Nitrate fertilization enhances manganese phytoextraction in Tanzania guinea grass: a novel hyperaccumulator plant?

The objective was to evaluate the Mn hyperaccumulator potential of Tanzania guinea grass grown as affected by proportions of nitrate/ammonium (NO3-/NH4+). An experiment in a growth chamber with nutrient solution, combining NO3-/NH4+ proportions (100/0 and 70/30) and Mn rates (10, 500, 1500, and 3000 μmol L-1), was carried out. The highest Mn concentration was verified in plants grown with 100/0 NO3-/NH4+ and Mn at 3000 μmol L-1, reaching up to 5500 and 21,187 mg kg-1 in shoots and roots, respectively, an overall concentration of 13,345 mg kg-1. These numbers are typically seen in hyperaccumulators. At that combination, Mn accumulation in shoots was also the highest, reaching up to 76.2 mg per pot, a phytoextraction rate of 23.1%. Excess Mn increased both H2O2 concentration in roots and non-photochemical quenching and therefore decreased net photosynthesis, stomatal conductance, electron transport rate, and photochemical quenching. Nevertheless, proline concentration in roots affected by excess Mn was high and indicates its important role for mitigating stress since Mn rates did not even affect the dry biomass. Tanzania guinea grass is highly tolerant to excess Mn as much as a hyperaccumulator. However, to show all its potential, the grass needs to be supplied with N as NO3-. We indicate Tanzania guinea grass as a Mn hyperaccumulator plant.PMID:38194170 | DOI:10.1007/s11356-023-31548-8
Source: Environmental Science and Pollution Research International - Category: Environmental Health Authors: Source Type: research