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Tolerance of Scapania undulata (L.) dum. to fluoride
Aquatic Botany, 37 ( 1 9 9 0 ) 163-170
163
Elsevier Science Publishers B.V., A m s t e r d a m
Tolerance of Scapania undulata (L.) Dum. to fluoride A. S a m e c k a - C y m e r m a n I a n d A.J. K e m p e r s 2 ~Department of Eeology and Nature Protection, Institute of Botany. Wroclaw UniversiO', Kanonia Str. 6/8, 50-328 Wroclaw,(Poland) 2Department of Aquatic Ecology and Biogeology, Faculty of Sciences, Universityof Nijmegen, Toernooiveld, 6525 ED Nijmegen, (The Netherlands) (Accepted for publication 21 November 1989 )
ABSTRACT Samecka-Cymerman, A. and Kempers, A.J., 1990. Tolerance of Seapania undulata (L.)Dum. to fluoride. Aquat. Bot., 37: 163-170. Studies were made of the aquatic liverwort Scapania undulata (L.)Dum. from 21 Sudeten streams in Poland. It was found that this species, containing from 10 to 652 mg kg ~ dry weight ( D W ) of fluoride, grows in water with fluoride contents from traces to 0.3 ppm. According to bioassays the lethal concentration o f F - (48 h LC 100) for S. undulata appeared to be 400 or 450 ppm, depending on the population the liverworts were chosen from. Exposure to 100 ppm F - during 16 days may be recognized as harmless for S. undulata. This liverwort is characterized by an ability to accumulate fluoride whereby the accumulation capacity depends on the fluoride level in the water of the growing site. This was demonstrated by an increase of 21-67% of F - in plants cultivated in water with a concentration of 250 ppm F - .
INTRODUCTION
F - is a common ion in surface- and groundwater, usually occurring in low concentrations. Increased concentrations of F - may be provoked by e.g. fluorite mineralization. In Poland fluorite containing rocks occur frequently in the Sudeten Mountains. F - content in plants usually ranges from 2-20 mg kg-1 dry weight (DW) (Mengel and Kirkby, 1983 ) increasing up to 6000 mg kg-~ DW in mosses growing near an industrial plant emitting fluorides (Richardson, 1981 ). Little is known concerning the resistance mechanism of plants to high concentrations of F - , as F - is varying widely between individual plants of the same species (Mengel and Kirkby, 1983 ). Higher concentrations of F - damage cell membranes, limit photosynthesis, phosphate and carbonate metabolism and cause changes in RNA structure (Le Blanc et al., 1971; Kabata-Pendias and Pendias, 1984). 0 3 0 4 - 3 7 7 0 / 9 0 / $ 0 3 . 5 0 © 1990 - - Elsevier Science Publishers B.V.
164
A. SAMECKA-CYMERMAN AND A.J. KEMPERS
The purpose of this investigation was to determine: ( 1 ) the natural fluoride level in the liverwort Scapania undulata (L.)Dum. growing in streams embedded in fluoride and non-fluoride containing rocks in the Sudeten Mountains; (2) the reaction of S. undulata exposed to experimental toxic levels of F-; (3) the ecological susceptibility of S. undulata to F - including dependence between this susceptibility and natural mineral nutrition; (4) whether S. undulata possesses an ability to accumulate fluoride. MATERIALS AND METHODS
Nineteen S. undulata populations were chosen from source areas from streams and two (nos. 2 and 6, see Table 1 ) from rivers. These populations were exposed in various degrees to F - concentrations both of natural origin (fluorite containing rocks and sediments: Populations 12 and 13; areas of expected fluorite mineralization in geological fractured zones with increased uranometrical anomaly: Population 10 ) as well as of industrial origin: Populations 2, 4-6. Populations 1, 3, 7-9, 11, 14-21 were relatively free of any human and natural pollution. Plant samples were collected from an area of 100 cm 2. The following properties were chosen to characterize the investigated plants: length of gametophyte, length and number of lateral branches, biomass per 100 cm 2, number of plants growing per 100 cm 2, frequency distribution of gametophyte length (chi-square distribution test ).
Chemical analyses The following parameters were measured in the water samples: pH (potentiometrically ), total N by Kjeldahl digestion, distillation and acid-base titration, nitrate colorimetrically with natriumsalicylate, phosphate colorimetrically with molybdate blue, iron colorimetrically with ammonium persulphate, calcium and magnesium by EDTA complexometry and potassium using flame photometry. After collection the liverworts were dried at 50°C and ashed in a muffle furnace at 450°C. Ash was dissolved in 20% HCI and the extract was used for analysis of phosphorus, potassium, calcium and magnesium. Iron was determined colorimetrically with 2,2-bipyridyl. Total nitrogen content in plants was determined by acid-base titrimetry after Kjeldahl digestion and distillation. All analyses were performed in triplicate. Water samples for fluoride determination were taken in triplicate from each location and analysed within 12 h of sampling. Plant samples in triplicate were thoroughly washed in distilled water, dried at 105 °C and homogenized. Total F - content in water and liverworts was determined using the alkali fusion selective ion electrode technique by McQuaker and Gurrey ( 1977 ) with
TOLERANCE OF SCAPANIATO FLUORIDE
165
standard sodium fluoride solutions. Analyses were done in triplicate and the standard deviation was calculated.
