The Mostonga, once the tributary of the Danube river, now a water-stream with a conducted regime it represents an important water-streams in West Backa (Serbia, Yugoslavia). The most wide-spread hydrophytes (i.e. plant species with the biggest abundance, covering values and occurrence degree) are: Wolffia arrhiza, Lemna gibba, Lemna minor, Lemna trisulca, Spirodela polyrrhiza, Ceratophyllum demersum, Elodea canadensis, Vallisneria spiralis, Stratiotes aloides, Nuphar lutea, Bolboschoenus maritimus, Typha angustifolia, Typha latifolia and Phragmites communis. Based on the analysis of bioindicating values of mentioned hydrophytes of the Mostonga it can be concluded that the present plant species are significant indicators of eutrophication (considerable organic pollution) as well as the increased contents of nitrogen and nitrogen compounds (nutrients), presence of salt in the soil and weakly aerated and mud base.

In order to determinate the concentration of elements: K, Ca, Na, Mg, Cu, Pb, Cr, and Cd in sea water and seagrasses Posidonia oceanica and Cymodocea nodosa sampling were done in the area of the Boka Kotorska Bay (Adriatic sea, Montenegro (Yugoslavia)). For majority of these elements variability of contents in the samples was great, but in the range of expectations. The concentrations of Pb and Cr in the seagrasses were higher from values in literature. Because of bioaccumulation and biomagnification of these metals, we have to investigate causes of these higher concentrations and possibility of toxic effects on the seagrasses and other organisms.

The lake Provala near Vajska (Serbia, Yugoslavia) was created by the embankment performation during high Danube river levels in 1924. It is a very important water ecosystem of natural origin, which is a fact of great importance for exact biological and ecological research. Miljanovic (1996) and Pujin (1997) present the first lake Provala water state data. They emphasise the reinforced eutrophication process in the shore region. This paper presents the review of the macrophytes vegetation of the lake Provala recent state for the first time, with special attention to dominant plant species. Based on the present taxons analysis, as well as water chemical parameters analysed (NH4(+), NO3(-), NO2(-), PO4(3-), HPK, BPK, pH), it can be concluded that the eutrophication process is present in this water micro-reservoir. It is especially true for the shore region and shallow waters, where the process is already well under way and very fast. These research results can be used to efficiently protect this natural water ecosystem.

Base characteristic melioration territory "Upper Danube" inclusion round about 1.4 million ha area in Backa and Banat (Serbia, Yugoslavia) are presented in this paper. Specification problem maintenance of the drainage of system to originate because of discharge wastewater and sludge in channel and suggest in decides these problems are considered.

In this paper there were given research results obtained during many years of investigation of hydrophytes of the Tisza river, Serbia (Yugoslavia), and their bioindicating values. The plant world of the Tisza river is characterized by floristical diversity, with three characteristics band: band of submerged, band of floating and band of emerged hydrophytes. Among submerged plants these are distinguished by abundance, covering values and occurrence degree: Ceratophyllum demersum, Elodea canadaensis, Potamogeton crispus, Potamogeton perfoliatus and Potamogeton pectinatus. In the floating band species of the fam. Lemnaceae: Lemna minor, Lemna gibba, Spirodela polyrrhiza and Potamogeton fluitans are most frequent. In the closest coastal band, these species are most frequent: Typha angustifolia, Typha latifolia, Phragmites communis, Sagittaria sagittifolia and Typhoides arundinacea. On the basis of determined floristical composition and bioindicating values there can be noticed the organic pollution increasing trend.

The paper presents results of research on hydrophilic flora of the Grosnica reservoir in the Kragujevac basin (Serbia, Serbia&Montenegro). The obtained results confirm that the development of hydrophilic vegetation is dependent on the time, manner, and place of reservoir formation, as well as on the extent of human influence. Analysis of floristic composition of hydrophilic plants of this reservoir indicates presence of 30 species belonging to 20 families. Floristic composition of the hydrophilic flora with flora elements, life forms and ecological factors are presents.

In this paper is given the comparative review of investigation of the macrophytic vegetation and ichthyofauna in 4 localities (Grasnica, Gradiste, Veli Dab, and Cerava) from the littoral region of the Lake Ohrid. In the investigated localities are evidenced macrophytic species and fish species as bioindicators for saprobility. Based on the obtained results, it can be concluded that qualitative composition of macrophitic vegetation and ichthyofauna are different and depend from locatities where investigated made.

In this paper are presented the investigation of macrophytic vegetation along Macedonian shore of Lake Ohrid (Radozda-Sv.Naum). The meterial were collected from 59 localities. The results of investigations show that in investigated localities were evidenced 25 different plant species. The number of macrophytic species in different localities vary from 2 to 18 macrophytic species. The differences in the number of macrophyte species are most due to the different ecological conditions in the investigated localities: temperature, light regime, type of soil, configuration of the lake bottom, water level, nutrient amount etc.

Nitrogen and phosphorus contents in water, sediment and shoots of Phragmites communis Trin, and Typha latifolia L., as possible indicators of trophic state were used in the area of the Bardaca fish-pond. The results of total nitrogen and phosphorus contents during growing season indicate the hypertrophic state of waters in all locations.