Fertile allotetraploid from the cross betweenPhaseolus coccineus L. andPhaseolus acutifolius A. Gray

Summary As somatic hybridization and genetic transformation are not yet applicable to beans, a programme of hybridization between a male sterile line ofP. coccineus and a wild genotype ofP. acutifolius var.tenuifolius was carried out in order to introduce useful characters from the wild parent into the genome of the cultivated species. This interspecific cross is of particular interest sinceP. acutifolius is a source of resistance to many diseases, drought and high temperature. The difficulties in producing these hybrids were overcome by repeated pollinations and with the help of embryo culture. The F₁ hybrid shows a high sterility which may be explained by the poor pollen quality and the presence of a chromosomic asynapsis at meiosis. Fertile allotetraploids (Co) were successfully produced in progeny from colchicine treated cuttings of F₁ hybrids. Several (C₂) mature seeds were harvested from selfed allotetraploid plants.Abbreviations Co initial allotetraploid plants - C₁, C₂ first and second allotetraploid generation - PMC pollen mother cell     

Plant use in a city in Northern Italy during the late Mediaeval and Renaissance periods: results of the archaeobotanical investigation of “The Mirror Pit” (14th–15th century a.d.) in Ferrara

Results are presented from archaeobotanical analyses carried out in ‘The Mirror Pit’, a rectangular pit, situated in the city of Ferrara, in Emilia Romagna—Northern Italy. The study is part of wider research focused on the Mediaeval period of this city. The pit belongs to a building which was in use from the second half of 14th to the end of 15th century a.d. The pit itself was filled with domestic rubbish during a few years in the middle of the 15th century. The layers were preserved by waterlogging and are therefore extraordinarily rich in organic remains and artifacts, among which was the beautiful spherical mirror which gave its name to the pit. Approximately 256,000 well-preserved seeds and fruits belonging to 98 species or carpological types were identified in 12 l of sediment from the different layers. Ficus carica, Brassica rapa subsp. rapa/subsp. sylvestris and Vitis vinifera subsp. vinifera prevailed. Many cultivated plants and weeds were present, together with a smaller number of wild plants of wet environments and woodlands. Altogether they provided much new information on the diet (cultivated and wild fruits, cereals and pulses, vegetables, spices and medicinal/fibre/oil plants) of the middle to upper class inhabitants of a city in Northern Italy during the Renaissance period. The records also yielded evidence of domestic activities such as winemaking, oil making, mustard making and other kitchen practices.     

Using seed purity data to estimate an average pollen mediated gene flow from crops to wild relatives

Gene flow from crops to wild related species has been recently under focus in risk-assessment studies of the ecological consequences of growing transgenic crops. However, experimental studies addressing this question are usually temporally or spatially limited. Indirect population-structure approaches can provide more global estimates of gene flow, but their assumptions appear inappropriate in an agricultural context. In an attempt to help the committees providing advice on the release of transgenic crops, we present a new method to estimate the quantity of genes migrating from crops to populations of related wild plants by way of pollen dispersal. This method provides an average estimate at a landscape level. Its originality is based on the measure of the inverse gene flow, i.e. gene flow from the wild plants to the crop. Such gene flow results in an observed level of impurities from wild plants in crop seeds. This level of impurity is usually known by the seed producers and, in any case, its measure is easier than a direct screen of wild populations because crop seeds are abundant and their genetic profile is known. By assuming that wild and cultivated plants have a similar individual pollen dispersal function, we infer the level of pollen-mediated gene flow from a crop to the surrounding wild populations from this observed level of impurity. We present an example for sugar beet data. Results suggest that under conditions of seed production in France (isolation distance of 1,000 m) wild beets produce high numbers of seeds fathered by cultivated plants. Received: 5 February 2001 / Accepted: 26 March 2001     

