EFFECT OF CHROMIUM ON MORPHOLOGICAL AND BIOCHEMICAL RESPONSES ON AQUATIC MACROPHYTE PISTIA STRATIOTES L. (WATER LETTUCE)

EFFECT OF CHROMIUM ON MORPHOLOGICAL AND BIOCHEMICAL RESPONSES ON AQUATIC MACROPHYTE PISTIA STRATIOTES L. (WATER LETTUCE)

S. B. Kakkalameli ^{* 1}, Azharuddin Daphedar ², M. Govindappa ¹ and T. C. Taranath ²

Davangere University ¹, Shivagangotri, Davangere - 577002, Karnataka, India.

Environmental Biology Laboratory ², P. G. Department of Studies in Botany, Karnatak University, Dharwad - 580003, Karnataka, India.

ABSTRACT: The current work reports an ecofriendly approach to study morphological and biochemical responses of Pistia stratiotes L. (Water lettuce) were investigated. The assessment of morphological, biochemical parameters, and accumulation of chromium in free-floating macrophyte exposed at its various concentrations viz. 0.25, 0.50, 1.25, and 2.5 ppm of chromium at the regular intervals of 4, 8, and 12 days, respectively. Pistia showed morphological toxicity like withering of roots, chlorosis, and necrosis at higher concentrations (2.5 ppm) of chromium. However, the plant showed normal growth at a lower concentration of 0.25 and 0.50 ppm. The evaluation of biochemical parameters of test plants showed Total Chlorophyll, Carbohydrate, and Protein content was increased at lower concentrations (0.25 ppm) and decreased at higher concentrations (2.5 ppm) of chromium. The toxicity of chromium was found to be directly proportional to its concentration and duration of exposure. It is evident from the results that the accumulation of chromium can produce adverse effects on the morphology of test plant species at a higher concentration of chromium. This may be attributed to the stress-induced by chromium.

Pistia stratiotes L., Chromium accumulation, Phytoremediation, Biochemical Parameters

INTRODUCTION: The rapid development of industrialization and urbanization, coupled with an alarming rate of population growth, has resulted in the large scale pollution of aquatic ecosystems by industrial and domestic wastewater discharge. Our environment, which consists of biotic and abiotic functions, is a part of the giant ecosystem called the biosphere or ecosphere. Biosphere complexly inter-faces with other systems: hydrosphere, lithosphere, and atmosphere. Each of the systems is unique, with its own physicochemical factors and biotic components.

Man-made pollutants affect the quality, causing abnormal functioning of these ecosystems and thus adversely affect plant species, animals, including humans.

Man-made pollutants can be broadly classified into biodegradable and non-biodegradable categories. Non-biodegradable or persistent organic pollutants (POPs) include Aluminum tins, Mercurial salts, Long-chain phenolic compounds, Dichlorodi-phenyltrichloroethane (DDT), metals like Cu, Mn, Zn, Cr, and Ni, etc., which mostly do not degrade and further results in bio-magnification. Domestic wastewater is one of the quantifiable sources of biodegradable pollutants. Heavy metals are so heavy that even at lower concentrations can cause toxicity to humans and other forms of life. Microbial degradation is considered the best option to counter such toxic pollutants.

From a biological point of view, heavy metals can be divided into two categories: essential and non-essential. However, essential heavy metals have also been reported to be toxic at high concentrations. These heavy metal influences at the cellular level affecting the entire metabolic process, whereas the intracellular and extracellular accumulation of metals is usually energy-driven processes and thus can take place only in living cells ^{1, 2, 3, 4}. The presence of heavy metals in water and wastewater is mainly due to the industrial effluent sewage disposal or into the water bodies. The occurrence of toxic metals in pond, ditch, and river water affects the lives of local people that depend upon these water sources for their daily requirements ⁵. Several of the submerged, emergent, and free-floating aquatic macrophytes are known to accumulate heavy metals ^{6, 7}. Macrophytes are aquatic plants growing in or near water that is emergent, submerged, or floating. Macrophytes are beneficial to the lake because they provide food, shelter, and breeding habitats for fish and aquatic invertebrates.

