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EFFECTS OF WATER AND SALT STRESS AND THE GIBBERELLlN ACTION IN Senna spectabilis SEEDS

Helma Jeller Sonia Cristina Juliano Gualtierres de Andrade Perez About the authors

ABSTRACT

Senna spectabilis (DC.) Irwin et Barn. variedade excelsa (Schrad.) Irwin et Barn. is a leguminosae woody species of low frequency in cerrado and caatinga of the Brazilian northeast. It is used in landscaping designs due to it’s natural beauty, streets arborization and in reflorestation of degraded areas. The aim of this work was to extend the knowledge about the biology of this species and to study the effects of water and salt stress and gibberellins on seed germination. Four replications of 50 seeds were used for each treatment and germination was carried out in 9cm Petri lived with filter paper moistened with test-solution. Senna espectabilis seeds did not present a wide tolerance to water stress and the germination was supressed at -0,7MPa. The reduction of NaCl osmotic potential decreased germination and synchrony of the process. The maximal tolerance limit was at -1,6MPa, when germination was totally inhibited. The addition of gibberellic acid reduced partially the effects of water and salt stress.

Key words:
seeds; Cassia excelsa; Senna espectabilis; stress; gibberellin

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