Can pollen match shoes to a previously visited indoor location?

This paper is part of an investigation dedicated to indoor pollen from a forensic point of view. Previous studies documented the ‘natural’ pollen content of a flat and how it was ‘artificially’ altered by ornamental plants. The present study investigated if this ‘artificial pollen trace’ can be transferred to shoes. Brand new sneakers were worn in the flat and afterwards examined for pollen on their soles. The results showed that the shoes gathered pollen and that some pollen types correlated to those found in the flat. Afterwards, some of these shoes were worn while walking through the city for approximately 1.8 km. On these shoes, flat pollen was also detectable, but in low abundances. This study shows that, from a palynological point of view, shoes are worth a look at when a crime is investigated. Uncommon pollen grains on shoes can point to an indoor location with the corresponding ornamental plants.     

Forensic Palynology as Classroom Inquiry

This activity introduces the science of forensic palynology: the use of microscopic pollen and spores (also called palynomorphs) to solve criminal cases. Plants produce large amounts of pollen or spores during reproductive cycles. Because of their chemical resistance, small size, and morphology, pollen and spores can be used to link individuals or objects to specific locations where the parent plants grow. Students will use a digital pollen database and Google Earth to link pollen trace evidence to a specific crime scene. The methods presented are based on those used in criminal cases and palynological techniques used by forensic scientists. Step-by-step instructions for a hands-on investigation and a case simulation are presented.     

Effects of soil phosphorus on pollen production,pollen size,pollen phosphorus content,and the ability to sire seeds in Cucurbita pepo (Cucurbitaceae)

To determine the effects of soil phosphorus on pollen production, pollen grain size, phosphate concentration per pollen grain, and the siring ability of pollen, two cultivars of the common zucchini (Cucurbita pepo) were grown under two soil phosphorus conditions in an experimental garden. Overall, soil phosphorus availability had a significant effect on reproductive output through the female function and on traits affecting the male function of plants (staminate flower production, pollen production per flower, and pollen grain size). In addition, pollen produced by plants in the high phosphorus soils had a higher phosphate concentration than pollen produced by plants in the low phosphorus soils. A pollen mixture experiment revealed that pollen produced by plants in the high phosphorus treatment sired significantly more seeds than pollen produced by plants in the low phosphorus treatment. This study showed that growing conditions such as soil phosphorus can influence the size of a pollen grain and its chemical composition, which, in turn, can affect its ability to sire mature seeds.     

燕山南部花粉散布特征

燕山南部花９粉用布特性研究表明,空气中的花粉反映的是植物花期的季节性变化,表 粉是植物多年花粉散布的混合,冲积物花粉与空气中和表土花粉显著不同,是取样点上游表土花粉的混合,与取样点周围植被关系较小。因此,根据冲积物花粉恢复古植被,反映的是整个流域的植被面貌,而不是某一点的植被特征。     

Monitoring indoor pollen over two years

The present study monitored a private apartment for pollen that had settled on the floor. Pollen was sampled and analysed from two rooms over a period of two years. The study showed that pollen accumulations indoors are dominated by wind-pollinated species reflecting the current flowering season. The adjacent vegetation and the cleaning activities influenced the pollen content. Pollen from zoophilous plants mostly originated from ornamental plants within the flat. Similarities and differences between the two rooms and the two years were observed. These findings have implications for forensic investigations as well as allergological research.     

植物花粉培养研究进展

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。     

Pollen quality limits seed set in Burchardia umbellata (Colchicaceae)

In self-incompatible plants, interference by self pollen or genetically related pollen can potentially exacerbate pollen limitation, although this has rarely been demonstrated. We examined the breeding system, pollen limitation, and pollen interference using self- and cross- pollinations and pollen supplementations in Burchardia umbellata, an insect-pollinated lilioid monocot. Ovule fertilization and seed set were less following selfing than crossing (22 vs. 78% and 4 vs. 73%, respectively), indicating partial self-incompatibility. Flowers were partially protandrous, and flowers opened concurrently on plants potentially allowing self pollen interference. Natural seed set was pollen limited and varied within and among years, probably due to variation in flowering plant density. Interference by self or genetically related pollen caused pollen limitation as evidenced by increased seed set of bagged cross-pollinated plants compared to unbagged pollen-supplemented plants in two years. In 1996, both fertilization and seed set increased in response to cross-pollination, indicating that interference occurred in the style and ovary. In 1997, only seed set increased after cross-pollination indicating that interference occurred in the ovary. Inappropriate pollen deposition may contribute to pollen limitation more often than previously recognized and should select for floral traits that decrease deposition of self or related pollen.     

