Present study was conducted to investigate the Cadmium (Cd) phytoextraction potential of two plants ( Veronica anagallis-aquatic and Epilobium laxum Royle ) for Cd removal from induced saline water. In hydroponic system, various concentrations of the Cd (50, 100, and 150 ppm) and NaCl salt (1000, 3000, and 6000 ppm) were used alone and in various combinations to evaluate the effect of salt (NaCl) concentrations on Cd absorption and accumulation in Veronica anagallis and Epilobium plants. The Cd at higher concentrations (100 and 150 ppm) significantly reduced the growth and biomass of both plants and addition of salt (NaCl) to growth media (Hoagland solution) further reduced the growth. The Cadmium (Cd) translocation factor (TF) of Epilobium plant was more than one (1), while the Veronica plant showed translocation factor less than 0.5. Veronica plant showed higher Bio-concentration factor (BCF) as more than 3.5 and Epilobium plant demonstrated Bio-concentration f actor less than 1 (BCF 1 is a threshold limit for a plant to be hyper-accumulator of Cd). Conclusively, the Veronica anagallis plant is reported as Cd hyper-accumulator, while Epilobium laxum plant as non hyper-accumulator on the basis of BCF values in the present findings. Further study on Veronica and Epilobium plants is recommended.
Water is essential for survival and existence of life. The increasing competition for clean water, due to ever increasing demand for drinking and irrigation water, resulted in a steady and irreversible spread of salinization thus disturbing fresh water reservoirs mostly in arid and semiarid regions of the world [
Heavy metals can enter the water through urban and municipal runoff, sewage, storm water, industrial effluents, atmospheric deposition, mining operations and agricultural activity [
Veronica anagallis-aquatica belongs to family Plantaginaceae. It is also known as water speedwell and blue speedwell. It is a perennial herb with root-like subterranean stem, commonly horizontal in position and occurs in moist, wet and semi-aquatic habitat. The Epilobium laxum Royle, commonly known as willow herbs, is a dicot angiosperm plant belongs to family Onagraceae. It is herbaceous, annual or perennial having stunted stem with simple alternate, ovate to lanceolate leaves. It is mostly present in moist temperate regions, very common in the western Himalaya. These two plants were selected for the hydroponic experiment due to their natural aquatic and semi aquatic habitat, and the objectives were to evaluate the Cd removal (phytoaccumulation) potential of Veronica and Epilobium plants (from induced saline water).
Uniform size plantlets of Veronica anagallis and Epilobium laxum (2 cm roots and 3 cm shoot) were collected from river of Miandam, Pakistan, in the month of April 2012. The plantlets were kept under cool condition to avoid evaporation and wilting during transportation to laboratory for experiments. .
Hoagland’s solution was used as plant growth media (GM). The solution was prepared and then poured into flasks (150 ml media per flask). Cadmium was added to the flasks in the form of Cadmium acetate dihydrate [Cd(CH3COO)2∙2H2O] and three different concentrations (50, 100 and 150 ppm) of Cd were used during the experiment. Salt of Sodium (NaCl) was added to flasks in different concentrations (1000, 3000 and 6000 ppm). Calculated amount of Cadmium acetate dihydrate and sodium chloride was added into their respective flask and thoroughly mixed and dissolved. Three replicate flasks were used for each treatment and control. The following treatments and control (
The selected plantlets were transplanted into the flasks (one plant per flask). After transplantation, each flask was covered with aluminum foil to avoid evaporation. To keep the volume of media at constant level (150 ml) fresh media was regularly added to the flasks. The experiment was conducted under natural light/dark conditions (14/10) with temperature 30/25˚C.
Treatments | Denoted | Treatments | Denoted |
---|---|---|---|
Growth media (GM) only | C | GM + 100 ppm Cd + 1000 ppm NaCl | T4 |
GM + 50 ppm Cd | C1 | GM + 100 ppm Cd + 3000 ppm NaCl | T5 |
GM + 100 ppm Cd | C2 | GM + 100 ppm Cd + 6000 ppm NaCl | T6 |
GM + 150 ppm Cd | C3 | GM + 150 ppm Cd + 1000 ppm NaCl | T7 |
GM + 50 ppm Cd +1000 ppm NaCl | T1 | GM + 150 ppm Cd + 3000 ppm NaCl | T8 |
GM + 50 ppm Cd + 3000 ppm NaCl | T2 | GM + 150 ppm Cd + 6000 ppm NaCl | T9 |
GM + 50 ppm Cd + 6000 ppm NaCl | T3 |
The plants were harvested after four weeks treatments. After harvesting, the root, stem and leaf length was measured using centimeter ruler. Then the plants were separated into three parts i.e. roots, stem and leaves. The fresh biomass of the different parts was measured for each plant using analytical balance, and each part was packed in labeled paper envelope, dried at 80˚C for 48 hrs in oven. The dried samples were crushed into powdered form using mortar and pestle, and each sample was kept in small polythene bags for further use.
