The effect of preinoculation with the mycorrhizal fungus (Glomus fasiculatum)
on growth and tolerance 0 f cowpea plants irrigated with different concentrations of
waste effluents drained from fertilizers' industry was studied. The results indicated
that, the relative growth rate, dry weight, nodule formation, total pigment content as'
well as tolerance indices of mycorrhizal cowpea plants were significantly reduced by
irrigation with different levels of the polluted water. Mycorrhizal association irnproved
not only the all above parameters but also aided in overcoming the detrimental growth
effect of the polluted irrigation water. The macro- and micro-element contents. (P, N,
Na, Mg. Cu, Co. Zn and Fe) of cowpea plants grown on polluted soil were much
higher than those of nonpolluted ones. Results emphasized that vesicular arbuscular
(VA) mycorrhizal symbiosis' can increase metal tolerance of cowpe.a plants. The
percentage of VA mycorrhizal infection showed marked reduction with raising the
pollution level. The mycorrhizal dependencies for plant dry mass decreased at 10 &
20% pollution level. but, it increased at higher pollution level (40.%).