Experimental To establish the susceptibility ofS. undulata to the toxic influence of fluoride, liverworts of nine populations were chosen by criteria of extreme or mean values of macroelements and fluoride content. The populations were also characterized by maximal, minimal or mean length of gametophytes, length and number of lateral branches. Ten gametophyte stems of equal length of S. undulata were placed in triplicate into 100 ml of fluoride solution at concentrations of 0, 10, 50, 100, 150, 200, 250, 300, 350, 400, 450 p p m o f F - . This bioassay was run in an unheated glasshouse by daylight under temperatures not exceeding 15 ° C, which in previous experiments appeared to offer optimal growing conditions for S. undulata. The increase in length of gametophytes and lateral branches, the increase in a m o u n t of lateral branches and dead plants were determined after 16 days. These features were taken as a bioassay criterion and used as a verification test for fluoride toxicity. The results of these experiments are given as average per plant. At the end of the bioassay the fluoride content in liverworts, treated with the critical concentration of 250 p p m F - , was examined. Analysis of variance was applied to the bioassay results. Correlations between the concentration of nutritional elements in plants and water and the growth of plants treated with 250 p p m F - of fluoride were calculated. RESULTS
Most of the investigated waters and their corresponding populations of liverworts differ with respect to their fluoride content (Table 1 ). Fluoride conTABLE 1 Fluoride c o n t e n t in water ( p p m ) a n d fluoride c o n t e n t in S. undulata (mg k g - 1 D W ); R S D < 3%, n = 3 Microhabitat
Water
Plant
Microhabitat
Water
Plant
1 2 3 4 5 6 7 8 9 10 11
0.20 0.10 0.12 0.10 0.08 0.30 0.08 0.20 0.12 0.19 0.08
68 72 74 95 15 136 61 51 59 528 104
12 13 14 15 16 17 18 19 20 21
0.18 0.26 0.06 0.08 0.06 0.06 0.06 traces 0.02 traces
272 652 96 56 37 23 10 39 21 12
166
A. SAMECKA-CYMERMANAND A.J. KEMPERS
tent in water ranges from traces (microhabitats 19 and 21 ) to 0.3 ppm (microhabitat 6). S. undulata contains from 10 (Population 18)to 652 mg kg -1 F - (Population 13 ). High concentrations of F - are also measured in plants o f Population 10 ( 528 mg kg- ~) and Population 12 (272 mg kg- ~). In most populations fluoride content exceeds 2-20 mg kg- l as reported for plants by Mengel and Kirkby ( 1983 ). A positive, significant correlation has been found between fluoride content in water and fluoride content in plants (correlation coefficients 0.61, n = 63, significance level = 0.001 ). According to the bioassay the lethal concentration of fluoride (48 h LC 100) was estimated at 400 ppm for liverworts of all populations except 7, 10, 12, 13 and 18 for which a lethal concentration of 450 ppm was found. At concentrations up to 250 ppm F - all plants (except those from Population 9 ) survived. The mortality rate at different concentrations of fluoride is presented in Table 2. In the experiment described above ecological differentiation of S. undulata populations to the toxic influence of fluoride was ascertained. Liverworts originating from different populations characterize different growth of gametophytes and lateral branches at the same concentrations of fluoride (Tables 3-5 ). Increase in length ofgametophytes, length and number of lateral branches of plants, treated with the critical fluoride concentration (250 ppm) over a period of 16 days, is positively correlated with the concentration of nutritional elements in water and the treated plants (Table 6). The fluoride content in plants was examined after completion of the bioassay. The content of fluoride in liverworts cultivated in 250 ppm F - increased by 20.8, 35.7, 36.2, 36.6, 39, 53, 63.8, 64.9, and 67.5% in Populations 6, 9, 18, 4, 1, 7, 12, 10, and 13 respectively.
TABLE 2 Effect of concentration of fluoride over a period of 16 days on the mortality (%, rounded to whole numbers) ofS. undulata Fluoride (ppm)
0-200 250 300 350 400 ~Ztest LSD
Populations
F-test (0.05) LSD
1
4
6
7
9
10
12
13
18
0 0 20 53 100
0 0 13 60 100
0 0 20 73 100
0 0 7 40 80
0 7 27 67 100
0 0 0 20 47
0 0 0 20 53
0 0 0 13 40
0 0 7 47 87
(0.05 6.1
14.1
LSD = least significant difference.
