Three VAM-fungi were isolated from roots of onion (Allium cepa,
Liliaceae), broad bean (Vicia faba, Leguminosae) and Swiss cheese (Monstera
deliciose, Araceae). Another isolate was isolated from roots of maize (Zea mays
Graminae) plants raised from sterilized seeds sown in sterilized soil. All fungi
have coenocytic coarse aseptate mycelium and reproduced asexually by sporangia
and sporangiospores. Chlamydospores with different sizes were produced also by
all fungi. Chlamydospores were formed apically and/or intercalary, either singly
and/or in chains.
Fungal growths on barely-sand medium and suspensions of
sporangiospores (obtained from cultures grown on solid medium) were used for
inoculating sterilized soil (at different levels) 7 days before and after sowing,
respectively. Maize (Zea maize) seedlings showed significant improvement in
their growth when grown in sterilized soil inoculated by these isolated fungi.
However rate of growth improvement was quite varied and depended on source
of fungal isolate and its inoculum level. Onion-isolate was more effective at the
lowest inoculum level and this trend was completely reversed in Swiss cheese
isolate. Broad bean-isolate gave the best results at the intermediate inoculum
levels. Roots of maize plants raised in soils inoculated with fungal materials
showed structures characterizing mycorrhizal infections i.e. inter- and
intracellularly aseptate hyphae, chlamydospores, arbuscules and vesicles.
These findings are innovative and reported herein for the first time. |
