Aluminum accumulation and tolerance in four <i>Amaranthus </i>species

About one-third of the earth’s land area consists acidic soils. The rhizotoxic Al3+ is one primary constraints associated with low soil pH. Various Amaranthus species are important components weed flora in tea plantations on acid soils north Iran. In this study, four (A. blitoides, A. retroflexus, cruentus, and tricolor) were grown under hydroponic conditions total Al concentrations 0, 20, 50, 200, 400 µM corresponding to free activity 3.75, 11.97, 60.34, 125 µM, respectively. Low (20, or 200 µM) stimulated plant growth, tricolor demonstrated highest improvement shoot growth (93%), whereas retroflexus exhibited greatest root biomass (367%), length (173%), aproot (32%). Although response varied among species, all able accumulate leaves above critical level considered for hyperaccumulation (1 mg g–1 DW). Our findings revealed accumulation first time at genus family levels, suggesting that these suitable restoration revegetation acid-eroded