Article in HTML

Author(s): Samiksha Sharma1

Email(s): 1samikshasharma0129@gmail.com

Address:

    1Chhattisgarh Institute of Medical Sciences, Bilaspur, Chhattisgarh, India
    *Corresponding Author Email- samikshasharma0129@gmail.com

Published In:   Volume - 4,      Issue - 2,     Year - 2022


Cite this article:
Samiksha Sharma (2022) Biostimulants: An Eco-friendly Approach in Reducing Heavy Metal Toxicity. NewBioWorld A Journal of Alumni Association of Biotechnology,4(2):1-7.

  View PDF

Please allow Pop-Up for this website to view PDF file.



 NewBioWorld A Journal of Alumni Association of Biotechnology (2022) 4(2):1-7 

REVIEW ARTICLE

Biostimulants: An Eco-friendly Approach in Reducing Heavy Metal Toxicity

Samiksha Sharma

Chhattisgarh Institute of Medical Sciences, Bilaspur, Chhattisgarh, India

samikshasharma0129@gmail.com

*Corresponding Author Email- samikshasharma0129@gmail.com

ARTICLE INFORMATION

 

ABSTRACT

Article history:

Received

25 August 2022

Received in revised form

18 October 2022

Accepted

25 October 2022

Keywords:

Biostimulant;

Heavy Metal;

Humic Substance;

Protein Hydrolysates; Silicon

 

One of the most serious issues in the nation is heavy metal toxicity. It severely affects both plant and animal kingdom as well as disrupts the soil ecosystem. The consequence of heavy metal toxicity is the generation of osmotic and oxidative stress, membrane dysfunctioning, metabolic imbalances and cellular toxicity. To combat the prevailing issue, seeking eco-friendly ways to enhance and stimulate plant tolerance against stress, is the vital step. Hence, the application of biostimulants can be the best and effective alternative. Biostimulant is a non nutrient preparation of microorganism and/ or substances which enhance the crop quality enrich nutrient uptake efficiency and show tolerance against abiotic stresses. The super dynamic substances utilized in such arrangements are humic and fulvic acids, compounds containing nitrogen, protein hydrolysates, silicon, melatonin, seaweed extracts, and valuable microorganisms. The review briefly articulates the definition of biostimulants, its various types as well as its role towards reducing the heavy metal toxicity. Apart from these, the review also takes in consideration the ameliorating effects of silicon against heavy metal toxicity. Hence, biostimulants play an important role as reactive oxygen scavengers, stimulate antioxidant system of the plant, and induce gene expression of stress responsive gene thereby fostering plant tolerance to heavy metal toxicity.

 


Introduction

One of the major agronomic challenges that have seriously threatened food safety is heavy metal accumulation. This is the main reason behind raised concerns over heavy metal pollution, which unpleasantly disturbing agro ecosystems and crop production. Once the toxic heavy metals deposited beyond certain permissible limits, they badly affects the soil fertility, density, presence and physiological activities of microbiota. Therefore, the metal induced phytotoxicity problems warrant urgent and immediate attention (Jägermeyr, 2020).

DOI: 10.52228/NBW-JAAB.2022-4-2-1

All abiotic stresses conditions such as low/ high temperature, nutrient deficiency, drought, metal toxicity, UV exposure and photo-inhibition are periodic in nature .Plants under stress start various physiological, cell, and sub-atomic changes to adjust and react to such sort of stresses. Distinctive abiotic stress prompts diverse physiological or metabolic changes in the plant. The noticed changes might be inordinate reactive oxygen species (ROS) creation, membrane damage, lower water potential, accumulation of osmolyte, nutritional disorder, rolling of leaves, hormonal imbalances, membrane dysfunction, increased photo oxidation, reduced photosynthesis and protein synthesis etc . Among all the stresses, heavy metal contamination is one of the concern environmental issues which severely affect the productivity of crop as well as has the negative impact on human health (Hu et al. 2017; Singh et al. 2020).

