PROCESSO GERMINATIVO E VIGOR DE SEMENTES DE Cedrela odorata L. SOB ESTRESSE SALINO

Abstract

The objective of this study was to evaluate the effects of salt stress on the viability and the vigor of Cedrela odorata L. seeds. The experiment was conducted at conditions of laboratory (temperature medium from 28 \ub0C and humidity medium of 84 %), under continuous light where four replicates of 25 seeds were put to germinate on blotting paper and moistened with solutions of NaCl, KCl and CaCl2 at different concentrations (0, 25, 50, 75 and 100 mM). The parameters analysed were: germination, first germination count, germination speed index, primary root and hypocotyl length and dry weight matter of the seedling. The adverse effects of salt stress on germination and seedling vigor of 'cedro' are indeed evident from the concentration of 25 mM NaCl, KCl and CaCl2, indicating that their use in saline environments may be limited. The 'cedro' seeds are more sensitive to CaCl2 and KCl compared to NaCl, the effect of salinity was more aggressive on the germination and vigor than in seedling vigor.O objetivo deste trabalho foi avaliar o efeito do estresse salino na viabilidade e vigor de sementes de Cedrela odorata L. O experimento foi conduzido em ambiente de laborat\uf3rio (temperatura m\ue9dia de 28 \ub0C e UR m\ue9dia 84 %), sob regime de luz cont\uednua, onde quatro repeti\ue7\uf5es de 25 sementes foram colocadas para germinar em papel mata-borr\ue3o e umedecidos com solu\ue7\uf5es de NaCl, KCl e CaCl2 em diferentes concentra\ue7\uf5es (0, 25, 50, 75 e 100 mM). Os par\ue2metros avaliados foram: porcentagem de germina\ue7\ue3o, primeira contagem de germina\ue7\ue3o, \uedndice de velocidade de germina\ue7\ue3o, comprimento da raiz prim\ue1ria e do hipoc\uf3tilo e massa seca da pl\ue2ntula. Os efeitos adversos do estresse salino sob a germina\ue7\ue3o e o vigor de pl\ue2ntulas de cedro s\ue3o efetivamente evidentes a partir da concentra\ue7\ue3o de 25 mM de NaCl, KCl e CaCl2, o que indica que sua utiliza\ue7\ue3o em ambientes salinos pode ser limitada. As sementes de cedro s\ue3o mais sens\uedveis ao CaCl2 e KCl em rela\ue7\ue3o ao NaCl, o efeito da salinidade foi mais agressivo sobre a germina\ue7\ue3o e vigor das sementes do que no vigor das pl\ue2ntulas