Dried and powdered sample each (0.25 g) was taken into 50 ml volumetric flask, then 5 ml of Nitric acid (HNO3), 0.5 ml of perchloric acid (HClO4) and 1 ml sulfuric acid (H2SO4) was added to it (Allen, 1974). The flask was then kept on hot plate for 15 minutes at 300˚C until white fumes comes out from the flasks. The samples were cooled, filtered into plastic bottle and the volume of filtrate was raised up to 50 ml by addition of distilled water. This procedure was repeated for all the samples. The digested samples were then analyzed for the Cd concentration using atomic absorption spectrometer.
The data was subjected to ANOVA and the mean values were compared by using Turkey’s Honestly Significant Difference (HSD) test, at P < 0.05. The data was analyzed using SPSS-16 and MS-excel (2010).
Cadmium induced the significant reduction in root and stem length of Veronica plant when the treatments having Cd (C1 = 50, C2 = 100 and C3 = 150 ppm) were compared with the control without Cd (C) as shown in
In Epilobium plant, the lower concentration of Cd (C1) has no significant effect on growth, biomass and water content in any part of Epilobium plant as compared to control C (
Treatments | Length (cm) ± SD | Fresh Biomass (g) ± SD | Dry Biomass (g) ± SD | Total Water Content (g) ± SD | ||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Root | Stem | Leaves | Root | Stem | Leaves | Root | Stem | Leaves | Root | Stem | Leaves | |
C | 9.5 ± 0.5 a | 20.5 ± 0.5 a | 5.4 ± 0.4 a | 3.89 ± 0.27 a | 8.4 ± 0.35 a | 2.21 ± 0.13 a | 1.95 ± 0.14 a | 4.2 ± 0.18 a | 1.1 ± 0.06 a | 1.95 ± 0.13 a | 4.2 ± 0.18 a | 1.1 ± 0.06 a |
C1 | 7.5 ± 0.5 b | 14.75 ± 0.25 b | 4.8 ± 0.2 ab | 2.94 ± 0.60 ab | 5.71 ± 0.71 b | 1.85 ± 0.19 ab | 1.47 ± 0.30 ab | 2.86 ± 0.36 b | 0.93 ± 0.09 ab | 1.47 ± 0.30 ab | 2.86 ± 0.36 b | 0.93 ± 0.09 ab |
C2 | 5.25 ± 0.15 cd | 13.25 ± 0.75 bc | 4.15 ± 0.15 bc | 1.68 ± 1.24 bcde | 3.98 ± 2.77 bcde | 1.34 ± 0.99 abcde | 0.84 ± 0.62 bcde | 1.99 ± 1.39bcde | 0.67 ± 0.49 abcde | 0.84 ± 0.62 bcde | 1.99 ± 1.39 bcde | 0.67 ± 0.49 abcde |
C3 | 4.2 ± 0.2 ef | 11 ± 1 cd | 2.8 ± 0.3 efg | 0.83 ± 0.21 cdef | 2.13 ± 0.24 def | 0.54 ± 0.05 def | 0.42 ± 0.10 cdef | 1.06 ± 0.12 def | 0.27 ± 0.03 def | 0.42 ± 0.10 cdef | 1.06 ± 0.12 def | 0.27 ± 0.03 def |
T1 | 5.8 ± 0.2 c | 14 ± 1 b | 4.25 ± 0.25 bc | 2.07 ± 0.28 bc | 4.93 ± 0.15 bc | 1.5 ± 0.07 abc | 1.03 ± 0.14 bc | 2.47 ± 0.08 bc | 0.75 ± 0.03 abc | 1.03 ± 0.14 bc | 2.47 ± 0.08 bc | 0.75 ± 0.03 abc |