Heavy metal toxicity has many major effects on the plants. Heavy metals are generally accumulated in the root cells as Casparian strips blocks the further movement of heavy metals into the vascular system. This causes physiological, biochemical, and morphological changes in plants affecting crop productivity (Shahid et al. 2015; Guo et al. 2016). Protein oxidation and the generation of reactive oxygen species (ROS) such hydroxyl radicals (OH), superoxide radicals (O-2), and hydrogen peroxide (H2O2) are caused by the phytotoxic effects of heavy metals. Accumulation of heavy metals are also responsible for production of methylglyoxal, a cytotoxic compound which leads to peroxidation of membrane lipids thereby damaging cellular membranes causing membrane leakage as well as fragmentation of DNA causing oxidative stress. These overall mechanism harm cell and subcellular organelles (Hayat et al. 2012; Ali et al. 2013; Qadir et al. 2014; Ghori et al. 2019).

To mitigate the magnitude of metal induced changes a novel and eco-friendly approach is the practice of plant biostimulants, having potential which can improve nutrient uptake and efficiency, abiotic stress tolerance as well as securing yield stability under unfavorable environmental and edaphic conditions (Colla and Rouphael, 2015; Colla et al., 2014). The aim of this review article is to highlight recent advances on the use of biostimulants and discuss about the major silicon-related mechanisms to reduce the toxicity of heavy metals in plants to improve plant nutrition and organic farming.

Biostimulants and their benefits

Research on new agricultural technologies and approaches is taking a tremendous leap and aimed to improve crop quality and productivity under existing environmental conditions by preserving soil quality. The application of bio based material such as ‘Biostimulant’ is one such approach. It is considered as one of the efficient and sustainable way as well as a better alternative to agrochemicals to promote plant growth (Rouphael and Colla 2020). As per the the European Biostimulants Industry Council lists the benefits of biostimulants are as follows (Fig. 1).

•Refining the efficacy of the plant’s metabolism to increase the yield and crop quality.

•Increasing tolerance to and recovery from abiotic stresses in plants.

•Enabling nutrient assimilation and their translocation.

•Enhancing quality attributes of produce, including sugar content, color, fruit seeding, etc.

•Rendering water use more efficient.

Different Categories of Biostimulants and their role in reduction of Heavy metal toxicity

Biostimulants are classified on the basis of different properties. One includes the classification on the basis of their origin into biological and chemical or physical type (Rafiee et al. 2016). Another order approach separates biostimulants in microbial, which are acquired from plant growth promoting bacteria and arbuscular mycorrhizal organisms, and non-microbial biostimulants which incorporate, humic substances, micro-algae extracts and biopolymers, for example, chitosan (Ahemad and Kibret 2014; Rouphael and Colla 2020). Thus both microbial and non-microbial substances are further categorized into different types;

1.       Protein Hydrolysate

These protein hydrolysates have the capacity to accumulate proline in many plants, subjected to heavy metal stress. Proline performs a variety of crucial tasks, including osmoregulation, scavenging free radicals during the intake of heavy metals, and chelation of metal ions in plant cells and xylem sap. It has been reported that  amino acids including cysteine, asparagine, glutamine and glutathione peptides as well as phytochelatins are potentially involved in  chelation of Zinc (Zn), Nickle (Ni), Copper (Cu), Arsenic (As) and Cadmium (Cd) (Sharma and Dietz 2006; Sytar et al. 2013).

2.       Humic and fulvic acids

Soil microbial activity like decomposition of microbial, plant and animal residues results in the formation of Humic substances (HS). It is naturally found in soil. On the basis of their solubility and molecular mass, HS are classified into humic acids, humins and fulvic acids. HS have been recognized for their major contribution in increasing soil fertility. HS also enhance the plasma membrane H+-ATPase activity which results in cell wall loosening, enlargement and organ growth etc., (Jindo et al. 2012). HS also activate the antioxidant property and induce the synthesis of secondary metabolites (Jindo et al. 2020).

