THE CONTENT OF MACRO-AND MICROELEMENTS IN THE SHOOTS OF GLYCERIA MAXIMA OF THE SŁUPIA RIVER

The study shows the content of macroand microelements in the leaves and rhizomes of Glyceria maxima of the Słupia River in Słupsk. The content of macroand microelements in G. maxima was analyzed for each component separately and in an integrated way, and comparing the demand for nutritions. The largest quantity of nitrogen, phosphorus, potassium, magnesium and calcium were found in the leaves, meanwhile zinc, iron, manganese, nickel and copper in the G. maxima rhizomes. The amount of Zn and Cu, in all of the tested positions, within the range of the limit for the plants, and the concentrations of Ni and Mn exceed physiological needs. The U Mann Whitney test showed a number of statistically significant differences in the concentration of the analyzed elements in leaves – rhizomes, leaves – bottom sediment and rhizome bottom sediment relation. The relations between designated heavy metals formed a following series: Mn>Fe>Zn>Ni>Cu in leaves and Fe>Mn>Zn>Ni>Cu in rhizomes. The G. maxima shoots accumulated 985.8 do 1441.4 mmolc·kg -1 in all the analyzed components, and the lower value of the sum of the accumulated macroand microelements were found in rhizomes. The sum of ion comospition of the macronutrients in the leaves and rhizomes was similar. The content of nitrogen was 51.7–53.7% of this amount, 5.8–8.6% phosphorus, potassium 22.8 – 26.6%, 4.9-5.8% of magnesium, calcium, 8.2–11.9%, and trace elements were 0.58% in total, in the case of leaves and 8.70% in the rhizomes.


INTRODUCTION
The pollution of urban ecosystems with the anthropogenic substances, including heavy metals, significantly affects the increase in the concentration of the macro-and microelements in the bottom sediments and the coastal vegetation of many rivers [Buszewski et al. 2000 The macrophytes, which next to the phytoplankton, macrozoobenthos and fish, are one of the basic elements of the assessment of the ecological status of rivers, are used to bioindicate aquatic ecosystems [Skorbiłowicz 2003 Klink et al. 2013].Currently, a significant impact on the chemical composition of the bottom sediments has the intensity of catchment area use and sewage inflow [Misztal et al. 1996, Salati andMoore, 2009].This leads to an increase in the content of many elements in river sediments, which are important part of the water environment.Most of the heavy metals entering the river are connected and transported with the slime, which leads to the rise of sediments [Kruopiene 2007] and may be a second-ary source of pollution, which despite the cut-off of primary sources continues to threaten aquatic ecosystems [Grynkiewicz et al. 2006 The aim of the study was to compare the ability of accumulation of the above and belowground shoots of the Glyceria maxima nutrients and selected heavy metals.The contents of macro-and microelements in G. maxima were analyzed considering each component separately and in an integrated way -by comparing the demand for nutrients.The study takes into account the effect of the bottom sediments to the tested macrophyt.

The study area
The study was conducted on a section of the Słupia River within the city of Słupsk.The Słupia River is located in the central part of Pomerania (northern Poland).The lowland watercourse is 138,6 km long and the catchment occupies the area of 620 km 2 .From the north, the catchment is bordered by the Baltic Sea catchment, from the west by the Wieprza River catchment, from the south by the Brda River catchment, from the east by the of Leba and Łupawa catchment.The sources of the Słupia River are located in the Kashubian Lake District, near Sierakowska Huta, at an altitude of 178 m above sea level.The width of the riverbed ranges from 7 m in the upper part of the river to 40 m at the estuary, where the average flow is 15,5 m³ .s -1 .The area of the city of Słupsk includes 8 km section of the Słupia River with varying degrees of transformation of the riverbed (low, medium or high) [Obolewski 2010], with shores covered with numerous macrophytes (Table 1).