T2 | 4.5 ± 0.5 def | 10.5 ± 0.5 cde | 3.8 ± 0.2 cd | 1.3 ± 0.01 cdef | 3.09 ± 0.46 cdef | 1.11 ± 0.05 bcdef | 0.65 ± 0.01 cdef | 1.54 ± 0.23 cdef | 0.55 ± 0.03 cdef | 0.65 ± 0.01 cdef | 1.54 ± 0.23 cdef | 0.55 ± 0.03 cdef |
T3 | 3.95 ± 0.35 efg | 8.5 ± 0.5 def | 2.5 ± 0.5 fg | 0.53 ± 0.009 def | 1.14 ± 0.04 f | 0.33 ± 0.04 f | 0.26 ± 0.001 def | 0.57 ± 0.02 f | 0.17 ± 0.02 f | 0.26 ± 0.001 def | 0.57 ± 0.02 f | 0.17 ± 0.02 f |
T4 | 5.25 ± 0.25 cd | 13 ± 1 bc | 4.25 ± 0.25 bc | 1.74 ± 0.005 bcd | 4.34 ± 0.53 bcd | 1.41 ± 0.02 abcd | 0.87 ± 0.01 bcd | 2.17 ± 0.26 bcd | 0.71 ± 0.01 bcd | 0.87 ± 0.01 bcd | 2.17 ± 0.26 bcd | 0.71 ± 0.01 bcd |
T5 | 4.5 ± 0.5 def | 8 ± 1 ef | 3.3 ± 0.3 def | 0.93 ± 0.67 cdef | 1.4 ± 0.84 ef | 0.67 ± 0.48 cdef | 0.46 ± 0.33 cdef | 0.7 ± 0.42 ef | 0.34 ± 0.24 ef | 0.46 ± 0.34 cdef | 0.7 ± 0.42 ef | 0.34 ± 0.24 ef |
T6 | 3.15 ± 0.15 gh | 6 ± 1 fg | 2.75 ± 0.25 efg | 0.4 ± 0.14 ef | 0.73 ± 0.18 f | 0.37 ± 0.18 f | 0.2 ± 0.07 ef | 0.36 ± 0.09 f | 0.19 ± 0.09 f | 0.2 ± 0.07 ef | 0.36 ± 0.09 f | 0.19 ± 0.09 f |
T7 | 4.85 ± 0.15 cde | 12.5 ± 0.5 bc | 3.45 ± 0.25 cde | 1.04 ± 0.05 cdef | 2.71 ± 0.33 cdef | 0.75 ± 0.12 cdef | 0.52 ± 0.02 cdef | 1.35 ± 0.17 cdef | 0.37 ± 0.06 cdef | 0.52 ± 0.02 cdef | 1.35 ± 0.17 cdef | 0.37 ± 0.06 cdef |
T8 | 3.7 ± 0.2 fgh | 7.5 ± 2.5 f | 2.25 ± 0.25 gh | 0.69 ± 0.03 def | 1.4 ± 0.48 ef | 0.42 ± 0.05 ef | 0.34 ± 0.01 def | 0.7 ± 0.24 ef | 0.21 ± 0.03 ef | 0.34 ± 0.01 def | 0.7 ± 0.24 ef | 0.21 ± 0.03 ef |
T9 | 2.75 ± 0.25 h | 4.5 ± 0.5 g | 1.45 ± 0.05 h | 0.32 ± 0.003 f | 0.52 ± 0.02 f | 0.17 ± 0.02 f | 0.16 ± 0.07 f | 0.26 ± 0.01 f | 0.08 ± 0.01 f | 0.16 ± 0.01 f | 0.26 ± 0.01 f | 0.08 ± 0.01 f |
root and stem length of Epilobium plant occurred at 100 ppm (C2) and 150 ppm (C3) Cd concentrations while the leaf length was reduced only at the highest Cd concentration C3 (150 ppm) when compared with control C (without Cd). With a few exceptions (i.e. root and leaves dry biomass) the biomass and water contents of the Epilobium plant showed significant reduction only at the highest Cd concentration 150 ppm (C3) as compared to the control C as shown in (
Treatments | Length (cm) ± SD | Fresh Biomass (g) ± SD | Dry Biomass (g) ± SD | Total Water Content (g) ± SD | ||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Root | Stem | Leaves | Root | Stem | Leaves | Root | Stem | Leaves | Root | Stem | Leaves | |
C | 10.20 ± 2.35 a | 21.00 ± 1.00 a | 3.50 ± 0.50 a | 1.35 ± 0.05 a | 2.43 ± 0.78 a | 0.55 ± 0.05 a | 0.61 ± 0.04 a | 0.97 ± 0.31 a | 0.23 ± 0.02 a | 0.74 ± 0.05 a | 1.46 ± 0.47 a | 0.32 ± 0.03 a |