3.       Seaweed extracts & botanicals

Seaweed has been used for hundreds of years as a fertilizer and to improve soil structure.  Polysaccharides laminarin (From brown algae Laminaria), alginates, carrageenans (originate from red seaweeds) and their breakdown products are comes under this criteria. They include micro- and macronutrients, nitrogen-containing compounds like betaines, sterols and hormones (Khan et al. 2009; Craigie 2011). In soils, polysaccharides obtained from seaweed leads to water retention, gel formation and soil aeration. ‘Botanicals’ are the substances taken out from plants and are used in pharmaceutical and cosmetic products. They are used as food ingredients and also in plant protection products (Seiber et al. 2014). Further-more botanicals includes allelochemicals i.e. plant active compounds involved in plant interactions with ecosystems are receiving more attention in the context of sustainable crop management (Ziosi et al. 2012; Ertani et al. 2013).

4.       Chitosan & other biopolymers

Chitosan is a biopolymer, deacetylated form of the chitin, produced naturally and industrially. Chitin and chitosan apparently use different signaling pathways. Agricultural applications of chitosan have been focusing on plant protection against fungal pathogens, tolerance for abiotic stress like drought, salinity, cold stress. Chitosan induces stomatal closure via an ABA-dependent mechanism to down the environmental stress (Iriti et al. 2009). Laminarin is a storage glucan of brown algae used in agricultural applications (Gozzo and Faoro 2013).


Figure: 1 Role of biostimulants in plant growth


5.       Inorganic compounds

In this criterion mineral like cobalt (Co), silica (Si), and selenium (Se) are present which promote plant growth, plant products and tolerance to abiotic stress. Insoluble forms like amorphous silica (SiO2.nH2O) are present in Graminaceaous species. Function of inorganic compounds includes rigidification of cell wall, reduction in transpiration by crystal deposits, osmoregulation, enzyme activity by co-factors, antioxidant protection, symbiotic associations, protection against heavy metals toxicity and plant hormone synthesis and signaling (Pilon-Smits et al. 2009; Hoque et al. 2021).

6.       Beneficial bacteria and fungi

There are many beneficial bacterial-plant connections:

(i) As for fungi there is a continuum between mutualism and parasitism;

(ii) Bacterial niches extend from the soil to the interior of cells, with intermediate locations called the rhizosphere and the rhizoplane;

(iii) Transient or permanent associations, some bacteria being even vertically transmitted via the seed;

(iv) Functions influencing plant life cover participation to the bio-geochemical cycles, supply of nutrients, and increase in nutrient use efficiency, induction of disease resistance, enhancement of abiotic stress tolerance, modulation of morphogenesis by plant growth regulators. With regard to the agricultural practices of biostimulants, mutualistic and rhizospheric plantgrowth-promoting rhizobacteria (PGPRs) are used as microbial inoculants facilitating nutrients acquisition by plants (Ahmad et al. 2019).Apart from bacteria, Arbusculer Forming Mycorrhiza (AMF) are well-known endomycorrhiza associated with crop and horticultural plants. This association involves fungal hyphae of Glomeromycota species to penetrate root cortical cells and form branched structures called arbuscules (Bonfante and Genre 2010; Behie and Bidochka 2014).

Silicon-mediated alleviation of metal toxicity in plants

In the crust of the planet, silicon is the second most prevalent element.  Silicon is a helpful element that is important in reducing abiotic stress, like the toxicity of heavy metals to plants. Si can alleviate and decrease the heavy metal uptake and its transportation in plants. During plant growth enhancement, silicon could increase malic and formic acid and they consequently diminish the uptake of Aluminum (Al). Silicon role has been reported as barrier because can expand the epidermal layer of maize and causes accumulation of Mn in non-photosynthetic tissue (Kaya et al. 2009; Santiago et al. 2021). Root anatomy plays an important role in reducing heavy metal toxicity (Mn and Cd) because roots are the first line exposed to heavy metals. By decreasing the apoplastic bypass flow, silicon promotes the binding of metal ions and reduces the transfer of hazardous metals from roots to shoots. (Ma and Yamaji 2006; Ye et al. 2012). Most of the plants use silicon to augment their defenses against the entrance of toxic heavy metals via the root apoplast. This process is achieved by Sodium ions, which cross the symplast through the apoplastic pathway which is also called a bypass flow. Casparian bands and suberin lamellae are the main constituents of apoplastic barriers, poor development of this barrier leads to the generation of bypass flow. Silicon also alleviates metal ion toxicity. In cucumber plants formation of hydroxy-aluminum silicates in the apoplast of the root apex may be the reason behind the reduction in apoplastic Aluminium (Al) mobility and the binding of excess Magnese (Mn) and Copper (Cu) to cell walls (Horst et al. 2010; Bosni et al. 2019; Cristofano et al. 2021).