Not all macrophytes are effective for heavy metal remediation. Earlier reports reported that on certain aquatic macrophyts includes Phragmites communis, Scirpusla custris, Eichhornia crassipes, Spirodela polyrrhiza, Chara corallina, Vallisneria spiralis, Alternanthera sessilis and Hygrorrhiza aristata Elodea canadensis, Egeriadensa, Ceratophyllum demersum, Bacopa monnieri, Limnanthemum cristatum, Potamogeton malaianus, Nymphoides peltata, Hydrilla verticillata and the algal macro-phytes, Hydrodictyon reticulatum, have been found suitable for the removal of different metals ^{8, 9, 10}.

P. stratiotes is a monotypic genus, and free-floating herb mostly thrives best in still water or streams of minimal flow. Being warm loving, it is abundantly found in tropical and subtropical regions of P.stratiotes are a perennial and having light yellow, green leaves arranged in rosettes. Unbranched clusters of long fibrous roots extending from the centre of underwater rhizome (Rhizome bears root pockets). Seed production is limited, and propagation is mainly by offsets and buds. Leaves are densely clothed on both surfaces with short depressed hairs, which give the foliage a velvety appearance. Chromium (Cr) occurs naturally at trace levels in most soils and water, but disposal of industrial waste and sewage sludge containing Cr compounds has created a number of contaminated sites, which could pose a major environmental threat. Cr primarily exists as a soluble, highly toxic Cr₆ anion as against its reduced form Cr₃, which is less soluble and less toxic. Reduction /oxidation reactions between the two states are thermo-dynamically possible under physiological conditions ^11, and hence reduction of Cr₆ to Cr₃ is potentially useful for remediation of Cr affected environments ¹².

MATERIALS AND METHODS:

Collection of Test Plant Species: The plant Species of P. stratiotes belonging to the family Araceae were collected from Srinagar pond near Karnatak University, Dharwad, Karnataka, India.

Experimental Design: The collected young and healthy plants were acclimatized for two weeks in the experimental tubs of 10-liter capacity containing Hoagland solution. About 50g of plant material was introduced simultaneously into experimental tubs containing 0.25, 0.50, 1.25, and 2.5 ppm of chromium at the interval of 4, 8, and 12 days, tap water was used as control. After treatment, the plants were washed with double distilled water for morphometric and biochemical analysis.

Assessment of Morphometric and Biochemical Responses of Heavy Metals: The study of biochemical response reveals using standard protocols of chlorophyll, carbohydrate, protein and proline were estimated. The chlorophyll estimation was carried out as suggested by the standard method of Arnon and Hongland ¹³, the protein by the method of Lowry (1951) using Bovine Serum Albumin (BSA) as a standard, carbohydrate by phenol sulphuric acid method ¹⁴ using glucose as a standard and proline by Bates method (1973).

Statistical Analysis: The experiments were carried out using statistical analysis IBM (SPSS windows software) version 20. The standard error (Mean ± SE) was performed from three replicates for every set of data.

RESULTS AND DISCUSSION:

Plant Morphological Changes and Chromium Accumulation: The morphological changes of P. stratiotes in response to chromium are presented in Table 1. P. stratiotes showed morphological toxicity at 0.25 ppm of chromium. However, at higher concentrations (2.5 ppm) the lower rosette of leaves becomes whitish-yellow, resulting in degradation and withering of leaves. The root caps get degenerated, and roots become dark brown in color. Our investigation revealed that the lower concentration of chromium (0.25 ppm) promotes the root length (12.93 cm), laminal length (2.93 cm), and breadth (3.53 cm) when compared with control at 12 days of exposure. The higher concentration (2.5 ppm) of chromium was found to inhibit the root length (7.96 cm), laminal length (1.83 cm) and breadth (2.37 cm) at 12 days of exposure (Table 1). The results were statistically not significant at p˂0.01 and p˂0.05 level at all tested concentrations when compared to control. From the data, it is evident that the chromium accumulation in Pistia was directly proportional to its concentration and duration of exposure. Our results are in substantiation with that of ^{15, 16}.