9.3
10.9
13.9
8.7
28.6
8.9
10.3
6.6 8.6 5.2
TOLERANCEOF SC41~4NIATO FLUORIDE
167
TABLE 3 Effect of the concentration of fluoride over a period of 16 days on the reduction of the increase in length ( mm ) of gametophytes of S. undulata (average per plant ) Fluoride (ppm)
Populations 4
6
7
9
10
12
13
18
F-test (0.05) LSD
7.5 5.9 5.3 4.1 3.9 3.2 3.0 1.2 0.6 0
6.0 4.5 5.0 3.9 3.7 3.0 2.9 1.1 0.3 0
4.0 3.4 3.0 2.8 2.5 2.4 2.0 0.6 0.2 0
6.9 6.8 6.0 5.7 5.4 5.2 4.9 1.3 1.0 0
5.0 5.5 4.8 4.0 3.7 3.5 3.2 1.6 0.9 0
8.2 8.8 8.2 7.5 5.2 5.0 4.6 3.8 2.0 0.4
5.5 7.9 7.3 6.5 5.7 5.3 5.0 3.1 1.7 0.3
6.1 8.4 8.1 7.2 6.0 5.7 4.0 3.5 2.5 0.6
4.8 6.3 5.2 4.7 4.5 4.4 4.2 2.5 1.3 0.2
1.0 1.4 0.8 0.8 1.0 0.8 0.8 0.6 1.0 0.3
(0.05) 1.1
0.5
0.5
0.5
0.4
0.5
0.8
0.8
0.8
1 Control 10 50 100 150 200 250 300 350 400 b~test LSD
TABLE 4 Effect of the concentration of fluoride over a period of 16 days on the reduction of the increase in length ( m m ) of lateral branches of S. undulata (average per plant) Fluoride (ppm)
Populations 4
6
7
9
10
12
13
18
/--test (0.05) LSD
5.8 5.4 4.6 5.3 5.0 4.3 4.0 3.0 1.8 0
5.0 4.8 4.4 4.2 3.8 3.2 3.0 2.0 1.0 0
4.4 4.3 4.0 3.6 3.1 2.7 2.2 1.5 0.8 0
6.0 5.2 4.9 4.4 3.9 3.5 3.1 2.2 1.7 0.9
4.6 4.9 4.6 4.0 3.5 3.0 2.6 2.4 0.9 0
8.7 9.0 7.5 6.7 6.1 5.8 5.6 3.8 2.2 1.2
6.5 7.0 5.1 4.7 4.2 3.9 3.4 2.8 1.6 0.7
7.4 6.8 6.0 5.1 3.3 2.9 2.5 1.9 1.5 1.4
5.9 6.3 6.1 5.5 5.2 4.7 4.5 2.5 1.4 1.0
0.8 0.9 0.8 0.9 1.0 0.6 0.8 0.8 0.6 0.3
(0.05) 0.4
0.3
1.1
0.7
0.6
0.6
0.6
0.6
0.8
1 Control 10 50 100 150 200 250 300 350 400 ~test LSD
168
A. SAMECKA-CYMERMANAND A.J. KEMPERS
TABLE 5 Effect of the concentration of fluoride over a period of 16 days on the reduction of the increase in number of lateral branches (average per plant) of S. undulata Fluoride (ppm)
Populations 4
6
7
9
10
12
13
18
F-test (0.05) LSD
4.0 3.2 2.6 2.2 2.2 2.0 1.8 1.0 0.2 0
3.0 2.8 2.4 2.0 1.8 1.8 1.6 0.8 0 0
2.6 2.4 2.2 2.0 1.8 1.6 1.4 0.8 0 0
3.8 4.0 3.8 3.4 3.0 2.6 2.4 0.6 0.4 0
2.0 3.0 3.0 2.6 2.2 2.2 2.0 0.4 0.2 0
4.4 4.2 4.0 3.2 2.8 2.6 2.4 1.4 0.8 0.4
3.6 3.4 3.4 3.0 2.6 2.4 2.2 1.0 0.6 0.2
3.4 3.6 3.2 3.0 2.6 2.4 2.2 1.3 0.4 0.2
3.6 3.6 3.8 3.6 3.4 3.0 2.8 0.6 0.2 0
0.6 0.9 0.3 0.6 0.3 0.4 0.5 0.4 0.4 0.1
(0.05) 0.6
0.2
0.4
0.5
0.3
0.8
0.5
0.3
0.3
1 Control 10 50 100 150 200 250 300 350 400 ~test LSD TABLE 6
Correlation coefficients between concentration of nutritional elements in plants and water and growth of plants treated with 250 ppm of F - (n = 27, significance level = 0.001, r tabular = 0.597 ) Calcium in plants and increase in length of gametophytes Total nitrogen in water and increase in length of lateral branches Nitrate in water and increase in length of lateral branches Calcium in water and increase in number of lateral branches Calcium in plants and increase in number of lateral branches Magnesium in water and increase in number of lateral branches Magnesium in plants and increase in number of lateral branches Phosphate in water and increase in number of lateral branches
0.62 0.82 0.86 0.78 0.85 0.96 0.96 0.87
DISCUSSION
As a result o f research on the presence o f fluoride in Sudeten waters Mroczkowska ( 1978 ) proposes as a natural background value a fluoride content of 0 - 0 . 2 ppm, as a presumable anomaly value a content o f 0 . 2 - 0 . 4 ppm and as an evident anomaly value a content o f > 0.4 ppm. In accordance with the above mentioned criteria fluoride content in waters of almost all microhabitats examined in this paper may be accepted as a natural background value (Table 1 ), except for microhabitats 6 and 13 where the fluoride content o f the water is higher. The high fluoride level in water o f microhabitat 6 is probably due to industrial contaminations from a glass work factory. Increased F concentrations up to 652 ppm in S. undulata were found in streams embed-
TOLERANCE OF SCAPANIA TO FLUORIDE
169