植物花粉培养研究进展

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。     

Patterns and sources of variation in pollen deposition and pollen tube formation in flowers of the endemic monoecious shrub Cnidoscolus souzae (Euphorbiaceae)

Pollen deposition and pollen tube formation are key components of angiosperm reproduction but intraspecific variation in these has rarely been quantified. Documenting and partitioning (populations, plants and flowers) natural variation in these two aspects of plant reproduction can help uncover spatial mosaics of reproductive success and underlying causes. In this study, we assess variation in pollen deposition and pollen tube formation for the endemic monoecious shrub Cnidoscolus souzae throughout its distribution range in Mexico, and determine how this variation is structured among populations, plants and flowers. We also infer the relative importance of pollen quantity and quality in determining pollination success in this species. While we found no evidence suggesting that pollen receipt limits C. souzae reproduction across 19 populations, we did find extensive variation in pollen load size and pollen tube number per flower. Total variation in pollen receipt and pollen tube number was mostly explained by intra‐individual and among‐population variance. Furthermore, pollen load size had a stronger effect on the number of pollen tubes at the base of the style than pollen germination rate, suggesting that pollen quantity may be more important than quality for pollen tube success in C. souzae. Our results suggest that both small within‐plant flower differences and broad‐scale differences in community attributes can play an important role in determining pollination success. We emphasise the need to evaluate patterns and sources of variation in pollen deposition and pollen tube formation as a first step in understanding the causes of variation in pollination success over broad spatial scales.     

空气致敏花粉污染研究进展

对空气致敏花粉污染概念的提出 ,空气致敏花粉污染的特点和影响因素 ,花粉采集方法的改进以及空气致敏花粉污染的研究进展等方面进行了总结 ,指出了研究中存在的问题 ,并对研究前景进行了展望     

花粉形态与风媒植物母体地理分布间的关系

本文对部分风媒植物花粉形态特征,及其母体植物地理分布情况进行了对照研究。在此基础上发现,同一分类系统内,小个体花粉者,其母体植物地理分布趋向于较优越环境。对于具气囊花粉而言,具较大气囊者,或者花粉本体较小者,其母体植物趋向于分布在低纬度或较低海拔环境。并且,产大个体或球状花粉者,往往具有较强的单种成林倾向。本文首次指出了花粉形态与母体植物地理分布间存在着一定的统计学关系,并首次将动态概念引入植物生态学领域,认为花粉形态特征作为一项重要的参变量,通过种间生存竞争过程对母体植物适应倾向施加影响,进而影响物种的生活习性。那些在花粉的传播及授粉过程中稍占优势的物种,其自然分布域趋向于比较优越的环境。本文仅作为一种尝试,试图为动态植物生态学研究,乃至植物生态演化学研究提供一个新的研究思路。     

Reproductive isolation and hybrid pollen disadvantage in Ipomopsis

One cause of reproductive isolation is gamete competition, in which conspecific pollen has an advantage over heterospecific pollen in siring seeds, thereby decreasing the formation of F1 hybrids. Analogous pollen interactions between hybrid pollen and conspecific pollen can contribute to post-zygotic isolation. The herbaceous plants Ipomopsis aggregata and I. tenuituba frequently hybridize in nature. Hand-pollination of I. aggregata with pollen from F1 or F2 hybrids produced as many seeds as hand-pollination with conspecific pollen, suggesting equal pollen viability. However, when mixed pollen loads with 50% conspecific pollen and 50% hybrid pollen were applied to I. aggregata stigmas, fewer than half of the seeds had hybrid sires. Such pollen mixtures are frequently received if plants of the two species and F1 and F2 hybrids are intermixed, suggesting that this advantage of conspecific over hybrid pollen reduces backcrossing and contributes to reproductive isolation.     

Pollen grains: Why so many?

