正相关在套袋处理花中高于自然状态, 显示自然状态下花蜜特征的高变异性。研究结果表明花蜜的变异性包括: (1)花蜜的种间差异可能与传粉昆虫类群有关; (2)同一植株相邻花朵间花蜜糖浓度显著相关, 表明花蜜体积和含糖量相互调节使得花蜜糖浓度保持在相似区间内; (3)花蜜特征在个体间和花朵间较高的变异性可促使传粉者在植株间访问, 从而提升植物繁殖成功率。     

中国野生稻收集、鉴定和保存现状

本通过介绍我国野生稻种质资源的考察、收集、繁种、编目、鉴定、评价和保存、保护状况,论述了我国野生稻丰富的遗传多样性和种质资源研究成就,针对目前存在的突出问题,提出了我国野生稻种质资源研究目标和主要任务。     

传粉生物学中几种花蜜采集和糖浓度测定方法的比较

花蜜的研究是花生物学中的一个重要内容,探寻实用的方法将方便野外操作。我们分别还用毛细管、注射器、滤纸条和离心法采集了5种花的花蜜,以比较各种方法的优劣,并用3种旋光测糖仪测量了慈姑Sagittaria trifolia L,的雌雄花的花蜜糖含量。目的是为寻找一种适合小型花的花蜜采集测量方法。结果表明,几种方法的适用性受花的大小、形状、蜜的分泌量及蜜腺位置的影响非常大,不同的花要采用不同的方法。对于一般的野外工作建议用毛细管采集后使用便携式旋光测糖仪测其糖含量。特别小的花和蜜量微小的花可以采用离心法收集。     

国家多年生牧草种质圃资源收集、保存及利用

本文简述了国家种质多年生牧草圃概况,介绍了多年生牧草种质资源收集、保存及利用状况.截止到2008年底,共收集保存了600份牧草种质资源材料,隶属10科,49属,152种.禾本科(Gramineae)牧草有24属95种,豆科(Leguminosae)牧草15属35种,占保存材料85%以上,其中野生种有496份材料,引进栽培种有104份材料.每年向国内外相关科研单位及教学单位提供利用种质材料100余份,提供的种质材料多数用于科学研究,还有部分用于推广利用.指出了国家种质多年生牧草圃今后在多年生牧草资源收集、保存、鉴定及利用方面的研究重点.     

热带牧草种质圃资源收集、保存及分发利用研究

简述了农业部儋州热带牧草种质圃概况,介绍了热带牧草种质资源收集、保存及分发利用状况。截止到2013年底,共收集国内外热带牧草种质7760份,先后从中选育出22个牧草及饲料作物新品种通过全国牧草品审会审定。圃内无性繁殖材料活体保存草种质1552份,隶属3科68属202种,其中禾本科牧草种质有60属186种,豆科牧草资源有6属42种,莎草科有4属5种,引进种质有378份。每年向国内外相关科研院所、大专院校及企业和个人提供实物草种质材料300余份,提供种质数据信息400余条,指出了今后热带牧草种质圃在热带牧草资源收集、保存、分发利用方面的研究重点和研究方向。     

松墨天牛成虫标本保存及其DNA提取质量比较

【目的】探讨适合DNA提取的天牛成虫标本保存方法。【方法】采用SDS-蛋白酶K消化法对液氮中冷冻保存、无水乙醇-20℃冷冻保存、无水乙醇室温保存和干标本室温保存且保存时间在2年以上的松墨天牛Monochamus alternates Hope成虫标本基因组DNA进行提取,并对不同保存方式提取的DNA样本进行了质量比较和分析。【结果】在上述常见的松墨天牛成虫标本4种保存方式中,以液氮中冷冻保存效果最佳,其次为无水乙醇-20℃冷冻保存,插针干标本室温保藏效果最差。利用昆虫线粒体基因CO I和CO II的通用引物从上述DNA中均能够成功扩增出目的片段,测序结果证实扩增片段符合预期。【结论】液氮和无水乙醇-20℃冷冻保存适合松墨天牛成虫标本长期保存,且不影响后续的PCR扩增和测序。     

蜜蜂选择性采蜜与花蜜温度有关

澳大利亚莫纳什大学的昆虫学家MelanieNorgate和AdrianDyer经研究发现,生长于澳大利亚本土的无刺蜜蜂会在寒冷的天气喝“热饮”来暖身,而在温暖的天气会喝“冷饮”来给自己降温。     

粉蚧标本保存与DNA提取方法的比较

【目的】探讨适合粉蚧的标本保存及DNA提取方法。【方法】采用改良CTAB法、改良SDS法、Gen Mag Bio动物细胞组织/细胞基因组磁珠法以及Gene JET Genomic DNA纯化试剂盒法4种方法分别对新鲜活体4℃、无水乙醇﹣20℃和无水乙醇4℃3种保存方式且保存一年以上的扶桑绵粉蚧Phenacoccus solenopsis成虫进行DNA提取,并对不同提取方法所获取的DNA纯度与质量浓度进行分析比较验证。【结果】3种保存方式中,新鲜活体效果最好,其次为无水乙醇-20℃。无水乙醇4℃效果和无水乙醇﹣20℃无明显区别,均存在一定程度的降解。对于新鲜活体标本,以CTAB法提取的DNA质量最高,其次为Gen Mag Bio磁珠法和SDS法,Gene JET试剂盒法最差;对于无水乙醇﹣20℃和4℃保存时间较长的标本,磁珠法提取的DNA质量明显优于其余3种方法。【结论】无水乙醇﹣20℃可用于粉蚧长期保存,可满足后续分子研究需要;改良CTAB法对新鲜粉蚧成虫DNA提取效果较好,磁珠法对长时间保存DNA存在一定程度降解的粉蚧成虫效果较好。     

外泌体提取及保存技术研究进展

外泌体是多种活细胞经过内吞-融合-外排等一系列过程主动向胞外分泌的纳米级双层膜结构小囊泡,广泛存在于血液和尿液等生物体液中.因其携带着多种蛋白质、核酸和脂质等生物活性分子,所以外泌体不仅在细胞间物质交换和信息传递中发挥重要作用,而且对疾病诊断、预后预测和治疗管理等均具有提示意义.外泌体的高效提取、分离和完整保存是研...     