In general, the aquatic macrophytes show normal growth and no visible symptoms at 0.5 ppm chromium treatment. The leaves are a greenish healthy and marginal increase in their size at 0.5 ppm. The exposure of Chromium to the plants to 2.5 and 5 ppm was found to inhibit the growth of the plant, resulting in etiolation and withering of leaves. In cellular activities of plants are affected by heavy metal pollution, including mineral nutrition, photosynthesis, respiration, membrane structure, gene expression, and other properties ¹⁷ Plant growth is a function of the complex interplay between sources and sinks limitations of the two main organs of a plant, the root, and shoots system, establishing functional equilibrium ¹⁸. Heavy metals lead potential pollutants that readily accumulate at the cellular level, causing physiological, biochemical, and ultrastructural changes due to chromium toxicity resulting in dysfunction in plants. Heavy metal toxicity may cause multiple direct and indirect effects in certain tissues of plants such as the epidermis; cortex, and endodermis. There are several substantiations to show that metal toxicity has a direct effect on growth inhibition of many plants, cereals, pulses, vegetables, forages, and trees ¹⁹.

Recent studies suggest that the induction of metal toxicity caused by two reasons:

(a) Inhibition of cell division and (b) decrease of cell expansion, which can be disturb mitochondrial outer membrane permeabilization during oxidative stress, stopping oxidative phosphorylation, ATP production, and inhibition of cell division or cessation of mitosis due to heavy metal stress ^{20, 21}.

The 2.5 ppm of chromium found to inhibit root and plant length with an exposure duration of 4, 8, and 12 days for P. stratiotes. The change in the pigment content in heavy metal exposed plants is one of the first visible symptoms. Additionally, these changes are used as an indicator of photosynthetic damage in plant tissues. Similar observations were observed with heavy metals (Ni and Cd) uptake, distribution, and accumulation in plants. Their effects on physiological and morphological traits have been summarized in several recent reviews ^{22, 23}. Though beneficial (Ni) or harmless (Cd) at lower concentrations, both elements induce phytotoxic effects at concentrations higher than the tolerance threshold of the different plant species since they are taken up through metal transporters with low specificity ^{24, 25, 26}.

Many physiological processes are impaired by stress Cd and Ni, resulting not only in common but also in specific symptoms of metal toxicity ^{27, 28, 29}. The morphological changes observed in Salvinia. adanata, in response to chromium shows symptoms of morphological toxicity and normal growth. However, at higher concentrations, leaves turn yellowish-white, the margin of the lamina becomes dark brown, brownish discoloration, and shows degeneration of root. These results are in agreement with those reported for aquatic plants in general ³⁰.

A decrease in the number of roots is a well-documented effect due to heavy metals in trees and crops. It was reported that the order of metal toxicity to new root primordial in Salix viminalis is Cd>Cr>Pb whereas root length was more affected by other heavy metals. The adverse effect of chromium on plant height and shoot growth was reported. Growth inhibition by Chromium can be attributed to chromosomal aberrations, which lead to inhibition of cell division. It is known that in many plant species, the mobility of Cr is low due to the fact that there are barriers or lack of transport mechanism suitable for Cr transport from roots to shoot lengths activities of enzymes catalase and peroxidase were found to be significantly decreased as compared to control. Several workers have reported that symptoms like reduced growth, Chlorosis necrosis, leaf epinasty, red-brownish discoloration due to Chromium metal toxicity ³¹.

TABLE 1: EFFECT OF CHROMIUM ON MORPHOLOGY OF PISTIA STRATIOTES L.

Values are expressed in cms,  Mean values ± Standard Error

TABLE 2: EFFECT OF CHROMIUM ON BIOCHEMICAL PARAMETERS OF PISTIA STRATIOTES L.

