Avaliação ex-vivo da tolerância de cultivares da mamoneira (Ricinus communis L.) ao défict hídrico

Detalhes bibliográficos
Ano de defesa: 2010
Autor(a) principal: Ana Paula de Faria
Orientador(a): Não Informado pela instituição
Banca de defesa: Não Informado pela instituição
Tipo de documento: Dissertação
Tipo de acesso: Acesso aberto
Idioma: por
Instituição de defesa: Universidade Federal de Minas Gerais
UFMG
Programa de Pós-Graduação: Não Informado pela instituição
Departamento: Não Informado pela instituição
País: Não Informado pela instituição
Palavras-chave em Português:
Link de acesso: http://hdl.handle.net/1843/TJAS-89TNJY
Resumo: Water deficit is critical for plant development and productivity. Castor (Ricinuscommunis L.) oil is rich in ricinoleic acid (omega 9), a fatty acid widely used for medicinalpurposes, besides its great potential as a raw material for biodiesel production. This studyfocused on the biochemical and physiological screening of five castor bean cultivarsregarding the tolerance degree toward water deficit conditions. The relative water content(RWC), electrolyte leakage (EL), membrane damage index (MDI), lipid peroxidation andprotein oxidation were then investigated in leaf disks treated with PEG-6000 solutions at YWin the range of 0 to -2.4 MPa. All cultivars recovered at different extents from water deficitstress. BRS-Energia reached the best recovery percentage while BRS-Paraguaçu had poorlyrecovered. Maximum MDI was observed for BRS-Paraguaçu at YW of -1,8 MPa, a conditionthat slightly affected BRS-Energia and IAC-80 cultivars. Biochemical analyses showed thatcultivar IAC-80 exhibited the lowest levels of lipid hydroperoxides (LOOH), that remainedunaffected regardless the stress intensity. In contrast, LOOH levels BRS-Paraguaçu leavesdecreased when under severe water déficit. The protein oxidation levels in BRS-Energia was 50%lower than those for the cultivars IAC-80 and BRS-Paraguaçu under Yw of -1,8 MPa. Overall,these results indicate that, under our experimental conditions, BRS-Energia is the mosttolerant genotype to water deprivation; BRS-Paraguaçu is the most sensitive and IAC-80 fitsas an intermediate genotype.Keywords: castor bean, water deficit, relative water content, membrane damage index, lipidperoxidation, protein oxidation.