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。     

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。     

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。     

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。     

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...     

不同方法保存的蜜蜂基因组DNA提取的比较

目的:找出适合DNA提取的昆虫标本保存方法。方法:用几种常用的昆虫标本保存方法对蜜蜂处理不同时间后,用蛋白酶K法对其基因组DNA进行提取和纯化,然后对提取产物做琼脂糖凝胶电泳及紫外吸收分析。结果:75%乙醇及冻存处理材料的基因组DNA得率较高,为7.13～8.85μg/g,电泳条带较亮;甲醛处理材料的基因组DNA得率较低,为1.50～3.21μg/g。结论:用75%乙醇及冻存处理蜜蜂较适合于其基因组DNA的提取,不宜用甲醛。     

Nectar yeasts in Delphinium nuttallianum (Ranunculaceae) and their effects on nectar quality

Microorganisms colonize the nectar of many angiosperms. Variable diversity and spatio-temporal dynamics of nectar-inhabiting microorganisms (e.g., yeasts) may drive variation in nectar sugar composition and subsequent plant–pollinator interactions. We assessed yeast frequency of occurrence and density in the nectar of the perennial herb, Delphinium nuttallianum, across multiple spatio-temporal scales, including flower lifetime and sex-phase transition, flowering season, populations, and years. We tested the hypothesis that pollinators vector yeasts by comparing densities between virgin flowers and those open to visitation. Finally, we identified yeasts using molecular methods and tested for an association between yeast density and nectar composition using ultra-performance liquid chromatography. Yeasts were frequent colonists of Delphinium nectar, occurring in all populations and years sampled. Yeast frequency of occurrence and density varied across most spatio-temporal scales examined. Pollinators were vectors of yeast: virgin flowers remained yeast-free, while those open to visitation became inoculated. Nectar samples were species-poor, with a majority colonized by Metschnikowia reukaufii. Finally, increasing yeast density was correlated with a decrease in sucrose and an increase in monosaccharides. Our results document that yeasts form species-poor communities in populations of this hermaphroditic perennial, in addition to highlighting their spatio-temporal dynamics and effects on nectar quality. Spatio-temporal variation in frequency of occurrence, density, and changes in nectar may have important implications for the nature and strength of interactions between Delphinium and its pollinators.     

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.     

Morphology,nectar characteristics and avian pollinators in five Andean Puya species (Bromeliaceae)

Five Andean Puya species (Puya alpestris, Puya chilensis, Puya coerulea, Puya raimondii and Puya venusta) were studied to determine the relationship between their avian visitors, and plant morphology and nectar characteristics. Our results showed a significant relationship between nectar concentration, presence of sterile apex and avian pollinators's species. In contrast, nectar composition was not related to the frequency of avian visits. We found that Puya species were mainly visited by specialist nectarivorous birds such as hummingbirds (i.e., P. coerulea and P. venusta), lacked a sterile apex and produced high nectar concentration in low volumes. In contrast, species mainly visited by generalist passerines (i.e., P. chilensis and P. alpestris) were characterized by the presence of a sterile apex and production of highly diluted nectar in large volumes. In a mono-specific group we found that P. raimondii produces highly concentrated nectar in large volumes, and its flowers were visited by hummingbirds and passerine birds. We found no effect of nectar composition on bird's visits. Our study highlights the interplay between morphological traits, nectar characteristics and the ecological framework to explain specialized and generalized birds pollination systems.     

The occurrence and significance of amino acids in floral nectar

Approximately 1 500 angiosperm species, in previous papers, have been sampled for the assessment of the amino acids (a. a.) in their nectar. We reaffirm that the findings provide statistically significant data linking differences in the concentration with pollinator type. Flowers that are pollinated by animals that have alternative sources of protein-building a. a.’s show lower a. a. concentration than those that are not. There is a tendency for woody plant nectar a. a.’s to be less concentrated than those of herbaceous plants, but there can be “phylogenetic constraints” which may reduce the correlations of a. a. concentration with pollinator type and with life form. The individual a. a.’s form complements which are qualitatively extremely constant within species. Proline is a normal constituent of many nectars and does not necessarily indicate contamination of the nectar by pollen. Criticism of our findings byGottsberger & al. (1984) is answered by reference to our previous publications and those of other workers, and to the presentation of data from California native species, not published previously. All previous postulates are borne out by these new data with the exception of positive correlations of a. a. concentration with “primitive” and “advanced” floral characteristics taken one at a time, which appear to be inconsistent and are affected strongly by the nature of the family in which they occur. Summary data are provided for families and genera which indicate that high or low a. a. concentration can typify certain families and genera of both relatively “primitive” and relatively “advanced” nature. Needs for future research on an ecosystem basis are quoted.     

