The influence of zinc on the accumulation of cadmium and copper in the terrestrial isopod Porcellio scaber (Crustacea, Isopoda)

Abstract

Relative to data derived from single-metal exposure not much is known about metal kinetics in terrestrial isopods exposed to a mixture of metals. In the work presented the accumulation pattern of Zn, Cd and Cu were studied in Porcellio scaber , one of the most investigated isopods. Animals were fed with hazel leaves dosed with single metals or their binary mixtures. After twenty-one days of exposure, food consumption and metal accumulation were measured. Results revealed that the accumulation of Zn is not affected by a decreased food consumption rate or by possible interactions between the mixture constituents. In contrast, the accumulation of Cd and Cu is significantly reduced when food is also contaminated with Zn. The lower accumulation of Cd and Cu can be ascribed to interactions with Zn that affect uptake and/or loss of metals.

Keywords

Isopods, Porcellio scaber , metal mixtures, zinc, copper, cadmium, food consumption, accumulation

Analysis of Cell Motility with a Successive Sequence of Images

Abstract

Analysis of cell motility usually requires several hours of continuous video recording of a single view field. Consequently, the method is very much time consuming and only a small number of cells is usually included into analysis. To increase the number of cells monitored in an experiment we developed a simple and expeditious method for analysing the cell motility. A combination of successive series of images of individual cells relocated on CELLocate coverslips and vector graphic editing software Adobe Illustrator 9.0 enabled simultaneous monitoring of locomotion for up to ten times more cells as with previous methods.

Keywords

Cell motility, digital camera, successive sequence of images, software Adobe Illustrator 9.0.

The macrophytes of lake Velenjsko Jezero, Slovenia – the succession of macrophytes after restoration of the lake

Abstract

The macrophyte vegetation in the artificial lake Velenjsko jezero has been monitored since 1996. The pH of the lake was around 12 up to 1994, when it was remediated. After that macrophytes started to colonize a large proportion of the littoral very quickly. The pioneer species, which appeared in the first survey year (1996), were Chara sp., Nuphar lutea , Potamogeton crispus and Myriophyllum spicatum . Potamogeton crispus was the dominant species till 1997. In the following years Najas marina and Potamogeton filiformis prevailed over other species in the lake. Since the beginning of the colonization, the species composition had become more heterogeneous and the quantitative relationships between the species varied enormously. In the year 2004, 9 species were detected in the lake. While species Najas marina , Potamogeton filiformis, Potamogeton lucens, Potamogeton nodosus show positive development progress, in the last years minor appearance of Chara sp., Potamogeton crispus and Najas minor was observed.

Keywords

lake Velenjsko jezero, succession of macrophytes, species composition and distribution, relative plant mass, maximal depth colonization

Secular trend in body dimensions in boys from Tuzla region in period 1980 – 1996

Abstract

Within 16 year-period secular trend in seven measurements of physical growth of male children and youth from Tuzla Region, was researched by corresponding analysis of the sample that involved 1329 researched subjects. Our data were compared with the results of research from 1980 in the sample of 1349 boys. Nine successive generations in 1980 and 1996, from Tuzla region, were involved in this research. Analysis of the data obtained is based primarily on scientific elaboration of the situation registered in 1996 in the tested part of the broader population, after an unnatural and extremely unfavorable period for physical growth of the large majority of that population. The aim of this research was to establish secular trend (negative or positive) for the seven measurements of physical growth of male children and youth comparing our results from 1996 to corresponding research results on growth and development from 1980, the sample of about same population (nearly same number of investigated persons). Although the unfavorable war living conditions negatively affected ontogenesis of the researched subjects, body dimensions of male children and youth were established as harmonious, in the limits of average European standards. However, it seems the unfavorable living conditions caused temporary slowdown in body dimensions, so, for these generations (11 to 19 years old), we could not find any increase of mean values (for certain number) of the researched parameters in comparison with the sample from 1980 year. So, 16 year-acceleration trend for most parameters was established and it is particularly evident in postpubertal period.

Keywords

secular trend, boys' growth and development

Thinning of 'Golden Delicious' apples with the combination of ethephon and CPPU

Abstract

A synthetic cytokinin forchlorfenuron (CPPU) 5 ppm was sprayed at the time of petal fall (PF) on eight years old 'Golden Delicious’/M.9 apple trees with the aim of enlarging the fruit growth. Since CPPU is not recognized as a thinning agent which increases the return bloom, a low dose of ethephon was sprayed on CPPU treated trees to enhance flower bud formation and increase flowering in the next season. Ethephon was applied in successive treatments (alone or in the combination with CPPU) 3 x 30 ppm or 5 x 50 ppm, starting at PF, and continued in week intervals.

The single application of CPPU 5 ppm or the combination of ethephon 3 x 30 ppm with CPPU 5 ppm decreased the fruit set and enhanced the fruit growth to reach the commercial demand. The combination spraying of ethephon 5 x 50 ppm + CPPU 2 x 5 ppm resulted in a too strong thinning response while the yield of bigger size fruit was not enhanced. The alone application of ethephon 3 x 30 ppm had no influence on the fruit thinning or fruit weight while the application of ethephon 5 x 50 ppm reduced the fruit set but, consequently, did not enhance the fruit growth. None of the treatments influenced the return bloom.

Keywords

apple thinning, CPPU, ethephon, alternate bearing