Why are heavy metal hyperaccumulating plants so amazing?

Fahad

Rehman

et al. 2020

PeerJ

Kenaf (Hibiscus cannabinus L.) is a fibrous crop, grown in tropical climate having huge biomass and can be a good candidate for the phytoremediation of different heavy metals. Consequently, the present study was conducted to explore morpho-physiological traits, photosynthetic pigments, gaseous exchange attributes, antioxidative response and phytoextraction of copper (Cu) in H. cannabinus grown under different levels of Cu i.e. 0 (control), 60, 120 and 180 µmol L−1 in Hoagland nutrient solution (pH 6.2). The results from the present study revealed that Cu toxicity reduced plant height, plant diameter, plant fresh weight, plant dry weight, photosynthetic pigments and gaseous exchange attributes compared to control. Moreover, excess Cu in the nutrient solution ameliorates contents of malondialdehyde (MDA), hydrogen peroxide (H2O2) and electrolyte leakage (EL) which showed that Cu induced oxidative damage in the roots and leaves of H. cannabinus. The oxidative stress which was induced by a high concentration of Cu in the nutrient solution is overcome by enzymatic activities of antioxidants which increased with the increase in Cu concentration, i.e. 60 and 120 µmol L−1, while the addition of Cu (180 µmol L−1) caused a reduction in the activities of superoxidase dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX) in the roots and leaves of H. cannabinus. The results also demonstrated that an increase in Cu concentration in the nutrient solution causes an increase in Cu accumulation through roots, leaves and stems of H. cannabinus, although the highest Cu concentration was accumulated in roots while only a little transported to the above ground parts (leaves and stems) of the plants. All the values of bioaccumulation factor (BAF) and translocation factor (TF) were less than 1, which also indicated that a small quantity of Cu concentration is transported to the aboveground part of the plants. These findings suggested that phytotoxicity of Cu affected plant growth and biomass and increased ROS production while accumulation of Cu in different parts of plant proved that H. cannabinus is an ideal specie for phytoremediation of Cu when grown under Cu contaminated sites.

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Morpho-physiological traits, biochemical response and phytoextraction potential of short-term copper stress on kenaf (Hibiscus cannabinus L.) seedlings

Fahad

Rehman

et al. 2020

PeerJ

“…Based on tolerance mechanisms, plant species can been divided into two types: (1) Metal excluders accumulate heavy metals from the substrate in their roots, but restrict their transport and entry into their aerial parts; (2). Hyperaccumulators are able to accumulate large amounts of metals in their above-ground parts rather than in belowground parts [55]. Furthermore, bioaccumulation factor (BAF) and translocation factor (TF) are important in screening hyperaccumulators for phytoremediation of heavy metals.…”

Section: Discussionmentioning

confidence: 99%

Assessing the Correlations between Different Traits in Copper-Sensitive and Copper-Resistant Varieties of Jute (Corchorus capsularis L.)

Ali

Seleiman

et al. 2019

Plants

The current study was conducted to explore the potential for phytoremediation in different varieties of jute grown under toxic concentrations of copper (Cu). For this purpose, a Petri dish experiment was conducted under controlled conditions using four varieties of jute, i.e., HongTieGuXuan, C-3, GuBaChangaJia, and ShangHuoMa, grown in double filter paper under 50 µmol L−1 of artificially spiked copper (Cu) using CuSO4.H2O. The results of the present study revealed that jute varieties C-3 and HongTieGuXuan were able to survive under high concentrations of Cu without a significant decrease in plant height, plant fresh and dry weights, total chlorophyll content, or seed germination, while varieties GuBaChangaJia and ShangHuoMa exhibited a significant reduction in their growth and biomass. Furthermore, high concentrations of Cu in the medium resulted in lipid peroxidation. This could be due to the oxidative damage induced in the roots and leaves of the jute varieties, which might be a result of by hydrogen peroxide (H2O2) and electrolyte leakage. Reactive oxygen species (ROS) generated due to Cu toxicity can be overcome by the increasing activity of antioxidants, and it was also noted that GuBaChangaJia and ShangHuoMa exhibited high Cu stress, while C-3 and HongTieGuXuan showed some resistance to Cu toxicity. Contrastingly, Cu accumulation and uptake was higher in C-3 and HongTieGuXuan, while a little Cu was accumulated in the roots and leaves of GuBaChangaJia and ShangHuoMa. On the basis of these findings, it can be suggested that C-3 and HongTieGuXuan have the potential to cope with Cu stress and can be considered Cu-resistant varieties, while GuBaChangaJia and ShangHuoMa are considered Cu-sensitive varieties. Moreover, C-3 and HongTieGuXuan have the potential to revoke large amounts of Cu, and can be cultivated as phytoremediation tools in Cu-contaminated soil.

“…This method is also used for the reduction of the metal content of soil, the assembly of very large amounts of toxic metal contents through repeating harvesting, and the cycling of planting of the plant species [29,30]. The phytoremediation mechanism is species-specific, which is mostly built upon some anatomical and morphological as well as physiological characteristics of the plants [4,26,[31][32][33][34][35]. Phytoremediation is a technology which is widely applicable for metal contaminated areas, with some long-term aesthetic merits and it is famous due to its low cost and eco-friendly nature, so it is used on large scale areas with high contents of heavy metals due to some industry or mining activities.…”

Section: Introductionmentioning

confidence: 99%

“…This method depends on the abnormal capability of some plant species in accumulating heavy metals, and heavy metal tolerance is essential for plants used in phytoremediation methods. It is very important to select a plant species with a large biomass and great ability to accumulate heavy metals from the soil [31]. It is well known that heavy metals such as Cd, Ni, Zn, As, Se, and Cu are readily bioavailable for plants while Co, Mn, and Fe are moderately available, and Pb, Cr, and U are not easily available for plants.…”

Section: Introductionmentioning

confidence: 99%

Flax (Linum usitatissimum L.): A Potential Candidate for Phytoremediation? Biological and Economical Points of View

Ali

Hussain

et al. 2020

Plants

123

Flax (Linum usitatissimum L.) is an important oil seed crop that is mostly cultivated in temperate climates. In addition to many commercial applications, flax is also used as a fibrous species or for livestock feed (animal fodder). For the last 40 years, flax has been used as a phytoremediation tool for the remediation of different heavy metals, particularly for phytoextraction when cultivated on metal contaminated soils. Among different fibrous crops (hemp, jute, ramie, and kenaf), flax represents the most economically important species and the majority of studies on metal contaminated soil for the phytoextraction of heavy metals have been conducted using flax. Therefore, a comprehensive review is needed for a better understanding of the phytoremediation potential of flax when grown in metal contaminated soil. This review describes the existing studies related to the phytoremediation potential of flax in different mediums such as soil and water. After phytoremediation, flax has the potential to be used for additional purposes such as linseed oil, fiber, and important livestock feed. This review also describes the phytoremediation potential of flax when grown in metal contaminated soil. Furthermore, techniques and methods to increase plant growth and biomass are also discussed in this work. However, future research is needed for a better understanding of the physiology, biochemistry, anatomy, and molecular biology of flax for increasing its pollutant removal efficiency.