* Values are expressed in µg/gm tissue, Mean values ± Standard Error

Effect of Chromium on Biochemical Parameters of P. stratiotes: Most of the aquatic plants growing in a contaminated site have the ability to tolerate the high intensity of metal concentration. The accumulation of the high amount of heavy metals without showing any phenotypic damage/ expressions, but there are certain alterations in their internal physiology ³². The reduction of photosynthetic pigments is mainly due to metal stress, which is very common in chloroplasts and plays a significant role in modifying many metabolic pathways through the biochemical and physiological process ³³.

Hadif et al., ³⁴, suggested that the amount of chlorophyll such as chlorophyll a, chlorophyll b, total chlorophyll (a+b), and chlorophyll (a/b) ratio, were affected by the chromium concentration in the leaves of paddy. It is found that the higher concentrations of chlorophyll decrease with increase in the concentration of chromium. The results exhibit there has been an increased in the total chlorophyll content, which varies from (1.88 mg/g to 1.94 mg/g at 0.25ppm) Chromium during exposure duration of 4^th and 12^th days. The results are statistically significant when compared to control. Similar results were found in Marselia sp. (16. 94%). Total chlorophyll content showed strong negative correlations with Fe (0.974, Eclipta sp.), Cr (0.997 Eclipta sp.), Cd (0.998, Eclipta sp.), Pb (0.999, Alternanthera sp.), Zn (0.981, Marselia sp.) and Cu (0.998, Eclipta sp.). Reduction in chlorophyll content was due to the substitution of central Mg²⁺ with metal ions; besides, excess accumulation of metals can also lead to higher chlorophyllase activity and the destruction of the structure of chloroplasts.

Similarly, chlorophyll concentration in S. polyrhiza was negatively correlated with Pb exposures nutrient enrichment attenuated the observed reduction in chlorophyll concentration caused by Pb exposures. When Spirodela fronds were exposed to Pb concentrations of 5 mg/L or higher, a dose-dependent decrease of chlorophyll pigments were also observed, with minimum chlorophyll “a” value of 0.414 mg/g fresh weight on day 7 at 50 mg/L compared to 1.601 mg/g in controls ³⁵.

A decrease in soluble sugar in all the aquatic plants was also noticed due to high metal stress, which is consistent with the findings of Warrier and Saroja ³⁶. Marselia sp. Showed the highest reduction of soluble sugars (53.28%), which is highly sensitive to environmental stress. The reduction of sugar content in stressed plants probably corresponds with the photosynthetic inhibition or stimulation of respiration for higher energy requirements ³⁷.

A significant negative correlation exists between soluble sugars Fe (0.983, Eclipta sp.) and soluble sugars Cr (0.983, Ipomea sp.). Both biotic and abiotic stress may inhibit the synthesis of some proteins and cause protein misfolding leads to inhibiting the expression of genes ³⁸.

TABLE 3: TWO WAY ANOVA FOR EFFECT OF BIOCHEMICAL PARAMETERS OF P. STRATIOTES L.

*Significant at 0.01 level, **Significant at 0.05 level

There are several earlier investigations on the metal accumulation capacity of Ipomea sp. ³⁹, Eclipta sp., Marselia sp. ⁴⁰, Alternanthera sp and Typha sp. ⁴¹. Aquatic macrophytes showed varied affinities for different metal uptake. Most of the aquatic macrophytes exhibited higher metal accumulations in the leafy vegetative parts except Typha sp., which indicated high metal concentrations in its underground part due to its well-developed roots and rhizome system. Among amino acids, Proline responds most sensitively to stress conditions ⁴². Proline accumulation is accepted as an indicator of environmental stress, including metal contamination considered to have important protective roles ⁴³. The Proline content of the macrophytes species exhibited strong positive correlations with Fe (0.967, Ipomea sp.; 0.978, Eclipta sp.) and Cr (0.998, Eclipta sp.), The proline accumulation changes in plant tissue may be explained by a decrease in proline degradation or an increase in proline biosynthesis and hydrolysis of proteins ⁴⁴.

