Does nitrogen source influence cadmium distribution in Arabidopsis plants?

RECALDE, LAURA; BENAVIDES, MARÍA PATRICIA; CABRERA, ANDREA; VAZQUEZ, ANALÍA; GROPPA, MARÍA DANIELA

ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY

ACADEMIC PRESS INC ELSEVIER SCIENCE

Lugar: Amsterdam; Año: 2020 vol. 191

0147-6513

uptake, translocation and partition and its associated toxicity in hydroponically-grown Arabidopsis plants. Aftera short growth period on a complete Hoagland nutrient solution, Arabidopsis seedlings continued in the samegrowth medium (NA) or were switched to NO3? (N) or NH4+ (A) as sole N sources and supplied with 2.5 μM Cd.Unrelated to the nitrogen source, Cd reached higher levels in roots than in leaves. However, when ammoniumwas the source of nitrogen, Cd accumulation in roots was lower than in N or NA medium and the metaltranslocation to the aerial part was restricted, reaching values 25%?35% below the levels observed in plantsgrown with N or NA. Cadmium negatively affected chlorophyll content and PSII quantum yield, independently ofthe nitrogen source, with the highest decrease (35%) under NA treatment. Proline content increased, either withNA, N or A supplied in the presence of Cd, whereas a rise in total anthocyanin content was clearly favored whenammonium was the source of nitrogen, with or without Cd. In leaves, while NIA1 and NIA2 expression wasmarkedly reduced by Cd in the presence of N or NA, ammonium source slightly reduced NIA1 expression butgreatly upregulated NIA2 expression upon Cd exposure. The decay in NR activity was independent of the nitrogensource when Cd was applied and this decay was accompanied by a great increase in NH4+ levels eitherwith nitrates or ammonium in the medium in the presence of Cd. Only NIA1 was detected in roots and itsexpression, together with NR activity and nitrates levels, was the highest in N medium devoid of Cd. The possibilityof reducing Cd health risks through nitrogen fertilization practices is discussed