小报春与岩生报春种间杂交亲和性研究

以报春花属报春花组的小报春(Primula forbesii)和指叶报春组的岩生报春(Primula saxatilis)为亲本,对种间杂交的结实性及花粉管行为进行了观察。结果表明:小报春与岩生报春种间杂交表现为不亲和,正反交组合正常结实率为0,但正交、反交组合花粉在柱头表面的萌发和花粉管伸长过程有明显差异,小报春花粉授粉4h后可以在岩生报春柱头表面萌发,但花粉管伸长的速度明显比对照组[岩生报春(P)×岩生报春(T)、岩生报春(T)×岩生报春(P)]慢,并且花粉管生长弯曲,授粉192h后花粉管仍未到达子房;岩生报春的花粉可以在小报春柱头上正常萌发,授粉48h后花粉管到达子房;4个对照授粉组合均分别于24h(短花柱为母本)、48h(长花柱为母本)时完成受精过程。研究表明,岩生报春×小报春杂交存在受精前障碍,小报春×岩生报春杂交亲和性较好,并可通过幼胚拯救的方法获得组间杂种后代;花柱长度可能是影响种间杂交结实能力的因素之一。     

濒危植物安徽羽叶报春两种花型的繁育特性及其适应进化

二型花柱的维持机制和自然选择压力多年来一直是生态学和进化学研究领域的热点之一。通过实验室栽培和野外观察统计相结合的方法,对安徽羽叶报春两种花型(长柱花和短柱花)的形态特征、花粉活力、柱头可授性、花粉/胚珠比、自然授粉及结籽能力、自交亲和性等繁育特性进行了比较研究。结果表明:长、短柱花的花冠直径和裂片宽无明显差异,而花冠筒、雌蕊和雄蕊高、花粉数目及大小、P/O比均有显著差异。在自然条件下,长柱花所接受的总花粉数要明显高于短柱花的总花粉数,但所接受的异型花花粉数和平均每果结籽数两者无显著差异。长柱花和短柱花的花粉和柱头活力相似,均能在较长时间内维持较高活力,仅在开花末期显著下降。两种花型的花在自花授粉、同型异花授粉、异型花授粉条件下均能结籽,但异型花授粉的结籽数均明显高于自花授粉和同型异花授粉结籽数。在长柱花各种授粉方式中,花粉萌发率无明显差异,但异型花花粉管的生长速度明显比同型异花花粉和自花花粉的快,而在短柱花柱头上表现为异型花授粉的萌发率最高,但只要萌发后在花柱中的生长速度无显明差异。此外,综合上述结果,对二种花型花部综合征的维持机制及自然选择压力进行了探讨。     

Establishing the genetic relationships between the wild and cultivated olives using a nuclear intron from nitrate reductase (nia-i3)

In Oleaceae the most outstanding biological issue is to clarify the taxonomic relationships of cultivated and wild olives. To establish the genetic relationships between the wild (Olea europaea subsp. europaea var. sylvestris (Mill.) Lehr.), the cultivated olive (Olea europaea subsp. europaea var. europaea), and other taxa of the genus Olea (Olea europaea subsp. cuspidata (Wall. ex G. Don) Cif., Olea europaea subsp. cerasiformis G. Kunkel & Sunding, Olea paniculata R. Br.) and other Oleaceae (represented by Ligustrum vulgaris) we carried out the amplification by polymerase chain reaction (PCR) and the sequencing of the third nuclear intron of the nitrate reductase gene (nia-i3). Sequence analyses showed the presence of two different functional variants of the intron (nia1 and nia2) in the Oleaceae, in addition to a shorter non-functional one. Notably, while the shortest and the nia1 variants were present in all the taxa analysed, the nia2 variant was present only in the wild and the cultivated olive. These data confirm the close phylogenetic relationship between wild and cultivated olives and suggest that this gene could be duplicated in these two taxa after its divergence from the remaining Oleaceae. The presence of a target for AflII enzyme in nia2 and its absence in nia1 variant enables easy distinction by PCR-RFLP between, on the one hand, wild and cultivated olive, and on the other the remaining subspecies of the Olea europaea L. complex (O. e. subsp. cuspidata and O. e. subsp. cerasiformis) as well as other Oleaceae (O. paniculata, L. vulgaris L.). Additionally, nia1 sequences provide useful information about phylogeny of the wild and cultivated olives inside the genus Olea.     

The reproductive biology of the genusBaldellia (Alismataceae)

The reproductive biology of the genusBaldellia was studied under cultivation and in nature.B. ranunculoides subsp.repens is self-incompatible whereasB. ranunculoides subsp.ranunculoides andB. alpestris are self-compatible. Bud-pollination occurs in theB. alpestris. Self-incompatibility correlates with the production of fewer, larger, more showy flowers, higher pollen production (but reduced pollen grain size), fewer carpels and smaller seeds. Resource allocation to sexual reproduction is inversely correlated with the degree of vegetative growth.B. ranunculoides subsp.repens produces more ramets than subsp.ranunculoides, which reproduces mainly by seeds.B. alpestris is intermediate between the two since it is self-compatible, produces fewer, larger seed than subsp.ranunculoides and is also able to propagate by vegetative means.     

