International Nuclear Information System (INIS)

Pollen morphology of 30 species of the family Acanthaceae belonging to 11 genera has been investigated using light and scanning electron microscope. Acanthaceae is a eurypalynous family. Pollen are usually radially symmetrical, isopolar, sub-prolate to prolate rarely prolate-spheroidal or sub-oblate to oblate-spheroidal, generally tricolporate or heterocolporate rarely colpate or porate. Exine ornamentation varies from medium to coarse reticulate, or often lopho-reticulate with luminae perforated to baculate or scabrate. On the basis of apertural type, exine ornamentation and colpal membrane eight distinct pollen types have been recognized viz., Pollen type-I: Barleria cristata-type, Pollen type-II: Blepharis ciliaris-type, Pollen type-III: Hygrophila polysperma - type, Pollen type-IV: Justicia adhatoda-type, Pollen ...

British Library Electronic Table of Contents (United Kingdom)

Long term storage of viable pollen is important for bank germplasm constitution to preserve resources that can be used in breeding programs, biotechnologies and genetic engineering. Pollen from 12 olive (Olea europaea L.) cultivars was stored for 1?year in liquid nitrogen at ?196?C. The morphology of pollen grains and germination rates on fresh and long term stored pollen were observed. Results on in vitro pollen germinability, both before and after cryopreservation, showed highly significant responses among the 12 cultivars. The relationship between germinability and pollen grain size did not reveal any significant relationships in both treatments. Our findings will contribute to the improvement of olive pollen preservation and lead to find a more efficient method for its long term storag...

Science.gov (United States)

... data on pollen from red maple, birch, beech, ash, oak, hemlock and elm trees isolated from cores of ...

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

UK PubMed Central (United Kingdom)

BackgroundPlant biologists have long speculated about the mechanisms that guide pollen tubes to ovules. Although there is now evidence that ovules emit a diffusible attractant, little...Full Text Available

Science.gov (United States)

... doi: 10.2112/JCOASTRES-D-09-00089.1 Alexandria's Eastern Harbor, Egypt: Pollen, Microscopic Charcoal, and ... STANLEY, J.-D. an...

British Library Electronic Table of Contents (United Kingdom)

`Success' or `Red Splendor' plants propagated by shoot tip culture or embryogenesis had higher pollen germination than those propagated by cutting. All clones of `Pepride', `Peter Star' and `Nobel Star' propagated by cutting or by embryogenesis or shoot tip culture did not have viable pollen. `Peter Star' mutants through mutagenesis could recover pollen viability. When both parents were propagated by tissue culture, fruit set increased compared to when one or both parents were propagated by cuttings. Furthermore, the number of the harvested seeds doubled per pollination set, when the tissue culture parents were used instead of cutting-propagation plants.

British Library Electronic Table of Contents (United Kingdom)

This article describes the complete microsporogenesis and pollen formation in cassava (Manihot esculenta Crantz) at the various developmental stages (pollen mother cell, meiosis, tetrads, early free spore, mid uninucleate, late uninucleate, binucleate and mature pollen grain). Light microscopy, transmission electron microscopy and confocal laser scanning microscopy were used for the study. Floral bud size and other inflorescence characteristics were correlated with specific stages of the microspore development. This association allows a rapid selection of floral buds with similar microspore developmental stages, useful when a large number of homogeneous cells are needed for analysis and for in vitro induction of androgenesis. This article also compares methods for digestion the exine wall ...

British Library Electronic Table of Contents (United Kingdom)

Plant meiotic prophase I is a complicated process involving the late zygotene and pachytene stages, both crucial for completing synapsis and recombination. Using David Lily (Lilium davidii var. Willmottiae) as our research material, we performed suppression subtractive hybridization to construct EST library of anthers at various stages of development by the pollen mother cells. From this library, we identified small heat shock protein LimHSP16.45 was highly expressed during the late zygotene to pachytene stages. Our results also showed that LimHSP16.45 was almost specifically expressed in the anther compared with the root, stem, or leaf, and in situ expression of LimHSP16.45 mRNAs showed strong signals in the pollen mother cells and tapetal cells. LimHSP16.45 could be induced by heat and c...

International Nuclear Information System (INIS)

The purpose of this work was to evaluate the quality of a rural area near Faenza (Italy) by using an active biomonitoring approach, i.e., by placing homogeneous individuals of the perennial shrub Rosa rugosa in different sites throughout the area. Further sites, within the city or its environs, were used for comparison. Soil and leaves of R. rugosa were analyzed for their heavy metal content. The total heavy metal pattern of leaves closely paralleled the pattern registered in soil, with the highest content (both in total and assimilable forms) at the site in the urban area, which is exposed to heavy traffic. Pollen quality (abortiveness and viability) was also tested as a potential indicator of pollution. Pollen abortiveness was strictly related to Pb levels in leaves, while viability was inversely related to leaf Cr content. Our results suggest that R. rugosa has the potential to be a good biomonitoring system. - Rosa rugosa leaves and ...

British Library Electronic Table of Contents (United Kingdom)

The purpose of this work was to evaluate the quality of a rural area near Faenza (Italy) by using an active biomonitoring approach, i.e., by placing homogeneous individuals of the perennial shrub Rosa rugosa in different sites throughout the area. Further sites, within the city or its environs, were used for comparison. Soil and leaves of R. rugosa were analyzed for their heavy metal content. The total heavy metal pattern of leaves closely paralleled the pattern registered in soil, with the highest content (both in total and assimilable forms) at the site in the urban area, which is exposed to heavy traffic. Pollen quality (abortiveness and viability) was also tested as a potential indicator of pollution. Pollen abortiveness was strictly related to Pb levels in leaves, while viability was ...