Silicon and Heavy metal Tolerance

In plants, silicon frequently enters interior structures (cell walls and lumens) as mono silicic acid and precipitates. In addition, it is deposited as amorphous silica (Sio2 ⋅ 𝑛H2o) in intercellular sites and space between the plant cells like phytoliths (Greek: stone of plant) Silicon’s defense mechanisms appear throughout plants parts. In leaves silicon forms epidermal trichomes and hair like structure while in spines it is present as amorphous silica (SiO2) and phytoliths (Tripathi et al., 2014; Hartley and De Gabriel, 2016). There are various channels and methods through which silicon reduces heavy metals in plants and soil.  Silicon detoxification mechanisms can be grouped into chemical or physical mechanisms. Co-precipitation of heavy metals along with silicon comes under Chemical mechanism, while physical mechanisms involves changes in apoplastic barrier which stimulates silicon to reduce the translocation of toxic metals to shoot and different  aerial parts (Gu et al., 2011). Generally, Si mediated toxic metals alleviation process in plants includes (a) stimulation of antioxidant enzyme action to increase ROS scavenging, (b) complexation and immobilization of heavy metal in plants (Liang et al., 2007) (c) accumulation and deposition in plant tissue to enrich the rigidity and stability in leaves, (d) mobilization of water, and (e) providing plant nutrient and co-precipitation of metal toxicity (Savvas and  Ntatsi, 2015)

Silicon detoxification in plants

Mechanism One: Reduction in Heavy Metal uptake in Plants

Silicon can potentially reduce the heavy metal uptake and its transportation in plants. Free metals in plant organs decrease apoplasmic metal uptake and translocation activity. Silicon has been found in the cell walls of plant roots, stems, leaves, and hulls, which increases the durability of plant tissue as a physical barrier. Transportation of metal ions from roots to aerial organs is regulated by silicon accumulation inside the cell wall (Ma and Yamaji, 2006; Ye et al., 2012). In rice plants extension of apoplastic barriers, such as endodermis development under metal stresses, is an important factor to prevent the translocation of cadmium to aerial parts (Pontigo et al., 2017). Most prominent role of silicon can be reported in the cell walls of root, stems, leaves, and hulls, which improve the stability of plant tissue as a physical barrier. In Roots, reduction of toxic metal translocation from roots to shoots achieved by binding of metal ions through decreasing the apoplastic bypass flow. Moreover, a buildup of silicon in the stem, leaf, and hull cell walls restricts cuticle transpiration and strengthens the plant's tolerance to heavy metal stress. In shoots, silicon decreases uptake of cadmium and its translocation. During the silicon precipitation, silica precipitates as phytoliths in the water evaporation sites of plant shoot and simultaneously shifts Mn to the leaf blade that leads to decrease in Mn uptake (Ma J.F. 2004; Rizwaan et al., 2012).

  Mechanism Two: Changes in pH Value in Soil and Plant Culture

The mobility and bioavailability of heavy metals in soil are significantly influenced by pH. Biosolids, a Si compound raises the pH value and improves the absorption of silicon. Further it can lead to an immobilization of cadmium in plants. Amelioration of Al by silicon in soybeans includes soil sodium metasilicate or alkaline pH action, playing an important role in the reduction of metal availability in soil and consequently amelioration of metal toxicity to plants. Additionally, silicon can facilitate the transportation of aluminium from the root to the shoot by causing the formation of hydroxyl aluminium silicate complexes in shoots, which lowers the pH level to below 4.0 and promotes aluminium detoxification (Zhao et al., 2007; Violante et al., 2010; . Caporale and Violante, 2016).