ded in fluorite containing rocks (microhabitat 13 ) and were in accordance with the results of Mroczkowska ( 1978 ). The high concentration of fluoride (272 mg k g - ' ) in plants of Population 12 is due to the presence of fluorite containing fractured rocks. Population 10 is characterized also by S. undulata with higher amounts of fluoride (528 mg k g - ' ). They are growing in streams where tectonic dislocation was found confirmed by uranometrical anomaly (S. Przenioslo, personal communication, 1986 ) resulting in an increase in the fluoride content of spring waters probably contacting fluoride containing rocks in the underground. Positive correlation between fluoride content in plants and fluoride content in water confirms the data of Kabata-Pendias and Pendias (1984) that fluoride content in phytoplankton and macrophytes is a function of fluoride content in water. Optimal levels of nitrogen, potassium, phosphorus, magnesium, and calcium in plants increase their resistance to the toxic influence of fluoride which is confirmed in this paper (see Table 6 ) by positive correlations between: calcium content in plants and increase in length of gametophytes; total nitrogen and nitrate content in water and increase in length of lateral branches; calcium content in water, calcium content in plants, magnesium content in water, magnesium content in plants, phosphate content in water and increase in number of lateral branches. After the completion of the experiments, fluoride content in plants treated with 250 ppm of fluoride was examined. It became evident that the fluoride content in S. undulata increased by 20.8% in plants from Population 6 to up to 67.5% in plants from Population 13. This confirms the results of the investigations by Kabata-Pendias and Pendias (1984) showing that certain plants (especially those from growing sites with higher contents of fluoride ) possess the ability of accumulating high amounts of fluoride. Frequency distribution of gametophyte length and chi-square tests proved that Populations 10, 12 and 13 with the highest fluoride content in plants are characterized by a normal distribution of gametophyte length. It may be concluded that concentrations up to at least 652 mg k g - ' of F - in S. undulata have no restrictive influence on the development of the population. The conclusions are: ( 1 ) elevated contents of fluoride were found in S. undulata populations growing in streams embedded in fluoride containing rocks (Populations 12 and 13) or streams fed by spring waters contacting fluoride containing rocks in the underground (Population 10 ). These streams are relatively free of any human pollution; (2) a concentration of 100 ppm of F - may be recognized as harmless to S. undulata over the 16-day experimental period; (3) ecological susceptibility to the toxic influence of fluoride depends upon water chemistry ofS. undulata microhabitats which is confirmed in positive correlations between the nutritional elements in water and plants under influence of the critical concentration of fluoride (250 ppm); (4) S. undulata is characterized by an ability to accumulate fluoride.
170
A. SAMECKA-CYMERMAN AND A.J. KEMPERS
REFERENCES Kabata-Pendias, A. and Pendias, H., 1984. Trace elements in soils and plants. CRC Press Inc., Boca Raton, 336 pp. Le Blanc, F., Comeau, G. and Rao, D.N., 1971. Fluorine injury symptoms in epiphytic lichens and mosses. Can. J. Bot., 9: 1691-1698. McQuaker, N.R. and Gurrey, M., 1977. Determination of total fluorides in soil and vegetation using alkali fusion selective ion electrotechnique. Anal. Chem., 49: 53-56. Mengel, K. and Kirkby, E.A., 1983. Podstawy zywienia roslin. PWRiL, Warszawa, 527 pp. Mroczkowska, B., 1978. Wystepowanie fluoru w wodach sudeckich. Archiwum Instytutu Geologicznego we Wroclawiu, Wroclaw, 46 pp. Richardson, D.H.S., 1981. The Biology of Mosses. Blackwell Scientific Publications, London, 220 pp.
