AUTHOR=Jerez María Paz , Ortiz José , Castro Catalina , Escobar Elizabeth , Sanhueza Carolina , Del-Saz Néstor Fernández , Ribas-Carbo Miquel , Coba de la Peña Teodoro , Ostria-Gallardo Enrique , Fischer Susana , Castro Patricio Alejandro , Bascunan-Godoy Luisa 

TITLE=Nitrogen sources differentially affect respiration, growth, and carbon allocation in Andean and Lowland ecotypes of Chenopodium quinoa Willd

JOURNAL=Frontiers in Plant Science

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2023.1070472

DOI=10.3389/fpls.2023.1070472

ISSN=1664-462X

ABSTRACT=<p><italic>Chenopodium quinoa</italic> Willd. is a native species that originated in the High Andes plateau (Altiplano) and its cultivation spread out to the south of Chile. Because of the different edaphoclimatic characteristics of both regions, soils from Altiplano accumulated higher levels of nitrate (<inline-formula><mml:math display="inline" id="im1" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msubsup><mml:mrow><mml:mtext>NO</mml:mtext></mml:mrow><mml:mn>3</mml:mn><mml:mo>−</mml:mo></mml:msubsup></mml:mrow></mml:math></inline-formula>) than in the south of Chile, where soils favor ammonium (NH<sub>4</sub><sup>+</sup>) accumulation. To elucidate whether <italic>C. quinoa</italic> ecotypes differ in several physiological and biochemical parameters related to their capacity to assimilate <inline-formula><mml:math display="inline" id="im3" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msubsup><mml:mrow><mml:mtext>NO</mml:mtext></mml:mrow><mml:mn>3</mml:mn><mml:mo>−</mml:mo></mml:msubsup></mml:mrow></mml:math></inline-formula> and NH<sub>4</sub><sup>+</sup>, juvenile plants of Socaire (from Altiplano) and Faro (from Lowland/South of Chile) were grown under different sources of N (<inline-formula><mml:math display="inline" id="im5" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msubsup><mml:mrow><mml:mtext>NO</mml:mtext></mml:mrow><mml:mn>3</mml:mn><mml:mo>−</mml:mo></mml:msubsup></mml:mrow></mml:math></inline-formula> or NH<sub>4</sub><sup>+</sup>). Measurements of photosynthesis and foliar oxygen-isotope fractionation were carried out, together with biochemical analyses, as proxies for the analysis of plant performance or sensitivity to NH<sub>4</sub><sup>+</sup>. Overall, while NH<sub>4</sub><sup>+</sup> reduced the growth of Socaire, it induced higher biomass productivity and increased protein synthesis, oxygen consumption, and cytochrome oxidase activity in Faro. We discussed that ATP yield from respiration in Faro could promote protein production from assimilated NH<sub>4</sub><sup>+</sup> to benefit its growth. The characterization of this differential sensitivity of both quinoa ecotypes for NH<sub>4</sub><sup>+</sup> contributes to a better understanding of nutritional aspects driving plant primary productivity.</p>