Mechanism Three: Formation of Si-Heavy Metal Complex

Detoxification of heavy metals in plants with Silicon includes solution chemistry mechanism (heavy metals complex formation) and plant mechanism i.e., stimulation of organic acid exudate in plants to chelate metals ions. In first mechanism, silicon creates a complex with heavy metals by making silicates and oxides, unavailability of Si in plants results in complex formation. For example, Al-Si complex decreases the toxicity of Al3+. Similarly in Minuartia verna, Zn silicate precipitated in the leaf epidermis and acts as an essential pathway for Zn detoxification (Wu et al., 2013; Lu et al., 2017). Gunes et al. (2007) revealed that silicon limited translocation of baron from root to shoot in spinach.  In Cardaminopsis sp., during the silicate formation Zn precipitates in to the cytoplasm along with silica. Then Zn-silicate degrades to SiO2 and Zn immediately. After that, Zn is transferred to the vacuole, and in the cytoplasm, SiO2 precipitates. The compartmentation method in plants involves the formation of pinocytotic vesicles by the plasma membrane and tonoplast, which directly transferred Zn from extracellular portions to vacuoles. (Adrees et al., 2015; Tubana and Heckman, 2015).

 

Mechanism Four: Antioxidant Defense Mechanism

Heavy metal toxicity induces an excess formation of reactive oxygen species (ROS), which results in some metabolic disorders in crop plants (Adrees et al., 2015; Ahmad et al., 2019). To overcome these issues Si induced enzymatic and non-enzymatic antioxidant system helps to lower oxidative stress by decreasing the production of ROS. In cucumber, mitigation of Mn toxicity by Si was attributed to a significant drop in lipid peroxidation (LPO) caused by excess Mn. Si also helps in significant increase in enzymatic antioxidants i.e. Superoxide dismutase, glutathione reductase and ascorbate peroxidase as well as non-enzymatic antioxidants such as ascorbate and glutathione (Shi et al., 2005). Similarly, under Cd stress, application of Si reduced the H2O2 and electrolytic leakage (EL) in Solanum nigrum (Liu et al., 2013). Thiobarbituric acid reactive substances (TBARS) is widely used marker for reactive oxygen contents, it has been found that with Si supplementation in rice and maize plants grown under Cd stress condition, TBARS reduced significantly Si-mediated detoxification through stimulating enzymatic and non-enzymatic antioxidants has also been seen under Zn, Pb, Mn and Cu stress (Bhat et al., 2019).

Conclusion

Sustainable agriculture always emphasizes on preserving the soil quality and enhancing the crop yield. It also focuses on the well-functioning of soil ecosystem. However, plants have to face multiple environmental challenges (variety of stresses) everyday which affects its overall physiology, growth and development thereby reducing the yield and productivity. The production of reactive oxygen species, disturbing the plant nutrient homeostasis, affecting photosynthetic processes and other metabolic cycles are the common outcomes of any stress. Heavy metal contamination is becoming one of the important stressor against which the plant should initiate the defensive mechanism. And the application of biostimulants is one such support to enhance the defensive approach to regulate and control the overall processes of growth and development. Biostimulants fight various biotic and abiotic stresses through a combination of an array of mechanisms. Thus, the purpose of this review is to briefly explain the biostimulant, its types and the role of few important biostimulant to ameliorate the toxic effect of heavy metals. This will provide a basis to understand the types of biostimulants and open the area to study their detail mechanism in response to heavy metal toxicity. The overall impact of this review will be to set a scientific frame to identify how the plant biostimulants treatments (substances and/or microorganisms) have the potential to enhance plant resilience to nutrient limitation typical of organic farming, and consequently reducing the gap between organic and conventional yields.

References

Adrees M, Ali S, Rizwan M, Zia-ur-Rehman M, Ibrahim M. et al., Mechanisms of silicon-mediated alleviation of heavy metal toxicity in plants: A review. Ecotoxicol. Environ. Saf. 2015; 119:186–197.

