title: Prognosis of physiological disorders in physic nut to N, P, and K deficiency during initial growth.
abstract: The description of physiological disorders in physic nut plants deficient in nitrogen (N), phosphorus (P) and potassium (K) may help to predict nutritional imbalances before the appearance of visual symptoms and to guide strategies for early nutrient supply. The aim of this study was to evaluate the growth of physic nuts (Jatropha curcas L.) during initial development by analyzing the gas exchange parameters, nutrient uptake and use efficiency, as well as the nitrate reductase and acid phosphatase activities and polyamine content. Plants were grown in a complete nutrient solution and solutions from which N, P or K was omitted. The nitrate reductase activity, phosphatase acid activity, polyamine content and gas exchange parameters from leaves of N, P and K-deficient plants indicates earlier imbalances before the appearance of visual symptoms. Nutrient deficiencies resulted in reduced plant growth, although P- and K-deficient plants retained normal net photosynthesis (A), stomatal conductance (gs) and instantaneous carboxylation efficiency (k) during the first evaluation periods, as modulated by the P and K use efficiencies. Increased phosphatase acid activity in P-deficient plants may also contribute to the P use efficiency and to A and gs during the first evaluations. Early physiological and biochemical evaluations of N-, P- and K-starved plants may rely on reliable, useful methods to predict early nutritional imbalances.
authors.affiliation: USP - University of São Paulo, Center for Nuclear Energy in Agriculture, 13416-000 Piracicaba, SP, Brazil. Electronic address: elciokw@yahoo.com.br.
authors.forename: Elcio Ferreira
authors.initials: EF
authors.lastname: Santos
authors.affiliation: USP - University of São Paulo, Center for Nuclear Energy in Agriculture, 13416-000 Piracicaba, SP, Brazil. Electronic address: giovannetti_agro@yahoo.com.br.
authors.forename: Fernando Giovannetti
authors.initials: FG
authors.lastname: Macedo
authors.affiliation: USP - University of São Paulo, Center for Nuclear Energy in Agriculture, 13416-000 Piracicaba, SP, Brazil. Electronic address: bruno.zanchim@yahoo.com.br.
authors.forename: Bruno José
authors.initials: BJ
authors.lastname: Zanchim
authors.affiliation: UNESP - São Paulo State University, 18600-000 Botucatu, SP, Brazil. Electronic address: gpplima@ibb.unesp.br.
authors.forename: Giuseppina Pace Pereira
authors.initials: GPP
authors.lastname: Lima
authors.affiliation: USP - University of São Paulo, Center for Nuclear Energy in Agriculture, 13416-000 Piracicaba, SP, Brazil. Electronic address: jlavres@usp.br.
authors.forename: José
authors.initials: J
authors.lastname: Lavres
mesh_terms: D031286:Jatropha / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism*; D050901:Nitrate Reductase / Q000235:genetics / Q000378:metabolism*; D009584:Nitrogen / Q000172:deficiency / Q000378:metabolism*; D010758:Phosphorus / Q000172:deficiency / Q000378:metabolism*; D011073:Polyamines / Q000378:metabolism; D011188:Potassium / Q000378:metabolism*
chemical_list: D011073:Polyamines; D010758:Phosphorus; D050901:Nitrate Reductase; D009584:Nitrogen; D011188:Potassium
keywords: Jatropha curcas L.; Nitrate reductase; Nutrient deficiency; Phosphatase acid; Polyamines