01670naa a2200253 a 450000100080000000500110000800800410001910000190006024501210007926000090020052009370020965000170114665000220116365300290118565300110121465300090122565300100123465300290124465300200127370000160129370000190130970000200132877300680134810527632010-09-02       1994    bl ---       0--  u    #d1 aMELO, D. F. de  aEffect of salt stress on mitochondrial energy metabolism of Vigna unguiculata cultivars differing in NaCl tolerance.  c1994  aMitochondria have been purified from hypocotyls of two cultivars of Vigna unguiculata (L.) Walp, known to be sensitive (Vita 5) and tolerant (Vita 3) to salinity. For Vita 5 mitochondria, 0.1 M NaCl treatment resulted in a lowering of the phosphorylative efficiency, while the mitochondrial ATPase activity was not modified. By contrast, stimulation of the ATPase activity in Vita 3 mitochondria under salt stress was in good agreement with the maintenance of the phosphorylative properties of the mitochondria. Under salt stress, the enzyme displays a lower affinity for the substrate (MgATP) and a higher Vmax. Consequently, under stress conditions, the two cultivars could be distinguished by the level of ATPase activity in the hypocotyl mitochondria. In the tolerant Vita 3 cultivar, the higher efficiency to phosphorylate could account for the better ability of this cultivar to sequestrate Na+ in the lower stem of the plant.  aMitocôndria  aVigna Unguiculata  aactivity phosphorylation  aATPase  aBean  aCaupi  aMitochondrial properties  aNaCl treatmente1 aJOLIVET, Y.1 aFACANHA, A. R.1 aGOMES FILHO, E.  tPlant Physiology an Biochemistrygv. 32 n. 3, p. 405-412, 1994.