C1 | 7.75 ± 0.25 ab | 17.33 ± 2.08 b | 3.15 ± 0.15 ab | 1.19 ± 0.35 ab | 1.90 ± 0.10 ab | 0.45 ± 0.05 ab | 0.56 ± 0.05 ab | 0.74 ± 0.41 ab | 0.2 ± 0.01 a | 0.62 ± 0.3 abc | 1.15 ± 0.31 ab | 0.25 ± 0.05 abc |
C2 | 6.50 ± 0.50 bc | 16.00 ± 1.00 bc | 2.50 ± 0.50 abc | 1.10 ± 0.10 abc | 1.68 ± 0.16 abc | 0.33 ± 0.04 bcde | 0.46 ± 0.03 bc | 0.67 ± 0.06 ab | 0.16 ± 0.01 b | 0.64 ± 0.11 abcd | 1.01 ± 0.09 abc | 0.17 ± 0.04 abcd |
C3 | 4.50 ± 0.50 cde | 12.50 ± 0.50 d | 2.17 ± 0.29 bc | 0.80 ± 0.01 cde | 1.47 ± 0.13 bcd | 0.24 ± 0.04 cdef | 0.37 ± 0.02 cd | 0.59 ± 0.05 abc | 0.11 ± 0.01 cde | 0.43 ± 0.02 bcd | 0.88 ± 0.08 bc | 0.14 ± 0.04 bcd |
T1 | 5.50 ± 0.50 bcd | 13.50 ± 0.50 cd | 2.83 ± 0.29 ab | 0.85 ± 0.05 bcd | 1.6 ± 0.18 bcd | 0.39 ± 0.09 abc | 0.35 ± 0.05 cde | 0.64 ± 0.07 abc | 0.13 ± 0.02 bc | 0.50 ± 0.1 ab | 0.96 ± 0.11 abc | 0.27 ± 0.07 ab |
T2 | 5.50 ± 0.50 bcd | 11.00 ± 1.00 de | 2.50 ± 0.20 abc | 0.73 ± 0.10 cde | 1.18 ± 0.25 bcde | 0.35 ± 0.13 bcd | 0.32 ± 0.04 def | 0.47 ± 0.10 bcd | 0.12 ± 0.02 c | 0.41 ± 0.12 abcd | 0.71 ± 0.15 bcd | 0.23 ± 0.15 abcd |
T3 | 4.00 ± 1.00 cde | 7.50 ± 0.50 f | 2.25 ± 0.25 bc | 0.57 ± 0.15 de | 1.14 ± 0.10 bcdef | 0.22 ± 0.02 cdef | 0.24 ± 0.04 efg | 0.46 ± 0.04 bcd | 0.1 ± 0.002 cde | 0.32 ± 0.11 bcd | 0.68 ± 0.06 bcd | 0.12 ± 0.02 bcd |
T4 | 5.33 ± 0.577 bcd | 13.00 ± 1.00 d | 2.50 ± 0.50 abc | 0.73 ± 0.03 cde | 1.17 ± 0.38 bcde | 0.31 ± 0.01 bcde | 0.25 ± 0.05 efg | 0.47 ± 0.15 bcd | 0.11 ± 0.01 cd | 0.47 ± 0.04 abcd | 0.70 ± 0.23 bcd | 0.20 ± 0.02 abcd |
T5 | 5.25 ± 1.75 bcd | 11.33 ± 0.58 de | 2.25 ± 0.25 bc | 0.61 ± 0.09 de | 1.07 ± 0.11 cdef | 0.30 ± 0.02 bcde | 0.25 ± 0.05 efg | 0.46 ± 0.04 bcd | 0.1 ± 0.01 cde | 0.36 ± 0.04 abcd | 0.61 ± 0.15 bcd | 0.20 ± 0.04 abcd |
T6 | 3.25 ± 0.25 de | 7.83 ± 0.76 f | 1.50 ± 0.50 cd | 0.43 ± 0.07 ef | 0.90 ± 0.10 cdef | 0.16 ± 0.02 ef | 0.18 ± 0.04 hi | 0.31 ± 0.01 bcd | 0.07 ± 0.001 ef | 0.25 ± 0.03 cd | 0.59 ± 0.10 cd | 0.09 ± 0.02 cd |
T7 | 4.00 ± 1.00 cde | 9.00 ± 1.00 ef | 1.75 ± 0.25 cd | 0.73 ± 0.15 cde | 0.85 ± 0.05 def | 0.20 ± 0.1 def | 0.24 ± 0.04 ghi | 0.38 ± 0.05 bcd | 0.08 ± 0.005 de | 0.49 ± 0.17 bcd | 0.47 ± 0.03 cd | 0.13 ± 0.09 bcd |
T8 | 3.25 ± 0.25 de | 6.67 ± 0.58 fg | 1.15 ± 0.15 d | 0.53 ± 0.06 def | 0.50 ± 0.01 ef | 0.19 ± 0.01 def | 0.23 ± 0.03 ghi | 0.18 ± 0.12 cd | 0.07 ± 0.01 ef | 0.30 ± 0.04 bcd | 0.32 ± 0.12 d | 0.12 ± 0.02 bcd |