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Elsevier Science Publishers B.V., A m s t e r d a m
Tolerance of Scapania undulata (L.) Dum. to fluoride A. S a m e c k a - C y m e r m a n I a n d A.J. K e m p e r s 2 ~Department of Eeology and Nature Protection, Institute of Botany. Wroclaw UniversiO', Kanonia Str. 6/8, 50-328 Wroclaw,(Poland) 2Department of Aquatic Ecology and Biogeology, Faculty of Sciences, Universityof Nijmegen, Toernooiveld, 6525 ED Nijmegen, (The Netherlands) (Accepted for publication 21 November 1989 )
ABSTRACT Samecka-Cymerman, A. and Kempers, A.J., 1990. Tolerance of Seapania undulata (L.)Dum. to fluoride. Aquat. Bot., 37: 163-170. Studies were made of the aquatic liverwort Scapania undulata (L.)Dum. from 21 Sudeten streams in Poland. It was found that this species, containing from 10 to 652 mg kg ~ dry weight ( D W ) of fluoride, grows in water with fluoride contents from traces to 0.3 ppm. According to bioassays the lethal concentration o f F - (48 h LC 100) for S. undulata appeared to be 400 or 450 ppm, depending on the population the liverworts were chosen from. Exposure to 100 ppm F - during 16 days may be recognized as harmless for S. undulata. This liverwort is characterized by an ability to accumulate fluoride whereby the accumulation capacity depends on the fluoride level in the water of the growing site. This was demonstrated by an increase of 21-67% of F - in plants cultivated in water with a concentration of 250 ppm F - .
INTRODUCTION
F - is a common ion in surface- and groundwater, usually occurring in low concentrations. Increased concentrations of F - may be provoked by e.g. fluorite mineralization. In Poland fluorite containing rocks occur frequently in the Sudeten Mountains. F - content in plants usually ranges from 2-20 mg kg-1 dry weight (DW) (Mengel and Kirkby, 1983 ) increasing up to 6000 mg kg-~ DW in mosses growing near an industrial plant emitting fluorides (Richardson, 1981 ). Little is known concerning the resistance mechanism of plants to high concentrations of F - , as F - is varying widely between individual plants of the same species (Mengel and Kirkby, 1983 ). Higher concentrations of F - damage cell membranes, limit photosynthesis, phosphate and carbonate metabolism and cause changes in RNA structure (Le Blanc et al., 1971; Kabata-Pendias and Pendias, 1984). 0 3 0 4 - 3 7 7 0 / 9 0 / $ 0 3 . 5 0 © 1990 - - Elsevier Science Publishers B.V.
164
A. SAMECKA-CYMERMAN AND A.J. KEMPERS
The purpose of this investigation was to determine: ( 1 ) the natural fluoride level in the liverwort Scapania undulata (L.)Dum. growing in streams embedded in fluoride and non-fluoride containing rocks in the Sudeten Mountains; (2) the reaction of S. undulata exposed to experimental toxic levels of F-; (3) the ecological susceptibility of S. undulata to F - including dependence between this susceptibility and natural mineral nutrition; (4) whether S. undulata possesses an ability to accumulate fluoride. MATERIALS AND METHODS
Nineteen S. undulata populations were chosen from source areas from streams and two (nos. 2 and 6, see Table 1 ) from rivers. These populations were exposed in various degrees to F - concentrations both of natural origin (fluorite containing rocks and sediments: Populations 12 and 13; areas of expected fluorite mineralization in geological fractured zones with increased uranometrical anomaly: Population 10 ) as well as of industrial origin: Populations 2, 4-6. Populations 1, 3, 7-9, 11, 14-21 were relatively free of any human and natural pollution. Plant samples were collected from an area of 100 cm 2. The following properties were chosen to characterize the investigated plants: length of gametophyte, length and number of lateral branches, biomass per 100 cm 2, number of plants growing per 100 cm 2, frequency distribution of gametophyte length (chi-square distribution test ).
Chemical analyses The following parameters were measured in the water samples: pH (potentiometrically ), total N by Kjeldahl digestion, distillation and acid-base titration, nitrate colorimetrically with natriumsalicylate, phosphate colorimetrically with molybdate blue, iron colorimetrically with ammonium persulphate, calcium and magnesium by EDTA complexometry and potassium using flame photometry. After collection the liverworts were dried at 50°C and ashed in a muffle furnace at 450°C. Ash was dissolved in 20% HCI and the extract was used for analysis of phosphorus, potassium, calcium and magnesium. Iron was determined colorimetrically with 2,2-bipyridyl. Total nitrogen content in plants was determined by acid-base titrimetry after Kjeldahl digestion and distillation. All analyses were performed in triplicate. Water samples for fluoride determination were taken in triplicate from each location and analysed within 12 h of sampling. Plant samples in triplicate were thoroughly washed in distilled water, dried at 105 °C and homogenized. Total F - content in water and liverworts was determined using the alkali fusion selective ion electrode technique by McQuaker and Gurrey ( 1977 ) with
TOLERANCE OF SCAPANIATO FLUORIDE
165
standard sodium fluoride solutions. Analyses were done in triplicate and the standard deviation was calculated.