Botanical and geographical origin of honey from the dry and humid Chaco ecoregions (Argentina)

To characterise the botanical and geographical origin of honey from the Chaco region (Argentina), 189 samples of honey were examined for pollen content using standard methodology. A general feature was the high representation of pollen from native arboreal plants, mainly of Fabaceae and the scarcity of pollen from herbaceous plants. One hundred and twenty-three samples proved to be unifloral. The most common were from: Prosopis alba, Helianthus annuus, Sarcomphalus mistol, Eugenia uniflora and Schinopsis balansae followed by those of Copernicia alba, Trithrinax schizophylla, Tessaria integrifolia, Baccharis-Eupatorium, Cynophalla retusa, Schinopsis lorentzii, Gleditsia amorphoides, Heimia salicifolia, Pisonia zapallo, Sagittaria montevidensis and Bulnesia sarmientoi. The pollen spectrum allowed the Dry and Humid Chaco ecoregions to be distinguished. The presence of pollen from cultivated crops and naturalised plants reflects a transitional complex between both ecoregions.     

Use of 2n pollen-producing triploid hybrids to introduce tetraploid Mexican wild species germ plasm to cultivated tetraploid potato gene pool

Summary Tetraploid (2n=4x=48) 2EBN Mexican wild species in the series Longipedicellata, which consists of Solanum fendleri, S. hjertingii, S. papita, S. polytrichon, and S. stoloniferum, were crossed with two 2EBN cultivated diploid (2n=2x=24) clones. The resulting triploid hybrids (2n=3x=36) produced 2n pollen (triplandroids) by the mechanism of parallel orientation of anaphase II spindles. The percentage of stainable pollen in 520 triploids ranged between 0 and 23.5%, with a mean of 2.7%. Triploids producing between 13.0 and 23.5% stainable pollen were crossed as staminate parents to the tetraploid cultivars, resulting in abundant pentaploid (2n=5x=60) and near-pentaploid hybrid progeny. Crosses of triploids with lower percentage of stainable pollen as pollen parent to the tetraploid cultivars did not yield fruit, unless rescue pollen from a tetraploid cultivar was added 2 days later. Pentaploid hybrids were selected among selfed tetraploid progenies using morphological and isoxyme markers transmitted from their cultivated diploid parents. These pentaploid hybrids were vigorous and had uniformly sterile pollen. They were female fertile and were crossed with tetraploid cultivars, yielding an average of 19 seeds per fruit. Triplandroids provide the opportunity of transferring 2EBN tetraploid Mexican wild species in the series Longipedicellata germ plasm into the 4EBN cultivated potatoes.Cooperative investigations of the ARS, USDA, and the Washington State University Agricultural Research Center, Prosser, WA 99350, USA. H/LA Paper No. 90-03, College of Agriculture and Home Economies Research Center, Washington State University, Pullman, WA 99164, USA     

栽培与野生化血丹不同部位中两种化学成分含量分析

为探讨并分析栽培与野生化血丹植株中不同部位中两种化学成分的含量差异,该研究采用超声法提取、高效液相色谱法(HPLC)测定栽培与野生化血丹根、茎、叶、花、混合样等部位中桃叶珊瑚苷和梓醇的含量,并进行比较。结果表明:(1)桃叶珊瑚苷在栽培与野生化血丹植株内均有分布,含量均以根中最高,其在栽培与野生化血丹植株内的含量表现分别为根叶混合样茎花、根混合样茎花叶,栽培化血丹不同部位中桃叶珊瑚苷的含量均高于野生化血丹。(2)梓醇在栽培化血丹的茎中未检出,在栽培与野生化血丹其他部位均有分布,含量均以叶中最高,其在栽培与野生化血丹植株内的含量分别表现为叶花混合样根、叶混合样茎花根,野生化血丹不同部位中梓醇的含量均高于栽培化血丹。(3)桃叶珊瑚苷和梓醇在栽培和野生化血丹植株不同部位中的含量均存在显著差异(P0.05),栽培与野生同一部位间总体上无显著差异,为该濒危药用植物资源药用部位选择和合理开发利用提供实验参考。     

Inheritance and genetic mapping of two nuclear genes involved in nuclear–cytoplasmic incompatibility in peas (Pisum sativum L.)