My objective is the examination of selective forces that affect pollen number. Relationships among other floral traits of animalpollinated plants, including pollen size, stigma area and depth, and the pollen-bearing area of the pollinator may affect pollen number and also provide a model to examine how change in one trait may elicit change in other traits. The model provides a conceptual framework for appreciating intra- and inter-specific differences in these traits. An equivalent model is presented for wind-pollinated plants. For these plants the distance between putative mates may be the most important factor affecting pollen number. I briefly consider how many pollen grains must reach a stigma to assure fruit set. I use pollen-ovule ratios (P/Os) to examine how breeding system, sexual system, pollen vector, and dispersal unit influence pollen grain number. I also compare the P/Os of plants with primary and secondary pollen presentation and those that provide only pollen as a reward with those that provide nectar as part or all of the reward. There is a substantial decrease in P/O from xenogamy to facultative xenogamy to autogamy. Relative to homoecious species the P/Os of species with most other sexual systems are higher. This suggests that there is a cost associated with changes in sexual system. The P/Os of wind-pollinated plants are substantially higher than those of animal-pollinated plants, and the available data suggest there is little difference in the pollination efficiency of the various animal vectors. The P/Os of plants whose pollen is dispersed in tetrads, polyads, or pollinia are substantially lower than those of species whose pollen is dispersed as monads. There was no difference in the P/Os of plants with primary and secondary pollen presentation. The P/Os of plants that provide only pollen as a reward were higher than those that provide nectar as a reward. All of these conclusions merit additional testing as they are based on samples that are relatively small and/or systematically biased.     

Isolated pollen culture: plant reproductive development in a nutshell

Abstract

Isolated pollen can develop into two different directions when cultured in vitro. In a rich medium, microspores and young pollen grains develop into mature pollen that is fertile. When pollen is treated by a stress treatment such as a hunger treatment in a sucrose - and/or nitrogen - free medium, embryogenic pollen is formed that, after transfer to a rich medium, develops into embryos and haploid plants. This system of isolated pollen culture offers an opportunity to study two developmental processes, i.e. pollen development and embryogenesis, as well as a basic regulatory event, i.e. the transition from the gametophytic to the sporophytic phase in the alternation of generations in higher plants. In addition, both systems offer various application-oriented possibilities, such as production of doubled haploids, to overcome self-incompatibility, to rescue sterile pollen, pollen selection and pollen transformation. An understanding of the cell biological and molecular events during embryogenic induction may promote a wider application of doubled haploid breeding and the use of such plants for gene transfer.     

Geographic patterns and pollination ecotypes in Claytonia virginica

Geographical variation in pollinators visiting a plant can produce plant populations adapted to local pollinator environments. We documented two markedly different pollinator climates for the spring ephemeral wildflower Claytonia virginica: in more northern populations, the pollen‐specialist bee Andrena erigeniae dominated, but in more southern populations, A. erigeniae visited rarely and the bee‐fly Bombylius major dominated. Plants in the northern populations experienced faster pollen depletion than plants in southern populations. We also measured divergent pollen‐related plant traits; plants in northern populations produced relatively more pollen per flower and anther dehiscence was more staggered than plants in southern populations. These plant traits might function to increase pollen dispersal via the different pollen vectors.     

Pollen competition between morphs in a pollen‐color dimorphic herb and the loss of phenotypic polymorphism within populations

Flower color polymorphism is relatively uncommon in natural flowering plants, suggesting that maintenance of different color morphs within populations is difficult. To address the selective mechanisms shaping pollen‐color dimorphism, pollinator preferences and reproductive performance were studied over three years in Epimedium pubescens in which some populations had plants with either green or yellow pollen (and anthers). Visitation rate and pollen removal and receipt by the bee pollinator (Andrena emeishanica) did not differ between the two color morphs. Compared to the green morph, siring success of the yellow morph's pollen was lower, but that of mixtures of pollen from green and yellow morphs was lowest. This difference, corresponding to in vivo and ex vivo experiments on pollen performance, indicated that pollen germination, rather than tube growth, of the green morph was higher than that of the yellow morph and was seriously constrained in both morphs if a pollen competitor was present. A rare green morph may invade a yellow‐morph population, but the coexistence of pollen color variants is complicated by the reduced siring success of mixed pollinations. Potential pollen competition between morphs may have discouraged the maintenance of multiple phenotypes within populations, a cryptic mechanism of competitive exclusion.     

Analysis of Airborne Pollen Fall in Edirne,Turkey

In the atmosphere of Edirne 12 691 pollen grains belonging to 42 taxa were identified by using of Durham sampler in 2000 and 2001. A total of 6 189 pollen grains per cm2 were recorded in 2000 and a total of 6 502 pollen grains per cm2 in 2001. Total pollen grains consisted of 71.81% grains from arboreal plants, 25.88% grains from non-arboreal plants and 2.31% unidentified pollen grains. Pollen from the following taxa were also found to be prevalent in the atmosphere of Edirne: Gramineae, Pinus sp., Quercus sp.,Cupressaceae/Taxaceae, Platanus sp., Salix sp., Morus sp., Populus sp., Carpinus sp., Juglans sp.,Chenopodiaceae/Amaranthaceae, Fraxinus sp., Fagus sp., Ulmus sp., Ailanthus sp., Alnus sp., Ostrya sp.,Helianthus sp. The season of maximum pollen fall was from April to June, with a prevalence of arboreal pollen in the first month, and of pollen from non-arboreal plants in the last months of the year.     