Experimental To establish the susceptibility ofS. undulata to the toxic influence of fluoride, liverworts of nine populations were chosen by criteria of extreme or mean values of macroelements and fluoride content. The populations were also characterized by maximal, minimal or mean length of gametophytes, length and number of lateral branches. Ten gametophyte stems of equal length of S. undulata were placed in triplicate into 100 ml of fluoride solution at concentrations of 0, 10, 50, 100, 150, 200, 250, 300, 350, 400, 450 p p m o f F - . This bioassay was run in an unheated glasshouse by daylight under temperatures not exceeding 15 ° C, which in previous experiments appeared to offer optimal growing conditions for S. undulata. The increase in length of gametophytes and lateral branches, the increase in a m o u n t of lateral branches and dead plants were determined after 16 days. These features were taken as a bioassay criterion and used as a verification test for fluoride toxicity. The results of these experiments are given as average per plant. At the end of the bioassay the fluoride content in liverworts, treated with the critical concentration of 250 p p m F - , was examined. Analysis of variance was applied to the bioassay results. Correlations between the concentration of nutritional elements in plants and water and the growth of plants treated with 250 p p m F - of fluoride were calculated. RESULTS
Most of the investigated waters and their corresponding populations of liverworts differ with respect to their fluoride content (Table 1 ). Fluoride conTABLE 1 Fluoride c o n t e n t in water ( p p m ) a n d fluoride c o n t e n t in S. undulata (mg k g - 1 D W ); R S D < 3%, n = 3 Microhabitat
Water
Plant
Microhabitat
Water
Plant
1 2 3 4 5 6 7 8 9 10 11
0.20 0.10 0.12 0.10 0.08 0.30 0.08 0.20 0.12 0.19 0.08
68 72 74 95 15 136 61 51 59 528 104
12 13 14 15 16 17 18 19 20 21
0.18 0.26 0.06 0.08 0.06 0.06 0.06 traces 0.02 traces
272 652 96 56 37 23 10 39 21 12
166
A. SAMECKA-CYMERMANAND A.J. KEMPERS
tent in water ranges from traces (microhabitats 19 and 21 ) to 0.3 ppm (microhabitat 6). S. undulata contains from 10 (Population 18)to 652 mg kg -1 F - (Population 13 ). High concentrations of F - are also measured in plants o f Population 10 ( 528 mg kg- ~) and Population 12 (272 mg kg- ~). In most populations fluoride content exceeds 2-20 mg kg- l as reported for plants by Mengel and Kirkby ( 1983 ). A positive, significant correlation has been found between fluoride content in water and fluoride content in plants (correlation coefficients 0.61, n = 63, significance level = 0.001 ). According to the bioassay the lethal concentration of fluoride (48 h LC 100) was estimated at 400 ppm for liverworts of all populations except 7, 10, 12, 13 and 18 for which a lethal concentration of 450 ppm was found. At concentrations up to 250 ppm F - all plants (except those from Population 9 ) survived. The mortality rate at different concentrations of fluoride is presented in Table 2. In the experiment described above ecological differentiation of S. undulata populations to the toxic influence of fluoride was ascertained. Liverworts originating from different populations characterize different growth of gametophytes and lateral branches at the same concentrations of fluoride (Tables 3-5 ). Increase in length ofgametophytes, length and number of lateral branches of plants, treated with the critical fluoride concentration (250 ppm) over a period of 16 days, is positively correlated with the concentration of nutritional elements in water and the treated plants (Table 6). The fluoride content in plants was examined after completion of the bioassay. The content of fluoride in liverworts cultivated in 250 ppm F - increased by 20.8, 35.7, 36.2, 36.6, 39, 53, 63.8, 64.9, and 67.5% in Populations 6, 9, 18, 4, 1, 7, 12, 10, and 13 respectively.
TABLE 2 Effect of concentration of fluoride over a period of 16 days on the mortality (%, rounded to whole numbers) ofS. undulata Fluoride (ppm)
0-200 250 300 350 400 ~Ztest LSD
Populations
F-test (0.05) LSD
1
4
6
7
9
10
12
13
18
0 0 20 53 100
0 0 13 60 100
0 0 20 73 100
0 0 7 40 80
0 7 27 67 100
0 0 0 20 47
0 0 0 20 53
0 0 0 13 40
0 0 7 47 87
(0.05 6.1
14.1
LSD = least significant difference.
