Several
species
of
Alnus
(A.
crispa,
A.
glutinosa.
A.
incana,
A.
japonica,
A.
rubra
A.
sinuata,
A.
viridis)
have
been
used,
where
rooted
plantlets,
after
their
transfer
to
nitrogen
free
substrate,
were
inoculated
with
pure
cultures
of
Frankia.
In
all
cases
effective
actinorrhizae
were
formed.
These
symbiotic
associations
of
actinorrhizae
not
only
fulfilled
completely
the
nitrogen
requirements
of
the
trees,
but
also
helped
in,
fixing
nitrogen
in
the
virgin
soil
thus
improving
the
fertility
of
the
degraded
lands.