Differentiation of embryogenic pollen in cold-treated buds ofNicotiana tabacum var. Badischer burley and nutritional requirements of the isolated pollen to form embryos

Summary Embryogenic pollen were selectively isolated from buds after cold treatment at 10 °C for 10 days; it was immaterial whether the buds were taken from short day and low temperature (SD and LT; 8 hours light, 18 °C) or long day and high temperature (LD and HT; 16 hours light, 24 °C) plants. However, in buds from SD and LT plants the differentiation of embryogenic pollen could be detected as early as 7 days after the cold treatment, and pollen from these plants formed embryos at higher frequency (up to 4% of cultured pollen) than those from LD and HT plants (up to 1% only).The embryogenic pollen, in isolated buds, differentiated by way of pollen dimorphism. During cold treatment a fraction of pollen remained small, retained clear cytoplasm and was capable of embryogenesis in comparison to gametophytic pollen which enlarged and acquired granular cytoplasm. In our experiments cold treatment was a key factor in the induction of pollen dimorphism. This aspect of cold treatment in pollen embryogenesis is reported for the first time and was possible on the basis of selection of embryogenic pollen by density gradient centrifugation. The ratio of embryogenic pollen was about one fifth of the total population.The nutritional requirements of isolated pollen for embryogenesis were rather simple. These pollen formed embryos which readily developed into plantlets on a mineral medium supplemented with sucrose provided the pH was 6.8.     

Analysis of airborne pollen fall in Sakarya, Turkey

In this study, pollen grains were identified using Durham sampler in the atmosphere of Sakarya in 2000 and 2001. During these two years, a total of 10 805 pollen grains were recorded. A total of 5 386 pollen grains per cm² were recorded in 2000 and a total of 5 419 pollen grains per cm² in 2001. Pollen fall in the years 2000–2001 comprised grains belonging to 40 taxa and some unidentified pollen grains. Of these taxa, 22 belonged to arboreal and 18 taxa to non arboreal plants. Total pollen grains consisted of 69.45% grains from arboreal plants, 28.11% grains from non-arboreal plants and 2.44% unidentified pollen grains. In the region investigated, Gramineae, Pinus sp., Quercus sp., Cupressaceae/Taxaceae, Salix sp., Platanus sp., Populus sp., Carpinus sp., Fagus sp., Chenopodiaceae/Amaranthaceae, Xanthium sp., Moraceae, Corylus sp., Fraxinus sp., and Urticaceae released the greatest amount of pollen. The season of maximum pollen fall was from March to May, with a prevalence of arboreal pollen in the first months, and of pollen from non-arboreal plants in the last months of the year.     

显花植物自体和异体花粉识别的分子机理研究(英文)

显花植物的受精涉及许多识别过程;其中第一个是雌性生殖组织心皮对花粉的识别。自交不亲和性（Ｓｅｌｆ－ｉｎｃｏｍｐａｔｉｂｉｌｉｔｙ,ＳＩ）是一种广泛分布于显花植物的种内生殖障碍。在多数自交不亲和的植物中,ＳＩ的遗传控制比较简单,受控于一个由复等位基因构成的单一位点,称为Ｓ位点。在以茄科、玄参科和蔷薇科为代表的配子体自交不亲和植物中,Ｓ位点编码一类核酸酶,即Ｓ核酸酶（Ｆｉｇ．１）,控制ＳＩ在花柱中的表达,但是与花粉自交不亲和性的表达无关。后者可能由与Ｓ核酸酶不同的基因控制,这种基因常被称为花粉Ｓ基因。它是目前了解显花植物花粉识别生化和分子机理的关键。近来;通过对影响花粉ＳＩ表达突变体的分子遗传分析提出了一个花粉Ｓ基因产物如何与Ｓ核酸酶相互作用完成自体和异体花粉识别过程的模型（Ｆｉｇ．２）。另外,描述了两个在金鱼草中克隆花粉Ｓ基因的方法,即Ｓ位点选择性的转座子标记和图位克隆。