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wrinkled with furrows and constricted. The mycelium produced fine zonation
and a great amount of white aerial hyphae. Hyphae were highly interwoven,
often adhered together and gave the appearance of simple cords. New
branches emerged irregularly and the hyphal walls showed some external
deposits at regular intervals, which stained deeply with toluidine blue. Since
septation was irregular, the single compartment could contain more than one
nucleus. The chlamydospores appeared singly or in clusters at the apex of
hyphae. They were distinctive due to their pear-shaped habit.
11 Conclusions
Mycorrhiza does not always promote the growth of agricultural crops. In
phosphorus-rich soils, they can parasitize plants such as citrus, wheat and
maize by tapping sugars from these plants without giving anything back.
Researchers ignore this darker side of the mycorrhiza. Theoretically, mycorrhiza
can also harm biodiversity. In the long run, specific mycorrhizas can
promote the growth of one plant at the expense of another.“What exactly happens
probably depends on the system itself,” states Van der Heijden (2002). In
any case, the interaction between plants and mycorrhiza forming fungi clearly
has at least as great an effect on the ecosystem’s species composition as the
interaction/competition between plants themselves.
P. indica, the fungus treated in this chapter, acts as biofertilizer, bioregulator
and bioprotector, and can be easily mass-multiplied on defined synthetic
media. It is thus, an interesting model fungus with respect to studies on
endomycorrhiza. In addition, commercial production of this fungus under
aseptic conditions could support biological hardening of tissue-cultureraised
plants as well as plant survival in general on poor soils.
Acknowledgements. The Indian authors are thankful to DBT, DST, CSIR, UGC, and the
Government of India for partial financial assistance.
References and Selected Reading
Ahuja MR (1986) In: Evans DA, Sharp WR and Ammirato PJ (eds) Handbook of plant
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Badoni RJ (1972) Terrestrial occurrence of some aquatic Hyphomycetes. Can J Bot
50:2283–2288
Galloway LD, Burgess R (1952) Applied mycology and bacteriology, 3rd edn. Leonard
Hill, London, pp 54–57
Herrmann S, Munch JC, Buscot F (1998) A gnotobiotic culture system with oak microcuttings
to study specific effects of mycobionts on plant morphology before, and in
the early phase of, ectomycorrhiza formation by Paxillus involutus and Piloderma
croceum. New Phytol 138:203–212