Sara Ramírez-Acosta

Salicornia species are halophyte plants that are an important source for food, pharmacy, and bioenergy. They can be consumed as a leafy vegetable, but they can accumulate heavy metals that carry a health risk when knowledge of how each species behaves in different types of soil is lacking. This present work aimed to determine to what extent S. ramosissima can be cultivated as food in estuaries contaminated by heavy metals and to what extent it can be used in phytoremediation works, by studying its behavior in populations that grow naturally in contaminated soils. We analyzed accumulation and translocation in different parts of the plant for 14 heavy metals and calculated the Health Risk Index value associated with their consumption as a leafy vegetable. The results obtained mean that the S. ramosissima plants that grow in most of the soils of this estuary are unfit for human consumption in some of the populations studied. In conclusion, Salicornia ramosissima J. Woods can accumulate Cd, As, and Pb—among other metals—in its leaves so its consumption should be limited to plants that grow in soils free of these metals.

The influence of different concentrations of heavy metals (Cu, Mn, Ni, Zn) was analyzed in the Salsola vermiculata germination pattern, seedling development, and accumulation in seedlings. The responses to different metals were dissimilar. Germination was only significantly reduced at Cu and Zn 4000 μM but Zn induced radicle growth at lower concentrations. Without damage, the species acted as a good accumulator and tolerant for Mn, Ni, and Cu. In seedlings, accumulation increased following two patterns: Mn and Ni, induced an arithmetic increase in content in tissue, to the point where the content reached a maximum; with Cu and Ni, the pattern was linear, in which the accumulation in tissue was directly related to the metal concentration in the medium. Compared to other Chenopodiaceae halophyte species, S. vermiculata seems to be more tolerant of metals and is proposed for the phytoremediation of soils contaminated by heavy metals.

The biological systems are exposed to a complex environment in which the contaminants can interact in a synergistic/antagonistic fashion and for this reason, the study of “chemical cocktails” is of great interest to fully understand the final biological effect. To evaluate the final biological response of a pollutant, it is essential to have an adequate analytical methodology that allows the correct monitoring of environmental systems in order to establish their quality, and, when appropriate, the application of corrective measures. Undoubtedly, massive methods “the omics” are among the most efficient current tools. To this end, transcriptomics, proteomics, metabolomics and chemical speciation can provide very useful information, mainly when they are combined. However, the combination of proteomics with metabolomics has some drawbacks as the temporal space is different (i.e. metabolomics gives information about what happens right now, but it can be related with numerous post-translational modifications happened previously). In this sense, it seems that the combination of genomics with metabolomics is easier. Thus, when metabolomics data are interpreted in combination with genomic, transcriptomic and proteomic results, in the so-called systems biology approach, a holistic knowledge of the organism/process under investigation can be achieved.