Roots of brown-midrib (F2bm1 and F292bm3) maize mutants and their normal isogenic counterparts (F2 and F292) were used to evaluate the changes in chemical cell wall features with regard to polysaccharides, lignin composition and interconnecting phenolic acids during root degradation in soil. To this end, the chemical variability of roots of brown-midrib mutants and their normal counterparts was compared and its subsequent impact on carbon (C) mineralization determined under controlled conditions. The bm1 mutation mainly caused an increase in lignin content and a decrease in polysaccharide content of maize roots whereas the bm3 mutation caused only a decrease in polysaccharide content. The lignin composition of bm roots differed from that of normal lines and the proportion of cell wall ester-linked hydroxycinnamic acids was also different. C mineralization kinetics differed markedly between the genotypes. Certain relevant factors concerning root decomposition in soil were studied from the relationships between the chemical characteristics of maize roots at different stages of decomposition and C mineralization rates. The Klason lignin-to-glucose ratio (KL/Glu), the Klason lignin-to-arabinoxylans ratio (KL/AX) and the arabinose-to-xylose ratio (A/X) were proposed as promising predictive indicators of C mineralization kinetics. Future estimations of soil residue decomposition could be improved by taking these initial chemical criteria into account on a wider range of residues.Décomposition dans le sol et évolution de la qualité chimique des racines de maïs présentant des modifications génétiques de la qualité des parois cellulaires'
RésuméLes racines des maı¨s mutants brown-midrib (F2bm1 et F292bm3) et celles de leurs ligne´es isoge´niques normales (F2 et F292) ont e´te´utilise´es pour e´valuer les modifications des caracte´ristiques chimiques des parois cellulaires, a`travers la composition des polysaccharides, de la lignine et la nature des acides phe´noliques, au cours de la de´gradation des racines dans le sol. Pour cela, nous avons examine´, en conditions controˆle´es, l'impact d'une variabilite´de la qualite´chimique des racines, en comparant les mutants bm et leurs ligne´es isoge´niques normales, sur la mine´ralisation du C. La mutation bm1 engendre principalement une augmentation de la teneur en lignine et une diminution de la teneur en polysaccharides dans les racines de maı¨s alors que la mutation bm3 cause uniquement une diminution de la teneur en polysaccharides. Dans les racines des mutants bm, la composition de la lignine ainsi que les proportions en acides hydroxycinnamiques este´rifie´s des parois cellulaires diffe`rent de celles des ligne´es non mutantes. Les cine´tiques de mine´ralisation du C varient fortement entre les ge´notypes. Les relations entre les caracte´r-istiques chimiques des racines de maı¨s a`diffe´rents stades de de´composition et les taux de mine´ralisation du C ont permis d'e´tudier certains facteurs pertinents concernant la de´composition des racines dans le sol. Les rapports lig...
Nickel (Ni) agromining aims to phytoextract heavy metals using hyperaccumulators whilst at the same time rehabilitating ultramafic soils. After removing the bioavailable metal, ultramafic soils are improved in terms of their agronomic properties with the aim of future agricultural uses. The low fertility of ultramafic soils can be compensated by integrating legumes already used in traditional agro‐systems because of their importance in soil nitrogen enrichment. However, few studies have evaluated the potential profits of legumes on Ni agromining and their potential benefits on soil biological fertility. Here, we characterized the effect of a crop rotation with two plants, a legume (Vicia sativa) and a hyperaccumulator (Alyssum murale), on the phytoextraction efficiency and on soil structure and biofunctioning. A pot experiment was set up in controlled conditions to grow A. murale and four treatments were tested: rotation with V. sativa (Ro), fertilized mono‐culture (FMo), non‐fertilized mono‐culture (NFMo) and bare soil without plants (BS). No significant difference was found between the Ro and NFMo treatments for the dry biomass yield. However, the Ro treatment showed the highest Ni concentrations ([Ni]) in A. murale shoots compared to FMo and NFMo treatments. The Ro treatment plants had more than twice as many leaves [Ni] compared to FMo. Soil physico‐chemical analyses showed that the Ro treatment was better structured and showed the highest presence of bacterial micro‐aggregates, as well as less non‐aggregated particles. Legumes integration in Ni‐agromining systems could be a pioneering strategy to reduce chemical inputs and to improve soil biofunctioning and thus fertility.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.