TOLERANCE OF PLANTS TO HIGH CONCENTRATIONS OF METALS IN THE SOIL IN ORDER TO ENSURE THE ECOLOGICAL STABILITY OF A PARTICULAR ECOSYSTEM
Keywords:
Tolerance, soil, plants, ecosystemAbstract
Heavy metals in the soil are often found in inaccessible form. By constantly growing plants on contaminated soil, it is possible to translate them from inaccessible to accessible forms and thus reduce the content of hard-to-reach metals. Specific plant communities, endemic species and endemic flora that grow and survive on contaminated soil with heavy metals are the result of many ecological studies. The survival of a certain plant species, on such land, enables the ability to adapt and adapt to specific environmental conditions. Heavy metal tolerance mechanisms allow plants to evolve. This system, in some plants, prevents the entry of toxic metals into root cells. While, in other plants, the process is the opposite. The flow of metals from the roots to the plant is not prevented. These types of plants, called accumulators, have developed special mechanisms for detoxifying high levels of accumulated metals in root cells. Also, bioaccumulation of extremely high concentrations of metals is possible. Indicators are called the third group of plants. These types of plants show increased accumulation of metals in the soil. By growing appropriate types of plants, it is possible to reduce the content of harmful effects of heavy metals in the soil, which is a very economical method with positive results. The movement of metals through intercellular membranes is conditioned by proteins, which perform this transport function. The metal uptake mechanism is selective. Plants absorb some ions more than others, while for some they do not have a developed ability to absorb. The selectivity of ion uptake depends on the structure and properties of the membrane as a transporter. These characteristics are responsible for the recognition, binding and transfer of certain ions. There are two ways to absorb heavy metals through plants. The first way is the adoption from the soil through the roots and transport to the aboveground parts of plants (tree and leaf). Another way is to adopt them through the leaves and transport them through the roots into the soil. With the growth of plants, the content of heavy metals gradually increases in plant organs. When the amount of bioavailable heavy metals cannot be accumulated by plants, there will be no increase in plant content. In addition to the ability of plants to adapt to specific environmental conditions, an important factor is the composition and structure of the soil. From these factors can be distinguished: pH value and content of organic matter in the soil. The pH value of the soil can affect the bioavailability of the metal and the very process of metal uptake through the roots. The dynamics of microelements and heavy metals in the soil is greatly influenced by organic matter itself. Special attention is paid to finding plant species that would accumulate certain heavy metals and thus remove them from the soil. The biomass of these plants is not used for food, but is dried, burned and deposited in designated places
References
Alagić, S.Č., Šerbula S.S., Tošić S.B., Pavlović A.N., & Petrović J.V. (2013). Bioaccumulation of Arsenic and Cadmium in Birch and Lime from the Bor Region, Arch Environ Contam Toxicol 65 (4), 671-682.
Antonijević, M.M., Dimitrijević, M.D., Milić, S.M., & Nujkić, M.M. (2012). Metal concentrations in the soils and native plants surrounding the old flotation tailings pond of the Copper Mining and Smelting Complex Bor (Serbia). Journal of Environmental Monitoring 14 (3), 866-877.
Bhargava, A., Carmona, F.F., Bhargava, M., & Srivastava, S. (2012). Approaches for enhanced phytoextraction of heavy metals, Review. J Environ Manage, 105:103-20.
Clemens, S., Palmgren, M.G., & Krämer, U. (2002). A long way ahead: understanding and engineering plant metal accumulation. Trends Plant Science. 7 (7): 309-315.
Cobbett, C. S. (2000). Phytochelatins and their roles in heavy metal detoxification. Plant Physiology. 123: 825–832.
Đukić, M. (2006). Fiziologija biljaka. Šumarski fakultet, Beograd.
Gonnelli, C., & Renella, G. (2012). Chromium and Nickel. In Alloway BJ (ed) Heavy Metals in Soils. Trace Metals and Metalloids in Soils and their Bioavailability. Environmental Pollution (22). Third Edition, Springer Dordrecht Heidelberg New York London, pp. 313-334.
Luka, Y., Highina, B.K., & Zubairu, A. (2018). Bioremediation: A Solution to Environmental Pollution-A Review” American Journal of Engineering Research (AJER), 7 (2), 101-109.
Mench, M., & Martin, E. (1991). Mobilization of cadmium and other metals from two soils by root exudates of Zea mays L., Nicotiana tabacum L. And Nicotiana rustica L. Plant and Soil. 132: 187–196.
Nešković, M., Konjević, R., & Ćulafić, L. (2003). Fiziologija biljaka. NNN International. Beograd.
Sarker, S. C., Ghosh, S. R., Hossain, M., Ghosh, R. C., Razia, S., Sushmoy, D. R., & Noor, M. M. (2019). Impact of aluminium (Al3+) stress on germination and seedling growth of five wheat genotypes. SAARC Journal of Agriculture, 17(1), 65-76. doi:https://doi.org/10.3329/sja.v17i1.42762
Sharma, I. (2020). Bioremediation Techniques for Polluted Environment: Concept, Advantages, Limitations, and Prospects. Trace Metals in the Environment – New Approaches and Recent Advances.
Sharma, P., & Dubey S.R. (2005). Lead toxicity in plants. Braz. J. Plant Physiol. vol.17 (1): 35-39.
Stikić, R., & Jovanović, Z. (2012). Fiziologija stresa biljaka. Poljoprivredni fakultet, Univerzitet u Beogradu, Beograd.
Veneklaas, E.J., Stevens, J., Cawthray, G.R., Turner, S., Grigg, A.M., & Lambers, H. (2003). Chickpea and white lupin rhizosphere carboxylates vary with soil properties and enhance phosphorus uptake. Plant and Soil 248: 187–197.
Verma, S., & Kuila, A. (2019). Bioremediation of heavy metals by microbial process. Journal Environmental Technology & Innovation, ISSN:2352-1864, Vol.14, Extent 100369.
Zhang, H., Yuan, X., Xiong, T., Wang, H., & Jiang, L. (2020). Bioremediation of cocontaminated soil with heavy metals and pesticides: Influence factors, mechanisms and evaluation methods. Chemical Engineering Journal, 398, 125- 657.