Archives

A pot culture experiment was taken up to examine the influence of AM inoculation on salinity
tolerance in Onion crop. Sodic soil isolates of AM viz., TRY 1, TRY 2, TRY 3 and TFS 1 with two
standard cultures (G. intraradices and S. calospora) and a control with salt alone were used. The
bulbs of onion were planted and then subjected to three levels of salinity. The results illustrated that
the host plants had significant rate of mycorrhizal dependency (MD) which was found to increase
with increase in salt levels when treated with AM fungal inoculants. The phosphatase and
dehydrogenase enzyme activities increased due to mycorrhizal inoculation at all the three levels of
salt while the defense enzymes registered remarkable increase with stress levels. Histochemical
studies in onion roots, exhibited a clear difference in root anatomy in the mycorrhizal treatments,
with lignification of the vascular cells and vacuole formation. These biochemical changes observed
in the plants confirmed the adaptation of mycorrhizal plants not only through defense activities but
also influence plant growth and nutrition over the control plants at salt stressed condition.
Key words: Sodic soil; Mycorrhizal dependency; Phosphatase; Dehydrogenase; Root anatomy