Science.gov (United States)

Polysomaty analysis of the succulent portulaca (Portulaca grandiflora Hook.) plant was carried out using flow cytometry. For both diploid and tetraploid plants, mature leaf tissue was found to have a higher level of polysomaty than young leaf tissue. Mesophyll (MP), bundle sheath (BSP) and water storage protoplasts (WSP) were isolated from leaf tissues of diploid portulaca plants. WSP had a higher degree of endopolyploidization than MP and BSP. The ploidy distribution was also variable in different floral organs. Tetraploid plants artificially induced by colchicine treatment showed a decline in the degree of polysomaty compared to diploid plants. Tetraploid plants had more spherical leaves, a larger number of petals and lower pollen fertility than diploid plants. PMID:10936528

CERN Document Server

Community ecologists are principally occupied with the proposition that natural assemblages of species exhibit orderliness and with identifying its causes. Plant-pollinator networks exhibit a variety of orderly properties, one of which is 'nestedness'. Nestedness has been attributed to various causes, but we propose a further influence arising from the phylogenetic structure of the biochemical constraints on the pollen diets of bees. We use an artificial assemblage as an opportunity to isolate the action of this mechanism. The properties of the network that we studied are consistent with the proposition that nestedness is caused by the phylogeny of diet range in bees, but the claim is preliminary and we propose that valuable progress in understanding plant-pollinator systems may be made through applying the techniques of chemical ecology at the community scale.

British Library Electronic Table of Contents (United Kingdom)

We evaluated the use of a novel gene porter (Den123-a nontoxic self-assembled dendritic spheroidal nanoparticle made of biodegradable monomers), aiming to enhance and improve the desired immune response in protection from allergy. Footpad DNA immunization in Balb/c mice was done three times using the Bet v 1a gene with or without Den123 with 2-week intervals followed by sensitization with rBetv1 (5mg) in alum twice in a weekly interval. Different doses of pCMV-Betv1 were used (10mg and 100mg). The protective role of different formulations was evaluated by measuring the IgG1, IgG2a and IgE antibody production, cytokine release of isolated splenocytes and b-hexosaminidase release from the RBL cells. Higher and increasing ratios of IgG2a/IgG1 were seen in mice which received plasmids in combi...

Energy Technology Data Exchange (ETDEWEB)

Understanding feedbacks between terrestrial and atmospheric systems is vital for predicting the consequences of global change, particularly in the rapidly changing Arctic. Fire is a key process in this context, but the consequences of altered fire regimes in tundra ecosystems are rarely considered, largely because tundra fires occur infrequently on the modern landscape. We present paleoecological data that indicate frequent tundra fires in northcentral Alaska between 14,000 and 10,000 years ago. Charcoal and pollen from lake sediments reveal that ancient birchdominated shrub tundra burned as often as modern boreal forests in the region, every 144 years on average (+/- 90 s.d.; n = 44). Although paleoclimate interpretations and data from modern tundra fires suggest that increased burning was aided by low effective moisture, vegetation cover clearly played a critical role in facilitating the paleo-fires by creating an abundance of fine fuels. These records suggest ...

Energy Technology Data Exchange (ETDEWEB)

In 2004, the Southeastern France regional council asked the regional health observatory to conduct an environmental health inventory to i) identify environmental health problems in this area; ii) examine the relations between environmental exposure to pollutants and human health; and iii) help public officials to identify priorities in this area. We collected and validated data from national, regional and local institutions, constructed environmental (levels of emissions and pollutants), health (mortality, incidence, prevalence) and behavioral indicators (e.g., complaints about odors), and compared these over time and between places when possible. For each topic, we summarized current knowledge about the links between environment and health. In southeastern France, as in other French areas, indoor air pollution, home and leisure injuries and other home-related risks are public health issues. Other topics are more significant or particular to southeastern France: transportation (air ...

Energy Technology Data Exchange (ETDEWEB)

The overall goal of the DOE fine particulate program is to ensure that the best science and technology is available for any regulatory decision-making related to the health and environmental impacts of ambient fine particulate matter and regional haze. Interest primarily lies in the particulate fraction having aerodynamic diameters of 2.5 microns and less (PM2.5). Particulates of this size are the focus of the newly established National Ambient Air Quality Standards. As such, the Federal Energy Technology Center (FETC) is establishing a fine particulate sampling station at the Center's Pittsburgh site located in South Park Township, PA. This sampling station is one of a group of stations scattered throughout Pennsylvania, West Virginia, and Ohio that constitute the Upper Ohio River Valley Project. The station is equipped with a full complement of fine particulate and gaseous monitors including the following: (1) R and P Sequential FRM sampler, (2) Grimm PM2.5 continuous ...

International Nuclear Information System (INIS)

Sesame varieties/genotypes showed a good response to radiation with gamma rays and treatments with EMS. In M_1 both gamma rays and EMS influenced germination, seedling height, survival of plants and pollen fertility/sterility, producing deleterious effects on these characters. Compared to black seeded genotypes, white seeded ones are more susceptible to radiation. Both gamma rays and EMS produced various types of morphological variations in M_2 generation. These were dwarf plant mutants, mottled and fleshy leaved mutants (sterile), fasciated stem, flower colour, altered phyllotaxy, early, uniculm, capsule size variations, multiple capsule/leaf axil, seed coat colour variations, indehiscent and semi-indehiscent type mutants. Moreover, studies on quantitative characters including seed yield revealed the induction of mutants in both positive and negative directions for such traits which made a good scope of selection of desirable mutants in M_2 generation. Mutants ...