title: Effect of root age on the allocation of metals, amino acids and sugars in different cell fractions of the perennial grass Paspalum notatum (bahiagrass).
abstract: This work aimed to compare the allocation of Al, Fe, Cu, Ni, amino acids and sugars in different fractions of root cells of Paspalum notatum with 21 and 120 days old grown in quartz sand. In general younger roots showed a higher content of Al, Fe, Cu Ni, amino acids and sugars, compared to older roots. This can be due to a higher metabolic activity of younger roots and/or to structural changes that can occur with cell ageing. Al and Fe were mainly allocated to fractions with pectin, hemicellulose and cellulose, both in younger and older roots. However, older roots also showed a significant fraction of Al allocated to the intracellular fraction. It seems that older roots were less able to prevent the entry of Al in the cytoplasm. The proportion of Cu was higher in intracellular components, both in younger and older roots, as expected from an essential nutrient. Ni content was very low in older roots and in younger roots it was mainly allocated to the intracellular fraction and to the cell wall polysaccharides fraction. The amino acids were mainly allocated to the cytoplasm and polysaccharide fraction. Although younger roots showed a higher total amount of amino acids compared to older roots, the amino acids profile and allocation, mainly in the cytoplasm polysaccharides, was quite similar. Arabinose, a major component of structural glycoproteins of the primary cell wall matrix, was only detected in younger roots. Thus, it seems that root cells of P. notatum suffered changes in the composition of the cell wall components with ageing. To further understand the structural changes of root cells with ageing and its effect on metal allocation, it is important to quantify several components of the cell wall matrix, namely pectins and glycoproteins.
authors.affiliation: Centro de Ecologia Funcional, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade de Coimbra, Apartado 3046, 3001-401 Coimbra, Portugal.
authors.forename: Cristina
authors.initials: C
authors.lastname: Nabais
authors.forename: Geórgia
authors.initials: G
authors.lastname: Labuto
authors.forename: Susana
authors.initials: S
authors.lastname: Gonçalves
authors.forename: Erika
authors.initials: E
authors.lastname: Buscardo
authors.forename: Décio
authors.initials: D
authors.lastname: Semensatto
authors.forename: Ana Rita A
authors.initials: AR
authors.lastname: Nogueira
authors.forename: Helena
authors.initials: H
authors.lastname: Freitas
mesh_terms: D000596:Amino Acids / Q000378:metabolism*; D001089:Arabinose / Q000378:metabolism; D002473:Cell Wall / Q000378:metabolism*; D016922:Cellular Senescence / Q000502:physiology*; D003593:Cytoplasm / Q000378:metabolism; D006023:Glycoproteins / Q000378:metabolism; D019216:Metals, Heavy / Q000378:metabolism*; D031781:Paspalum / Q000378:metabolism*; D010368:Pectins / Q000378:metabolism; D018517:Plant Roots / Q000378:metabolism*; D011134:Polysaccharides / Q000378:metabolism*
chemical_list: D000596:Amino Acids; D006023:Glycoproteins; D019216:Metals, Heavy; D011134:Polysaccharides; D010368:Pectins; D001089:Arabinose