Floral nectar chemical composition of some species from Patagonia. II

Floral nectar chemical compositions of 28 species native to Argentinian Patagonia are reported. Most data obtained are new reports at the generic and/or the specific level. Nectars of these species show high mean concentrations (42.35±15.56; %, wt/total wt of solution). Most of the species are hexose dominant (68%) and the remaining are sucrose rich (11%) or sucrose dominant (21%). The hexose ratio shows that in most species (71%) glucose predominates over fructose. The nectars of all species have amino acids. In 32% of them, lipids were detected, whereas phenols were present in around 60%. Most of the species are entomophilous, mainly melittophilous and psychophilous. These data together with those of our previous report include a total of 57 species from 19 families, and suggest three trends in the nectar sugar traits of Patagonian plants, regardless of their systematic relationship or floral syndrome: high concentration, hexose dominance, and predominance of glucose. These results suggest that nectar characteristics are not always as similar for plants pollinated by the same animal taxa as formerly thought.     

Phylogenetic constraints vs. ecology in the nectar composition of Acanthaceae

Nectar composition and concentration were analyzed for 75 samples of 70 species of Acanthaceae representing all major intrafamiliar groups. Analyses of variance were conducted to test for significant differences between pollination syndromes and between taxonomical or phylogenetic groups (genera). The available data indicate that the characteristics of nectar in Acanthaceae are predominantly determined by adaptation to needs of the pollinators rather than by phylogenetic constraints.     

Hummingbirds pay a high cost for a warm drink

Endotherms must warm ingested food to body temperature. Food warming costs may be especially high for nectar-feeding birds, which can ingest prodigious volumes. We formulated a mathematical model to predict the cost of warming nectar as a function of nectar temperature and sugar concentration. This model predicts that the cost of warming nectar should: (1) decrease as a power function of nectar concentration, and (2) increase linearly with the difference between body temperature and nectar temperature. We tested our model on rufous hummingbirds (Selasphorus rufus). A typical experiment consisted of feeding birds nectar of a given concentration at 39°C (equivalent to body temperature) and then at 4°C, and vice versa. We used the percentage change in metabolic rate between the two food temperatures to estimate the cost of warming nectar. The model's predictions were accurately met. When birds had to hover rather than perch during feeding bouts, estimated food-warming costs were only slightly lower. The cost of warming nectar to body temperature appears to be an important yet overlooked aspect of the energy budgets of nectar-feeding birds. Hummingbirds feeding on 5% sucrose solutions at 4^oC have to increase their metabolic rate by an amount equivalent to that elicited by a 15°C drop in ambient temperature.Abbreviations AE assimilation efficiency - C nectar concentration - H' cost of warming food to body temperature - SDA specific dynamic action - T_a ambient temperature - T_b body temperature - T_n nectar temperatureCommunicated by: G. Heldmaier     

Nectar Features in Esterhazya macrodonta, a Hummingbird-Pollinated Scrophulariaceae in Southeastern Brazil

Esterhazya macrodonta is scarcely visited by hummingbirds, a fact that may be related to its low flower production and nectar features. Received 14 September 2000/ Accepted in revised form 31 January 2001     

Flower morphology,nectar traits and pollinators of Cerinthe major (Boraginaceae-Lithospermeae)

In April and May 2010, a natural population of Cerinthe major (Boraginaceae-Lithospermeae) was investigated with regard to: floral morphology, phenology, sexual receptivity during anthesis, the production of nectar and its sugar and amino acid content. The pollinator array of this species was also investigated. Cerinthe major has showy, pentamerous, hermaphroditic flowers with a deep yellow corolla tube arranged on numerous scorpioid inflorescences. Nectar and pollen are the main floral rewards for pollinators. The arrangement of stamens limits access to nectar and promotes pollen loading onto pollinator bodies as they force their way towards the source of nectar. By limiting the direct exposure of nectar to the environment, the corolla tube and the arrangement of anther filaments seemingly protect nectar from evaporation resulting from high temperatures and low relative humidity during flower anthesis. The green, annular nectary located at the base of the ovary lobes is composed of a very thin epidermis enclosing a dense mass of parenchyma. The epidermis lacks stomata, and the thin cuticle has an irregular surface. The parenchyma cells do not store starch during the pre-secretory stage, suggesting that immediate photosynthesis is the most likely source of nectar carbohydrates. Generally, anthesis lasts 4–5 days; the gynoecium becomes fully receptive on the second day and this is synchronous with anther dehiscence. Since nectar production begins during the bud stage, a substantial volume is available for flower visitors at anthesis. Nectar production decreases drastically in senescent flowers and, if not consumed, the nectar can be re-absorbed. Analysis of sugars revealed a sucrose-dominant nectar (sucrose = 93.18 ± 1.35%). Proline, GABA, taurine, leucine, citrulline and alanine were the main amino acids present and are probably implicated in pollinator flight performance.