Phytoremediation potential of oilseed crops for lead- and nickel-contaminated soil

Abstract

Production of crops has been facing many environmental stresses from the past few decades, hence reducing the productivity and nutrient enrichment of crops worldwide. Climatic changes and environmental stress have led to interpret the stress on plants and the purpose of its low productivity. Today the most impor-tant type of crops are the oilseed crops. Oilseed crops are mostly grown for the oil contained in the seed. The oil content in grains like wheat is only 1-2% as compared to the oilseed crops which contain primarily 20-40% of oil. Major types of oilseed crops include sunflower, brassica, olive plant, soybean, safflower and rapeseed. Due to the environmental stress like shortage of rainfall, providing wastewater for irrigation purpose, dumping of solid waste on crop lands and excessive use of fertilizers lead to the contamination of oilseed crops by mainly lead and nickel which are the heavy metals. In order to treat the crops contaminated by heavy metals, a modern, efficient, novel and environment-friendly technology is introduced named as phytoremediation. Phytoremediation is the technique in which different plants are used in order to extract the heavy metals from their roots and aerial parts. Usually the green plants have more ability to remove the pollutants from the plant and can achieve decontamination by various mechanisms. Plants usually extract the heavy metals though phytoextraction, phytofiltration, phytovolatilization, phytodegradation and phytostabilization processes. There are some chemicals which assist the phytoremediation process. These hormones are present within the plants and are mostly present in the root’s rips and in the shoots. These organic chemicals not only assist the phytoremediation mechanism but also increase the growth and nutrient rate of oilseed crops. The heavy metals like nickel and lead affect the oilseed crops in any way such as decreasing the growth of plant and disturbing its natural processes like photosynthesis. Effective uptake of lead and nickel in oilseed plants is beneficial and acts as a good hyper-accumulator while excessive uptake harms the crops in various ways. Rotation of crops is another effective method in food crops in order to decrease the accumulation of heavy metals in crops and in food chain.