Can Clethra barbinervis Distinguish Nickel and Cobalt in Uptake and Translocation?

Abstract

Clethra barbinervis Sieb. et Zucc. accumulates Nickel (Ni) and Cobalt (Co) at high concentrations., We hypothesized that C. barbinervis cannot distinguish between Ni and Co because of the similar chemical properties of these two elements. To confirm this hypothesis and understand the role of these elements in C. barbinervis, we conducted a hydroponic split-root experiment using Ni and Co solutions. We found that the bioconcentration factor (BCF; metal concentration of each tissue/metal concentrations of each treatment solution) of Ni and Co did not significantly differ in the roots, but the BCF for Co was higher than that for Ni in the leaves. The leaves of C. barbinervis accumulated Ni or Co at high concentrations. We also found the simultaneous accumulation of Ni and Co by the multiple heavy metal treatments (Ni and Co) at high concentrations similar to those for the single treatments (Ni or Co). Elevated sulfur concentrations occurred in the roots and leaves of Co-treated seedlings but not in Ni. This result indicates that S was related to Co accumulation in the leaves. These results suggest that C. barbinervis distinguishes between Ni and Co during transport and accumulation in the leaves but not during root uptake.

Phytoremediation of Heavy Metals Spiked Soil by Polyscias fruticose

“…It was observed that Ni and Co interacts regularly and acts against each other in the plant 15 . Another opposite interaction between Co and Ni was recorded from Alyssum bertolonii and Berkheya coddii and this opposite relationship between Co and Ni may lead to great competition in their translocation, binding ligands and also their function 14 . The endurance and accumulation mechanism of Co are not sufficiently understood which could be due to some Co accumulator plants use to uptake and accumulate Cu 14,16 .…”

“…Another opposite interaction between Co and Ni was recorded from Alyssum bertolonii and Berkheya coddii and this opposite relationship between Co and Ni may lead to great competition in their translocation, binding ligands and also their function 14 . The endurance and accumulation mechanism of Co are not sufficiently understood which could be due to some Co accumulator plants use to uptake and accumulate Cu 14,16 . It was reported that a common criteria used to identify a metal hyper-accumulator plant followed the concentration of metal in dried leaf of a plant that grow in a natural way.…”

“…Accordingly, concentration of Co was found in the tissues of Luff cylindrica planted on two different soil samples (i) and (ii) with values 0.414 and 0.597 mg/ kg, respectively 13 . Clethra barbinervis was found to accumulate quiet a number of heavy metals such as Mn, Co, Zn, Ni and Cd but accumulated more Co and Ni in the leaf 14 . It was observed that Ni and Co interacts regularly and acts against each other in the plant 15 .…”

Regulation of Plant Mineral Nutrition: Transport, Sensing and Signaling

“…In the regulation of ion transport in plants, a very important question remains to be unanswered: can a plant distinguish different metals at the uptake or transport steps? The response seems to be affirmative for some transport steps based on an example investigated by Yamaguchi et al (2015) [ 5 ], in which the authors studied two metals, namely nickel (Ni) and cobalt (Co), that have similar chemical properties and are accumulated at high concentration in Clethra barbinervis . By performing a series of physiological experiments, including a hydroponic split-root experiment using Ni and Co solutions, Yamaguchi et al (2015) [ 5 ] suggested that C .…”

“…The response seems to be affirmative for some transport steps based on an example investigated by Yamaguchi et al (2015) [ 5 ], in which the authors studied two metals, namely nickel (Ni) and cobalt (Co), that have similar chemical properties and are accumulated at high concentration in Clethra barbinervis . By performing a series of physiological experiments, including a hydroponic split-root experiment using Ni and Co solutions, Yamaguchi et al (2015) [ 5 ] suggested that C . barbinervis was able to distinguish Ni and Co during transport and accumulation in the leaves, but not during their uptake through the root system.…”