Sodium chloride decreases cadmium accumulation and changes the response of metabolites to cadmium stress in the halophyte Carpobrotus rossii

Abstract

Our data provide the first evidence that NaCl decreased Cd shoot accumulation in C. rossii by decreasing Cd root uptake and root-to-shoot translocation even under constant Cd2+ activity. The present study also supports the important role of peptides and organic acids, particular of phytochelatins, in Cd tolerance and accumulation although the changes of those metabolites was not the main reason for the decreased Cd accumulation.

Use of Halophytes for the Remediation of Metal-Affected Soils in Arid Environments

“…The role of organic acids in metal chelation was also described in S. alterniflora in response to Cu (Chai et al 2014) and other halophytes, such as Atriplex halimus in response to Zn (Lutts et al 2004). A study performed by Cheng et al (2018) in the psammophyte Carpobrotus rossii treated with increasing Cd and NaCl revealed high root and leaf accumulation of Cd. Similar to the results of Min-Wei Chai (2012), metal accumulation was positively related to the synthesis of different organic compounds on each organ: in roots, it was related to amino acids and other organic acids, but in leaves it was related to a subgroup of amino and organic acids, along with phytochelatins, a peptide that has been widely described as a metal chelator (Cheng et al 2018).…”

“…A study performed by Cheng et al (2018) in the psammophyte Carpobrotus rossii treated with increasing Cd and NaCl revealed high root and leaf accumulation of Cd. Similar to the results of Min-Wei Chai (2012), metal accumulation was positively related to the synthesis of different organic compounds on each organ: in roots, it was related to amino acids and other organic acids, but in leaves it was related to a subgroup of amino and organic acids, along with phytochelatins, a peptide that has been widely described as a metal chelator (Cheng et al 2018). A possible effect of phytochelatins on metal accumulation was also described by Orrego et al (2020) on seedlings of Atriplex halimus and A. atacamensis subjected to increasing Cu concentration.…”

Salinity decreases Cd translocation by altering Cd speciation in the halophytic Cd-accumulatorCarpobrotus rossii

“…Plants of Carpobrotus rossii were grown in a controlled glasshouse with a 14-h photoperiod at 18-25 °C and 45-65 % relative humidity in Victoria, Australia (Cheng et al, 2018). Uniform cuttings (two nodes each cutting) were cut from mother plants and washed with tap water.…”

“…A 14-h photoperiod with a light intensity of 400 µmol m −2 s −1 was supplied. The solutions were maintained at pH ~6.0 with 1 m KOH and were renewed every 6 d. After rooting and acclimation for 2 weeks, rooted cuttings of similar size were weighed and transferred to new pots (four cuttings per pot) containing the treatment solutions described for Experiments 1 and 2 (Cheng et al, 2018). Four additional cuttings were washed with deionized water, ovendried (80 °C), and weighed to determine their initial weight.…”

“…Carpobrotus rossii, a halophytic succulent plant species, has been shown to have potential for phytoextraction of Cd in soils with high salinity (Zhang et al, 2016). Our previous study has shown that the addition of NaCl to Cd-containing solutions significantly reduced Cd accumulation in shoot tissues, particularly by decreasing Cd translocation from the root to the shoot even when the activity of Cd 2+ in nutrient solution was maintained constant (Cheng et al, 2018). These observations for C. rossii differ from those reported previously for Arabidopsis thaliana, Solanum nigrum and Beta vulgaris, where NaCl increased Cd concentrations in both shoots and roots (Smolders and McLaughlin, 1996;Xu et al, 2010).…”