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The growth events which are responsible for the phototropic curvature of seedlings towards blue light were investigated by growth analysis of seedlings of Avena sativa L. Time-lapse video analysis of coleoptiles given equivalent unilateral or bilateral blue light stimuli showed that both the duration and fluence-rate of the light treatments affected the growth responses which were recorded. The results suggest that the growth responses in bilateral light occur simultaneously with the growth changes which cause phototropic curvature, although they do not appear to make any contribution to the magnitude of curvature. Seedlings were also subjected to continuous unilateral microbeam (1mm) irradiation of discrete zones, to investigate whether 'message' transmission occurs in phototropism. The growth changes which occur in response to this treatment were recorded over the whole length of a 20 mm seedling, but began at different times in different zones. It was concluded that there must be some kind of 'message' transmission following perception of a phototropic stimulus in Avena. The kinetics of the response showed that it was unlikely that transmission could be simply due to tissue light-piping from the position of the original light beam. Unilateral irradiation of a small zone at the base of a coleoptile resulted in negative curvature. This experiment provided some evidence for acropetal transmission of the phototropic signal. A study was also made on the effects of wounding on the growth of Avena seedlings. This led to a re-evaluation of the significance of the traumatropic response to unilateral wounding. The experiments showed that even a slight wound can have severe effects on the growth of a coleoptile. The results are discussed in relation to previous theories on the mechanism of traumatropic curvature.

Region policy of the European Union seems to be one of the most important policy at the supranational level. While it represented only a negligible item on the european budget in the 80s, today it occupies, from the expenditure volume point of view, a second place already. During this dynamic period of time Cohesion policy has become an object of number of political but also special discussions, gained many favorers and opponents. With regard to the considerable amounts of money it has granted, it is worth of detailed attention. Italy has become the seond largest beneficiary from the Structural funds between 1989 an 2006. Its economy is characterised by a substantial geografic dualism where its Southern "periphery" has been struggling with continuous socio-economic difficulties. These regions have had a change to benefit from the generous Structural funds for a considerable period of time. This study tries to analyse the effectiveness of these financial resources, in other words, it considers empirical analysis of the marginal growth effects of these resources on the Southern Italian regions.

A literature review of metal mixture interaction analyses identified that there was not a consistent method to determine the impact of metal mixtures on an aquatic organism. The review also revealed that a majority of the research on mixtures made use of water concentrations only. Therefore research was conducted to determine the relationship between exposure, bioaccumulation and chronic effects of the four elements As, Co, Cr and Mn individually. Mechanistically based saturation models of bioaccumulation and toxicity were determined for the benthic invertebrate Hyalella azteca, from which lethal water concentrations and body concentrations were also determined. These models were then combined with those previously done for the metals Cd, Cu, Ni, Pb, Tl and Zn to model the impact of 10 metal mixtures on bioaccumulation in short term (1-week) exposures and on bioaccumulation and toxicity in chronic (4-week) exposures at “equi-toxic” concentrations. Interactions between the metals were identified in which; Cd, Co and Ni bioaccumulations were significantly inhibited, Tl and Zn bioaccumulations were marginally inhibited, there was no impact on Cr, Cu or Mn bioaccumulation, and both As and Pb bioaccumulation were enhanced by some mixtures of metals. It was determined that strict competitive inhibition may be a plausible mechanism of interaction affecting Co, Cd and Ni bioaccumulation but not for any of the other metals. However, it is possible that other interactions such as non-competitive or anti-competitive inhibition may have been responsible. A metal effects addition model (MEAM) was developed for Hyalella azteca based on both the bioaccumulation (body concentrations) to effects and the exposure (water concentration) to effects relationships developed from the single metal only studies The MEAM was used to predict the impact of metal mixture exposures on mortality. Toxicity was under-estimated when based on measured water or body concentrations, however, its best prediction was based on body concentrations. The MEAM, when based on measured body concentrations, takes bioavailability into account, which is important since the chemical characteristics of water can greatly alter the bioavailability and therefore toxicity of metals. The MEAM was compared to the traditional Concentration Addition Model (CAM), which calculates toxic units based on water concentrations and LC50s or body concentrations and LBC50s. The CAM overestimated toxicity, but had its best prediction when based on water concentrations. Over all, the best fit to observed mortality was the prediction by the MEAM, based on body concentrations. The measurement of bioaccumulated metals and the use of the MEAM could be important in field site assessments since it takes into account changes in bioavailability due to different site water chemistries whereas the traditional CAM based on water concentration does not.

A literature review of metal mixture interaction analyses identified that there was not a consistent method to determine the impact of metal mixtures on an aquatic organism. The review also revealed that a majority of the research on mixtures made use of water concentrations only. Therefore research was conducted to determine the relationship between exposure, bioaccumulation and chronic effects of the four elements As, Co, Cr and Mn individually. Mechanistically based saturation models of bioaccumulation and toxicity were determined for the benthic invertebrate Hyalella azteca, from which lethal water concentrations and body concentrations were also determined. These models were then combined with those previously done for the metals Cd, Cu, Ni, Pb, Tl and Zn to model the impact of 10 metal mixtures on bioaccumulation in short term (1-week) exposures and on bioaccumulation and toxicity in chronic (4-week) exposures at “equi-toxic” concentrations. Interactions between the metals were identified in which; Cd, Co and Ni bioaccumulations were significantly inhibited, Tl and Zn bioaccumulations were marginally inhibited, there was no impact on Cr, Cu or Mn bioaccumulation, and both As and Pb bioaccumulation were enhanced by some mixtures of metals. It was determined that strict competitive inhibition may be a plausible mechanism of interaction affecting Co, Cd and Ni bioaccumulation but not for any of the other metals. However, it is possible that other interactions such as non-competitive or anti-competitive inhibition may have been responsible. A metal effects addition model (MEAM) was developed for Hyalella azteca based on both the bioaccumulation (body concentrations) to effects and the exposure (water concentration) to effects relationships developed from the single metal only studies The MEAM was used to predict the impact of metal mixture exposures on mortality. Toxicity was under-estimated when based on measured water or body concentrations, however, its best prediction was based on body concentrations. The MEAM, when based on measured body concentrations, takes bioavailability into account, which is important since the chemical characteristics of water can greatly alter the bioavailability and therefore toxicity of metals. The MEAM was compared to the traditional Concentration Addition Model (CAM), which calculates toxic units based on water concentrations and LC50s or body concentrations and LBC50s. The CAM overestimated toxicity, but had its best prediction when based on water concentrations. Over all, the best fit to observed mortality was the prediction by the MEAM, based on body concentrations. The measurement of bioaccumulated metals and the use of the MEAM could be important in field site assessments since it takes into account changes in bioavailability due to different site water chemistries whereas the traditional CAM based on water concentration does not.