54
F. Dietz
carried out by flame photometer.
Trace elements were determined generally by atomic-absorption. The Davis x-ray
polarograph was used for the analysis of the water samples and for very low
concentrations of lead, copper and nickel. Wet decomposition of the substance with
concentrated sulfuricacid and hydrogen peroxide in an apparatus with reflux condenser
was necessary for the determination of mercury because of the volatility of mercury
compounds. The determination of mercury was by the fiameless atomic absorption
method of Hatch and Ott.
MACRO NUTRIENTS IN WATER PLANTS
The results of these investigations confirm the proportion for C : N : P, namely 145 :
14,5 : 1 as cited in the literature for all the higher developed water plants with one
exception: Ranunculus fluitans has an average content of 1,25 % P 2 0 5 giving a
proportion of N : P = 14,5 : 2,5. A deviation was observed in the case of mosses C : N : P
= 44 : 3,7 : 1, so that the proportion C : N was 12 : 1. The content of potassium (Table
1) in the higher developed plants (Spermatophyta) was much higher than in the mosses.
Table 1. Content of Potassium in Aquatic Plants
(g Potassium/kg dry weight)
Spermatophyta
Ranunculus fluitans
Nuphar luteum
Sagittaria sagittifolia
Myriophyllum spicatum
Bryophyta
Fontinalis antipyretica
Hygroamblystegium
Average
50
30
30
20
11
7
Minimum
45
20
28
13
7
4
Maximum
54
32
34
22
15
11
This agrees with general experience, according to which plants with leaves need a higher
content of potassium for building up chlorophyll. With regard to the fact that the content
of potassium in the aqueous medium lies between 0,5 and 5ppm this shows that the
potassium content of the water plants is determined by the species of plants and is not
dependent upon the nutrient supply.
To sum up: the most important result is that the content of macro nutrients
incorporated in the water plants is largely independent of the local medium and therefore
of the water quality.
ENRICHMENT OF TRACE ELEMENTS IN WATER PLANTS
For the purpose of this investigation it was necessary to carry out work under practical
aspects.
F. Dietz
carried out by flame photometer.
Trace elements were determined generally by atomic-absorption. The Davis x-ray
polarograph was used for the analysis of the water samples and for very low
concentrations of lead, copper and nickel. Wet decomposition of the substance with
concentrated sulfuricacid and hydrogen peroxide in an apparatus with reflux condenser
was necessary for the determination of mercury because of the volatility of mercury
compounds. The determination of mercury was by the fiameless atomic absorption
method of Hatch and Ott.
MACRO NUTRIENTS IN WATER PLANTS
The results of these investigations confirm the proportion for C : N : P, namely 145 :
14,5 : 1 as cited in the literature for all the higher developed water plants with one
exception: Ranunculus fluitans has an average content of 1,25 % P 2 0 5 giving a
proportion of N : P = 14,5 : 2,5. A deviation was observed in the case of mosses C : N : P
= 44 : 3,7 : 1, so that the proportion C : N was 12 : 1. The content of potassium (Table
1) in the higher developed plants (Spermatophyta) was much higher than in the mosses.
Table 1. Content of Potassium in Aquatic Plants
(g Potassium/kg dry weight)
Spermatophyta
Ranunculus fluitans
Nuphar luteum
Sagittaria sagittifolia
Myriophyllum spicatum
Bryophyta
Fontinalis antipyretica
Hygroamblystegium
Average
50
30
30
20
11
7
Minimum
45
20
28
13
7
4
Maximum
54
32
34
22
15
11
This agrees with general experience, according to which plants with leaves need a higher
content of potassium for building up chlorophyll. With regard to the fact that the content
of potassium in the aqueous medium lies between 0,5 and 5ppm this shows that the
potassium content of the water plants is determined by the species of plants and is not
dependent upon the nutrient supply.
To sum up: the most important result is that the content of macro nutrients
incorporated in the water plants is largely independent of the local medium and therefore
of the water quality.
ENRICHMENT OF TRACE ELEMENTS IN WATER PLANTS
For the purpose of this investigation it was necessary to carry out work under practical
aspects.