Ahemad M and Kibret M. Mechanisms and applications of plant growth promoting rhizobacteria: Current perspective. J. King Saud Univ. Sci, 2014; 26: 1–20.

Ahmad P, Tripathi DK, Deshmukh R, Singh VP, Corpas FJ. Revisiting the role of ROS and RNS in plants under changing environment. Environ. Exp. Bot. 2019.

Ali H, Khan E and Sajad MA. Phytoremediation of heavy metalsdConcepts and applications. Chemosphere, 2013; 91: 869–88.

Behie SW, Bidochka MJ. Nutrient transfer in plant-fungal symbioses. Trends Plant Sci. 2014;19: 734–740.

Bhat J, Shivaraj, Singh P, Devanna B, Navadagi ,Tripathi D.K, Dash P.K, Amolkumar U, Solanke, Sonah H, Deshmukh R. Role of Silicon in Mitigation of Heavy Metal Stressesin Crop Plants. Plants 2019;8;71; doi:10.3390/plants8030071.

Bonfante P, Genre A.  Interactions in mycorrhizal symbiosis. Nat. Commun. 2010; 1:1–11.

Bosni´c D, Nikoli´c D, Timotijevi´c G. et al., Silicon alleviates copper (Cu) toxicity incucumber by increased Cu-binding capacity. Plant Soil, 2019; 441:629–641.

Caporale AG and Violante A. Chemical processes affecting the mobility of heavy metals and metalloids in soil environments. Current Pollution Reports, 2016; 2(1):15–27.

Colla G, Rouphael Y, Canaguier R. et al, Biostimulant action of a plant-derived protein hydrolysate produced through enzymatic hydrolysis. Front. Plant Sci, 2014; 5:448. doi: 10.3389/fpls.2014.00448

Colla, G,  Rouphael Y. Biostimulants in horticulture. Sci. Hortic. 2015; 196:1–2

Craigie JS. Seaweed extract stimuli in plant science and agriculture. J. Appl.Phycol. 2011; 23: 371–393.

Cristofano F, El-Nakhel C, Rouphael Y. Biostimulant Substances for Sustainable Agriculture: Origin, Operating Mechanisms and Effects on Cucurbits, Leafy Greens, and Nightshade Vegetables Species. Biomolecules, 2021; 11:1103.

Ertani A, Schiavon M, Muscolo A, Nardi S. Alfalfa plant-derivedbiostimulant stimulate short-term growth of salt stressed Zea mays L. plants. Plant Soil, 2013; 364: 145–158.

Ghori, N. -H., Ghori, T., Hayat, M. Q., Imadi, S. R., Gul, A., Altay, V., & Ozturk, M. (2019). Heavy metal stress and responses in plants. International Journal of Environmental Science and Technology16(3), 1807-1828. https://doi.org/10.1007/s13762-019-02215-8

Gozzo F, Faoro F. Systemic acquired resistance (50 Years after discovery):moving from the lab to the field. J. Agric. Food Chem. 2013; 61:12473–12491.

Gu HH,  Qiu H, Tian T, et al., Mitigation effects of silicon rich amendments on heavy metal accumulation in rice (Oryza sativa L.) planted on multi-metal contaminated acidic soil. Chemosphere, 2011; 83(9):1234–1240.

Gunes A, Inal A, Bagci EG, Coban S, Pilbeam BT. Silicon mediates changes to some physiological and enzymatic parameters symptomatic for oxidative stress in spinach (Spinacia oleracea L.) grown under B toxicity. Scientia Horticulturae 2007;113(2): 113-119.

Guo H, Hong C, Xiao M, et al. Real-time kinetics of cadmium transport and transcriptomic analysis in low cadmium accumulator Miscanthus sacchariflorus. Planta. 2016;244(6):1289-1302. doi:10.1007/s00425-016-2578-3.

Hartley SE.  and De Gabriel JL. The ecology of herbivore induced silicon defences in grasses. Functional Ecology. 2016; 30(8):1311–1322.