T9 | 2.25 ± 0.25 e | 4.27 ± 0.25 g | 0.75 ± 0.25 d | 0.19 ± 0.01 f | 0.35 ± 0.05 f | 0.10 ± 0.01 f | 0.12 ± 0.02 i | 0.11 ± 0.01 d | 0.04 ± 0.005 f | 0.07 ± 0.01 d | 0.24 ± 0.06 d | 0.07 ± 0.01 d |
Addition of different concentration of salt (NaCl) to media induced reduction in all of the growth parameters when the treatments T1 to T9 (Cd + NaCl) were compared with C1 to C3 as shown in
The effect of different concentrations of salt (NaCl) on Cd concentration and accumulation in different parts of Veronica and Epilobium plant is presented respectively in
Treatment | Cd concentration (ppm) | Cd accumulation (mg/DBM) | Entire plant Cd (mg/DBM) | Cd accumulation % | Cd translocation factor (TF) | Cd bio-concentration factor (BCF) | |||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Root | Stem | Leaves | Root | Stem | Leaves | Root | Stem | Leaf | Root to stem | Root to leaves | |||
C1 | 928.6 ± 2.86 d | 329 ± 1.58 de | 231.4 ± 3.54 g | 1.347 ± 0.0032 a | 0.94 ± 0.01 a | 0.214 ± 0.0011 a | 2.5 ± 0.02 a | 53.66 | 37.72 | 8.62 | 0.36 | 0.25 | 9.55 |
C2 | 985.4 ± 1.36 c | 385 ± 0.9 bcd | 244 ± 1.28 f | 0.827 ± 0.0019 ab | 0.77 ± 0.003 abc | 0.163 ± 0.0007 ab | 1.76 ± 0.01 abc | 46.27 | 44.66 | 9.07 | 0.39 | 0.25 | 5.00 |
C3 | 1102.6 ± 1.34 c | 418 ± 1.8 bc | 388 ± 0.6 d | 0.46 ± 0.0009 b | 0.44 ± 0.002 abcde | 0.105 ± 0.0004 cdef | 1.01 ± 0.01 bcd | 45.2 | 44.34 | 10.5 | 0.38 | 0.35 | 3.83 |
T1 | 890 ± 1.02 e | 380 ± 1.54 cd | 107.4 ± 1.6 j | 0.92 ± 0.0021 cd | 0.94 ± 0.003 a | 0.07 ± 0.0016 bcd | 1.92 ± 0.01 ab | 47.82 | 49.03 | 3.15 | 0.43 | 0.09 | 9.01 |
T2 | 945 ± 0.9 d | 466 ± 1.58 ab | 128.4 ± 1.56 i | 0.616 ± 0.0019 c | 0.71 ± 0.005 abcd | 0.071 ± 0.0018 bc | 1.4 ± 0.01 abcd | 44.2 | 50.71 | 5.09 | 0.49 | 0.14 | 10.23 |
T3 | 1155.2 ± 0.58 d | 468 ± 0.86 ab | 451 ± 1.8 c | 0.305 ± 0.0023 cde | 0.27 ± 0.003 cde | 0.075 ± 0.0003 bcd | 0.65 ± 0.001 cd | 47.21 | 41.25 | 11.5 | 0.41 | 0.39 | 12.93 |
T4 | 860 ± 0.86 f | 408 ± 1.02 bcd | 217.2 ± 3 h | 0.75 ± 0.0016 e | 0.89 ± 0.007 ab | 0.153 ± 0.0012 bcde | 1.79 ± 0.008 abc | 41.99 | 49.42 | 8.59 | 0.48 | 0.25 | 4.78 |
T5 | 1040 ± 2.86 b | 468 ± 1.04 ab | 381.8 ± 1.34 d | 0.479 ± 0.0021 e | 0.32 ± 0.002 cde | 0.128 ± 0.0015 bcde | 0.93 ± 0.004 bcd | 49.3 | 37.48 | 13.2 | 0.45 | 0.37 | 6.17 |
T6 | 1198 ± 1.58 e | 521.6 ± 1.18 a | 732.6 ± 14.28 a | 0.24 ± 0.0017 e | 0.19 ± 0.001 e | 0.135 ± 0.0011 def | 0.57 ± 0.0034 cd | 42.39 | 34.42 | 23.2 | 0.44 | 0.61 | 7.52 |
T7 | 900 ± 1.84 c | 278 ± 0.92 e | 232 ± 1.2 g | 0.469 ± 0.0021 cd | 0.38 ± 0.0025 bcde | 0.087 ± 0.0005 ef | 0.93 ± 0.002 bcd | 50.46 | 40.26 | 9.28 | 0.31 | 0.26 | 2.77 |
