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1.
The collection of pollen by bees 总被引:4,自引:0,他引:4
R. W. Thorp 《Plant Systematics and Evolution》2000,222(1-4):211-223
Bees require pollen for their reproduction and pollen comprises the basic larval food for bees. Most bees acquire pollen passively during flower visitation, but female bees may also collect pollen actively with the aid of various structural and behavioral adaptations. Most bees have evolved adaptations to concentrate pollen into discrete loads and transport pollen back to their nests. The various structural and behavioral adaptations of female bees for acquiring and transporting pollen are the basis of this review. 相似文献
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City spore concentrations in the European Economic Community (EEC). VI. Poaceae (Grasses), 1982–1986
Frits Th. M. Spieksma Gennaro D'amato John Mullins Nicole Nolard Reinhard Wachter Eva R. Weeke 《Aerobiologia》1989,5(1):38-43
Summary Airborne grass-pollen concentrations in six cities in the EEC are compared, based on observations from five years, 1982–1986.
Results show that there are quantitative differences both between the monitoring stations and between the years. Very provisionally,
the average seasonal total of the European urban airborne grass-pollen concentration can be put at 4 to 5000 per m3 of air. Also qualitatively, regarding the seasonal fluctuations, there are differences between the stations, and between
the years. Generally, the results confirm that June is the most typical grass-pollen month in northwestern Europe, whereas
in mediterranean Europe May is the more prominent grass-pollen period. There seems to be little coherence between the starting
dates of the grass-pollen season even at relatively nearby stations in northwestern Europe, suggestive for a great influence
of the actual weather situation. 相似文献
4.
Summary
Betula pollen production and flowering, pollen transport and pollen deposition are considered for the mountain birch region of northern
Finland for the ten-year period 1984–1993. The most abundant flowering year was 1989 and, after that, 1985. In these years
the highest values were also recorded for pollen in the air. There is a significant correlation between the amount of pollen
released and the thermal sum of the previous year. In terms of pollen deposition the peak years were 1989 and 1986. The correlation
between the amount of pollen in the air and that being deposited on the ground is also statisticaly significant. It is evident
that some birch pollen is already present in the air before local flowering begins and that, in some years, this non-local
pollen can account for more than 20% of the yearly total. This preflowering proportion was highest in 1985 and 1993, the latter
being a prolific flowering year in the south of the country. There is a clear relationship between the proportion of the non-local
pollen in the air and the proportion ofBetula pubescens/pendula type pollen deposited on the ground and, conversely, there is a significant correlation between the amount of local pollen
in the air and the amount ofBetula tortuosa plusB. nana type pollen being deposited on the ground. The questions both of the viability of this long-distance pollen and of its ability
to cause allergic reactions are considered. An assessment is also made of the degree to which fossil birch pollen assemblages
can be realistically interpreted in terms of local vegetation if a varying proportion of the same pollen type is non-local. 相似文献
5.
Bruno Romano 《Aerobiologia》1988,4(1-2):20-26
Summary The results of six years (1982–1987) of aerobiological study in Perugia (central Italy) are reported. During this period a
total of 80 different types of pollen belonging to 52 families were identified in the Perugia atmosphere. The highest percentages
of pollens were found in the mid-March to mid-July period. For main taxa principal periods of pollination were identified.
The outlines for the weekly issue in a newspaper of the concentration pattern of the allergenic pollens are reported. 相似文献
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In Switzerland the concentration of allergenic pollendecreases with increasing elevation of the samplingsite of the Swiss pollen measuring network. The aim ofthis study was, to compare the pollen concentrationsof five different localities in the Swiss Alps and inthe Jura mountains, to get an idea of the differencesin the pollen abundance in altitudes above 1000 m. Theinvestigated localities are: La Chaux-de-Fonds(1040 m), Wiesen (1420 m), Davos (1600 m), Samedan(1705 m) and Gütsch (2287 m). These pollen sumswere compared to the Swiss plateau (Basel 273 m).Basel, La Chaux-de-Fonds and Wiesen show clearlyhigher pollen values than Davos, Samedan andGütsch. Pollen concentrations of Corylus,Alnus glutinosa-type and Fraxinus arereduced with increasing altitude and are only a smallproblem for allergies above 1000 m. Betulapollen are also reduced in the higher localities, butthere still occur many days with high pollenconcentrations. Especially Betula pollen frommedium range transport can play an important role forallergies in higher localities. The total grass pollensum does not decrease up to an altitude of 1500 m. Thegrass pollen concentration depends more on factorslike composition of the local grassland, land use andwind situation.Pollen concentrations at higher elevations isinfluenced by the local vegetation, a reduced pollenproduction, land use, topography, exposition, windvelocity and wind direction. These factors modify thepollen concentration considerably. Due to the complextopography of the Prealps and Alps, it is thereforenot possible to propose a general rule of pollenreduction with increasing altitude. 相似文献
8.
