Salinity tolerance induced by salicylic acid in seeds and hybrid corn seedlings

Diferentes compostos fen??licos s??o formados no metabolismo secund??rio dos vegetais, entre eles o ??cido salic??lico que possui fun????o de defesa atuando como agente antioxidante em situa????es de estresse. Portanto, o objetivo da realiza????o do trabalho foi avaliar a influ??ncia do cloreto de s??dio (NaCl) em tr??s lotes de sementes de milho h??brido, bem como do ??cido salic??lico (AS) como redutor dos efeitos da salinidade. Foram utilizados tr??s lotes de sementes de milho para os dois experimentos realizados. No primeiro as sementes foram expostas ??s concentra????es de zero; 30; 90 e 180 mM de NaCl e no segundo, as sementes foram previamente embebidas durante 60 minutos em duas concentra????es de ??cido salic??lico (zero e 1 mM) e em seguida submetidas as concentra????es de zero; 30; 90 e 180 mM de NaCl. Para a determina????o da viabilidade e vigor das sementes nos dois experimentos os seguintes testes foram conduzidos: teste de germina????o, ??ndice de velocidade de germina????o, comprimento da parte a??rea e das ra??zes das pl??ntulas, massa seca da parte a??rea e das ra??zes, condutividade el??trica, emerg??ncia de pl??ntulas em casa de vegeta????o, ??ndice de velocidade de emerg??ncia em casa de vegeta????o, comprimento da parte a??rea e das ra??zes das pl??ntulas e massa seca da parte a??rea e das ra??zes das pl??ntulas. Nas condi????es em que o experimento foi realizado podemos concluir que o ??cido salic??lico na concentra????o de 1 mM minimiza o efeito do NaCl quando as concentra????es de NaCl n??o ultrapassam 90 mM . No entanto, tem efeito prejudicial no sistema radicular das pl??ntulas submetidas ao tratamento.Several phenolic compounds are formed in plants secondary metabolism, such as salicylic acid which has a defensive function acting as an antioxidant agent under stress conditions. Therefore, the purpose in this research was to evaluate the influence of the sodium choride (NaCl) in three hybrid corn lots, as well as the salicylic acid (SA), as a reducer of the salinity effects. There have been used three corn seed lots for both of the experiments realized. In the first one, the seeds were exposed to concentratrions of zero, 30, 90 and 180 mM of NaCl. In the second one, the seeds were previously soaked for 60 minutes at two concentrations of salicylic acid (zero and 1mM) and soon after that subjected to concentrations of zero, 30, 90 and 180 mM NaCl. In order to determine the viability and vigor of seeds in these two experiments, the following tests were conducted: germination test, germination rate index, shoot and root seeds length, shoot and roots dry mass, electrical condutivity, seedlings growth in greenhouse, growth rate velocity in greenhouse, shoot and root seeds length and shoot and roots of seedlings dry mass. Taking into account the conditions in which the experiment was conducted it is possible to assume that the salicylic acid at concentrations of 1mM attenuates the effects caused by NaCl, when NaCl concentrations do not esceed 90 mM. However, it has a detrimental effect on the sedling root systems that were submitted to this teatment