T8 | 1040 ± 1.3 b | 351.6 ± 1.4 cde | 369.6 ± 1.22 e | 0.357 ± 0.002 c | 0.25 ± 0.005 de | 0.077 ± 0.0007 fg | 0.68 ± 0.002 bcd | 53.14 | 35.51 | 11.4 | 0.34 | 0.36 | 3.67 |
T9 | 1480 ± 2.32 a | 372.2 ± 0.88 cd | 680.2 ± 1.38 b | 0.234 ± 0.0015 de | 0.1 ± 0.0007 e | 0.057 ± 0.0004 g | 0.39 ± 0.0006 d | 60.4 | 24.82 | 14.8 | 0.25 | 0.46 | 5.16 |
comparing C1, C2, and C3 (
The highest total Cd accumulation in different parts of Veronica plant (root = 1.347 ± 0.0032, stem = 0.94 ± 0.01 and leaves = 0.214 ± 0.0011 mg/DBM) was shown by plants treated with lowest concentration of Cd (C1) in growth media, this increase might be due to high biomass production of plants in C1 as already described in
All the treatments showed translocation factor (TF) values less than 0.5 but the Cd bio-concentration factor (BCF) for all the treatments was found higher than 2.5 and the highest BCF value (12.93) was recorded for the treatment T3 (Cd 50 ppm + NaCl 6000 ppm). It shows that treatment T3 has efficiently concentrated Cd from the growth media into the plant tissues. The plants treated with Cd (C1 - C3) showed the BCF greater than 1 and
Treatment | Cd concentration (ppm) ± SD | Cd accumulation (mg/DBM) ± SD | Entire plant Cd (mg/DBM) ± SD | Cd accumulation % | Cd translocation factor (TF) | Cd bio-concentration factor (BCF) | |||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Root | Stem | Leaves | Root | stem | Leaves | Root | Stem | Leaf | Root to stem | Root to leaves | |||
C1 | 57.4 ± 2.86 d | 48.8 ± 1.58 ef | 70 ± 3.54 g | 0.032 ± 0.0032 a | 0.036 ± 0.0191 ab | 0.014 ± 0.0011 bc | 0.082 ± 0.0213 ab | 40.34 | 41.48 | 18.18 | 0.85 | 1.22 | 0.31 |
C2 | 64.4 ± 1.36 c | 54.2 ± 0.9 d | 114 ± 1.28 c | 0.03 ± 0.0019 ab | 0.036 ± 0.0037 a | 0.018 ± 0.0007 a | 0.084 ± 0.0032 a | 35.14 | 43.21 | 21.65 | 0.84 | 1.77 | 0.41 |
C3 | 66 ± 1.34 c | 59 ± 1.8 c | 128 ± 0.6 b | 0.025 ± 0.0009 b | 0.035 ± 0.0026 ab | 0.013 ± 0.0004 bc | 0.073 ± 0.0028 abc | 33.86 | 47.68 | 18.46 | 0.89 | 1.94 | 0.28 |
T1 | 45 ± 1.02 e | 50.8 ± 1.54 de | 86 ± 1.6 f | 0.016 ± 0.0021 cd | 0.032 ± 0.0033 ab | 0.011 ± 0.0016 cd | 0.059 ± 0.0071 cd | 26.86 | 55.07 | 18.07 | 1.13 | 1.91 | 0.28 |
T2 | 54.8 ± 0.9 d | 62.2 ± 1.58 bc | 118 ± 1.56 bc | 0.018 ± 0.0019 c | 0.029 ± 0.0057 ab | 0.014 ± 0.0018 bc | 0.061 ± 0.0056 bcd | 29.04 | 48.02 | 22.94 | 1.13 | 2.15 | 0.44 |