本文报道在沈阳地区1965—1985年间于空气中间断收集大气花粉5年,共收花粉玻片1100张,花粉45780粒,属于24科37属或种。其中9种(或属)超过千粒,为优势种类花粉。每年沈阳市大气中花粉出现两个高峰,一个为春季(四、五月),另一个为夏秋季(七八月)。通过长期观察发现,花粉种类和数量每年虽有不同,伹差异不大,唯有豚草花粉消长明显。大气中花粉种类及数量的变化往往受到气温、国家有关绿化政策以及社会风气的影响。花粉与过敏症关系十分密切,我们采用17种花粉制成浸液为病人皮试和治疗。皮试结果阳性率最高的为蒿属花粉,其次为其它夏秋花粉,春季花粉阳性率不高,致敏性不强。用花粉浸液对过敏症者进行免疫治疗,收到一定的疗效。 相似文献
9.
Carolina Carrizo García 《Grana》2013,52(1):13-19
The presence or absence of starch in microspore development and in pollen grains was recorded in eleven wild tomato species (Solanum sect. Lycopersicon) and two close relatives (S. lycopersicoides and S. sitiens). In all the species starch started to accumulate in the early microspore bicellular stage and continued until the cytoplasm was filled. At flower anthesis, pollen grains were mostly starchless in the wild tomatoes, except in S. pennellii, which had starchy pollen. Starchy pollen is also present in the two related species. The latter two species had larger pollen grains and grow in drier environments than the other species. The heterogeneity of pollen starch content among all these species, supposed to have the same pollination mechanism, is a new finding supporting the idea that starch content and pollination mechanism do not necessarily influence each other. The presence of starchy pollen in the self‐incompatible species, which grow in the driest environments, raises questions regarding the relationship between carbohydrates content and pollen survival. 相似文献
10.
Per Sjgren W.O. van der Knaap Jed O. Kaplan Jacqueline F.N. van Leeuwen Brigitta Ammann 《Review of Palaeobotany and Palynology》2008,149(3-4):208-218
The relative pollen productivity (RPP) of Pinus cembra, Larix, Picea, Gramineae, and Cyperaceae was estimated for the Upper Engadine area, an inner-alpine sub-continental valley in SE Switzerland lying above 1800 m a.s.l. The influx of pollen originating from lowlands was assumed constant between the investigated sites and could thus be used to establish relative pollen accumulation rates (rPAR) as a basis for further calculations. Wind above the canopy was assumed as the major mode of pollen transport and the effect of different wind speeds was tested. In order to evaluate the results pollen percentage values were simulated and compared with the empirical data. The method is sufficiently accurate for evaluation of spatially-explicit vegetation models, although the low number of sites eludes robust statistical testing. 相似文献
11.
In this study, pollens of Burdur dimriti, Sariemin, Tilki kuyrugu, Razaki, Buzgulu, Siyah buzgulu, and Siyah gemre table grape
varieties (Vitis vinifera L.) grown in Isparta, Turkey were tested in vitro for viability, germination capability, and production level. It was determined that active pollen levels varied between 23.8
% and 80.8 % in FDA (flourescein diacetat), 31.5 % and 68.8 % in TTC (2,3,5-triphenyl tetrazolium chloride) tests. In respect
to pollen germination rates, the best medium in hanging drop method and saturated petri method were 20 % sucrose concentration
and 1 % agar+15 % sucrose solution, respectively. The highest and the lowest pollen production levels per flower were determined
9000 in Siyah gemre and 2906 in Siyah dimrit grape varieties, respectively. 相似文献
12.
The use of sieving during standard pollen pre-treatment of samples of fossil deposits to enhance the concentration of large pollen grains 总被引:2,自引:1,他引:1
Small pollen grains and fine particles of the organic matrix in samples of a coarse detritus mud and a blanket peal deposit were removed by sieving through 30μ polyester mesh after digestion with KOH and acetolysis during standard pollen pre-treatment. The technique enhanced the number of large pollen grains m the sample. There was also an increase in the range of taxa which produce huge grains. The method provided a means of estimating the ratio of any scarce large pollen grain to the total grain sum in samples prepared by standard methods of pre-treatment. 相似文献
13.
滦河流域及周边地区空气中的花粉组合基本上反映了当地的植被面貌, 与植物的花期相对应, 乔木植物的花期多在春季, 草本植物的花期多在夏秋季, 该地冬季基本上无植物开花, 冬季空气中的花粉应是当年或多年春、夏、秋季散落在地上又被风吹到空气中的表土花粉和一些外来花粉 ;表土花粉随海拔高程的降低依次出现山地草甸、针阔混交林或以针叶树为主的针阔混交林、山地灌草丛、滨海平原草甸和滨海草甸或滨海盐生草甸的等 5个花粉组合带, 分别为蒿 (Artemisia)唐松草 (Thalictrum)松(Pinus)桦 (Betula) 孢粉组合带、松桦栎 (Quercus) 蒿孢粉组合带、藜科 (Chenopodiaceae)蒿禾本科 (Gramineae)中华卷柏 (Selaginellasinensis) 孢粉组合带、藜科蒿菊科 (Com positae)香蒲 (Typha) 孢粉组合带和藜科蒿莎草科 (Cyperaceae)禾本科孢粉组合带 ;由于花粉在河水中是以悬移质颗粒被搬运, 因此在不同时期沉积物花粉组合存在着一定的差异, 其中洪水期间河水对孢粉的分选作用最为明显。 相似文献
14.