The biochemical effects of chromium on P. stratiotes are presented in Table 2. The 0.25 ppm of chromium promotes the Chlorophyll synthesis by 1.36 mg/g and 1.32 mg/g at 4 and 12 days of exposure when compared to control. At higher concentrations (2.5 ppm) inhibit the synthesis of chlorophyll by 0.93 mg/g and 0.85 mg/g at 4 and 12 days of exposure Table 1. The higher concentration (2.5 ppm) of Chromium promotes the synthesis of carbohydrates at 4 and 12 days of exposure by 24.96 mg/g and 24.85 mg/g when Compared to control, Table 3. The lower concentration (0.25 ppm) of Chromium promotes the synthesis of protein by 5.78 mg/g and 5.74 mg/g at 4 and 12 days of exposure. Whereas at higher concentrations (2.5 ppm) it promotes the synthesis of protein at 4 and 12 days of exposure by be 2.9 mg/g and 2.79 mg/g when compared to (Table 1).

The higher concentration (2.5 ppm) induces the accumulation of Proline with 2.77 mg/g and 4.1mg/g at 4 and 12 days of exposure when compared to control Table 1. The three-way ANOVA with two-factor interaction among the concentration, exposure duration, and parameters were applied to know the relation between concentration and exposure duration, concentration and parameters, and exposure duration and parameters. The factors are related but not at the significant level in Table 2.

CONCLUSION: In the present investigation, it has been observed that the test plant species P. stratiotes showed visible symptoms such as Chlorosis and withering of roots at higher concentrations of Chromium. However, at the lower concentration, it showed normal growth. The total chlorophyll decreases with an increase in the concentration of Chromium. The lower concentration of Chromium promotes the production of chlorophyll, carbohydrate, and protein, whereas it showed a negative effect at higher concentrations. The Proline content has been found to increase with increased concentrations and duration of exposure. Thus, from the present investigation, it can be concluded that the higher concentration of Chromium is toxic to P. stratiotes, and its toxicity is directly proportional to its concentration and duration of exposure.

ACKNOWLEDGEMENT: The authors are thankful to the Chairman, P. G. Department of Botany, Davangere University, Shivagangotri, Davangere, and the Chairman, PG Department Botany, Karnataka University, Dharwad for providing necessary facilities to carry out this research work.

CONFLICTS OF INTEREST: The authors declare that there is no conflict of interest.

REFERENCES:

