Interrelações entre o estresse salino e a biossíntese de etileno no controle da germinação de sementes de Stylosanthes

• Autor(a) principal: Silva, Priscila Oliveira
• Data de Publicação: 2013
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/4337
• topic: ACC; Etileno; Germinação; Estresse salino; Sementes; ACC; Ethylene; Germination; Salt stress; Seeds; CNPQ::CIENCIAS BIOLOGICAS::BOTANICA::FISIOLOGIA VEGETAL

The effect of salt stress on germination of scarified seeds of Stylosanthes, a tropical forage legume genus was evaluated by examinating their interrelationships with the ethylene biosynthetic pathway via production of 1-aminocyclopropane-1-carboxylic acid (ACC). Germination and ethylene production of seeds of S. humilis were inhibited with NaCl solutions, but not with isosmotic solutions of PEG-6000. The inhibitory effects of NaCl on both germination and ethylene biosynthesis were fully reversible following seed transfer to deionised water. Moreover, ACC reversed the inhibition of germination induced by NaCl, a result positively that correlated with the production of ethylene. Thus, inhibition of seed germination by NaCl seems to be a consequence of a stressing condition triggered by a high concentrations of Na inhibiting ethylene production. The ability of ethylene biosynthesis showed much larger in S. guianensis seeds treated with NaCl than in S. humilis and S. capitata seeds, which was also reflected in their germination levels. S. guianensis seedlings also exhibited higher growth and survival rates than S. humilis and S. capitata under salt stress. Furthermore, different quantitative abilities to synthesize ethylene by S. humilis, S. capitata and S. guianensis seeds could explain the differences in tolerance to NaCl stress by the three species.