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Changes in soil resulting from agricultural practices can lead to acidification and the accumulation of toxic elements, such as Al3+. In acidic soils, aluminium solubility decreases nutrient availability, causing biochemical and morphophysiological changes that impede plant growth. This study aimed to determine how native species respond to the effects of Al3+ and its impact on their persistence in the environment. Soil samples were collected in areas with and without Al3+ in a natural regeneration zone. Leaves of three herbaceous species prevalent in the rainy season underwent biochemical analysis. The results revealed that Al3+ influenced enzymatic activity in Ayenia erecta, reducing superoxide dismutase and increasing ascorbate peroxidase and catalase. Pavonia varians exhibited an accumulation of H2O2 and a reduction in ascorbate peroxidase, while Sida galheirensis demonstrated an accumulation of sucrose and a reduction in proline levels in areas affected by Al3+, without changes in enzymatic activity or the accumulation of reactive oxygen species. The presence of 0.31 cmolc/dm³ of Al3+ was insufficient to induce lipid peroxidation in the studied species. Overall, the species responded differently to aluminium, impacting oxidative stress and potentially influencing their survival in the environment. These results provide insights into conservation practices and sustainable management in arid areas. [ABSTRACT FROM AUTHOR]

We evaluated the effects of isoforms of ammonium transporters (AMT) and amino acid transporters (AAT) on three rice varieties cultivated with different levels of ammonium (NH4+) and its biochemical responses. The rice varieties used were IAC-47 (improved), Manteiga and Piauí (landraces), cultivated under 0.2 mM NH4+ (low N, LN), 1 mM NH4+ (sufficient N, SN) or resupply with 1 mM of NH4+ after three days without nitrogen (N). When cultivated with LN, the Piauí variety presented a higher expression of AAT (Lysine-Histidine Transporter 4 (OsLHT4) and GABA Transporters (OsGAT1)) in roots, while Manteiga and IAC-47 presented higher expression of the Amino Acid Permease 1 (OsAAP1) and Ammonium Transporter 1.1 (OsAMT1.1), respectively. Additionally, Piauí had the higher expression of glutamine synthetase (OsGS1.1 and OsGS1.3) in shoots cultivated with LN or resupply. The Piauí variety displayed higher glutamine synthetase activity and amino acid content under resupply. Manteiga and Piauí presented a lower reduction in fresh weight of leaves and sheaths under LN compared to IAC-47. The results suggest that the improved variety IAC-47 is more efficient when cultivated with SN, while, under LN or resupply, the landrace varieties were superior. Overall, the molecular responses were different among the varieties, which may affected their nitrogen metabolism. [ABSTRACT FROM AUTHOR]