1. Volesky B: Biosorption of heavy metals. Ed. By B. Volesky (CRC Press, Boca Raton, FL 1990; 139.
2. Gadd GM: Heavy metal accumulation by bacteria and other microorganisms. Experientia 1990; 46: 834-40.
3. Macaskie LE: An immobilized cell bioprocess for the removal of heavy metals from aqueous flows. Journal of Chemical Technology and Biotechnology 1990; 49: 357-379.
4. Sag Y and Kutsal T: Determination of the biosorption activation energies of heavy metals on Zooglea ramigera and Rhizopus arrhizus. Process Biochemistry 2000; 35: 801-07.
5. Rai UN, Tripathi RD, Vajpayee P, Vidyanath J and Ali MB: Bioaccumulation of toxic metals (Cr, Cd, Pd and Cu) by seeds of Euryale ferox salisb (Makhana). Journal of Chemosphere 2002; 46: 267-72.
6. Bryan GW: The effects of heavy metals (other than mercury) on marine and estuarine organisms. Proceedings of the Royal Society of London, B 1971; 177: 389-410.
7. Chow TJ, Snyder CB, Snyder HG and Earl JL: Lead content of some marine organisms. Journal of Environmental Science and Health, A 1976; 11: 33-44.
8. Wolverton BC and McDonald RC: The water hyacinth from prolific pest to potential provider. Journal of Ambio 1975; 8: 2-9.
9. Sinha S and Chandra P: Removal of Cu and Cd from water by Bacopa monnieri L. Journal of Water Air Soil Pollution 1990; 40: 271-76.
10. Bai L, Liu XL, Hu J, Li J, Wang ZL, Han G, Li SL and Liu CQ: Heavy Metal Accumulation in Common Aquatic Plants in Rivers and Lakes in the Taihu Basin. International Journal of Environmental Research and Public Health 2018; 15: 2857.
11. Arias YM and Tebo BM: Chromium reduction by sulfidogenic and non sulfidogenic microbial consortia. Journal of Applied Environmental Microbiology 2003; 69: 1847-53.
12. Michel C, Brugma M, Aubert C, Bernadac A and Bruschi M: Enzymatic reduction of chromate: comparative studies using sulfate-reducing bacteria. Journalof Applied Microbiology Biotechnology 2001; 55: 95-100.
13. Arnon DI: Copper enzymes in isolated chloroplast polyphenol oxidase in Beta vulgaris. Journal of Plant Physiology 1940; 24: 1-15.
14. Dubois M, Gilles KA, Hamilton JK, Rebers PA and Smith F: “Calorimetric method for determination of sugars and related substances”. Analytical Chemistry 1956; 28(3): 350-356.
15. Rolli NM, Hujaratti RB, Giddanavar HS, Mulagund GS and Taranath TC: Toxicity Effect of Copper on Aquatic Macrophyte (Pistia stratiotes). International Journal of current Research Review 2007; 9: 15.
16. Li X, Zhang X, Wu Y, Li B and Yang Y: Physiological and biochemical analysis of mechanisms underlying cadmium tolerance and accumulation in turnip. Plant Diversity 2018; 40: 19-27.
17. Peixoto PHP, Cambraia J, Anna RS, Mosquim PR and Moreira MA: Aluminium effects on fatty acid composition and lipid peroxidation of a purified plasma membrane fraction of root apices of two sorghum cultivars. Journal of Plant Nutrition 2001; 24: 1061-70.
18. Anjum SA, Xie X, Wang L and Saleem MF: Morphological, physiological and biochemical responses of plants to drought stress. African Journal of Agriculture Research 2011; 6(9): 2026-32.
19. Singh HP, Mahajan P, Kaur S, Batish DR and Kohli RK: Chromium toxicity and tolerance in plants. Environmental Chemistry Letters 2013; 11: 229-54.
20. Ortega-Villasante CR, Rella AL, DelCampo FF, Carpena-Ruiz RO and Hern´andez LE: Cellular damage induced by cadmium and mercury in Medicago sativa. Journal of Experimental Botany 2005; 56: 2239-51.
21. Chen J: The Cell-Cycle Arrest and Apoptotic Functions of p53 in Tumor Initiation and Progression. Journal of Cold Spring Harbor Perspective in Medicine 2016; 6(3): a026104.
22. Seregin IV and Kozhevnikova AD: Roles of root and shoot tissues in transport and accumulation of cadmium, lead, nickel, and strontium. Russian Journal of Plant Physiology 2008; 55: 1-22.
23. Gallego S, Pena LB, Bracia RA, Azpilicueta CE, Iannone MF, Rosales EP, Zawoznik MS, Groppa MD and Benavides MP: Unravelling cadmium toxicity and tolerance in plants: Insight into regulatory mechanisms. Environmental and Experimental Botany 2012; 83, 33-46.
