Usefulness and limitations of pollen characters in environmental studies based on Viola L. species (sect. Melanium Ging.)

The aim of these studies was to determine the effect of environmental pollution on pollen development. Pollen heteromorphism (the presence of pollen morphs differing in aperture number in one flower of a plant), pollen viability (stainability) and pollen grain size in European metallophytes from sect. Melanium Ging. (Viola L., Violaceae) were analyzed by SEM and histochemical staining.Plants’ tolerance to heavy metals is positively correlated with their pollen viability, which should be termed stainability as it depends on the staining method applied and is not correlated with pollen germination. Abortive pollen can be produced as an effect of heavy metals but also may result from hybridization, a very common phenomenon in pansies. Pollen stainability in hybrids can be high (even exceeding 70%) or low (barely above 20%), and stainable pollen grains can differ greatly in size (from very small to giant), indicating a cytological imbalance resulting from disturbed meiosis. The number of pollen apertures is an adaptive character in facultative metallophytes. Plants from a metallicolous population produced a wider range of aperture number (3, 4, 5) than plants from a non-metallicolous population, which developed only 4- and 5-aperturate pollen. Three-aperturate longer-lived pollen are favored in the harsh conditions of a metal-polluted environment

Bathymetric Survey and Volumetric Analysis for Sustainable Management: Case Study of Suleja Dam, Niger State, Nigeria

Ocean floor and the shape of the shoreline are major influencers of the changes in tidal propagation. Bathymetry; a survey operation aimed at determining the nature of the underwater level and topography of a water body’s bed level plays a cogent role in the determination of both the shape of the shoreline and the ocean floor thereby aiding the monitoring and spatio-temporal modelling of the changes in tidal propagation as much as it ensures the availability of hydro-data which is the foundation of a Maritime Database Management System (MDBMS). This work presents the findings of the bathymetric survey and volumetric analysis of Suleja Dam located in the North central Region of Nigeria. The Differential Global Positioning System receiver (DGPS) (Promark 3), automatic level, echomap 50s in conjunction with the engine boat were used during this research. The data acquired was processed using the GNSS solutions software with the chart plotted in surfer 9 software environment. The surface area of the dam was discovered to be 24.64ha less than the designed area. Also the volume of water was found to be 3.6 x 106m3 in contrast to the design volume of 34.7x106m3. It was also observed that the lowest water depth was 0.56m and the highest water depth was 22.06m, therefore a difference of 5.94m was obtained as against the initial construction depth of 28.00m. The undulating nature of the reservoir bed and the difference in volume of water and surface area covered by the dam are pointers and clear indications of sedimentation and siltation process going on in the dam. Keywords: Bathymetry, sounding, chart, reservoir, MDBM

Spatio-Temporal Transmission Patterns of Black-Band Disease in a Coral Community

Transmission mechanisms of black-band disease (BBD) in coral reefs are poorly understood, although this disease is considered to be one of the most widespread and destructive coral infectious diseases. The major objective of this study was to assess transmission mechanisms of BBD in the field based on the spatio-temporal patterns of the disease

Understanding biological responses to degraded hydromorphology and multiple stresses. Deliverable 3.2 of REFORM (REstoring rivers FOR effective catchment Management), a Collaborative project (large-scale integrating project) funded by the European Commission within the 7th Framework Programme under Grant Agreement 282656

The aim of this deliverable is to conceptually model and empirically test the response of biota to the effects of both hydromorphological pressures acting in concert with one another or with other types of pressures. Best use is made of existing large national monitoring datasets (Denmark, UK, Finland, France, Germany, Austria & WISER datasets), case studies and modeling to provide evidence of multiple stressors interacting to alter river biota (Biological Quality Elements: BQE)

Effects of a selective mu opioid receptor agonist and naloxone on the intake of sodium chloride solutions

Endogenous opioid peptides are thought to play a role in mediating the palatability or rewarding aspects of sweet tastes. There is also evidence, however, which suggests that opioids may influence the preference for the taste of salt as well. In the present studies, we measured the effects of central administration of naloxone and the mu agonist [ d -Ala 2 ,MePhe 4 ,Gly-ol 5 ]enkephalin (DAGO) on the ingestion of salt solutions. In non-deprived rats given a choice of water and 0.6% saline, ICV injections of DAGO (1 and 3 nmol) significantly increased the intake of 0.6% saline; baseline water intake was minimal and was unaffected by DAGO. When rats were given a choice between water and 1.7% saline, DAGO stimulated both water and saline intake. Because 1.7% saline is a hypertonic solution, the increase in water intake may have been secondary to saline intake. In rats on a deprivation schedule in which water and 0.6% saline were available for only 2–3 h/day, there was a tendency for DAGO to increase 0.6% saline intake and decrease water intake, though these effects were not significant. In rats given water and 1.7% saline, DAGO increased saline intake and had no effect on water intake. Naloxone was also tested in water-deprived rats. Naloxone (20 and 50 µg) significantly decreased 0.6% saline intake; baseline water intake was low (3–5 ml) and was unaffected by naloxone. When rats were given a choice between water and 1.7% saline, naloxone (50 µg) significantly reduced water intake, while intake of 1.7% saline was slightly increased. These results suggest a role for central mu opioid receptors in mediating the preference for salt solutions.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46331/1/213_2005_Article_BF02245792.pd