Premise
Almost nothing is known about what happens to pollen grains once they attach to pollinators, although some have postulated that pollen from different donors may form complex, two- or three-dimensional landscapes (e.g., layers or mosaics) that can facilitate male–male competition. For example, pollen that is already on pollinators may preclude the deposition of subsequent pollen grains.Methods
Using quantum dots to mark the pollen of individual flowers, we explored the possibilities of layering and preclusion in a fly-pollinated iris, Moraea lurida.Results and Conclusions
The proportion of labeled pollen from the last flower visited diminished in sequential pollen samples taken from the top to the bottom of the pollen load, representing the first empirical evidence for pollen layering. However, the consequences in terms of pollen preclusion were equivocal: Although the pre-existing pollen load size was not a good predictor of new pollen receipt, labeled pollen loads from the last flower visited were significantly smaller than pollen loads from the previous flower visited. Thus, pollen from the previous flower may preclude pollen placement from a subsequently visited flower, and pollen from different flowers may compete for space on pollinators.15.
花粉培养又称为游离小孢子培养,指将发育到一定阶段的花粉从花药中游离出来成为分散或游离状态,通过培养使花粉粒脱分化,进而发育成完整植株的过程。花粉培养的主要目的是获得单倍体植株,进而得到双单倍体(double haploid,DH)植株,最终获得纯合系物种。本文对花粉培养形成植株的物种信息进行了收集整理,概述了国内外花粉培养的一些最新研究进展,包括影响花粉培养形成胚的因素以及提高花粉胚产量的措施,并对花粉培养的前景进行了展望。 相似文献
16.
The present article deals with the efficacy of seed hairs of poplar trees (Populus spp.) as a potent natural airborne pollen trap. Different species of Populus are commonly found planted along the streets in the cities of North China. The seed hairs and pericarp of poplar trees were collected from the trees and on the ground in Beijing Botanical Garden of Chinese Academy of Sciences and around Miyun Reservoir during May 2005 for pollen analysis. Different pollen spectra are recorded from different samples and are characterised by dominant occurrence of pollen grains of arboreal and anemophilous plants. In addition, pollen grains of non‐arboreal plants including grasses are also found trapped. Among the 46 trapped pollen grains, 26 are known to be allergenic. This study suggests that poplar seed hairs possibly make people feel uncomfortable due to the presence of allergenic pollen trapped in the hairs. 相似文献
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Cytophysiology of pollen presentation and dispersal 总被引:5,自引:2,他引:3
19.
Betula pendula pollen, under laboratory conditions, was exposed to three atmospheric pollutants: carbon monoxide (CO), ozone (O3) and sulphur dioxide (SO2). Two levels of each pollutant were used; the first level corresponds to a concentration on the atmospheric hour-limit value acceptable for human health protection in Europe, the second level to a higher, at least more than double of the first, concentration level. Experiments were done under artificial solar light with controlled temperature and relative humidity. Our results indicate that, in urban areas, concentrations of CO, O3 and SO2 on the limits established for human protection, can affect pollen fertility. We verified a decrease in the viability and germination of the pollen, indicating damage to the pollen membrane system. Also, a general decreasing trend in the total protein content of the exposed samples when compared with the control samples was observed, which suggests alterations in the antigenic characteristics of pollen. 相似文献
20.
Anna L. Hargreaves Lawrence D. Harder Steven D. Johnson 《Biological reviews of the Cambridge Philosophical Society》2009,84(2):259-276
Many of the diverse animals that consume floral rewards act as efficient pollinators; however, others 'steal' rewards without 'paying' for them by pollinating. In contrast to the extensive studies of the ecological and evolutionary consequences of nectar theft, pollen theft and its implications remain largely neglected, even though it affects plant reproduction more directly. Here we review existing studies of pollen theft and find that: (1) most pollen thieves pollinate other plant species, suggesting that theft generally arises from a mismatch between the flower and thief that precludes pollen deposition, (2) bees are the most commonly documented pollen thieves, and (3) the floral traits that typically facilitate pollen theft involve either spatial or temporal separation of sex function within flowers (herkogamy and dichogamy, respectively). Given that herkogamy and dichogamy occur commonly and that bees are globally the most important floral visitors, pollen theft is likely a greatly under-appreciated component of floral ecology and influence on floral evolution. We identify the mechanisms by which pollen theft can affect plant fitness, and review the evidence for theft-induced ecological effects, including pollen limitation. We then explore the consequences of pollen theft for the evolution of floral traits and sexual systems, and conclude by identifying key directions for future research. 相似文献