Download Data/hora: 06/05/2017 05:38:12 Biblioteca(s): Embrapa Mandioca e

Data/hora: 09/06/2017 05:42:03
Biblioteca(s): Embrapa Mandioca e Fruticultura.
Data corrente: 20/09/2013
Data da última atualização: 11/09/2014
Autoria: CRUZ, J. L.; ALVES, A. A. C.; LECAIN, DANIEL R.; ELLIS, D. D.; MORGAN, J. A.
Afiliação: JAILSON LOPES CRUZ, CNPMF; ALFREDO AUGUSTO CUNHA ALVES, CNPMF;
DANIEL R. LECAIN, USDA-ARS, Rangeland Resources Research Unit; DAVID D.
ELLIS, National Center for Genetic Resources Preservation, USDA-ARS; JACK A.
MORGAN, USDA-ARS, Rangeland Resources Research Unit.
Título: Effect of elevated CO2 concentration and nitrate: ammonium ratios on gas exchange and
growth of cassava (Manihot esculenta Crantz).
Ano de publicação: 2014
Fonte/Imprenta: Plant and Soil, v.374, p.33-43, 2014.
ISSN: 1573-5036
DOI: 10.1007/s11104-013-1869-8
Idioma: Inglês
Notas: Plublished online: 10 August 2013.
Conteúdo: Aims This study evaluated how different nitrogen forms affect growth and photosynthetic
responses of cassava to CO2 concentration. Methods Cassava was grown in 14-L pots in a
greenhouse at 390 or 750 ppm of CO2. Three nitrogen treatments were applied: (a) 12mM
NO3 , (b) 6mM NO3 + 6mM NH4 +, and (c) 12mM NH4 +. Results Thirty-six days after
treatments began, plants grown under elevated CO2 and fertilized only with NO3
(750_NO3) had photosynthetic rates similar to plants grown under 390_NO3, indicating
significant photosynthetic acclimation to CO2. In contrast, photosynthetic rates at
elevated CO2 increased as NH4 + increased in the nutrient solution, such that
photosynthetic acclimation was reduced for plants fertilized with only NH4 +. However,
this positive effect of NH4 + on photosynthesis was not observed in more advanced
growth stages, and the toxic effects of NH4 + severely reduced total dry mass for these
plants measured at the end of the experiment. Conclusions Our results indicate that
cassava will respond with increased biomass accumulation in response to raising
atmospheric CO2 levels, and that N form can have an important impact on the
photosynthetic response. However, the positive effect of NH4 + fertilization on cassava
photosynthetic CO2 response eventually led to a toxicity problem that reduced biomass
production. The challenge is to determine how to manage NH4 + fertilization so that the
photosynthetic benefit observed in the initial phase may persist throughout the crop cycle.
Palavras-Chave: Water use efficiency.
Thesagro: Mandioca.
Thesaurus NAL: Calvin cycle; Cassava; Climate change; Manihot esculenta; Nitrogen; Stomatal
conductance; Transpiration.
Categoria do assunto: -Registro original: Embrapa Mandioca e Fruticultura (CNPMF)
Exemplares: CNPMF - (29667-1) - UPC - SP - PP - SP/13121 - - 2013.13121 - DIS