Genetic analysis was performed to finely map and assess the mode of inheritance of two unlinked nuclear genes Scs1 and Scs2 involved in incompatibility of the nuclear genome of the cultivated pea Pisum sativum subsp. sativum with the cytoplasm of the wild pea of the subspecies P. sativum subsp. elatius, accession VIR320. Based on the segregation of genotypes in the progeny of the test-crosses, we concluded that if the cytoplasm was inherited from the wild pea VIR320, the Scs1 allele from the cultivated pea was gametophyte lethal and sporophyte recessive lethal. The Scs2 allele from the cultivated pea reduced male gametophyte viability. In homozygote, Scs2 from cultivated parent brought about nuclear–cytoplasmic conflict manifested as chlorophyll deficiency, reduction of blade organs, and low pollen fertility of about 20%. In heterozygote, Scs1 and Scs2 genes reduced pollen fertility by ca 50 and 30%, respectively. The Scs1 and Scs2 genes involved in nuclear–cytoplasmic incompatibility were genetically mapped. The distance between the markers bordering Scs1 comprised about 2.5 cM on linkage group III. The map distance between the bordering markers in the neighborhood of Scs2 varied substantially from cross to cross in the range of 2.0–15.1 cM on linkage group V.     

Inbreeding depression affects pollen performance in Cucurbita texana

Most studies of the effects of inbreeding focus on vegetative vigor and reproductive output through the female (fruit and seed) function. This study not only examines the effects of inbreeding on the female function but it also examines the effects of inbreeding on pollen performance both in vitro and in vivo. This study used Cucurbita texana, a wild gourd, and was performed under field conditions. In vivo performance was assessed by placing equal amounts of pollen from either the inbred or outcrossed plants onto a stigma together with pollen from a tester line. As with other studies, we found that outcrossed plants had greater reproductive output (male flowers and fruits) than plants produced from self pollinations. Unlike most studies of inbreeding depression, which mostly ignore the male function of plants, we also found that the pollen produced by outcrossed plants had faster pollen tube growth in vitro than the pollen produced on selfed plants. Moreover, pollen from selfed plants sired significantly fewer seeds than pollen from outcrossed plants under conditions of pollen competition (i.e. the number of pollen grains deposited onto the stigmas was larger than the number of available ovules). These findings indicate that inbreeding affects the performance of the resulting sporophytic generation and the microgametophytes they produce.     

Spontaneous hybridization between oilseed rape (Brassica napus) and weedy B. campestris (Brassicaceae): a risk of growing genetically modified oilseed rape

Frequencies of spontaneous hybridization between oilseed rape (Brassica napus L.) and weedy Brassica campesíris ssp. campestris L. were measured in agricultural fields. Hybrids were identified by enzyme electrophoresis, random amplified polymorphic DNA (RAPD) analysis, chromosome counting, morphology, and pollen fertility. When the two species were mixed 1:1, B. campestris produced 13% hybrid seeds and oilseed rape 9%. In two experiments with single plants of the self-incompatible B. campestris widely spaced within fields of oilseed rape, 56% and 93% hybrid seeds were produced. Analysis of a weedy population of B. campestris in oilseed rape revealed 60% hybrid seeds. Backcrossing of the hybrids to the weedy species seems to occur as supported by the finding in a natural population of two B. campestris-like plants with a marker specific to oilseed rape. The results suggest that transgenes could be dispersed from oilseed rape to B. campestris.     

