Effect of salinity on water absorption and germination of Phaseolus vulgaris L. seeds.

Abstract

Red kidney bean (Phascolus vulgaris L.) seeds were germinated using sodium chloride (NaCl) or Carbowax solutions as substrate. The water potentials of the substrates were 0, -2, -4, -8, -12, and -16 bars. Water absorption by red kidney bean seeds could be divided into two phases. The first phase, from 0 to 6 hours of imbibition, was primarily a function of the matric potential of the seeds, and the second, from 12 hours of imbibition on, depended mainly on the osmotic pressure of the seeds. Carbowax solutions of decreasing water potentials inhibited water absorption more than NaCl solutions, when the water potential was - 8 bars or less. Radicle emersion by red kidney bean seeds was more inhibited by Carbowax solutions than by NaCl solutions when the water potential of the substrate was - 8 bars or less. The effects of NaCl on red kidney bean seed germination were primarily osmotic when the seeds were in solutions of water potentials of - 8 bars or higher. When the water potential of the substrate was low (-12 bars) the inhibition of germination was due to both toxic and osmotic effects.