Floral traits variation, legitimate pollination, and nectar robbing in Polygala vayredae (Polygalaceae)

The variation of floral morphology and its effect on the flower visitors of Polygala vayredae Costa (Polygalaceae), a narrow endemic species from the Oriental pre-Pyrenees, were examined. First, to account for the main floral reward (i.e., nectar), the relationship between the dimensions of the nectar gland and nectar production was investigated. Second, floral traits variation was assessed within and between the three most representative populations of the species. Finally, the role of several floral traits in the female fitness was evaluated. Furthermore, as nectar robbing was highly frequent, preferences of robbers for specific floral traits and their impact on legitimate pollinations were also evaluated. The flowers of this species are characterized by significant variations in floral characteristics and nectar rewards. A significant and positive correlation between the nectar gland dimensions and nectar production per flower was observed, with the gland dimensions being a good measure to infer the rewards offered by the flowers of P. vayredae. In general, corolla traits were significant and positively correlated with each other. Nectar was revealed to be an important trait in flower–visitor interactions, with legitimate pollinations being primarily influenced by this floral reward. Negative correlations between robbing frequency and legitimate pollinations were observed in two of the studied populations, and positive correlations between flower size and robbing frequency were observed in one population. An indirect negative selection over phenotypic floral traits mediated by nectar robbers is proposed.     

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.     

Dynamics of forager arrivals and nectar renewal in flowers of Anchusa strigosa

Summary Long-tongued Anthophora spp. bees collecting nectar from flowers of Anchusa strigosa (Boraginaceae) exhibit systematic foraging. Successive forager arrivals at individual flowers are not independent, and the time elapsed between successive arrivals at a particular flower is distributed more uniformly than be expected on the basis of a random arrival process. Distributions of inter-arrival time for individual flowers show standard deviation/mean ratios of 0.44–0.79, a range which is consistent with results obtained for two other plant-pollinator systems. The rate at which nectar is renewed between successive forager arrivals is independent of the amount of nectar in the flower, and the renewal process is strongly linear. Practical and theoretical implications of these results are discussed.     

Effects of elevated CO2 on flowering phenology and nectar production of nectar plants important for butterflies of calcareous grasslands

Effects of elevated CO₂ on flowering phenology and nectar production were investigated in Trifolium pratense, Lotus corniculatus, Scabiosa columbaria, Centaurea jacea and Betonica officinalis, which are all important nectar plants for butterflies. In glasshouse experiments, juvenile plants were exposed to ambient (350 μl l⁻¹) and elevated (660 μl l⁻¹) CO₂ concentrations for 60–80 days. Elevated CO₂ significantly enhanced the development of flower buds in C. jacea. B. officinalis flowered earlier and L. corniculatus produced more flowers under elevated CO₂. In contrast, the number of flowers decreased in T. pratense. The amount of nectar per flower was not affected by elevated CO₂ in the tested legumes (T. pratense and L. corniculatus), but was significantly reduced (!) in the other forbs. Elevated CO₂ did not significantly affect nectar sugar concentration and composition. However, S. columbaria and C. jacea produced significantly less total sugar under elevated CO₂. The nectar amino acid concentration remained unaffected in all investigated plant species, whereas the total of amino acids produced per flower was reduced in all non-legumes. In addition, the amino acid composition changed significantly in all investigated species except for C. jacea. The observed effects are unexpected and are a potential threat to flower visitors such as most butterflies which have no alternative food resources to nectar. Changes in nectar production due to elevated CO₂ could also have generally detrimental effects on the interactions of flowers and their pollinators. Received: 12 September 1996 / Accepted: 9 September 1997