B. Lal et S. Khanna, SELECTION OF SALT-TOLERANT RHIZOBIUM ISOLATES OF ACACIA-NILOTICA, World journal of microbiology & biotechnology, 10(6), 1994, pp. 637-639
Among 35 Rhizobium isolates of Acacia nilotica, from different agro-cl
imatic zones, two, ANG4 and ANG5, tolerated up to 850 mM NaCl and one,
ANG3, was sensitive to NaCl above 250 mM. Nodulation and nitrogenase
activity of the three isolates decreased with increasing concentration
of salt up to 150 mM. Nodulation by ANG3 was 15% at 75 mM NaCl and ni
l at 100 mM. With ANG4 and ANG5, nodulation was only slightly decrease
d at 150 mM NaCl. Nitrogenase activity associated with plants inoculat
ed with ANG3 was halved at 25 mM NaCl compared with salt-free controls
, whereas isolates ANG4 and ANG5 retained 25% and 15% activity, respec
tively, even at 100 mM NaCl. Salt-tolerant Rhizobium isolates can ther
efore nodulate and fix N-2 in saline soils.