title: Biological limits on nitrogen use for plant photosynthesis: a quantitative revision comparing cultivated and wild species.
abstract: The relationship between leaf photosynthesis and nitrogen is a critical production function for ecosystem functioning. Cultivated species have been studied in terms of this relationship, focusing on improving nitrogen (N) use, while wild species have been studied to evaluate leaf evolutionary patterns. A comprehensive comparison of cultivated vs wild species for this relevant function is currently lacking. We hypothesize that cultivated species show increased carbon assimilation per unit leaf N area compared with wild species as associated with artificial selection for resource-acquisition traits. We compiled published data on light-saturated photosynthesis (Amax) and leaf nitrogen (LNarea) for cultivated and wild species. The relationship between Amaxand LNareawas evaluated using a frontier analysis (90thpercentile) to benchmark the biological limit of nitrogen use for photosynthesis. Carbon assimilation in relation to leaf N was not consistently higher in cultivated species; out of 14 cultivated species, only wheat, rice, maize and sorghum showed higher ability to use N for photosynthesis compared with wild species. Results indicate that cultivated species have not surpassed the biological limit on nitrogen use observed for wild species. Future increases in photosynthesis based on natural variation need to be assisted by bioengineering of key enzymes to increase crop productivity.
authors.affiliation: Facultad de Ciencias Agrarias, IICAR - UNR/CONICET, Zavalla, Santa Fe, Argentina.
authors.forename: José L
authors.initials: JL
authors.lastname: Rotundo
authors.affiliation: Depto. de Métodos Cuantitativos y Sistemas de Información - IFEVA, Facultad de Agronomía, UBA/CONICET, Buenos Aires, Argentina.
authors.forename: Pablo A
authors.initials: PA
authors.lastname: Cipriotti
mesh_terms: D000383:Agriculture; D002244:Carbon / Q000378:metabolism; D008027:Light; D009584:Nitrogen / Q000494:pharmacology*; D010788:Photosynthesis / Q000187:drug effects*; D063245:Plant Development / Q000187:drug effects*; D018515:Plant Leaves / Q000187:drug effects / Q000502:physiology; D012044:Regression Analysis; D012621:Seasons; D014934:Wood / Q000187:drug effects / Q000502:physiology
chemical_list: D002244:Carbon; D009584:Nitrogen
keywords: Rubisco; carbon sequestration; photosynthesis; photosynthetic nitrogen (N)-use efficiency; primary productivity