Hoque MN, Tahjib-Ul-Arif M, Hannan A. et al.,Melatonin Modulates Plant Tolerance to Heavy Metal Stress: Morphological Responses to Molecular Mechanisms.Int. J. Mol. Sci, 2021; 22: 11445.

Horst WJ, Wang Y, Eticha D. The role of the root apoplast in aluminium-induced inhibition of root elongation and in aluminium resistance of plants: A review. Ann Bot, 2010; 106:185–197.

Hu B, Jia X, Hu J, Xu D, Xia F, Li Y. Assessment of Heavy Metal Pollution and Health Risks in the Soil-Plant-Human System in the Yangtze River Delta, China. Int J Environ Res Public Health. 2017;14(9):1042. Published 2017 Sep 10. doi:10.3390/ijerph14091042

Iriti M, Picchi V, Rossoni M. et al. Chitosan antitranspirant activity is due to abscisic acid-dependentstomatal closure. Environ. Exp. Bot. 2009; 66:493–500.

Jägermeyr, J., 2020: Agriculture's historic twin-challenge towards sustainable water use and food supply for all. Front. Sustain. Food Syst.4, 35, doi:10.3389/fsufs.2020.00035.

Jindo K, Canellas LP, Albacete A. et al. Interaction between humic substances and plant hormones for phosphorous acquisition. Agronomy, 2020; 10: 640.

Jindo K, Martim SA, Navarro EC. et al.  Root growth promotion by humic acids from composted and non-composted urban organic wastes. Plant. Soil, 2012; 353: 209–220.

Kaya C, Tuna AL, Sonmez O. et al., Mitigation effects of silicon on maize plants grown at high zinc. J of Plant Nutri, 2009; 32(10):1788–1798.

Khan W, Rayirath UP, Subramanian S. et al, Seaweed extracts as biostimulants of plant growth and development. J. Plant Growth Regul. 2009; 28:386–399.

Liang Y, Sun W, Zhu Y, Christie P. Mechanisms of silicon-mediated alleviation of abiotic stresses in higher plants: a review. Environmental Pollution,2007; 147(2): 422–428.

Liu J, Zhang H, Zhang Y, Chai T. Silicon attenuates cadmium toxicity in Solanum nigrum L. by reducing cadmium uptake and oxidative stress. Plant Physiol. Biochem. 2013; 68: 1–7.

Lu G, Liu J, Wang Y. Bioavailability and mobility of heavy metals in soil in vicinity of a coal mine from Huaibei, China. Human and Ecological Risk Assessment. 2017;23(5), 1164–1177.

Ma JF and Yamaji N. Silicon uptake and accumulation in higher plants. Trends in Plant Sci, 2006;11(8):392–397.

Ma JF and Yamaji N. Silicon uptake and accumulation in higher plants. Trends in Plant Sci, 2006;11(8):392–397.

Pilon-Smits EAH, Quinn CF, Tapken W. et al. Physiological functions of beneficial elements. Curr. Opin. Plant Biol. 2009; 12:267–274.

Pontigo S,Godoy K, Jim´enez H, Guti´errez-Moraga A. et al., Silicon-mediated alleviation of aluminum toxicity by modulation of Al/Si uptake and antioxidant performance in ryegrass plants. Frontiers in Plant Science, vol. 8, article no. 642, 2017.

Qadir S, Jamshieed S, Rasool S, Ashraf S. et al. Modulation of plant growth and metabolism in cadmium-enriched environments. Rev. Environ. Contam. Toxicol, 2014; 229: 51–88.

Rafiee H, Badi HN, Mehrafarin A et al. Application of Plant Biostimulants as New Approach to Improve the Biological Responses of Medicinal Plants- A Critical Review. J. Med. Plants, 2016; 15: 1–39.

Rizwan M, Meunier JD, Miche H, Keller C. Effect of silicon on reducing cadmium toxicity in durum wheat (Triticum  turgidum L. cv. Claudio W.) grown in a soil with aged contamination. Journal of Hazardous Materials, 2012; 209-210.

Rouphael Y and Colla G. Toward a Sustainable Agriculture Through Plant Biostimulants: From Experimental Data to Practical Applications. Agronomy, 2020; 10: 1461.

