Information on localization of Al and As in Tamarix gallica is required in order to better understand the detoxification mechanisms that confer tolerance in this halophyte plant species. Plants were subjected to different Al and As concentrations with and without salt supplementation. High concentrations of As and Al have been found in Tamarix gallica leaves and roots without symptoms of toxicity to the plant, which may be related to the particular compartmentation. A sequential extraction was carried out on leaves and roots to determine and to compare the metal compartmentation in the plant. In this study, subcellular localization of As and Al was determined for the first time in roots and leaves of T. gallica, and provided evidence of the detoxification mechanisms of high As and Al concentrations. These results suggest that the subcellular distribution of As and Al play important roles in avoidance of metal toxicity. The most part of Al (that has high toxicity to the plant when available forms are present) was immobilized in cell wall, potentially suppressing its transportation to other subcellular compartments more susceptible to Al toxicity. On the other hand, the greater sequestration of As in the vacuole reduces its toxicity to the remaining cell organelles in the roots, but cell wall confinement remains an important tolerant mechanism in the leaves.
The lack of knowledge of plant tolerance and differential response to aluminum (Al) encouraged many researchers, in the last decade, to elucidate Al toxicity and tolerance mechanisms. The current study reported the impact of Al, a toxic element with negative effects on plant growth and development, in halophytic plant Tamarix gallica. Plants were subjected to different Al concentrations (0, 200, 500 and 800 µM) with or without NaCl (200 mM) supplementation. Growth, photosynthesis and mineral content were assessed. Al stress had a significant decrease on shoots' biomass production between 19 to 41%, and a little variation on chlorophyll content and photosynthetic efficiency (Fo, Fm, Fv fluorescence's and Fv/Fm). Furthermore, the Al-treatments did not affect significantly the content of potassium, calcium, and magnesium in different plant parts, whereas NaCl addition to the medium induced a decrease in these elements' concentrations. Our results have shown that T. gallica is able to accumulate the high levels of Al in shoots and roots, 6288 µg.g-1 DW and 7834 µg.g-1 DW respectively. It is considered as a hyperaccumulator plant of Al. In addition, Na + contents in shoots and roots exceed 23000 µg.g-1 DW. Therefore, T. gallica presents a high tolerance at the same time to Al and NaCl phytotoxicity, so it is interesting to use in phytoremediation programs.
Toxic compounds in the ecosphere are the consequence of environmental pollution, and have a disruptive influence in the environment. They affect ecosystems, entering food chains and ultimately touching human health. Metal consumption has increased by 300% in the last 50 years and the anthropogenic release of metallic elements such as Pb, Hg, As, Cd, Al and Cr has increased since the beginning of the industrial era. Different strategies have been identified to overcome metallic stress. Knowledge of plant stress responses and adaptations at physiological, biochemical and cellular levels is a priority in understanding the impact of these constraints on plant biodiversity. These adaptations have evolved naturally in halophytes as responses to their colonization of saline ecosystems, and therefore make halophytes good model plants. In this chapter we discuss the biophysical mechanisms underlying energy capture and transduction in halophytes and their relation to pigment profile alteration, compartmentation and subcellular localization, to devise sustainable strategies for environmental or ecosystem management and safety.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.