The methodology
The study was conducted in July 2013, within the 10 stations located throughout the city.Samples of the aboveground (leaves) and belowground (rhizomes) shoots of Glyceria maxima, collected in the river side zone of the Słupia River.Within each of the experimental stations sev- eral shoots were taken.Then the mixed samples were formed separately from the aboveground and belowground shoots.After transportation to the laboratory the plant material was cleaned from mineral soil portion, rinsed in distilled water and dried to constant weight at 65 °C and homogenized in a grinder.The total contents of nitrogen was determined by Kiejldahl method, and the phosphorus by the molybdate method, after mineralization in the mixture of concentrated H 2 SO 4 and 30% H 2 O 2 .In order to determine the metallic elements, the plant samples were mineralized wet in a closed system, in the mixture of concentrated HNO 3 and 30% H 2 O 2 (Sobczyński et al. 1996).To the resulting solution, the contents of K, Mg, Ca, Zn, Cu, Ni, Mn, and Fe by atomic absorption spectrometry (Aanalyst 300, PerkinElmer).The analysis were carried in airacetylene flame of the Ostrowska et al. [1991].
The study used the original standard solutions (Merck KGaA, 1g/1000 ml).

The desription of the results
In order to characterize and compare the concentration of selected macro-and microelements in the shoots above ground and belowground Glyceria maxima, medium, minimum and maximum values were calculated, standard aberration and coefficient of variation (CV).The distribution of the content of the analyzed elements was tested by the Shapiro-Wilk test.The significance of the differences in the macro-and microelements in the shoots of Glyceria maxima was verified by non-parametric Mann Whitney U test.For the calculations Statistica (7.1) was used.G. maxi-ma's demand for nutrients was described by the ANE (Accumulation Nutrient Elements) method [Ostrowska 1987].The sum of the components (Y) mmol c •kg -1 was calculated from the formula: where: Z -content of the element in mg .kg -1 , z -atomic weight/ion valency.
After the calculation of Y, the percentage (X) of each element in the sum of: The study contained the effect of the sediments on the tested macrophyt (Table 2).

RESULTS AND DISCUSSION
The sediments of the Słupia River were characterized by a low content of organic matter and erythrocyte and a slightly alkaline reaction (Table 2).The concentration of most elements in the studied sediments was low and remained within the limits of the geochemical background for most of the analyses [Kabata-Pendias and Pendias 1999].Only in the case of zinc, copper and nickel the concentration occasionally exceeded the geochemical background for stations in the central part of the city.According to the classification of Lawa [1998] and Wolska and Mędrzycka [2009], the Słupia River sediments were classified as class I, due to the presence of heavy metals assayed, as the non-contaminated sediments.The content of the tested components in the sediments of the Słupia River does not affect living organisms (Table 2).
The content of macronutrients in the shoots of Glyceria maxima reflects the supply of nutrients.The largest amount of nitrogen, phosphorus, potassium, magnesium and calcium were in the leafs and the largest amount of zinc, iron, manganese, nickel and copper the G. maxima rhizomes (Figures 1 and 2).round parts and it's excess is accumulated in the roots [Ostrowska et al. 1991].In the areas such as agglomerations, it's values are usually higher than the physiological demand, because nickel is easily bioaccumulated especially by the water plants [Sarosiek and Natkaniec-Wożakowska 1993].The relations between the designated heavy metals are arranged in the following series: Mn>Fe>Zn>Ni>Cu and in the leaves Fe >Mn>Zn>Ni>Cu in the rhizomes.
The results of the non-parametric Mann Whitney U test showed a number of statistically significant differences in the content of macroand microelements within 10 research stations in the city of Słupsk, in relations: leaves -rhizomes, leaves -bottom sediment and rhizome -bottom sediment (Table 3).-no differences, + statistically significant differences p<0,05, ++ statistically significant differences p<0,01, +++ statistically significant differences p<0,001.
In order to assess the content of macro-and microelements in the Glyceria maxima shoots the ANE (Accumulation Nutrient Elements) method was used [Ostrowska 1987].The sum of the components reflects the whole so-called nutritional factor.The shoots of G. maxima accumulated from 985.8 to 1441.4 mmol c •kg -1 of all the analyzed components, and the lower value of the sum of the accumulated macro-and microelements found in the rhizomes (Table 4).
Macronutrients were collected in 61.4% of the leaves and 38.6% of the rhizomes.Micronutrients were characterized by a different distribution, 8.9% was accumulated in the leaves, and 91.1% in the rhizomes.The composition of the macronutrients in the leaves and rhizomes was similar.The share of nitrogen was 51.7-53.7%The similar relations between the measured amount of ingredients in the various plant species were shown by Porębska and Ostrowska [2002] in their study.A large amount of manganese and iron in all of the measured components in the leaves and iron the rhizomes show excessive absorption from the bottom sediments, which favored slightly alkaline reaction of the bottom sediments (Table 2).The G. maxima leaves accumulated more nitrogen, calcium, magnesium, zinc, copper, nickel and manganese, since the rhizomes accumulated more of phosphorus, potassium and iron.