9.3
10.9
13.9
8.7
28.6
8.9
10.3
6.6 8.6 5.2
TOLERANCEOF SC41~4NIATO FLUORIDE
167
TABLE 3 Effect of the concentration of fluoride over a period of 16 days on the reduction of the increase in length ( mm ) of gametophytes of S. undulata (average per plant ) Fluoride (ppm)
Populations 4
6
7
9
10
12
13
18
F-test (0.05) LSD
7.5 5.9 5.3 4.1 3.9 3.2 3.0 1.2 0.6 0
6.0 4.5 5.0 3.9 3.7 3.0 2.9 1.1 0.3 0
4.0 3.4 3.0 2.8 2.5 2.4 2.0 0.6 0.2 0
6.9 6.8 6.0 5.7 5.4 5.2 4.9 1.3 1.0 0
5.0 5.5 4.8 4.0 3.7 3.5 3.2 1.6 0.9 0
8.2 8.8 8.2 7.5 5.2 5.0 4.6 3.8 2.0 0.4
5.5 7.9 7.3 6.5 5.7 5.3 5.0 3.1 1.7 0.3
6.1 8.4 8.1 7.2 6.0 5.7 4.0 3.5 2.5 0.6
4.8 6.3 5.2 4.7 4.5 4.4 4.2 2.5 1.3 0.2
1.0 1.4 0.8 0.8 1.0 0.8 0.8 0.6 1.0 0.3
(0.05) 1.1
0.5
0.5
0.5
0.4
0.5
0.8
0.8
0.8
1 Control 10 50 100 150 200 250 300 350 400 b~test LSD
TABLE 4 Effect of the concentration of fluoride over a period of 16 days on the reduction of the increase in length ( m m ) of lateral branches of S. undulata (average per plant) Fluoride (ppm)
Populations 4
6
7
9
10
12
13
18
/--test (0.05) LSD
5.8 5.4 4.6 5.3 5.0 4.3 4.0 3.0 1.8 0
5.0 4.8 4.4 4.2 3.8 3.2 3.0 2.0 1.0 0
4.4 4.3 4.0 3.6 3.1 2.7 2.2 1.5 0.8 0
6.0 5.2 4.9 4.4 3.9 3.5 3.1 2.2 1.7 0.9
4.6 4.9 4.6 4.0 3.5 3.0 2.6 2.4 0.9 0
8.7 9.0 7.5 6.7 6.1 5.8 5.6 3.8 2.2 1.2
6.5 7.0 5.1 4.7 4.2 3.9 3.4 2.8 1.6 0.7
7.4 6.8 6.0 5.1 3.3 2.9 2.5 1.9 1.5 1.4
5.9 6.3 6.1 5.5 5.2 4.7 4.5 2.5 1.4 1.0
0.8 0.9 0.8 0.9 1.0 0.6 0.8 0.8 0.6 0.3
(0.05) 0.4
0.3
1.1
0.7
0.6
0.6
0.6
0.6
0.8
1 Control 10 50 100 150 200 250 300 350 400 ~test LSD
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A. SAMECKA-CYMERMANAND A.J. KEMPERS
TABLE 5 Effect of the concentration of fluoride over a period of 16 days on the reduction of the increase in number of lateral branches (average per plant) of S. undulata Fluoride (ppm)
Populations 4
6
7
9
10
12
13
18
F-test (0.05) LSD
4.0 3.2 2.6 2.2 2.2 2.0 1.8 1.0 0.2 0
3.0 2.8 2.4 2.0 1.8 1.8 1.6 0.8 0 0
2.6 2.4 2.2 2.0 1.8 1.6 1.4 0.8 0 0
3.8 4.0 3.8 3.4 3.0 2.6 2.4 0.6 0.4 0
2.0 3.0 3.0 2.6 2.2 2.2 2.0 0.4 0.2 0
4.4 4.2 4.0 3.2 2.8 2.6 2.4 1.4 0.8 0.4
3.6 3.4 3.4 3.0 2.6 2.4 2.2 1.0 0.6 0.2
3.4 3.6 3.2 3.0 2.6 2.4 2.2 1.3 0.4 0.2
3.6 3.6 3.8 3.6 3.4 3.0 2.8 0.6 0.2 0
0.6 0.9 0.3 0.6 0.3 0.4 0.5 0.4 0.4 0.1
(0.05) 0.6
0.2
0.4
0.5
0.3
0.8
0.5
0.3
0.3
1 Control 10 50 100 150 200 250 300 350 400 ~test LSD TABLE 6
Correlation coefficients between concentration of nutritional elements in plants and water and growth of plants treated with 250 ppm of F - (n = 27, significance level = 0.001, r tabular = 0.597 ) Calcium in plants and increase in length of gametophytes Total nitrogen in water and increase in length of lateral branches Nitrate in water and increase in length of lateral branches Calcium in water and increase in number of lateral branches Calcium in plants and increase in number of lateral branches Magnesium in water and increase in number of lateral branches Magnesium in plants and increase in number of lateral branches Phosphate in water and increase in number of lateral branches
0.62 0.82 0.86 0.78 0.85 0.96 0.96 0.87
DISCUSSION
As a result o f research on the presence o f fluoride in Sudeten waters Mroczkowska ( 1978 ) proposes as a natural background value a fluoride content of 0 - 0 . 2 ppm, as a presumable anomaly value a content o f 0 . 2 - 0 . 4 ppm and as an evident anomaly value a content o f > 0.4 ppm. In accordance with the above mentioned criteria fluoride content in waters of almost all microhabitats examined in this paper may be accepted as a natural background value (Table 1 ), except for microhabitats 6 and 13 where the fluoride content o f the water is higher. The high fluoride level in water o f microhabitat 6 is probably due to industrial contaminations from a glass work factory. Increased F concentrations up to 652 ppm in S. undulata were found in streams embed-
TOLERANCE OF SCAPANIA TO FLUORIDE
169
