Journal of Resources and Ecology >
Physiological Responses of Pistia stratiotes and Its Fluoride
Removal Efficiency
Received date: 20200401
Accepted date: 20200525
Online published: 20200930
Supported by
The National Natural Science Foundation of China(E080402)
Two High Foundation of Xichang College(LGLZ201906)
Phytoremediation technology using aquatic plants is being used increasingly in constructed wetlands to purify wastewater. The physiological responses of water lettuce (Pistia stratiotes) and its effectiveness in removing fluoride (F ^{}) from water are described in this article. The results indicate that Pistia stratiotes has the ability to accumulate F ^{}. The removal efficiency ranged from 27.79% to 56.32% for the various initial F ^{}concentrations tested, and was highest (56.32%) in the highest initial concentration group 60mg/L. The F ^{} concentrations in control groups (without Pistia stratiotes) changed very little, from 1.135% to 0.007% of the initial concentrations. At the highest removal rate, the bioconcentration factor was 7.84. The rate of purification conformed to the MichaelisMenten equation, and the correlation coefficients (R ^{2}) were all greater than 0.97. The Specific Growth Rates (SGR) of the treatment groups were 8.03% to 1.22%, and the SGR of plants under F ^{}stress decreased during the experimental period. The partial correlation analysis showed that concentrations of F ^{} in water were strongly linearly correlated with peroxidase.
Key words： P. stratiotes; antioxidant enzyme; fluoride; dynamic; POD
ZHANG Yun
,
CHEN Jinfa
. Physiological Responses of Pistia stratiotes and Its Fluoride
Removal Efficiency[J]. Journal of Resources and Ecology, 2020
, 11(5)
: 525
530
.
DOI: 10.5814/j.issn.1674764x.2020.05.010
Fig. 1 Variation of F^{} concentrations over time starting from different initial F^{ }concentrations for treatment groups (AIAV) and control groups without plants (CICV).Note: Error bars represent one standard deviation from the mean, n = 3. 
Table 1 Kinetic parameters of fluoride removal from treated water 
Group  C_{0} (mg L^{1})  V_{max} (mg L^{1 }h^{1})  K_{m} (mg L^{1})  R^{2} 

AI  5  0.2533  3.4237  0.9806 
AII  10  0.485  7.1748  0.9808 
AIII  20  1.1145  16.4028  0.9766 
AIV  40  2.96  43.6132  0.9895 
AV  60  5.427  77.0471  0.9898 
Table 2 Effect of different concentrations of fluoride on the growth characteristics of P. stratiotes 
Treatment groups  AI  AII  AIII  AIV  AV  BI  

Fresh weight (g)  Initial  101.4  101.8  101.9  101.5  103.0  102.8 
Ending  92.0  86.9  76.3  65.6  54.2  143.6  
SGR (% d^{1})  1.22  1.98  3.62  5.46  8.03  4.18 
Note: Specific Growth Rate (SGR) = (lnW_{t}InW_{0})/t×100%. W_{t} is the weight of P. stratiotes at t days, g; W_{0 }is the initial weight of P. stratiotes, g. 
Fig. 2 Effect of initial F^{ }concentration on fluoride concentration in P. stratiotes leaves.Note: Error bars represent one standard deviation from the mean, n = 3 (for treatments with F^{ }concentrations of 0, 5, 10, 20, 40 and 60 mg L^{1}) 
Fig. 3 Effects of different concentrations of F^{} on the activities of SOD in P. stratiotes (treated with F^{ }concentrations of 0, 5, 10, 20, 40 and 60 mg L^{1}) 
Fig. 4 Effects of different concentrations of F^{ }on the activities of CAT in P. stratiotes (treated with F^{ }concentration of 0, 5, 10, 20, 40 and 60 mg L^{1}) 
Fig. 5 Effects of different concentrations of F^{} on the activities of POD in P. stratiotes (treated with F^{ }concentration of 0, 5, 10, 20, 40 and 60 mg L^{1}) 
Table 3 Significance and PCCs between fluoride and the physiological indexes of the plant 
Treatment groups  AI  AII  AIII  AIV  AV  

Variable Significance coefficient P  0.0057  0.0097  0.0095  0.0012  0.0167  
PCCs  Control SOD&CAT  F^{} in water / Fluoride in leaves  0.999  1.000  0.804  0.989  0.999 
Control SOD&POD  0.982  0.967  0.995  0.995  1.000  
Control CAT&POD  1.000  1.000  0.987  0.993  0.997  
Control SOD&CAT  F^{} in water / POD  0.900  0.848  0.999  0.781  0.706  
Control SOD&POD  F^{} in water / CAT  0.653  0.645  0.990  0.486  0.958  
Control CAT&POD  F^{} in water / SOD  0.911  0.804  1.000  0.855  0.672 
Notes: P: Significance coefficient; 0.01< P < 0.05: significant difference; P < 0.01: highly significant difference; PCCs: 00.19: very low correlation; 0.20.39: low correlation; 0.40.69: medium correlation; 0.70.89: high correlation; 0.91.0: very high correlation. 
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