CONCLUSIONS
The results indicate that the greatest amount of nitrogen, phosphorus, potassium, magnesium and calcium were in the leaves of Glyceria maxima.The rhizomes also accumulated significant amounts of macroelements so that they can act as a backup body.
The largest amounts of heavy metals were found in belowground stems (rhizomes).The content of zinc and copper at all tested locations ranged within the limit for the plant.The increased content of manganese was shown, both in the leaves and the rhizomes, which indicates a considerable share of the G. maxima in the purification of water and sediment river from the compounds of manganese.Fe content in the leaves maintained at an acceptable level, and in the rhizomes it reached a very high level, which may indicate the accumulating feature of this species relative to Fe.The content of Ni in both the above and belowground G. shoots exceeded the physiological need, indicating the little contamination of the aquatic environment of the Słupia River by this element.
The results of the non-parametric Mann Whitney U test showed a number of statistically significant differences in the content of macroand microelements in the relation: leaves -rhizomes, leaves -bottom sediment and rhizomebottom sediment.
Shoots of G.maxima accumulated 985.8 to 1441.4 mmol c •kg -1 in all analyzed components, where lower value of the accumulated sum of macro-and microelements were found in the rhizomes.The sum of the ionic composition of macronutrients in the leaves and rhizomes were similar.The content of nitrogen was 51.7-53.7% of this amount, 5.8-8.6%phosphorus, potassium 22.8-26.6%,4.9-5.8% of magnesium, calcium, 8.2-11.9%,and trace elements were 0.58% in the leaves and 8.70% in the rhizomes.
].Most of the chemical elements accumulated in the river sediments, is bioaccumulated in plant and animal tissue, what causes the increase of the risk of their poisoning within the trophic chain, on the top of which stands a man.The absorption and bioaccumulation of the components needed by the plants results from the physiological needs and is a part of the natural cycle [Kabata-Pendias and Szteke 2005].The proper functioning of the plants requires basic macroelements (N, P, K, Ca, Mg), as well as small amounts of microelements (Fe, Zn, Cu, Ni, Mn), that are natural components of the ecosystems [Wolf and Gworek 2009].However, their excessive concentration in the environment is harmful, because of their sufficiently high concentration interferes with the functioning of the ecosystems, threat to living organisms [Gruca-Królikowska and Wacławek 2006].Controlling the chemical composition of the coastal vegetation and bottom sediments in urban areas is necessary because it allows the identification of existing and potential risks arising from the toxic effects of heavy metals on the aquatic environment and human health.A good indicator of the quality of bottom sediments is Glyceria maxima (Hartm.)Holmb.), [Rabajczyk and Jóźwiak 2009, Teuchies et al. 2013].
These results are confirmed by the research conducted by Vardanyan and Ingol [2006] and Klink et al. [2013] on the ecology of aquatic plants.According to Sharma et al. [2006], the higher concentration of macroelements in aboveground shoots is determined by the processes of photosynthesis.The research conducted by Baldontini et al. [2009] also confirm the presence of high concentrations of macroelemnts in above-ground shoots rather than in the belowground water vegetation.The results also indicate that the rhizomes of the G.maxima contain significant amounts of macroelements and are a valuable reservoir of ingredients necessary for their growth and development.

Figure 1 .
Figure 1.The content of nitrogen, phosphorus, potassium, magnesium, calcium and zinc in the G. maxima sediments and shoots.The dot (average value), rectangle (standard deviation), mustache (minimum-maximum).

Table 1 .
The characteristics of the research stations

Table 2 .
The physical and chemical features of the bottom sediments of the Słupia River SD -standard deviation, CV -coefficient of variation.

Table 3 .
The results the Mann-Whitney test -the importance of the diversity of the content of macro-and microelements in the G. maxima leaves and rhizomes and the bottom sediments of the river

Table 4 .
The average accumulation of components in the above and belowground shoots of the G. maxima * * Expressed as the sum of the components and their share in the total.