24. Rogers EE, Eide DJ and Guerinot ML: Altered selectivity in an Arabidopsis metal transporter. Proceedings of the National Academy of Sciences of the United States 2000; 97: 12356-360.
25. Clemens S, Palmgren MG and Kramer U: A long way ahead: understanding and engineering plant metal accumulation. Trends in Plant Sciences 2002; 7: 309-31.
26. Sanz A, Llamas A and Ullrich CI: Distinctive phytotoxic effects of Cd and Ni on membrane functionality. Plant Signaling & Behavior 2009; 4: 980-82.
27. Foy CD, Chaney RL and White MC: The physiology of metal toxicity in plants. Annual Review Plant Physiology 1978; 29: 511-66.
28. Sun EJ and Wu FY: Along-vein necrosis as indicator symptom on water spinach caused by nickel in water culture. Botanical Bulletin- Academia Sinica Taipei 1998; 39: 255-59.
29. Toppi SL and Gabbrielli R: Response to cadmium in higher plants. Environmental and Expierimental Botany 1999; 41: 105-30.
30. Dixit S and Tiwari S: Effective utilization of an aquatic weed in an eco-friendly treatment of polluted water bodies. Appl Sci and Environ Management 2007; 11: 41-44.
31. Lepp OH, Rosenbrough NT, Farr AL and Randall RJ: Effects of heavy metal pollution on plants. Applied sciences publishers London 1951; 1-56.
32. Nayek S, Gupta S and Saha R: Effects of metal stress on biochemical response of some aquatic macrophytes growing along an industrial waste discharge channel. Journal of Plant Interactions 2010; 5(2): 91-99.
33. Khan N, Bano A and Ali Babar MD: Metabolic and physiological changes induced by plant growth regulators and plant growth promoting rhizobacteria and their impact on drought tolerance in Cicer arietinum Plos One 2019; 14(3): e0213040.
34. Hadif WM, Rahim SA, Sahid I, Rahman A and Ibrahim I: Impact of nickel on enzymes activity in leaves of paddy Plant Oryza sativa International Journal of ChemTech Research 2015; 8(4): 1710-20.
35. Leblebici Z and Aksoy A: Growth and Lead Accumulation Capacity of Lemna minor and Spirodela polyrhiza (Lemnaceae): Interactions with Nutrient Enrichment. Water Air Soil Pollution 2011; 214: 175-84.
36. Warrier RR and Saroja S. Histochemical studies on water hyacinth with particular reference to water pollution. International Journal of Integrative Biology 2008; 3(2): 9699.
37. John R, Ahma PK, Gadgil K and Sharma S: Heavy metal toxicity: Effect on plant growth, biochemical parameters and metal accumulation by Brassica juncea Int J of Plant Production 2009; 3(3): 65-76.
38. Ericson MC and Alfinito SH: Proteins Produced during Salt Stress in Tobacco Cell Culture. Plant Physiology 1984; 74(3): 506-9.
39. Rai, UN and Sinha S: Environmental Monitoring and Assessment 2001; 70(3): 241-52.
40. Gupta SS, Nayek RN, Saha and Satpati S: Assessment of heavy metal accumulation in macrophyte, agricultural soil and crop plants adjacent to discharge zone of sponge iron factory. Environmental Geology 2008; 55: 731-39.
41. Deng H, Ye ZH and Wong MH: Accumulation of lead, zinc, copper, and cadmium by12 wetland plant species thriving in metal contaminated sites in China. Environmental Pollution 2004; 132: 29-40.
42. Nover L, Scharf KD and Neumann D: Cytoplasmic heat shock granules are formed from precursor particles and are associated with a specific set of mRNAs. Molecular and Cellular Biology 1989; 1298-1308.
43. Alia P and Saradhi PP: Proline accumulation under heavy metal stress. Journal of Plant Physiology 1991; 138: 554-58.
44. Charest C and Phan CT: Cold acclimation of wheat (Triticum aestivum) properties of enzymes involved in proline metabolism. Physiol Plantarum 1990; 80: 159-68.
    

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    How to cite this article:

    Kakkalameli SB, Daphedar A, Govindappa M and Taranath TC: Effect of chromium on morphological and biochemical responses on aquatic macrophyte Pistia stratiotes L. (Water lettuce). Int J Pharm Sci & Res 2021; 12(1): 633-39. doi: 10.13040/IJPSR.0975-8232. 12(1).633-39.

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