T3 | 55 ± 0.58 d | 72.8 ± 0.86 a | 148 ± 1.8 a | 0.013 ± 0.0023 cde | 0.033 ± 0.0031 ab | 0.015 ± 0.0003 b | 0.061 ± 0.0012 bcd | 21.99 | 54.29 | 23.72 | 1.32 | 2.69 | 1.22 |
T4 | 32 ± 0.86 f | 50.4 ± 1.02 e | 86 ± 3 f | 0.008 ± 0.0016 e | 0.023 ± 0.0073 abc | 0.009 ± 0.0012 de | 0.041 ± 0.0081 de | 19.65 | 56.48 | 23.87 | 1.58 | 2.69 | 0.11 |
T5 | 34.2 ± 2.86 f | 52 ± 1.04 de | 96 ± 1.34 ef | 0.009 ± 0.0021 e | 0.024 ± 0.0023 abc | 0.009 ± 0.0015 de | 0.042 ± 0.0041 de | 20.37 | 57.26 | 22.37 | 1.53 | 2.82 | 0.44 |
T6 | 42.4 ± 1.58 e | 64.4 ± 1.18 b | 110 ± 14.3 cd | 0.008 ± 0.0017 e | 0.02 ± 0.001 abc | 0.008 ± 0.0011 de | 0.035 ± 0.0034 e | 21.81 | 56.66 | 21.53 | 1.52 | 2.59 | 0.52 |
T7 | 65.2 ± 1.84 c | 43.6 ± 0.92 g | 42 ± 1.2 h | 0.015 ± 0.0021 cd | 0.016 ± 0.0025 bc | 0.003 ± 0.0005 f | 0.035 ± 0.0021 e | 43.9 | 47.05 | 9.041 | 0.67 | 0.64 | 0.10 |
T8 | 73 ± 1.3 b | 45.8 ± 1.4 fg | 90 ± 1.22 ef | 0.017 ± 0.002 c | 0.008 ± 0.0053 c | 0.006 ± 0.0007 ef | 0.031 ± 0.0026 e | 54.01 | 25.72 | 20.28 | 0.63 | 1.23 | 0.17 |
T9 | 86.2 ± 1.4 a | 61 ± 0.88 bc | 100 ± 1.38 de | 0.01 ± 0.0015 de | 0.007 ± 0.0007 c | 0.004 ± 0.0004 f | 0.021± 0.0006 e | 50.11 | 32.78 | 17.11 | 0.71 | 1.16 | 0.27 |
on the basis of its BCF the Veronica plant can be reported as hyper-accumulator for Cd. In C1 (50 ppm Cd) the BCF is highest as compared to C2 (100 ppm Cd) and C3 (150 ppm Cd) (
In comparison to Veronica, the Epilobium plant showed much lower Cd concentration in its different parts under the same treatments used for Veronica plant (by comparing
The correlation of Veronica dry biomass (of root, stem and leaves) with the Cd concentration in roots, stem and leaves is presented respectively in Figures 2(a)-(c). The correlation was found negative and it was significant (R2 = 0.608) in case of plant leaves (
The result of this study showed that the Veronica anagallis plant is hyper-accumulator of Cd, while Epilobium laxum plant is non hyper-accumulator, as the Veronica plant showed Bio-concentration factor (BCF) more than one (01) and Epilobium plant demonstrated Bio-concentration factor less than one (01) (BCF 1 is a threshold limit for a plant to be hyper-accumulator of Cd). The Veronica plant demonstrated encouraging results for the removal of Cd from saline water, so it is further recommended to investigate the phytoextraction potential of Veronica plant for other metals from the saline water.
The Higher Education Commission HEC of Pakistan is highly acknowledged for the financial support through indigenous PhD scholarship program.