In order to examine the participation of α- and β-galactosidases in the cell expansion of stems from cowpea seedlings submitted to salt stress during plant establishment as well as to analyze the effect of salt stress on the development of seedlings and enzymatic activities, Pitiúba cowpea seeds were sown in distilled water and in 100 mM NaCl. Throughout seed germination and seedling development, stems were harvested from seedlings at different stages of development and at different times after planting. Growth was evaluated by measuring stem length and fresh and dry mass of stems. Salinity both inhibited and delayed the growth of seedling stems. The effects of NaCl on galactosidase activities of the cell wall were studied, both in vivo and in vitro. Galactosidase activities in vivo were related to effects of NaCl inhibition and delay of stem development. The increase in salt concentration inhibited isolated galactosidase activity of cell wall from stems of seedlings. Starting at 250 mM NaCl, β-galactosidases were more sensitive to salt than α-galactosidases.
development; cowpea; galactosidases; salinity