Santiago L.H., Leon E.N., Lopez-Moreno F.J., Arjo G., Gonzalez L.M., Ruiz J.M., Blasco B. The application of th silicon-based biostimulant Codasil® offset water deficit of lettuce plants. Scientia Horticulturae 2021;285, https://doi.org/10.1016/j.scienta.2021.110177 .

Savvas D and Ntatsi G. Biostimulant activity of silicon in horticulture. Scientia Horticulturae, 2015;196: 66–81.

Seiber JN, Coats J, Duke SO. et al. Biopesticides: state of the art and future opportunities. J. Agric. Food Chem. 2014; 62:11613–11619.

Shahid M, Khalid S, Abbas G, Shahid N, Nadeem M, Sabir M, Aslam M, Dumat C (2015) Heavy metal stress and crop productivity. In: Hakeem K et al (eds) Crop production and global environmental issues. Springer, Cham.

Sharma SS, Dietz KJ . The significance of amino acids and amino acid-derived molecules in plant responses and adaptation to heavy metal stress. J Exp Bot , 2006; 57:711–726.

Shi Q, Bao Z, Zhu Z, He Y, Qian Q, Yu J. Silicon-mediated alleviation of Mn toxicity in Cucumis sativus in relation to activities of superoxide dismutase and ascorbate peroxidase. Phytochemistry 2005;66:1551–1559.

Singh S, Kumar V, Dhanjal DS. et al. Endophytic microbes in abiotic stress management In: Microbial endophytes: Prospects for sustainable agriculture, 2020; 91-123.

Sytar O, Kumar A, Latowski D. et al, Heavy metal-induced oxidative damage, defense reactions, and detoxification mechanisms in plants. Acta Physiol Plant, 2013;35:985–999.

Tripathi D K, Singh V P, Gangwar S, Prasad S M. et al, Role of silicon in enrichment of plant nutrients and protection from biotic and abiotic stresses. Improvement of Crops in the Era of Climatic Changes, 2014 pp. 39–56, Springer.

Tubana BT and Heckman JR. Silicon and Plant Diseases, 2015 Eds., Springer International Publishing, Switzerland.

Violante A, Cozzolino V, Perelomov L, Caporale AG, Pigna M. Mobility and bioavailability of heavy metals and metalloids in soil environments. Soil Science & Plant Nutrition, 2010; 10(3): 268–292.

Wu JW, Shi Y, Zhu XY, Wang YC, Gong HC. Mechanisms of enhanced heavy metal tolerance in plants by silicon: a review. Pedosphere 2013; 23(6):815–825.

Ye J, Yan C, Liu J, Lu H, Liu T, Song Z. Effects of silicon on the distribution of cadmium compartmentation in root               tips of Kandelia obovata (L.). Environmental Pollution, 2012;162:369–373.

Zhao XL and Masaihiko S. Amelioration of cadmium polluted paddy soils by porous hydrated calcium silicate. Water, Air, & Soil Pollution. 2007; 183(1-4): 309–315.

Ziosi V, Zandoli R, Di Nardo A. Biological activity of different botanical extracts as evaluated by means of an array of in vitro and in vivo bioassays. Acta Hortic. 2012; 1009: 61–66.

 

 

 



Related Images:

Recomonded Articles:

Author(s): Rasleen Kaur; S. Keshavkant

DOI: 10.52228/NBW-JAAB.2021-3-2-1         Access: Open Access Read More

Author(s): Tikendra Kumar Verma; K. L. Tiwari; S. K. Jadhav

DOI: 10.52228/NBW-JAAB.2019-1-1-4         Access: Open Access Read More

Author(s): Jipsi Chandra; Apurva Mishra; S. Keshavkant

DOI: 10.52228/NBW-JAAB.2020-2-2-2         Access: Open Access Read More

Author(s): Tikendra Kumar Verma*; Vijeyata Verma; S.K. Jadhav

DOI: 10.52228/NBW-JAAB.2020-2-1-6         Access: Open Access Read More