Down‐regulation of OsSPX1 caused semi‐male sterility,resulting in reduction of grain yield in rice

OsSPX1, a rice SPX domain gene, involved in the phosphate (Pi)‐sensing mechanism plays an essential role in the Pi‐signalling network through interaction with OsPHR2. In this study, we focused on the potential function of OsSPX1 during rice reproductive phase. Based on investigation of OsSPX1 antisense and sense transgenic rice lines in the paddy fields, we discovered that the down‐regulation of OsSPX1 caused reduction of seed‐setting rate and filled grain number. Through examination of anthers and pollens of the transgenic and wild‐type plants by microscopy, we found that the antisense of OsSPX1 gene led to semi‐male sterility, with lacking of mature pollen grains and phenotypes with a disordered surface of anthers and pollens. We further conducted rice whole‐genome GeneChip analysis to elucidate the possible molecular mechanism underlying why the down‐regulation of OsSPX1 caused deficiencies in anthers and pollens and lower seed‐setting rate in rice. The down‐regulation of OsSPX1 significantly affected expression of genes involved in carbohydrate metabolism and sugar transport, anther development, cell cycle, etc. These genes may be related to pollen fertility and male gametophyte development. Our study demonstrated that down‐regulation of OsSPX1 disrupted rice normal anther and pollen development by affecting carbohydrate metabolism and sugar transport, leading to semi‐male sterility, and ultimately resulted in low seed‐setting rate and grain yield.     

Impact of ecological factors on the initial invasion of Bt transgenes into wild populations of birdseed rape (Brassica rapa)

The inevitable escape of transgenic pollen from cultivated fields will lead to the emergence of transgenic crop-wild plant hybrids in natural patches of wild plants. The fate of these hybrids and that of the transgene depend on their ability to compete with their wild relatives. Here we study ecological factors that may enhance the fitness of genetically modified hybrids relative to wild plants for a Bacillus thuringiensis (Bt) transgene conferring resistance to insects. Mixed stands of wild plants and first-generation hybrids were grown under different conditions of herbivore pressure and density, with Bt oilseed rape (Brassica napus) as the crop and B. rapa as the wild recipient. Biomass and fitness components were measured from plant germination to the germination of their offspring. The frequency of transgenic seedlings in the offspring generation was estimated using the green fluorescent protein marker. The biomass of F₁ Bt-transgenic hybrids relative to that of wild-type plants was found to be sensitive to both plant density and herbivore pressure, but herbivore pressure appeared as the major factor enhancing their relative fitnesses. In the absence of herbivore pressure, Bt hybrids produced 6.2-fold fewer seeds than their wild neighbors, and Bt plant frequency fell from 50% to 16% within a single generation. Under high herbivore pressure, Bt hybrids produced 1.4-fold more seeds, and Bt plant frequency was 42% in the offspring generation. We conclude that high-density patches of highly damaged wild plants are the most vulnerable to Bt-transgene invasion. They should be monitored early to detect potential transgene spread.     

色季拉山10种报春花属植物花粉形态及其分类学意义

采用扫描电镜法,观察和比较了西藏色季拉山 10 种报春花的花粉形态特征,同时进行聚类分析,以期为该属植物分类提供孢粉学证据,并进一步为西藏报春花属植物杂交育种及种质资源的利用提供参考。结果表明:(1)供试 10 种报春花属植物的花粉形状为扁球形、近球形,其中,工布报春(Primula kongboensis)的花粉粒最小,暗紫脆蒴报春(P. calderiana)的花粉粒最大,西藏报春(P. tibetica)为多沟型花粉,其余报春花的花粉一般具 3 孔沟,大部分孔沟在极区汇合形成复合沟。(2)花粉外壁纹饰大多为穴状或网状,其中,中甸灯台报春(P. chungensis)和西藏报春为网状纹饰中的粗网状类型。(3)虽然基于花粉形态的聚类分析与植物学分类表现出一定的一致性,但粉报春组的西藏报春和工布报春则由于在孢粉学特征上具有明显差异,因此保持了相对较远的亲缘关系。该研究初步认为,色季拉山 10 种报春花粉形态存在种间差异,研究结果可为植物分类提供一定的参考依据。然而,在进行分类时,仍然需要结合形态学特征、分子生物学等方面综合考虑。     

Molecular assays of pollen use consistently reflect pollinator visitation patterns in a system of flowering plants

