Tuesday, November 28, 2017 by Tracey Watson
Imagine there was a plant that could miraculously mop up dangerous heavy metals from contaminated soil. In an amazing display of incredible design, nature has given us just such a plant. In fact, scientists have identified not just one, but 721 different species of hyperaccumulators – plants that can absorb far greater amounts of heavy metal compounds in their leaves and stems than other plants.
A study documenting the amazing variety of hyperaccumulators was recently published in the journal New Phytologist.
Science Daily has reported that hyperaccumulators are so useful in the fight against heavy metal contamination that researchers have published a database that catalogs each of these amazing plants. The Global Hyperaccumulator Database can be found at Hyperaccumulators.SMI.UQ.edu.au.
Sadly, these precious plants are in danger of disappearing if they are not urgently cataloged and preserved.
“By virtue of their existence on metalliferous soils, hyperaccumulator plants are actively threatened by mining, and timely identification is necessary to take advantage of their unique properties,” said the study’s senior author, Dr. Antony van der Ent, of The University of Queensland.
Hyperaccumulators have the amazing ability to both tolerate and accumulate exceptionally high concentrations of heavy metals. As such, researchers are extremely interested in examining their potential use in:
Phytoremediation – The use of living green plants to remove or degrade contaminants in surface and groundwater, as well as in soil, sludge and sediment;
Phytomining – Using plants to absorb metals, particularly copper, through their roots. The plants can then be burned, and copper compounds extracted from the ash; and
Food crop biofortification – Increasing the nutrient value (including micronutrients, vitamins and minerals) of staple crops during the plant growth process.
A study published in the journal Plant Science in 2011, describes the three key things that differentiate hyperaccumulators from other plants:
Three basic hallmarks distinguish hyperaccumulators from related non-hyperaccumulating taxa: a strongly enhanced rate of heavy metal uptake, a faster root-to-shoot translocation and a greater ability to detoxify and sequester heavy metals in leaves.
You might be wondering what causes heavy metals to accumulate in soil in the first place. The Saudi Journal of Biological Sciences explains:
Soils irrigated by wastewater accumulate heavy metals, such as Cr, Zn, Pb, Cd and Ni, in the surface soil. When the capacity of the soil to retain heavy metals is reduced due to the repeated application of wastewater, heavy metals leach into the ground water or the soil solution, which are available for plant uptake. (Related: Oregon glass plant putting toxic heavy metals into soil, groundwater.)
Unfortunately, as healthy as they are, even vegetables can pose a risk in this regard. Heavy metals are readily taken up by the roots of certain veggies and can accumulate at high levels in the edible parts of the plant, even when planted in soil with relatively low heavy metal levels. (Related: Discover the myriad benefits of fresh fruit and vegetables at Fresh.news)
If you are an avid gardener who is serious about protecting their family’s health, therefore, it might be worth investing in some hyperaccumulator plants for your veggie patch.