Plants are very essential, as they provide numerous goods and services to the human beings. They provide us oxygen, without which living organisms wouldn’t be able to survive. As it is required for the breaking down of food(glucose), the process called respiration. It also helps in decomposition of the organic wastes. The organic wastes from dead plants and animals would be a huge problem, if the consortium of microbes are not at work to decompose it. So all thanks to plants for providing us oxygen for respiration and decomposition. Plants are taking up carbon dioxide from the atmosphere and converting it into carbohydrates (Food), the process called photosynthesis. The carbon dioxide is the leading contributor to global climate change. The planting more and more plants would result in capturing of more and more carbon dioxide from the atmosphere. Which will help us in combating the gobal climate change, which has become biggest threat to mankind. More the carbon dioxide is immobilised in different forms, better it would be. As it the carbon dioxide present, along with other green house gases, which are warming the earth. Many plants have got ability to clean up the soil and water from hazardous wastes by the process of phytoremediation. Phytoremediation is the process by which plants stabilise, remediate and reduce or restore contaminated soil, sediment and surface or ground waters. Phytoremediation relies on the plant’s ability to act as solar driven pumping and filtering system. Some plants have got the ability to uptake, tolerate and even hyperaccumulate heavy metals and other toxic substances from soil and water through their roots and concentrate them in roots, stems and leaves. These include some aquatic weeds such as species of Salvinia, Lemna, Azolla and Eichornia, sedges like Typhia latifolia and some herbaceous as well as woody flowering plants. These plants can then be harvested and the metals and other substances could be extracted from them. These plants would be containing higher concentration of the substance and hence would be called bio-ores. So Phytoremediation would clean up the soil, water and sediments from the pollutants and the hyperaccumulation of these substances would make it possible extract these substances from the plants economically. Which wouldn’t be economically feasible by traditional methods due to low concentrations. The phytoremediation is in its infancy, but has the potential to serve as cost effective, sustained and ecologically sound method to remediate the contaminated soil and water. Plants release some factors into the soil which helps micro-organisms to augment the process of degradation of pollutants. The cometabolism occurs in the rhizosphere of the soil, where in the plants release nutrients which speed up the process of biodegradation by the consortium of microbial communities.
Phytoremediation has been divided into six major types: I) Enhanced rhizosphere degradation: the degradation of the contaminants by plant rhizosphere microorganisms. II) Phytodegradation: Degradation of the contaminants by the release of some factors by the plants. III) Phytoextraction: The metals and radionuclides are taken up from the soil and water by the roots of the plants and accumulated into their harvestable parts. Which are later harvested to obtain these metals and radionuclides. IV) Rhizofiltration: Plants precipitate the metals and other radionuclides from aqueous solutions. Hence immobilizing them. V) Phytovolatilisation: The toxic substances are transformed into volatile compounds and are released into the atmosphere. VI) Phytostabilisation: The plants stabilise the metal contaminated soil and prevents its movement. Plants act as dust collectors, as they collect large amount of dust from the air. The plants also absorb many poisonous gases from the atmosphere. Hence keeping the air clean for breathing which prevents different respiratory diseases? the stomata present on the leaves take in large amount of gaseous pollutants. The plants thus have become an important sink for the pollutants.
(The author is a teacher by profession. Views are his own)