Determining how pollinators visit plants vs. how they carry and transfer pollen is an ongoing project in pollination ecology. The current tools for identifying the pollens that bees carry have different strengths and weaknesses when used for ecological inference. In this study we use three methods to better understand a system of congeneric, coflowering plants in the genus Clarkia and their bee pollinators: observations of plant–pollinator contact in the field, and two different molecular methods to estimate the relative abundance of each Clarkia pollen in samples collected from pollinators. We use these methods to investigate if observations of plant–pollinator contact in the field correspond to the pollen bees carry; if individual bees carry Clarkia pollens in predictable ways, based on previous knowledge of their foraging behaviors; and how the three approaches differ for understanding plant–pollinator interactions. We find that observations of plant–pollinator contact are generally predictive of the pollens that bees carry while foraging, and network topologies using the three different methods are statistically indistinguishable from each other. Results from molecular pollen analysis also show that while bees can carry multiple species of Clarkia at the same time, they often carry one species of pollen. Our work contributes to the growing body of literature aimed at resolving how pollinators use floral resources. We suggest our novel relative amplicon quantification method as another tool in the developing molecular ecology and pollination biology toolbox.     

Floral resources and risk of exposure to pesticides for Melipona quadrifasciata anthidioides Lepeletier 1836 in a Cerrado of São Paulo (Brazil)

Honey and bee bread samples from storage pots of Melipona quadrifasciata anthidioides were collected monthly from April 2015 to May 2016 in the Mogi Guaçu Biological Reserve (22º 10? S, 47º 11? W). The flora in the site is characteristic of the Atlantic Forest with preserved areas of savanna-like vegetation surrounded by commercial forests, orchards and various crops of exotic and native plants. Samples were analysed with the use of melissopalynological methodology and 46 pollen types from 38 genera and 30 families were identified in 25 honey samples. Fabaceae, Asteraceae, Myrtaceae, Sapindaceae showed the greatest pollen richness in honey. Predominant nectariferous pollen types were Anadenanthera, Cordia, Eucalyptus, Mimosa scabrella, Schefflera, Sida, Serjania and Vernonia. Twenty-eight types of pollen from 21 genera and 19 families were identified in 22 bee bread samples. Fabaceae, Asteraceae and Myrtaceae showed the highest pollen richness. Anadenanthera, Cecropia, Eucalyptus, Melastomataceae, Mimosa scabrella, Mimosa verrucosa and Myrcia were the most frequent polliniferous pollen types. Principal component analysis (PCA) demonstrated that honey and pollen samples formed two main groups of similarity, mainly due to Eucalyptus’ nectar and pollen of Melastomataceae, respectively. Melipona quadrifasciata anthidioides collected nectar and pollen from the preserved areas as well as in the secondary and ‘ruderal’ vegetation and in cultivated forests/fields, suggesting their importance as pollinators both of native flora and exotic species. The use of trophic resources of plants grown with pesticides is a concern for the conservation of these species of bee and should be better studied.     

Effects of pollen selection on progeny vigor in a Cucurbita pepo x C. texana hybrid

We examined the effects of pollen selection for rapid pollen-tube growth on progeny vigor. First, we crossed a wild gourd (Cucurbita texana) to a cultivated zucchini (Cucurbita pepo cv Black Beauty) to produce an F₁ and then an F₂ generation. Half of the F₁ seeds were produced by depositing small loads of C. texana pollen onto the stigmas of C. pepo. These small pollen loads were insufficient to produce a full complement of seeds and, consequently, both the fast- and the slow-growing pollen tubes were permitted to achieve fertilization. An F₂ generation was then produced by depositing small loads of F₁ pollen onto stigmas of F₁ plants. The F₂ seeds resulting from two generations of small pollen loads are termed the non-selected line because there was little or no selection for pollen-tube growth rate on these plants. The other half of the F₁ and F₂ seeds were produced by depositing large pollen loads (>10 000 pollen grains) onto stigmas and then allowing only the first 1% or so of the pollen tubes that entered the ovary to fertilize the ovules. We did this by excising the styles at the ovary at 12–15 h after pollination. The resulting F₂ seeds are termed the selected line because they were produced by two generations of selection for only the fastest growing pollen tubes. Small pollen loads from the F₂plants, both the selected and the non-selected lines, were then deposited onto stigmas of different C. pepo flowers, and the vigor of the resulting seeds was compared under greenhouse and field conditions. The results showed that the seeds fertilized by pollen from the selected line had greater vegetative vigor as seedlings and greater flower and fruit production as mature plants than the seeds fertilized by pollen from the non-selected line. This study demonstrates that selection for fast pollen-tube growth (selection on the microgametophyte) leads to a correlated increase in sporophyte (progeny) vigor.