ded in fluorite containing rocks (microhabitat 13 ) and were in accordance with the results of Mroczkowska ( 1978 ). The high concentration of fluoride (272 mg k g - ' ) in plants of Population 12 is due to the presence of fluorite containing fractured rocks. Population 10 is characterized also by S. undulata with higher amounts of fluoride (528 mg k g - ' ). They are growing in streams where tectonic dislocation was found confirmed by uranometrical anomaly (S. Przenioslo, personal communication, 1986 ) resulting in an increase in the fluoride content of spring waters probably contacting fluoride containing rocks in the underground. Positive correlation between fluoride content in plants and fluoride content in water confirms the data of Kabata-Pendias and Pendias (1984) that fluoride content in phytoplankton and macrophytes is a function of fluoride content in water. Optimal levels of nitrogen, potassium, phosphorus, magnesium, and calcium in plants increase their resistance to the toxic influence of fluoride which is confirmed in this paper (see Table 6 ) by positive correlations between: calcium content in plants and increase in length of gametophytes; total nitrogen and nitrate content in water and increase in length of lateral branches; calcium content in water, calcium content in plants, magnesium content in water, magnesium content in plants, phosphate content in water and increase in number of lateral branches. After the completion of the experiments, fluoride content in plants treated with 250 ppm of fluoride was examined. It became evident that the fluoride content in S. undulata increased by 20.8% in plants from Population 6 to up to 67.5% in plants from Population 13. This confirms the results of the investigations by Kabata-Pendias and Pendias (1984) showing that certain plants (especially those from growing sites with higher contents of fluoride ) possess the ability of accumulating high amounts of fluoride. Frequency distribution of gametophyte length and chi-square tests proved that Populations 10, 12 and 13 with the highest fluoride content in plants are characterized by a normal distribution of gametophyte length. It may be concluded that concentrations up to at least 652 mg k g - ' of F - in S. undulata have no restrictive influence on the development of the population. The conclusions are: ( 1 ) elevated contents of fluoride were found in S. undulata populations growing in streams embedded in fluoride containing rocks (Populations 12 and 13) or streams fed by spring waters contacting fluoride containing rocks in the underground (Population 10 ). These streams are relatively free of any human pollution; (2) a concentration of 100 ppm of F - may be recognized as harmless to S. undulata over the 16-day experimental period; (3) ecological susceptibility to the toxic influence of fluoride depends upon water chemistry ofS. undulata microhabitats which is confirmed in positive correlations between the nutritional elements in water and plants under influence of the critical concentration of fluoride (250 ppm); (4) S. undulata is characterized by an ability to accumulate fluoride.
170
A. SAMECKA-CYMERMAN AND A.J. KEMPERS
REFERENCES Kabata-Pendias, A. and Pendias, H., 1984. Trace elements in soils and plants. CRC Press Inc., Boca Raton, 336 pp. Le Blanc, F., Comeau, G. and Rao, D.N., 1971. Fluorine injury symptoms in epiphytic lichens and mosses. Can. J. Bot., 9: 1691-1698. McQuaker, N.R. and Gurrey, M., 1977. Determination of total fluorides in soil and vegetation using alkali fusion selective ion electrotechnique. Anal. Chem., 49: 53-56. Mengel, K. and Kirkby, E.A., 1983. Podstawy zywienia roslin. PWRiL, Warszawa, 527 pp. Mroczkowska, B., 1978. Wystepowanie fluoru w wodach sudeckich. Archiwum Instytutu Geologicznego we Wroclawiu, Wroclaw, 46 pp. Richardson, D.H.S., 1981. The Biology of Mosses. Blackwell Scientific Publications, London, 220 pp.