Priming in cássia-do-nordeste seeds under water, thermic and salt stress

The objective of this work was to evaluate osmoconditioning effects on seed germination of Cassia excelsa Schrad. under water, thermic and salt stress. Four replicates of 25 seeds were placed to imbibe in PEG solutions with osmotic potentials of -0.2, -0.4 and -0.6 MPa during 72, 96, 168 hours, respectively and in distilled water for 48 hours, at 20ºC. After that, the seeds were placed to germinate in conditions of water stress, ranging from -0.2 to -0.8 MPa at 27ºC, in thermic stress conditions at 12ºC and 39ºC and in NaCl solutions with osmotic potential ranging from -0.2 to -1.4 MPa at 27ºC, simulating salt stress. The parameters evaluated were the number of germinated seeds and the rate of radicle emergence. The osmoconditioning technique was efficient to increase the germinability under water and thermic stress, when PEG or distilled water was used. The germination percentage under salt stress increased with PEG conditioning, without increase in the germination rate.

Cassia excelsa; solutions; soaking; salinity

Embrapa Secretaria de Pesquisa e Desenvolvimento, Pesquisa Agropecuária Brasileira Caixa Postal 040315, 70770-901 Brasília DF Brazil, Tel. +55 61 3448-1813, Fax +55 61 3340-5483 - Brasília - DF - Brazil